The Convention on Early Notification of a Nuclear Accident (the Early Notification Convention) [56] and the Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency (the Assistance Convention) [57] cover situations in which an accident involving activities or facilities in one state have resulted or may result in a transboundary release that could be of radiological safety significance for other states. In this context, legally binding obligations as adapted in national legislations may arise for radiobiologists, requiring them to notify, directly or through the IAEA, those states which are or may be affected by a nuclear accident. The nature of the nuclear incident, the time of its occurrence and its exact location should be promptly provided to those States affected in order to minimize the radiological consequences in those states.


The nuclear liability conventions cover neither radiation damage caused by radioisotopes used for scientific, medical, commercial, and other purposes nor radiation damage caused by X-rays. This is because the use of radioisotopes and X-ray equipment does not present risks comparable to those for which the conventions were designed. The regime created by the conventions is intended for extraordinary nuclear risks only.


Even though experience has shown that radioisotopes and medical irradiation equipment can also cause serious damage if not handled properly, most states deal with liability for radiation damage caused by radioisotopes and X-rays under general tort law. States are free to enact, at the national level, special liability laws for damage caused by these types of exposure, providing for modified strict liability where the principle of liability without fault is maintained but the person liable may be exonerated if they can prove that they could not prevent the occurrence of the damage even though they complied with all radiation protection requirements and if they prove that any equipment used was not defective.


In a medical context, harm caused could potentially amount to a breach of the duty of care that is owed to a patient from a medical professional or radiologist. If the person liable owes a duty of care to the patient, it must be proven that this duty was breached, resulting directly in the harm suffered by the patient. Where the breach is caused by gross carelessness, the liable party may be criminally negligent.


One of the key principles of the radiation protection system recommended by ICRP is the principle of optimization of protection. The aim is to select the best protection option under the prevailing circumstances in order to keep the likelihood of exposure, the number of people exposed, and the magnitude of the individual doses incurred, all “as low as reasonably achievable” often abbreviated to the acronym “ALARA,” taking into account economic and societal factors alongside health factors.


It is important to stress that “ALARA” does not simply mean “as low as reasonably achievable” in the sense that it should always be the “very lowest” level of radiation exposure that can technically be achieved. “ALARA” should rather be the “best” protection option, nuanced and well-reasoned, where the highest level of safety that can be achieved from a health perspective, always needs to be balanced by social, environmental, and economic considerations.


Standards are established and safety measures prescribed in order to ensure that facilities and activities with radiation risks achieve the highest level of safety throughout the lifetime of the facility or duration of the activity, without unduly limiting its utilization or usefulness. In order to determine whether radiation risks are at a level as low as reasonably achievable, any and all risks, whether arising from normal operations, abnormal conditions, or accidents, must be assessed using a graded approach that is periodically reassessed throughout the progression of the activity or lifetime of the facility.


The optimization of protection requires careful judgment on the basis of scientific fact that is generally highly influenced by subjective appraisal tailored to individual situations, which makes it a difficult principle difficult to implement uniformly and consequently legally. The relative significance of various goals, events, and factors have to be judged, including the number of people (both workers and the general public) who may be exposed to radiation, the likelihood of exposure, the magnitude and the radiation doses likely to be received as a result of foreseeable and unforeseeable events, as well as the economic, social, and environmental factors involved with the installation or activity.


The ICRP recommends, develops, and maintains the International System of Radiological Protection, based on an evaluation of the large body of scientific studies available to equate risk to received dose levels.


The system’s health objectives are relatively straightforward “to manage and control exposures to ionizing radiation so that deterministic effects are prevented, and the risks of stochastic effects are reduced to the extent reasonably achievable” (ICRP Publication 103).


To this end, the ICRP has established a system of radiological protection with three main principles: justification, optimization of protection, and individual dose limitation that apply to planned, emergency, and existing exposure situations. Planned exposure situations are situations involving the deliberate introduction and operation of sources of radiation, either anticipated (normal exposures) or not anticipated to occur (potential exposures). Emergency exposure situations are situations that may occur during the operation of a planned situation, or from a malicious act, or from any other unexpected situation requiring urgent action. Existing exposure situations are exposure situations that already exist when a decision relating to control has to be taken, including prolonged exposure situations after emergencies. The ICRP considers exposure to cosmic radiation to be an existing exposure situation.


The first two principles, justification and optimization of protection are source-related and apply in all exposure situations. The principle of justification states that any decision that alters the radiation exposure situation should be more beneficial than detrimental. The principle of optimization of protection states that the likelihood of incurring exposures, the number of people exposed, and the magnitude of their individual doses should all be kept As Low As Reasonably Achievable (ALARA), also taking into account economic and societal factors. The third principle concerning individual dose limitation is individual-related and applies in planned exposure situations: the total dose to any individual from regulated sources in planned exposure situations other than medical exposure of patients should not exceed certain appropriate limits.


The ICRP further distinguishes between three categories of exposures: occupational exposures, public exposures, and medical exposures of patients. Occupational exposure is defined as all radiation exposure of workers incurred due to their work. ICRP limits the use of “occupational exposures” to radiation incurred at work in situations that can reasonably be regarded as being the responsibility of the operating management. The employer has the main responsibility for the protection of workers. Public exposure encompasses all exposures of the public other than occupational exposures and medical exposures of patients. The component of public exposure due to natural sources is by far the largest, but this provides no justification for reducing the attention paid to smaller, but more readily controllable, exposures to man-made sources. Exposures of the embryo and fetus of pregnant workers are considered to be public exposures and regulated as such.


While dose is a measure of the total amount of radiation received, the dose limit is a value of the effective or equivalent dose to individuals that may not be exceeded in activities under regulatory control. The regulatory body sets the dose limits for various activities. These dose limits are sometimes found in the nuclear laws, but more often in the accompanying and more detailed regulations, where regulatory bodies principally rely on IAEA publications.


Restricting an individual’s radiation dose is another key factor of the international radiation protection system. Restrictions include dose limits, dose constraints, and reference levels of dose. Each of these restrictions has different legal implications.


The dose limit is the value of dose to individuals from planned exposure situations that shall not be exceeded. A dose constraint is a prospective and source-related restriction on the individual dose from a source, which provides a basic level of protection for the most highly exposed individuals from a source, and serves as an upper bound on the dose in optimization of protection for that source.


For occupational exposures, the dose constraint is a value of individual dose used to limit the range of options, both short- and long-term, considered in the process of optimization. For public exposure, the dose constraint is an upper limit on the annual doses from the planned operation of any controlled source that members of the public should not exceed. In emergency or existing controllable exposure situations, a reference level is established to represent the level of dose or risk, above which it is judged to be inappropriate to plan to allow exposures to occur, and below which optimization of protection should be implemented. The chosen value for a reference level will depend upon the prevailing circumstances of the exposure under consideration.


Dose limits are not uniform, neither in concept nor in the quantities that they are expressed. The three dose quantities used for establishing dose limits are the absorbed dose, the equivalent dose, and the effective dose. The absorbed dose is a measurable, physical quantity expressing the amount of energy deposited by radiation in a mass. The equivalent dose is a weighted absorbed dose designed for specific radiation protection purposes and is calculated for individual organs while the effective dose, which is also designed for specific radiation protection purposes, is calculated for the whole body. Dose limits may vary depending on factors such as pregnancy. It is worth noting again that dose limits do not apply to emergency, existing, or medical exposures. Dose limits only apply to occupational, public, and planned exposure. The current dose limits set out by the ICRP in Publication 103 are as set out in Table 12.1 below.Table 12.1
Recommended dose limits in planned exposure situations

Type of limit

Occupational

Public

Effective dose

20 mSv/year, averaged over defined periods of 5 years

Annual equivalent dose in:

Lens of the eye

150 mSv

15 mSv

Skin

500 mSv

50 mSv

Hands and feet

500 mSv

–


Dose limits set by the ICRP are not hard law but most countries have implemented these limits into their national legislation making the exceeding of dose limits illegal. The industry may also choose to set dose limits for their workers even lower than those required by law to both ensure the safety of their employees and reduce the likelihood of lawsuits.


Radiation workers are obviously more at risk to be exposed to radiation than the average individual and dose limits for occupational exposure are different from dose limits for public exposure, specifying an upper limit and a relevant time span.


In case of a nuclear emergency, workers will likely be exposed to significantly higher doses, often much higher than the annual recommended dose limit. A very careful assessment will have to be made weighing the rescuer’s own risk versus a clear benefit to others.


The ALARA principle encourages practitioners and other individuals who have an influence on radiation dosage to limit dosage as much as practically possible, even when accounting for the benefits the exposure situation might bring. This also means that if the exposure does not present a direct and sufficient benefit, it should be avoided. In order to optimize protection for radiation workers, the duration of the exposure should always be minimized while the distance between the source of the radiation and the individual should be maximized. A third essential factor is shielding.


The legally binding obligations related to occupational radiation protection are established in the Radiation Protection Convention No. 115 adopted by The General Conference of the International Labour Organization [58]. This Convention, which has been ratified by most countries, applies to all activities involving exposure of workers to ionizing radiations in the course of their work and who, in applying its provisions the state party’s competent authority, have to consult with representatives of employers and workers.


Sources of ionizing radiation are essential to modern healthcare as they span a range of purposes, such as the sterilization of disposable medical supplies, central to combating disease [59]. To give a more recent example, China has optimized the use of radiation to cut down sterilization times from 7 days to just 1 in order to combat the COVID-19 pandemic [60]. Radiology is also a vital diagnostic tool; CT and X-rays have been crucial to healthcare in terms of diagnostic precision, which in turn improve treatment response.


However, as ionizing radiation can be detrimental to living organisms, humans included, it is essential that sources of ionizing radiation be covered by measures to protect individuals. Medical treatment involving planned exposure to ionizing radiation can only take place if the patient has agreed after being carefully informed about the risks.


Radiation exposures of patients occur in diagnostic, interventional, and therapeutic procedures. There are several features of radiological practices in medicine that require an approach that differs from radiological protection in other planned exposure situations. The exposure is intentional and for the direct benefit of the patient. Particularly in radiotherapy, the biological effects of high-dose radiation, e.g., cell killing, are used for the benefit of the patient to treat cancer and other diseases. The medical uses of radiation therefore require separate guidelines.


A relatively recent topic of discussion is that of adventitious exposure, i.e., unintended exposure happening as a result of primary, intended exposure. A patient undergoing therapeutic exposure to ionizing radiation—exposure that is considered to be beneficial, contributing to a positive medical outcome—probably will suffer to some extent, effects that are neither intended nor desired because these are an unavoidable by-product of radiotherapy procedures. Adventitious exposure can occur in any part of the body and cause secondary cancers as a malignant result of radiotherapy, the effects remaining latent, manifesting only after the treatments. It is important to distinguish that cancer forming due to adventitious exposure is not a metastasis of the original malignancy, but rather a primary malignancy in itself. The incidence of such cancers is being investigated worldwide, also by UNSCEAR, and may contribute to litigation initiated by patients or their next of kin against radiobiologists or other radiation specialists in the medical field. A deep understanding of this complex mechanism is still evolving, but the medical professional would do well to document—either by measurement or estimation—the scenario of adventitious exposure situations through dosimetric quantities or suitable proxies. It may even prove to be necessary to dutifully inform and obtain explicit patient agreement on the subject.


Most countries have regulations to guide the medical professional involved with treatment that includes medical exposure of a patient to ionizing radiation in order to protect both the professional and the patient. In the EU, Council Directive 2013/59/Euratom Chapter VII [61] centers the relevant articles 55 and 56 once again around the principles of justification and optimization. In the assessment and justification of the use of radiology with any specific patient, the practitioner should consider all relevant aspects of their medical history and decide, with feedback and consent from the patient, the radiation therapy most suited to that individual patient.


Cosmic rays at ground level are not considered to warrant regulatory control. Mankind has been exposed to—and has evolved with—radiation from the universe reaching Earth since the beginning of time. However, at high altitudes, where cosmic rays are less attenuated by the atmosphere or, even higher, by the Earth’s magnetic field, they undoubtedly pose a risk to people and equipment because of the very high energies involved. As a consequence, astronauts and aircraft personnel need to be well informed about these exposure risks during the course of their careers and possible consequences and outcomes as a result.


Disregarding the Space Treaties that arguably do not really deal with exposure to ionizing radiation, the protective framework for astronauts in this context is not regulated by international law, but rather designed and governed by the space agencies by which they are employed, on the basis of an ever-evolving scientific insight and assessment. All major space agencies have very stringent safety precautions in place, specifying dose, dose rate, and career limits for their astronauts in order to make sure there is no statistical risk of radiation exposure-induced death (REID) and other adverse effects. Even though astronauts are generally extremely healthy and are unlikely to suffer health effects at a level worse than that of the general population, the advent of deep space travel, notably the Moon and Mars missions planned in the near future, will likely expose them to high fluxes of solar energetic particles and heavy ions, in possibly problematic amounts. Radiation mitigation strategies, shielding and careful mission planning, and astronaut selection will prove to be crucial to attempt these types of interplanetary exploratory missions. Being continuously monitored and genetically screened for suitability may however create some legal issues as well. Not only are privacy issues imaginable with the extreme scrutiny astronauts are subjected to, but unequal treatment and an imbalance in career opportunities due to individual genetic predisposition to adverse health effects from ionizing radiation may at some point also become an object of contention, as is discussed more in depth in Sect. 12.3.8 on emerging occupational challenges from new methods to determine individual radiosensitivity (supra).


Guidance and protection for other jobs at slightly lower altitudes are much more regulated. Airline pilots and personnel—and even frequent flyers—repeatedly expose themselves to ionizing radiation, primarily from charged particles and therefore require employment protection. Compared to astronauts, aircraft personnel make up a substantially larger group of radiation workers, inspiring governments to implement special mandatory protection measures. For example, Directive 96/29/Euratom 1996 requires appropriate radiological protection of aircrew. Article 42 of the Directive obliges member states to regulate the sector, specifically regarding the exposure to cosmic radiation at flight altitudes. As a result, each member state is obliged to force airline companies to take account of exposure to cosmic radiation of aircrew who are liable to be subject to exposure to more than 1 mSv/year. EU airline companies need to record a continual assessment of the exposure of the crew concerned and use this information when organizing working schedules with a view to reducing the doses of highly exposed aircrew. Aircraft personnel needs to be informed of the health risks their work involves and female aircrew in particular, when pregnant, will have the terms of her employment adapted to ensure that the equivalent dose to the child to be born is ALARA and that it will be unlikely that this dose will exceed 1 mSv during at least the remainder of the pregnancy. As soon as a nursing woman informs her employer of her condition, she cannot be employed in work involving a significant risk of bodily radioactive contamination. This is of course not to say that female airline crew are the only radiation workers protected through nuclear law; different rules for pregnancy, varying from country to country, are applicable for workers in other nuclear industries.


Legal action based on radiation harm, i.e., legal proceedings or a lawsuit, generally requires two elements to succeed; attribution and imputation. First, a causal link must be established; a certain health effect needs to be attributed to a certain radiation exposure using objective factual evidence. Second, there needs to be imputation, meaning someone’s responsibility for the radiation harm needs to be determined. In a legal context, imputation means placing the responsibility for the physical injury (actual or potential ill effects) that is attributable to the radiation exposure, on another (natural or legal) person. While “attribution,” meaning establishing the factual link between a nuclear incident and a health effect and “imputation,” meaning ascribing responsibility for the radiation harm are closely related in that they both attempt to establish a causal link, they have often been used as synonyms, causing confusion. Examples range from the use by the International Labour Organization (ILO), International Atomic Energy Agency (IAEA) to the World Health Organization (WHO).


When attribution between the incident and the effect is established, imputation is crucial to allow for subsequent legal actions such as charging, indicting, and prosecuting—if a criminal element is involved—or simply initiating a civil suit if another form of negligence can be demonstrated. The end goal for the plaintiff is to obtain reparation for damages incurred.


Attribution and imputation both generate controversy and two basic challenges dominate the issue. The first challenge is the attribution of specific health effects to a specific radiation exposure situation, which requires qualified experts to demonstrate that a factual occurrence can be causally linked—meaning without a doubt—to radiation harm. The second challenge is of a more formal nature; how to proceed with relevant legal actions consistent with the legal practice in the applicable jurisdiction or legal system. In high-exposure incidents with obvious harmful effects, this is relatively straightforward. On the other hand, a challenge arises in situations involving low to very low radiation doses. This issue is amply discussed in the literature [62–64] but no clear solution, let alone a consensus between experts, has been found yet.


The attribution of health effects to radiation means no more than factually linking the health effects of radiation exposure to objective and indisputable evidence of any given radiation exposure situation. When establishing attribution, there can generally be no reasonable doubt between the cause and the health effect. When moving away from a high-dose, high-probability scenario, in cases where low or lower doses are concerned, the lines become blurred and direct attribution can be problematic. As a consequence, in low-dose scenarios the causal link often needs to be inferred, meaning a reasonable conclusion needs to be reached on the basis of evidence and experience. In contrast to attribution, inference entails the process of drawing conclusions from subjective conjectures involving indirect conclusions based on scientific observations and reasoning on radiation risks, while allowing an element of uncertainty. The discussion involving the attribution of health effects to radiation and the inference of radiation risks is closely followed on an international level by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (UNSCEAR [65] Report to the General Assembly with Scientific Annexes). UNSCEAR, which has been compiling and discussing decades of case material, scientific research, and expert opinions on the subject, periodically reports its findings to the United Nations General Assembly [66]. The United Nations Environment Program (UNEP) has summarized the progressing UNSCEAR insights and has made an abridged version available to the general public, in an illustrated volume [67] containing the illustrations that are used in this chapter. The UNSCEAR findings are simplistically condensed in a dose–response relationship, a graphical representation of the probability that people would suffer health effects and the radiation doses they have incurred, shown in Fig. 12.1.

A chart illustrates the relationship between radiation doses and health effects for the probability of the effect versus dose of natural background, occupational, Chernobyl child thyroid dose, Chernobyl firemen. The increasing values of biologically plausible, statistically observable in populations, and clinically observable in individuals.

Fig. 12.1
Adapted from UNSCEAR 2012, Annex A Schematic of the relationship between dose, additional to that from typical exposure to natural background radiation, and probability of occurrence of health effects, Fig. AV-I p68


A chart illustrates the relationship between radiation doses and health effects for the probability of the effect versus dose of natural background, occupational, Chernobyl child thyroid dose, Chernobyl firemen. The increasing values of biologically plausible, statistically observable in populations, and clinically observable in individuals.


UNSCEAR has highlighted the importance of distinguishing between two types of effects (see yellow ellipses in Fig. 12.1). Purely observational health effects in exposed individuals and populations will lead to attribution if the health effect to radiation exposure situation is observed and then attested. On the other hand, plausible health effects for which occurrence is likely conceivable but not directly verifiable, only allow one to infer health effects from known risks, but without clear attribution.


In the figure, the doses on the x-axis are expressed from very low to high. A “high dose” indicates an effective dose around 1 Sv and up, many orders of magnitude higher than the annual levels of natural background radiation. A “moderate dose” is situated between 100 mSv and 1 Sv, while a “low dose” is in the tens of mSv, and a “very low dose” is around 1 mSv.


Note too that the probabilities on the y-axis are expressed in percentages between 0% and 100%, where 100% corresponds to the certainty that the effect will occur and 0% corresponds to the certainty that the effect will not occur. In between these values, probabilities need to be calculated, which can be done in two ways. Frequentist probabilities are most often used in the high-dose range and take into account the verifiable existence of radiation health effects, defined as the limit of the relative frequency of incidence of the effect in a series of certifiable epidemiological studies. Frequentist probabilities are based on fact. In low-dose ranges, clear-cut evidence and unambiguous studies are scarce and a frequentist probability is out of the question. The solution then would be to include subjective—or “Bayesian”—probabilities, that are expressed as an expectation that radiation health effects could occur, but these are not so much based on and quantified by scientific reasoning as on an expert’s judgment that may arguably not be substantiated by the frequency or propensity that the effects actually occur. In other words, reasoned conjecture.


The attribution of radiation harm is an essential component of any legal action. A professionally qualified expert witness should provide clear evidence on the occurrence of radiation effects, caused by a radiation incident, by formally declaring that a causal effect exists. It is obviously not necessary for an expert to have witnessed first-hand the incident at the origin of a radiation-related lawsuit, but he or she does need to be a specialist in radiation effects and able to offer, without reasonable doubt, an expert opinion after considering the chronology of events and factual occurrence of the causes and the effects.


Crucially, the type of expert a plaintiff would rely upon to bring evidence to the case is related to the dose and dose rate, or more precisely the dose–response relationship connected to the incident. This of course is related to the factual observability and thus the scientific attestability of the effects—ranging from attributing to inferring. In a high-dose scenario, the effects are most likely clinically observable, easily attributable and therefore diagnosable in exposed individuals by a qualified expert radiopathologist. In the region of moderate doses, the effects are not directly attributable in individuals because similar effects can occur due to other causes, but they are statistically consistent with the background incidence of the effect that has been studied in certain population cohorts. This incidence can be mathematically quantified as a probability and attested by a radioepidemiologist. Both radiopathologists and radioepidemiologists rely on frequentist probabilities with a high degree of certainty. In the low to very low-dose range, most effects are neither observable nor attributable and thus their occurrence is not attestable with any reasonable certainty. However, a case can be made that the effects of a low-dose incident may be biologically plausible and therefore risk and potential radiation harm could be inferred through the personal judgment of radioprotectionists by assigning probabilities. The probabilities offered in these low-dose cases by radioprotectionists are arguably less objective than the frequentist probabilities demonstrated by radiopathologists and radioepidemiologists since they are skewed towards expert opinion based on experience rather than indisputable scientific fact. This is visible in Fig. 12.2.

A chart illustrates the probability of effect versus dose of natural background, occupational doses, Chernobyl child thyroid doses, and Chernobyl firemen of radio-protection, radio-epidemiology, and radio-pathology.

Fig. 12.2
Adapted from UNSCEAR 2012, Annex A Schematic of the relationship between dose, additional to that from typical exposure to natural background radiation, and probability of occurrence of health effects, Fig. AV-I p68


A chart illustrates the probability of effect versus dose of natural background, occupational doses, Chernobyl child thyroid doses, and Chernobyl firemen of radio-protection, radio-epidemiology, and radio-pathology.


Radiopathologists, radioepidemiologists, and radioprotectionists can all be qualified expert witnesses in the context of legal action, the first attesting the factual occurrence of health effects that can be diagnosed in individuals, the second attesting the factual occurrence of radiation health effects that can be estimated in population cohorts using statistics on the incidence and distribution of diseases associated with radiation exposure, and the third by inferring radiation risks from theory rather than fact. Radiobiologists are a fourth group of scientists that could be situated somewhere between radiopathologists and radioepidemiologists. A radiobiologist has expertise in the branch of biology concerned with the effects of ionizing radiation on organisms, organs, tissues, and cells which can be useful—without directly attesting the factual occurrence of biological changes in an individual—to demonstrate probable effects on tissue after radiation exposure by extrapolating data collected during the study and analysis of specialized bioassay specimens, hematological and cytogenetic samples.


The ability to attribute health effects to specific exposure situations and to attest their occurrence by means of a qualified expert witness has a direct influence on the chances of successful litigation if the radiation harm can be clearly attributed to an incident, imputed to the persons responsible and subsequently compensation awarded to the victims by a court of law. Physical injuries and harmful effects inflicted by those who have caused the exposure, if proven, allow radiation workers or the general public to bring a lawsuit against employers, licensees of nuclear installations, or even the regulatory authorities in the event of a lack of oversight or effective control.


The legal playing field however is not quite level. Legislation and regulatory frameworks that deal with the attribution of radiation health effects are inhomogeneous, sometimes incoherent, and inconsistent among countries and even within countries. A major fault line exists between legal systems based on jurisprudential legislation and those who rely on detailed codified legislation. A comparison of case law exceeds the scope of this chapter, but—at the risk of being overly coarse—we could state that jurisprudential legal systems that employ a case-by-case approach are generally more flexible and provide a higher degree of legal certainty for the plaintiff. Jurisdictions that rely on codified legislation are not bound by legal precedent, placing a high degree of autonomy on the court in applying the rule of law, which can lead to less predictable results.


Figure 12.3 attempts to broadly define what would be feasible when litigating the following situations.

A chart illustrates the relationship between radiation doses and the health effects of probability of effect versus dose for uncertain claims, ambiguous facts, subjective judgment, class action lawsuits, and classic lawsuits.

Fig. 12.3
Adapted from UNSCEAR 2012, Annex A Schematic of the relationship between dose, additional to that from typical exposure to natural background radiation, and probability of occurrence of health effects, Fig. AV-I p68


A chart illustrates the relationship between radiation doses and the health effects of probability of effect versus dose for uncertain claims, ambiguous facts, subjective judgment, class action lawsuits, and classic lawsuits.


In the high-dose region, individual health effects are clinically attributable and attestable, and imputation of harm incurred by the affected individual is therefore straightforward. Attribution is clear; imputation is often directly linking the individual suffering radiation harm to the responsible person and a classic lawsuit, where civil legal action by one person or entity against another person or entity has a high chance of success.


In the moderate dose region, increased incidences of harmful effects in population groups are epidemiologically attributable and attestable and imputation to the responsible person is therefore feasible. When dealing with the harmful effects of moderate doses, a collective or group imputation is more logical, e.g., via a class action lawsuit where the plaintiffs are more likely than not a group of people presenting a collective claim.


In the low-dose region, radiation harm is neither attributable nor attestable on an individual or collective level, but some radiation risk might be inferred. From a legal perspective, claims based on a low dose or low dose rate exposure are uncertain. Since radiation harm might not yet have presented itself or, if present, might be quite removed in time from the alleged exposure situation, a court might struggle with establishing, beyond a reasonable doubt, a causal link between the exposure situation and any health effects allegedly suffered by the plaintiff. The problem presented here is one of objectivity. The cause cannot be attested, the harmful result is only inferred considering theoretical risk and perhaps statistical probability, and any judgment based on these ambiguous facts would have a high degree of subjectivity.


The scientific consensus on health effects attributable to radiation exposure—consensus that in itself is not entirely uniform and still progressing—should serve as a basis for the development of legal instruments in order to have a more uniform treatment of legal actions. In particular, the issue of legal imputation when considering low dose rates should be carefully considered. This issue has not yet crystallized in any type of universal approach, in large part given the fundamental differences between case-based and codified legal systems. The scientific community is eager to provide legal experts with guidance based on the progressing insight into the attribution of radiation effects following radiation exposure situations.


Given the cultural, regulatory, and legislative differences among countries, two fundamental objectives stand out. First, it seems imperative to foster a common legal understanding of cause and effect when dealing with radiation harm and radiation exposure situations. From a scientific perspective, this seems feasible, and if adopted by the legal community, this would greatly enhance legal certainty. Second—and perhaps even more optimistically—the establishment of a universal scientific and legal consensus to direct the application of the law in any situation would reduce uncertainty even further and might even benefit the development and harmonization of different national legislations. In reality however “the law” is not a uniform concept and nations, courts and judges, prosecutors and lawyers will always want to look at the facts of any individual case, assess the differences and exceptions to the rules if there are any and, in general, assert their independent reasoning. Today, the road ahead for the legal community dealing with nuclear law seems long and far from determined.


Human behavior is primarily driven by perception and not by facts [68]. In practice, this pattern is clearly demonstrated also in people’s behavior related to ionizing radiation. For instance, exposure to the medical application of ionizing radiation is highly acceptable for most people, while food irradiation used to increase the safety of food may be unacceptable for many people, although in the first case the patient may receive a relatively high radiation dose and in the second case the consumer will not receive any radiation due to the sterilization [69, 70].


Likewise, 10 mSv received as a worker’s exposure or 10 mSv received during an accidental release of radioactivity to the environment may cause different behavior. This section examines the social and psychological aspects of radiation exposure. First, we will explain the phenomena of radiation risk perception and second we will identify and discuss determinants of health and radiation protection behavior. Finally, we will conclude this chapter with radiation risk communication advice for experts in radiobiology in order to be able to communicate effectively and help people to make informed decisions related to radiation risks.


Risk perception mainly denotes the ways individuals think and feel about the risks they face [71–73]. Radiation risk perception has been extensively studied, for example, in the context of nuclear power [74–76], nuclear testing [77], radioactive waste [78], radon [79], food sterilization by irradiation [80], and nuclear accidents [81]. It is interesting that people perceive radiation risks differently, depending on the origins of this radioactivity, and the contexts in which it is encountered.


In order to demonstrate diversity in radiation risk perception, we present the results of a public opinion survey conducted in a high radon-prone area in Belgium [82]. Figure 12.4 illustrates how residents of radon-prone areas think and feel about environmental and radiation risks. It shows that residents living in radon-prone areas in Belgium perceive the risk from environmental pollution as the highest potential risk to their health within the next 20 years, followed by the risk of a climate crisis. Among risks related to radon and naturally occurring radioactive material, the risk of indoor air pollution due to radon is perceived as the highest potential risk to their health within the next 20 years, followed by the use of recycled material with low levels of radioactivity for buildings. The lowest risk for health within the next 20 years is perceived to come from natural radiation from the soil or from space. Interestingly, in this 2021 survey, the risk of medical applications of ionizing radiation is perceived as one of the lowest radiation risks by residents of radon-prone areas in Belgium, although medical exposure presents the most significant dose in Belgium.

A horizontally stacked bar graph of risk perception for environmental pollution, climate crisis, natural radiation, the use of recycled material with low levels of radioactivity for buildings, the use of ionizing radiation for medical tests or treatments, indoor air pollution due to radon of no, very low, low, moderate, high, very high risk, and don't know or no answer.

Fig. 12.4
Perception of environmental and radiation risks by residents of high radon-prone area in Belgium, 2021 [82]


A horizontally stacked bar graph of risk perception for environmental pollution, climate crisis, natural radiation, the use of recycled material with low levels of radioactivity for buildings, the use of ionizing radiation for medical tests or treatments, indoor air pollution due to radon of no, very low, low, moderate, high, very high risk, and don't know or no answer.


Research also shows that experts and the general public often disagree about the potential danger posed to their health by nuclear waste, an accident in a nuclear installation, natural radioactivity, medical X-rays, or the Daiichi nuclear accident in Fukushima [83]. In the study of Perko [84], the public had significantly higher risk perceptions of all radiation risks when compared to experts, with the only exception being medical exposure. However, expert opinion and lay perception need to be perceived as complementing rather than competing with each other [85]. Remarkably, empirical results show that experts too do not think and feel the same about radiation risk. When a distinction was made between experts that received a dose of more than 0.5 mSv due to their professional exposure, and those who did not, those who were exposed to more than 0.5 mSv perceived the risk of radiation waste and an accident in a nuclear installation significantly lower than their colleagues did. Similarly to this, they also did not agree about risks from nuclear accidents in Japan. On the other hand, the employees receiving a dose higher than 0.5 mSv had significantly higher risk perceptions of natural radioactivity and medical use of ionizing radiation than their colleagues. These results can be explained by the characteristics of risk, suggesting that familiarity with risk, knowledge, personal control, and voluntariness decrease risk perception.


Characteristics of risk and their impact on (un)acceptability have been studied and identified by scholars using a psychometric method [68, 86, 87]. Studies of risk perception examine the opinions people express when they are asked, in various ways, to characterize and evaluate hazardous activities and technologies [85, 88]. The method is based on a number of explanatory scales corresponding to various risk characteristics, which are an explanation of contextual traits that people use when they make decisions related to risks. Some of these scales involve traits focusing on whether the risk has an influence on children, whether it is involuntary or not, whether people are familiar with the risk or it is new to them, whether the risk has a catastrophic potential, whether it can cause delayed or immediate consequences, whether the risk is already known to science or not. Table 12.2 demonstrates the characteristics of risks, their influence on risk (un)acceptance, how they can be explained in a scale from maximum to minimum, as well as providing descriptive examples of radiation risk acceptance as hypothetical scenarios.Table 12.2
Examples of acceptable radiation risks in relation to risk perception

Descriptive example of an acceptable radiation risk—a hypothetical scenario

Selected characteristics of risk

Influence on risk (un)acceptability

Explanatory scale

A catastrophic potential of a nuclear accident made the risk more threatening since low-probability high-consequence radiation risks are usually perceived as more threatening than more probable risks with low or medium consequences.

Catastrophic potential

Decreases risk acceptability

Catastrophic—chronic

Medical personnel is wearing assigned personal radiation dosimeters during a procedure using ionizing radiation, which gives a feeling of control and increases the acceptability of radiation exposure.

Personal control

Increases risk acceptability

Controllable—not controllable

A phosphate factory is recognized as a trustworthy organization since they communicate openly about the risks of naturally occurring radioactive material as a side product.

Institutional control

Depends upon confidence in institutional performance

Trust, confidence in the institution

Population density around nuclear installation is low thus controlled releases of radioactivity from a nuclear installation in an environment is acceptable.

Number of exposed

Decreases risk acceptability

Local—global

Workers get employed at a nuclear installation on a voluntarist basis thus they accept workers’ exposure to ionizing radiation.

Voluntariness

Increases risk acceptability

Voluntary—involuntary

A patient receives a low dose of ionizing radiation during X-ray which makes it acceptable.

Mortality

Decreases risk acceptability

Fatal—not fatal

Visitors learned about radiation and technology used by researchers during an open-door day at a nuclear research institute. New insights and knowledge influenced their acceptability of potential radiation risks.

Knowledge

Increases risk acceptability

New technology—established technology

Living in a home with high radon concentration for many years (more generations) made residents accept radon risk and not performing radon test or necessary remediation of a house

Familiarity

Increases risk acceptability

Familiar—not familiar

A traffic accident with transport of radionuclides for a hospital in a citizen’s region is not as dreadful as a nuclear accident in another continent is.

Dread/fear

Decreases risk acceptability

Fear—no fear

High natural background of radiation is for many people acceptable because it is natural due to the geological characteristics of a region.

Artificiality of risk source

Amplifies attention to risk
Often decreases risk acceptability

Human—natural

During an environmental remediation process, residents had a feeling of fairness since they could co-decide on how, where, and to which level should be environment remediated. Thus, they accepted radioactive residues in a dedicated part of their administrative community.

Fairness

Increases quest for social and political responses

Fair—unfair

Receiving compensation for radioactive waste disposal made the project acceptable.

Benefit

Increase risk acceptability

Benefit to self-vs. unclear or inequitable

Intake of stable iodine as an effective countermeasure for reducing the risk of thyroid cancer in an eventual release of radioactive iodine following a nuclear accident, especially for children, made the pre-distribution of the iodine tablets to residents and un uptake of a tablet if necessary, an acceptable option.

Effect on children

Decrease risk acceptability

Children specifically at risk


Research shows that only one person in five is prepared to take health-related actions at any given time [89, 90]. Radiation protection behavior is not an exception to this finding. Authorities and other radiation protection actors are often challenged with what has been termed a “value-action gap.” This gap refers to a situation where the values or attitudes of an individual or a group of people do not correlate with their actions; a positive attitude towards good health does not lead to an action to improve/protect health [91].


For instance, testing for radon and remediating your home if radon concentrations are too high are scientifically and technically straightforward actions. However, empirical studies indicate that testing and remediation are generally low among those exposed to high indoor radon, although these persons have relatively high-risk perceptions [92], the cost of radon mitigation measures for most homes is similar to that of common home repairs, and this cost is often an eligible expense covered by national health care programs [93–95].


A similar value-action gap is repeatedly reported in studies related to the behavior of people before, during, and after nuclear or radiation emergencies. For example, the study of Turcanu et al. [54] conducted in Belgium, Norway, and Spain, provides empirical evidence that people in the analyzed countries have difficulties complying with some protective actions in case of a nuclear accident. Leaving children at school, avoiding the use of phones during an emergency, not rejecting food produced in affected areas even when it satisfies legal norms or taking iodine tablets when not needed, were identified as the most critical protective actions with which a large number of people would not comply [96].


This raises the question what determinants of health and radiation protection behavior can be discerned. Different determinants have been studied in the context of health behavior models. The most known and tested models in the radiation protection field are the Protection-Motivation Model [97], the Health Belief Model [98], the Theory of Planned Behavior [99], the Transtheoretical Model of Health Behavior Change (TTM) [90], and the Precautionary Adoption Process Model [100].


Those health protection models suggest that knowledge about the risk is only one of the health behavior determinants, other determinants, explained in Table 12.3 below, being attitudes, perceived behavioral control, subjective norm, descriptive norms, moral norms, self-efficacy, risk perception, protective efficiency of an action, threat, and trust among others. Table 12.3 presents potential health protection determinants, descriptive explanations, and a reference to selected studies that have been tested in the radiation protection field.Table 12.3
Determinants of health and radiation protection behavior tested in radiation risk studies

Potential determinants of health and radiation behavior

Descriptive explanation

Selected studies from radiation protection field

Anticipatory emotion—worry

The anticipatory emotion—worry is an emotion where a person experiences increased levels of anxiety by thinking about an event or situation in the future.

McGlone et al. [101], Witte et al. [102]

Anticipatory emotion—severity

Anticipatory emotion—severity refers to people’s beliefs about how serious are the negative consequences of a hazard. In the radon exposure situations, the threat involves cancer, which is severe.

Mazur and Hall [103], Dragojevic et al. [104]

Conditional/perceived susceptibility

Perceived susceptibility is the subjective belief that a person may acquire a disease or enter a dire state due to a particular behavior.

D’Antoni et al. [105], Weinstein et al. [106], Niemeyer and Keller [107]

Coping of efficacy appraisal: response efficacy

Coping appraisal is needed to adopt or maintain a health protection behavior and is essential for overcoming fears and mental blocks. Coping appraisal consists of three dements: response efficacy/response costs/self-efficacy. Only if the individual is convinced that a behavior leads to the desired outcome will she or he be more likely to intend to perform the behavior.

Weinstein et al. [108, 109], Witte et al. [110], Dragojevic et al. [104]

Coping or efficacy appraisal—self efficacy

Self-efficacy refers to the belief in one’s own competence to perform a behavior even in the face of barriers or in other words, the individual in carrying out the recommended coping response.

Hahn et al. [111], Larsson [112], Rhodes et al. [113]

Perceived costs

The “Perceived costs” captures the person’s perceptions of the disadvantages of, or barriers to, undertaking the behavior.

Hampson et al. [114], Sheeran [115]

Anticipated emotions/regret

Anticipated emotions are a component of the immediate consequences of the decision; they are emotions that are expected to occur when outcomes are experienced. The most extensively researched anticipated emotions regret, guilt, and shame.

Hampson et al. [114], Sheeran [115]

Perceived informed choice

Informed choice means that people under radon risk make decisions that are consistent with their goals and values

Weinstein and Man [116, 117]

Subjective norms

Subjective norms refer to the belief that an important person or group of people will approve and support and particular behavior, for instance protection against radon

Clifford et al. [118], Park et al. [119]

Descriptive norms

Descriptive norms refer to what most people in a group think, feel, or do. Descriptive norms are a reflection on “What is typical or normal … what most people do”, including “evidence as to what will likely be effective and adaptive action.

Moral norms

Moral norms are internalised, unconditional and emotional internalised and enforced through self-generated emotions such as guilt.

Turcanu et al. [120]

Knowledge/awareness

Increasing radiation (specific) knowledge and awareness is often set as a primary objective of risk communication efforts.

Perko et al. [84, 121]

Trust

Trust concept includes different dimensions for instance fairness, unbiasedness, perceived competence, objectivity, consistency, commitment, caring, and predictability, social trust, general trust and transparency.

Perko and Martell [122], Perko et al. [123]


In particular, the Theory of Planned Behavior [124] proved that the higher the intent, the higher the probability an individual will engage in the action they intend. This theory has been for instance applied in research on attitudes and behavior related to new nuclear research installations [120]. In this study, authors found that attitudes towards participation and moral norms are the strongest determinants for the studied behavior—in this case, participation intention. Other determinants were time constraints, attitude towards nuclear energy, subjective and descriptive norms, and level of specific radiation-related knowledge. The Extended Parallel Process Model (EPPM) focuses on two constructs which mediate an individual’s level of fear and proposes an individual will engage in behavior change when they have a combination of (a) fear the health threat will happen to them (susceptibility) and (b) perception they are able to address/deal with the risk [108]. The Transtheoretical Model of Health Behavior Change which has been applied among others also to behavior related to radon exposure [125], postulates that individuals move through six stages of change: pre-contemplation, contemplation, preparation, action, maintenance, and termination. The model has two major components: change and decisional balance, where neither knowledge nor risk perception is not identified as the main health protection change determinants [126]. Similarly, the message design theories, such as the Extended Parallel Processing Model (EPPM) which has been used as the theoretical framework for formative and summative analysis of radon communication campaigns, indicate the importance of threat and efficacy [110].


Responsible risk communication requires a legitimate procedure, an ethically justified risk message, and concern for and valuation of the effects of the message and procedure. This way, it is stressed, that risk communication should not only be effective but also ethical, which requires taking moral values into consideration. During radiation risk communication moral values are at stake, which means that decisions have to be made in a democratic way, after serious debate about values and not merely about numbers [127].


Risk communication was in previous century seen as a form of a technical communication and education whereby the public should be informed about risk estimates. Later on, risk communication was seen as a marketing practice with the aim to persuade people to adopt a certain message. In nowadays societies (sic), risk communication is seen as a socio-centric communication based on public participation with which the gaps between stakeholders can be bridged. The procedure should be legitimate (requires legitimate procedure for discussing the moral values and emotions associated with risks), it should be ethically justified (ethical deliberation about the values and emotions involved in different messages) and the effects should be adequately addressed. [128, p. 8–9].


Radiation risk communication has several aims: (a) to warn people in case of radiation danger, (b) to the enlightenment of people to be able to understand risks and become “risk-literate,” (c) to prevent panic and outrage, (d) to empower stakeholders to make informed decisions related to radiation risks, (e) to establish two-way communication and joint problem solving including conflict resolution, and (f) to build trust between different stakeholders.


Bauder and colleagues (2021) guide communication practitioners towards radiation risk communication which is strategic (e.g., based on formats and methods that have been proven to reach its preconceived objectives), evidence-based (e.g., based on the qualitative and quantitative empirical data, surveys, experiments), and theory-based (e.g., drawing from empirically supported theories of health behavior, behavior, and information processing) [129].


For instance, information processing theories applied in radiation risk communication [130] show that efficient communication about radiation risks requires thorough insight into the factors that influence people’s attentiveness, recall of risk-related information, level of agreement with the communicated message, and behavior change or more generally speaking: how people process risk-related information and turned it in a behavior.


The information processing models are seen as applicable for each individual, regardless of the societal or cultural bias [131–139] however countries may differ in beliefs, cultural values, past social and risk experiences, the saliency of particular aspects of a policy issue, the socioeconomic profile and trust in regulatory agencies. In general, people process information using two different modes: (1) heuristic and (2) systematic mode [140]. Heuristic processing is characterized by low effort and reliance on existing knowledge and simple cues for instance trust. Systematic processing on the other hand is characterized by greater effort and the desire to evaluate information formally [141].


Radiobiologists may be challenged by public communication due to the following reasons [122]: there is no single audience for scientific information; the complexity of scientific methods and information, and the ways in which science progresses; the ways in which people process such information; in the radiobiology, the societal implications of science are controversial, for instance, Linear Dose Response Model; there is substantial disagreement about the findings within the scientific community, for instance, related to low doses; the complex, dynamic, and competitive communication media environment, with evolving social media and pace of information flow; and because the results of research can be insufficient, ambiguous or uncertain, and scientific conclusions can change over time as new findings emerge.


Science Media Centre (2012) developed practical guidance to be used by scientists during their public and mass media communication. For a complete and original guide, look at https://www.sciencemediacentre.org/wp-content/uploads/2012/09/10-best-practice-guidelines-for-science-and-health-reporting.pdf.


Some of the central points are summarized here:
Headlines should not mislead the reader about a story’s contents and quotation marks should not be used to dress up overstatement.

During your communication related to health risks, include the absolute risk whenever it is available in the press release or the research paper (e.g., if “low dose exposure increases the cancer risk” state the outright risk of that cancer, with and without particular exposure).

Especially on a story with public health implications, try to present a new finding in the context of other evidence (e.g., does it reinforce or conflict with previous studies?). If it attracts serious scientific concerns, they should not be ignored.

When reporting a link between two things, it is recommended to indicate whether or not there is evidence that one causes the other.

Specify the size and nature of the study (e.g., who/what were the subjects, how long did it last, what was tested or was it an observation?). Provided there is enough space and time, it could be of interest to mention also the major limitations.

State where the research has been published or presented or reported (e.g., conference, journal article, survey, etc.). Ideally, the article should include a web link or enough information for readers to look it up.

Give a sense of the stage of the research (e.g., new dosimeter, clean-up stage, cells in a laboratory, or trials in humans), and a realistic time frame for any new technology.

If there is enough space, quote both the researchers themselves and external sources with appropriate expertise. Be wary of scientists and press releases over-claiming for studies.

Distinguish between findings and interpretation or extrapolation; do not suggest health advice if none has been offered.


Headlines should not mislead the reader about a story’s contents and quotation marks should not be used to dress up overstatement.


During your communication related to health risks, include the absolute risk whenever it is available in the press release or the research paper (e.g., if “low dose exposure increases the cancer risk” state the outright risk of that cancer, with and without particular exposure).


Especially on a story with public health implications, try to present a new finding in the context of other evidence (e.g., does it reinforce or conflict with previous studies?). If it attracts serious scientific concerns, they should not be ignored.


When reporting a link between two things, it is recommended to indicate whether or not there is evidence that one causes the other.


Specify the size and nature of the study (e.g., who/what were the subjects, how long did it last, what was tested or was it an observation?). Provided there is enough space and time, it could be of interest to mention also the major limitations.


State where the research has been published or presented or reported (e.g., conference, journal article, survey, etc.). Ideally, the article should include a web link or enough information for readers to look it up.


Give a sense of the stage of the research (e.g., new dosimeter, clean-up stage, cells in a laboratory, or trials in humans), and a realistic time frame for any new technology.


If there is enough space, quote both the researchers themselves and external sources with appropriate expertise. Be wary of scientists and press releases over-claiming for studies.


Distinguish between findings and interpretation or extrapolation; do not suggest health advice if none has been offered.


1.
The most difficult thing in finding trust in decision-making on nuclear today might be in the way we deal with moral pluralism. What is moral pluralism? Simply the idea that if we all know the same thing, opinions on what to do can still be different, and this is because our opinions do not only rely on knowledge but also on ethical values. As an example choosing for retrievability or non-retrievability of underground stored nuclear waste is making a choice dealing with moral pluralism: science can describe the options, but not help us to make a choice. Some would say we should dispose and seal the waste so that future generations do not need to bother about it anymore, while others would argue that we should give them the possibility to intervene or do something better with the waste. Imagine yourself being a moderator in this discussion: what are the values and interests at stake here, and how would you moderate this discussion towards a consensus, also taking into account that an important stakeholder (the future generations) cannot participate in the discussion?
 2.
Studies have shown that the public is more averse to relatively low radiation exposures from nuclear power than to higher doses from medical exposures. Is this irrational?
 3.
What other ethically relevant factors impact perceptions of radiation risks?


The most difficult thing in finding trust in decision-making on nuclear today might be in the way we deal with moral pluralism. What is moral pluralism? Simply the idea that if we all know the same thing, opinions on what to do can still be different, and this is because our opinions do not only rely on knowledge but also on ethical values. As an example choosing for retrievability or non-retrievability of underground stored nuclear waste is making a choice dealing with moral pluralism: science can describe the options, but not help us to make a choice. Some would say we should dispose and seal the waste so that future generations do not need to bother about it anymore, while others would argue that we should give them the possibility to intervene or do something better with the waste. Imagine yourself being a moderator in this discussion: what are the values and interests at stake here, and how would you moderate this discussion towards a consensus, also taking into account that an important stakeholder (the future generations) cannot participate in the discussion?


Studies have shown that the public is more averse to relatively low radiation exposures from nuclear power than to higher doses from medical exposures. Is this irrational?


1.
Which is the main underlying principle of nuclear law and how does this translate to the concept of optimization of protection? Can you give an example of two planned exposure situations?
 2.
Do you think the exposure to cosmic rays is a planned exposure situation or an existing exposure? Could it be both in the context of air travel? Is radiological protection different in either situation?
 3.
What attributes should a regulatory body have and what are some of its main tasks?
 4.
Nuclear liability is different from general tortious liability. Give an example and explain the reason.


Which is the main underlying principle of nuclear law and how does this translate to the concept of optimization of protection? Can you give an example of two planned exposure situations?


Do you think the exposure to cosmic rays is a planned exposure situation or an existing exposure? Could it be both in the context of air travel? Is radiological protection different in either situation?


What attributes should a regulatory body have and what are some of its main tasks?


Nuclear liability is different from general tortious liability. Give an example and explain the reason.


1.
Taking into consideration the legal structure of your country, please elaborate on the potential legal developments of the following situations:(a)
A worker is damaged (burned) by an over-exposure to radiation and decides the damage is to be attributed to the exposure and imputed on his/her employer;
 (b)
A large group of conscripts is subjected to a collective medical screening using old X-ray equipment when joining the army. About a decade later, those still meeting in social encounters discover that a large number among them are suffering from unusual cancers for their young age and decide to impute the army;
 (c)
A family is living near a nuclear power plant that appears to function as designed. There have been no reports of any anomalous events, incidents, or anomalous measured values. One of their children incurs thyroid cancer. The parents have contacted a lawyer.


Taking into consideration the legal structure of your country, please elaborate on the potential legal developments of the following situations:(a)
A worker is damaged (burned) by an over-exposure to radiation and decides the damage is to be attributed to the exposure and imputed on his/her employer;
 (b)
A large group of conscripts is subjected to a collective medical screening using old X-ray equipment when joining the army. About a decade later, those still meeting in social encounters discover that a large number among them are suffering from unusual cancers for their young age and decide to impute the army;
 (c)
A family is living near a nuclear power plant that appears to function as designed. There have been no reports of any anomalous events, incidents, or anomalous measured values. One of their children incurs thyroid cancer. The parents have contacted a lawyer.


A worker is damaged (burned) by an over-exposure to radiation and decides the damage is to be attributed to the exposure and imputed on his/her employer;


A large group of conscripts is subjected to a collective medical screening using old X-ray equipment when joining the army. About a decade later, those still meeting in social encounters discover that a large number among them are suffering from unusual cancers for their young age and decide to impute the army;


A family is living near a nuclear power plant that appears to function as designed. There have been no reports of any anomalous events, incidents, or anomalous measured values. One of their children incurs thyroid cancer. The parents have contacted a lawyer.


Nuclear medicine  ( nuclear radiology ,  nucleology ), [ 1 ] [ 2 ]  is a  medical specialty  involving the application of  radioactive  substances in the  diagnosis  and treatment of  disease . Nuclear imaging is, in a sense,  radiology  done inside out , because it records  radiation   emitted  from within the body rather than  radiation  that is  transmitted  through the body from external sources like  X-ray generators . In addition, nuclear medicine scans differ from radiology, as the emphasis is not on imaging anatomy, but on the function. For such reason, it is called a  physiological imaging modality .  Single photon emission computed tomography  (SPECT) and  positron emission tomography  (PET) scans are the two most common imaging modalities in nuclear medicine. [ 3 ]


In nuclear medicine imaging,  radiopharmaceuticals  are taken internally, for example, through inhalation, intravenously, or orally. Then, external detectors ( gamma cameras ) capture and form images from the radiation emitted by the radiopharmaceuticals. This process is unlike a diagnostic X-ray, where external radiation is passed through the body to form an image. [ citation needed ]


There are several techniques of diagnostic nuclear medicine.


Nuclear medicine tests differ from most other imaging modalities in that nuclear medicine scans primarily show the physiological function of the system being investigated as opposed to traditional anatomical imaging such as CT or MRI. Nuclear medicine imaging studies are generally more organ-, tissue- or disease-specific (e.g.: lungs scan, heart scan, bone scan, brain scan, tumor, infection, Parkinson etc.) than those in conventional radiology imaging, which focus on a particular section of the body (e.g.: chest X-ray, abdomen/pelvis CT scan, head CT scan, etc.). In addition, there are nuclear medicine studies that allow imaging of the whole body based on certain cellular receptors or functions. Examples are whole body  PET scans  or  PET/CT  scans,  gallium scans ,  indium white blood cell scans ,  MIBG  and  octreotide scans .


While the ability of nuclear metabolism to image disease processes from differences in metabolism is unsurpassed, it is not unique. Certain techniques such as  fMRI  image tissues (particularly cerebral tissues) by blood flow and thus show metabolism. Also, contrast-enhancement techniques in both CT and MRI show regions of tissue that are handling pharmaceuticals differently, due to an inflammatory process.


Diagnostic tests in nuclear medicine exploit the way that the body handles substances differently when there is disease or pathology present. The radionuclide introduced into the body is often chemically bound to a complex that acts characteristically within the body; this is commonly known as a  tracer . In the presence of disease, a tracer will often be distributed around the body and/or processed differently. For example, the ligand methylene-diphosphonate ( MDP ) can be preferentially taken up by bone. By chemically attaching  technetium-99m  to MDP, radioactivity can be transported and attached to bone via the hydroxyapatite for imaging. Any increased physiological function, such as due to a fracture in the bone, will usually mean increased concentration of the tracer. This often results in the appearance of a "hot spot", which is a focal increase in radio accumulation or a general increase in radio accumulation throughout the physiological system. Some disease processes result in the exclusion of a tracer, resulting in the appearance of a "cold spot". Many tracer complexes have been developed to image or treat many different organs, glands, and physiological processes.


In some centers, the nuclear medicine scans can be superimposed, using software or hybrid cameras, on images from modalities such as CT or MRI to highlight the part of the body in which the radiopharmaceutical is concentrated. This practice is often referred to as image fusion or co-registration, for example SPECT/CT and PET/CT. The fusion imaging technique in nuclear medicine provides information about the anatomy and function, which would otherwise be unavailable or would require a more invasive procedure or surgery.


Although the risks of low-level radiation exposures are not well understood, a cautious approach has been universally adopted that all human radiation exposures should be kept  As Low As Reasonably Practicable , "ALARP". (Originally, this was known as "As Low As Reasonably Achievable" (ALARA), but this has changed in modern draftings of the legislation to add more emphasis on the "Reasonably" and less on the "Achievable".)


Working with the ALARP principle, before a patient is exposed for a nuclear medicine examination, the benefit of the examination must be identified. This needs to take into account the particular circumstances of the patient in question, where appropriate. For instance, if a patient is unlikely to be able to tolerate a sufficient amount of the procedure to achieve a diagnosis, then it would be inappropriate to proceed with injecting the patient with the radioactive tracer.


When the benefit does justify the procedure, then the radiation exposure (the amount of radiation given to the patient) should also be kept "ALARP". This means that the images produced in nuclear medicine should never be better than required for confident diagnosis. Giving larger radiation exposures can reduce the noise in an image and make it more photographically appealing, but if the clinical question can be answered without this level of detail, then this is inappropriate.


As a result, the  radiation dose  from nuclear medicine imaging varies greatly depending on the type of study. The effective radiation dose can be lower than or comparable to or can far exceed the general day-to-day environmental annual  background radiation  dose. Likewise, it can also be less than, in the range of, or higher than the radiation dose from an abdomen/pelvis CT scan.


Some nuclear medicine procedures require special patient preparation before the study to obtain the most accurate result. Pre-imaging preparations may include dietary preparation or the withholding of certain medications. Patients are encouraged to consult with the nuclear medicine department prior to a scan.


The result of the nuclear medicine imaging process is a dataset comprising one or more images. In multi-image datasets the array of images may represent a time sequence (i.e. cine or movie) often called a "dynamic" dataset, a cardiac gated time sequence, or a spatial sequence where the gamma-camera is moved relative to the patient.  SPECT  (single photon emission computed tomography) is the process by which images acquired from a rotating gamma-camera are reconstructed to produce an image of a "slice" through the patient at a particular position. A collection of parallel slices form a slice-stack, a  three-dimensional  representation of the distribution of radionuclide in the patient.


The nuclear medicine computer may require millions of lines of source code to provide quantitative analysis packages for each of the specific imaging techniques available in nuclear medicine. [ citation needed ]


Time sequences can be further analysed using  kinetic  models such as  multi-compartment models  or a  Patlak plot .


Radionuclide therapy can be used to treat conditions such as  hyperthyroidism ,  thyroid cancer , skin cancer and blood disorders.


In nuclear medicine therapy, the radiation treatment dose is administered internally (e.g. intravenous or oral routes) or externally direct above the area to treat in form of a compound (e.g. in case of skin cancer).


The radiopharmaceuticals used in nuclear medicine therapy emit ionizing radiation that travels only a short distance, thereby minimizing unwanted side effects and damage to noninvolved organs or nearby structures. Most nuclear medicine therapies can be performed as outpatient procedures since there are few side effects from the treatment and the radiation exposure to the general public can be kept within a safe limit.


In some centers the nuclear medicine department may also use implanted capsules of isotopes ( brachytherapy ) to treat cancer.


The history of nuclear medicine contains contributions from scientists across different disciplines in physics, chemistry, engineering, and medicine. The multidisciplinary nature of nuclear medicine makes it difficult for medical historians to determine the birthdate of nuclear medicine. This can probably be best placed between the discovery of artificial radioactivity in 1934 and the production of radionuclides by  Oak Ridge National Laboratory  for medicine-related use, in 1946. [ 6 ]


The origins of this medical idea date back as far as the mid-1920s in  Freiburg , Germany, when  George de Hevesy  made experiments with radionuclides administered to rats, thus displaying metabolic pathways of these substances and establishing the  tracer  principle. Possibly, the genesis of this medical field took place in 1936, when  John Lawrence , known as "the father of nuclear medicine", took a leave of absence from his faculty position at  Yale Medical School , to visit his brother  Ernest Lawrence  at his new radiation laboratory (now known as the  Lawrence Berkeley National Laboratory ) in  Berkeley ,  California . Later on, John Lawrence made the first application in patients of an artificial radionuclide when he used  phosphorus-32  to treat  leukemia . [ 7 ] [ 8 ]


Many historians consider the discovery of artificially produced radionuclides by  Frédéric Joliot-Curie  and  Irène Joliot-Curie  in 1934 as the most significant milestone in nuclear medicine. [ 6 ]  In February 1934, they reported the first artificial production of radioactive material in the journal  Nature , after discovering radioactivity in aluminum foil that was irradiated with a polonium preparation. Their work built upon earlier discoveries by  Wilhelm Konrad Roentgen  for X-ray,  Henri Becquerel  for radioactive uranium salts, and  Marie Curie  (mother of Irène Curie) for radioactive thorium, polonium and coining the term "radioactivity."  Taro Takemi  studied the application of  nuclear physics  to medicine in the 1930s. The history of nuclear medicine will not be complete without mentioning these early pioneers.


Nuclear medicine gained public recognition as a potential specialty when on May 11, 1946, an article in the Journal of the American Medical Association (JAMA) by Massachusetts General Hospital's Dr.  Saul Hertz  and Massachusetts Institute of Technology's Dr. Arthur Roberts, described the successful use of treating Graves' Disease with radioactive iodine (RAI) was published. [ 9 ]  Additionally,  Sam Seidlin . [ 10 ]  brought further development in the field describing a successful treatment of a patient with thyroid cancer metastases using radioiodine ( I-131 ). These articles are considered by many historians as the most important articles ever published in nuclear medicine. [ 11 ]  Although the earliest use of I-131 was devoted to therapy of thyroid cancer, its use was later expanded to include imaging of the thyroid gland, quantification of the thyroid function, and therapy for hyperthyroidism. Among the many radionuclides that were discovered for medical-use, none were as important as the discovery and development of  Technetium-99m . It was first discovered in 1937 by C. Perrier and E. Segre as an artificial element to fill space number 43 in the Periodic Table. The development of a  generator  system to produce Technetium-99m in the 1960s became a practical method for medical use. Today, Technetium-99m is the most utilized element in nuclear medicine and is employed in a wide variety of nuclear medicine imaging studies.


Widespread clinical use of nuclear medicine began in the early 1950s, as knowledge expanded about radionuclides, detection of radioactivity, and using certain radionuclides to trace biochemical processes. Pioneering works by  Benedict Cassen  in developing the first  rectilinear scanner  and  Hal O. Anger 's scintillation camera ( Anger camera ) broadened the young discipline of nuclear medicine into a full-fledged medical imaging specialty.


By the early 1960s, in southern  Scandinavia ,  Niels A. Lassen ,  David H. Ingvar , and  Erik Skinhøj  developed techniques that provided the first blood flow maps of the brain, which initially involved  xenon-133  inhalation; [ 12 ]  an intra-arterial equivalent was developed soon after, enabling measurement of the local distribution of cerebral activity for patients with  neuropsychiatric  disorders such as schizophrenia. [ 13 ]  Later versions would have 254  scintillators  so a two-dimensional image could be produced on a color monitor. It allowed them to construct images reflecting brain activation from speaking, reading, visual or auditory perception and voluntary movement. [ 14 ]  The technique was also used to investigate, e.g., imagined sequential movements, mental calculation and mental spatial navigation. [ 15 ] [ 16 ]


By the 1970s most organs of the body could be visualized using nuclear medicine procedures. In 1971,  American Medical Association  officially recognized nuclear medicine as a medical specialty. [ 17 ]  In 1972, the  American Board of Nuclear Medicine  was established, and in 1974, the  American Osteopathic Board of Nuclear Medicine  was established, cementing nuclear medicine as a stand-alone medical specialty.


In the 1980s, radiopharmaceuticals were designed for use in diagnosis of heart disease. The development of single photon emission computed tomography (SPECT), around the same time, led to three-dimensional reconstruction of the heart and establishment of the field of nuclear cardiology.


More recent developments in nuclear medicine include the invention of the first positron emission tomography scanner ( PET ). The concept of emission and transmission tomography, later developed into single photon emission computed tomography (SPECT), was introduced by  David E. Kuhl  and Roy Edwards in the late 1950s. [ citation needed ]  Their work led to the design and construction of several tomographic instruments at the University of Pennsylvania. Tomographic imaging techniques were further developed at the  Washington University School of Medicine . These innovations led to fusion imaging with SPECT and CT by Bruce Hasegawa from  University of California, San Francisco  (UCSF), and the first PET/CT prototype by D. W. Townsend from  University of Pittsburgh  in 1998. [ citation needed ]


PET and PET/CT imaging experienced slower growth in its early years owing to the cost of the modality and the requirement for an on-site or nearby cyclotron. However, an administrative decision to approve medical reimbursement of limited PET and PET/CT applications in oncology has led to phenomenal growth and widespread acceptance over the last few years, which also was facilitated by establishing 18F-labelled tracers for standard procedures, allowing work at non-cyclotron-equipped sites. PET/CT imaging is now an integral part of oncology for diagnosis, staging and treatment monitoring. A fully integrated MRI/PET scanner is on the market from early 2011. [ citation needed ]


99m Tc is normally supplied to hospitals through a  radionuclide generator  containing the parent radionuclide  molybdenum-99 .  99 Mo is  typically obtained  as a fission product of  235 U  in nuclear reactors, however global supply shortages have led to the exploration of  other methods of production . About a third of the world's supply, and most of Europe's supply, of medical isotopes is produced at the  Petten nuclear reactor  in the  Netherlands . Another third of the world's supply, and most of North America's supply, was produced at the  Chalk River Laboratories  in  Chalk River ,  Ontario , Canada until its permanent shutdown in 2018. [ 18 ]


The most commonly used radioisotope in PET,  18 F , is not produced in a nuclear reactor, but rather in a circular accelerator called a  cyclotron . The cyclotron is used to accelerate  protons  to bombard the stable heavy isotope of oxygen  18 O . The  18 O constitutes about 0.20% of ordinary  oxygen  (mostly  oxygen-16 ), from which it is extracted. The  18 F is then typically used to make  FDG .


Z = atomic number, the number of protons T 1/2  = half-life decay = mode of decay
 photons = principal photon energies in kilo-electron volts,  keV , (abundance/decay)
 β = beta maximum energy in kilo-electron volts,  keV , (abundance/decay)
 β +  =  β +  decay ; β −  =  β −  decay ; IT =  isomeric transition ; ec =  electron capture
 * X-rays from progeny,  mercury , Hg


A typical nuclear medicine study involves administration of a  radionuclide  into the body by intravenous injection in liquid or aggregate form, ingestion while combined with food, inhalation as a gas or aerosol, or rarely, injection of a radionuclide that has undergone  micro-encapsulation . Some studies require the labeling of a patient's own blood cells with a radionuclide ( leukocyte scintigraphy  and  red blood cell  scintigraphy). Most diagnostic radionuclides emit  gamma rays  either directly from their decay or indirectly through  electron–positron annihilation , while the cell-damaging properties of  beta particles  are used in therapeutic applications. Refined radionuclides for use in nuclear medicine are derived from  fission  or fusion processes in  nuclear reactors , which produce radionuclides with longer half-lives, or  cyclotrons , which produce radionuclides with shorter half-lives, or take advantage of natural decay processes in dedicated generators, i.e. molybdenum/technetium or strontium/rubidium.


The most commonly used intravenous radionuclides are technetium-99m, iodine-123, iodine-131, thallium-201, gallium-67, fluorine-18  fluorodeoxyglucose , and indium-111 labeled  leukocytes . [ citation needed ]  The most commonly used gaseous/aerosol radionuclides are xenon-133, krypton-81m, ( aerosolised ) technetium-99m. [ 23 ]


A patient undergoing a nuclear medicine procedure will receive a  radiation dose . Under present international guidelines it is assumed that any radiation dose, however small, presents a risk. The radiation dose delivered to a patient in a nuclear medicine investigation, though unproven, is generally accepted to present a very small risk of inducing cancer. In this respect it is similar to the risk from X-ray investigations except that the dose is delivered internally rather than from an external source such as an X-ray machine, and dosage amounts are typically significantly higher than those of X-rays.


The radiation dose from a nuclear medicine investigation is expressed as an  effective dose  with units of  sieverts  (usually given in millisieverts, mSv). The effective dose resulting from an investigation is influenced by the amount of radioactivity administered in mega becquerels  (MBq), the  physical properties  of the  radiopharmaceutical  used, its distribution in the body and its rate of clearance from the body.


Effective doses can range from 6 μSv (0.006 mSv) for a 3 MBq  chromium -51 EDTA measurement of  glomerular filtration rate  to 11.2 mSv (11,200 μSv) for an 80 MBq  thallium -201  myocardial imaging  procedure. The common bone scan with 600 MBq of technetium-99m  MDP  has an effective dose of approximately 2.9 mSv (2,900 μSv). [ 24 ]


Formerly, units of measurement were:


The rad and rem are essentially equivalent for almost all nuclear medicine procedures, and only  alpha radiation  will produce a higher Rem or Sv value, due to its much higher  Relative Biological Effectiveness  (RBE). Alpha emitters are nowadays rarely used in nuclear medicine, but were used extensively before the advent of nuclear reactor and accelerator produced radionuclides. The concepts involved in radiation exposure to humans are covered by the field of  Health Physics ; the development and practice of safe and effective nuclear medicinal techniques is a key focus of  Medical Physics .


Different countries around the world maintain regulatory frameworks that are responsible for the management and use of radionuclides in different medical settings. For example, in the US, the  Nuclear Regulatory Commission  (NRC) and the  Food and Drug Administration  (FDA) have guidelines in place for hospitals to follow. [ 26 ]  With the NRC, if radioactive materials aren't involved, like X-rays for example, they are not regulated by the agency and instead are regulated by the individual states. [ 27 ]  International organizations, such as the  International Atomic Energy Agency  (IAEA), have regularly published different articles and guidelines for best practices in nuclear medicine as well as reporting on emerging technologies in nuclear medicine. [ 28 ] [ 29 ]  Other factors that are considered in nuclear medicine include a patient's medical history as well as post-treatment management. Groups like  International Commission on Radiological Protection  have published information on how to manage the release of patients from a hospital with unsealed radionuclides. [ 30 ]


Angelika Bischof-Delaloye  is a former  emeritus   professor  at the  University of Lausanne  in  Lausanne , Switzerland. [ 1 ] [ 2 ]


From 1998 to 2009, Bischof-Delaloye was a full professor at the  Nuclear Medicine  Department at the University Lausanne, and the Department Head of Nuclear Medicine at  Lausanne University Hospital . [ 3 ]


She served on the  European Board of Nuclear Medicine  in 2006. [ 4 ]  In 2011, she wrote the editorial article for  European Journal of Nuclear Medicine and Molecular Imaging  (EJNMMI) to introduce the  open-access journal  called European Journal of Nuclear Medicine and Molecular Imaging Research (EJNMMI Res) [ 5 ]  in the area of basic, translational and clinical research in nuclear medicine. She currently serves as the  editor-in-chief  of the EJNMMI Res journal. [ 6 ]


She obtained her  MD degree  from the  University of Innsbruck , Austria in 1968. She published her first  scientific paper  in 1971 titled "Segmental, Sequential and Quantitative Pulmonary Investigations Using the Scintillation Camera" in the  Journal of Nuclear Biology and Medicine . [ 7 ]  During her career, she published over 254 scientific manuscripts with more than 4713 citations, [ 8 ]  written many book chapters, [ 9 ] [ 10 ] [ 11 ] [ 12 ]  and organised symposiums. [ 13 ]  She is also mentioned in the book  History of Nuclear Medicine in Europe , which was published in 2003. [ 14 ]


A  cardiac stress test  is a cardiological examination that evaluates the cardiovascular system's response to external stress within a controlled clinical setting. This stress response can be induced through physical exercise (usually a treadmill) or intravenous pharmacological stimulation of heart rate. [ 1 ]


As the heart works progressively harder (stressed) it is monitored using an  electrocardiogram  (ECG) monitor. This measures the heart's electrical rhythms and broader  electrophysiology . Pulse rate, blood pressure and symptoms such as chest discomfort or fatigue are simultaneously monitored by attending clinical staff. Clinical staff will question the patient throughout the procedure asking questions that relate to pain and perceived discomfort. Abnormalities in blood pressure, heart rate, ECG or worsening physical symptoms could be indicative of  coronary artery disease . [ 2 ]


Stress testing does not accurately diagnose all cases of coronary artery disease, and can often indicate that it exists in people who do not have the condition. The test can also detect heart abnormalities such as  arrhythmias , and conditions affecting  electrical conduction within the heart such as various types of fascicular blocks. [ 3 ]


A "normal" stress test does not offer any substantial reassurance that a future unstable coronary plaque will not rupture and block an artery, inducing a  heart attack . As with all medical diagnostic procedures, data is only from a moment in time. A primary reason stress testing is not perceived as a robust method of CAD detection — is that stress testing generally only detects arteries that are severely narrowed (~70% or more). [ 4 ] [ 5 ] [ 6 ]


A stress test may be accompanied by  echocardiography . [ 7 ]  The echocardiography is performed both before and after the exercise so that structural differences can be compared.


A resting echocardiogram is obtained prior to stress. The ultrasound images obtained are similar to the ones obtained during a full surface echocardiogram, commonly referred to as  transthoracic echocardiogram . The patient is subjected to stress in the form of exercise or chemically (often  dobutamine ). After the target heart rate is achieved, 'stress' echocardiogram images are obtained. The two echocardiogram images are then compared to assess for any abnormalities in wall motion of the heart. This is used to detect obstructive coronary artery disease. [ 8 ]


While also measuring breathing gases (e.g.,  oxygen saturation , maximal oxygen consumption), the test is often referred to as a cardiopulmonary exercise test. Common indications for a cardiopulmonary exercise test include evaluation of shortness of breath, workup before  heart transplantation , and prognosis and risk assessment of heart failure patients.


The test is also common in sport science for measuring athletes' maximal oxygen consumption,  V̇O 2  max . [ 9 ]  In 2016, the  American Heart Association  published an official scientific statement advocating that  cardiorespiratory fitness , quantifiable as  V̇O 2  max  and measured during a cardiopulmonary exercise test, be categorized as a clinical vital sign and should be routinely assessed as part of clinical practice. [ 10 ]


The CPX test can be done on a  treadmill  or  cycle ergometer . In untrained subjects, V̇O 2  max is 10% to 20% lower when using a cycle ergometer compared with a treadmill. [ 11 ]


A nuclear stress test uses a  gamma camera  to image radioisotopes injected into the bloodstream. The best known example  is  myocardial perfusion imaging . Typically, a  radiotracer  ( Tc-99 sestamibi ,  Myoview  or  thallous chloride 201 ) may be injected during the test. After a suitable waiting period to ensure proper distribution of the radiotracer, scans are acquired with a gamma camera to capture images of the blood flow. Scans acquired before and after exercise are examined to assess the state of the coronary arteries of the patient. By showing the relative amounts of radioisotope within the heart muscle, the nuclear stress tests more accurately identify regional areas of reduced blood flow. [ 12 ]


Stress and potential cardiac damage from exercise during the test is a problem in patients with ECG abnormalities at rest or in patients with severe motor disability. Pharmacological stimulation from vasodilators such as dipyridamole or adenosine, or positive chronotropic agents such as dobutamine can be used. Testing personnel can include a cardiac radiologist, a nuclear medicine physician, a nuclear medicine technologist, a cardiology technologist, a cardiologist, and/or a nurse. The typical dose of radiation received during this procedure can range from 9.4 to 40.7  millisieverts . [ 13 ]


The American Heart Association recommends ECG treadmill testing as the first choice for patients with medium risk of coronary heart disease according to risk factors of smoking, family history of coronary artery stenosis, hypertension, diabetes and high cholesterol. In 2013, in its "Exercise Standards for Testing and Training", the AHA indicated that  high frequency QRS  analysis during ECG treadmill test have useful test performance for detection of coronary heart disease. [ 14 ]


The common approach for stress testing recommended by the American College of Cardiology [ 17 ] [ 18 ]  and the American Heart Association [ 19 ]  involves several methods to assess cardiac health. These methods provide information for diagnosing and managing heart-related conditions. Two primary stress tests utilized are a treadmill test using  ECG / electrophysiology  metrics and nuclear testing, each have unique sensitivity and specificity values.


The treadmill test, employing the modified  Bruce protocol , [ 20 ]  demonstrates a sensitivity range of around 73-90% and a specificity range of around 50-74%. Sensitivity refers to the percentage of individuals with the condition correctly identified by the test, while specificity denotes the percentage of individuals without the condition correctly identified as not having it. [ 21 ]  The nuclear stress test exhibits a sensitivity of 81% and a specificity ranging from 85 to 95%. [ 22 ]