The UK General Medical Council's ethical guidelines indicate that the Council does not require consent prior to making recordings of X-ray images. [ 45 ]  However, the same guidance indicates that the images and recordings need to be anonimized, and acknowledges that in deciding whether a recording is anonymised, one should bear in mind that apparently insignificant details may still be capable of identifying a patient. As such, one should be particularly careful about the anonymity of a recordings of an X-ray image before using or publishing them without consent in journals and other learning materials, whether they are printed or in an electronic format. [ 46 ]


Organizations in the medical imaging industry include manufacturers of imaging equipment, freestanding radiology facilities, and hospitals.


The global market for manufactured devices was estimated at $5 billion in 2018. [ 47 ] [ 48 ]  Notable manufacturers as of 2012 included  Fujifilm , GE HealthCare ,  Siemens Healthineers ,  Philips ,  Shimadzu ,  Toshiba ,  Carestream Health ,  Hitachi ,  Hologic , and  Esaote . [ 49 ]  In 2016, the manufacturing industry was characterized as oligopolistic and mature; new entrants included in  Samsung  and  Neusoft Medical . [ 50 ]


In the United States, as estimate as of 2015 places the US market for imaging scans at about $100b, with 60% occurring in hospitals and 40% occurring in freestanding clinics, such as the  RadNet  chain. [ 51 ]


As per chapter 300 of the  Compendium of U.S. Copyright Office Practices , "the Office will not register works produced by a machine or mere mechanical process that operates randomly or automatically without any creative input or intervention from a human author" including "Medical imaging produced by X-rays, ultrasounds, magnetic resonance imaging, or other diagnostic equipment." [ 52 ]  This position differs from the broad copyright protections afforded to photographs. While the Copyright Compendium is an agency statutory interpretation and not legally binding, courts are likely to give deference to it if they find it reasonable. [ 53 ]  Yet, there is no U.S. federal case law directly addressing the issue of the copyrightability of X-ray images.


An extensive definition of the term  derivative work  is given by the United States Copyright Act in  17 U.S.C.   § 101 :


A "derivative work" is a work based upon one or more preexisting works, such as a translation... [ note 1 ]  art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications which, as a whole, represent an original work of authorship, is a "derivative work".


17 U.S.C.   § 103(b)  provides:


The copyright in a compilation or derivative work extends only to the material contributed by the author of such work, as distinguished from the preexisting material employed in the work, and does not imply any exclusive right in the preexisting material. The copyright in such work is independent of, and does not affect or enlarge the scope, duration, ownership, or subsistence of, any copyright protection in the preexisting material.


In Germany,  X-ray images  as well as  MRI ,  medical ultrasound ,  PET  and  scintigraphy  images are protected by (copyright-like)  related rights or neighbouring rights . [ 54 ]  This protection does not require creativity (as would be necessary for  regular  copyright protection) and lasts only for 50 years after image creation, if not published within 50 years, or for 50 years after the first legitimate publication. [ 55 ]  The letter of the law grants this right to the "Lichtbildner", [ 56 ]  i.e. the person who created the image. The literature seems to uniformly consider the medical doctor, dentist or veterinary physician as the rights holder, which may result from the circumstance that in Germany many X-rays are performed in ambulatory settings.


Medical images created in the United Kingdom will normally be protected by copyright due to "the high level of skill, labour and judgement required to produce a good quality X-ray, particularly to show contrast between bones and various soft tissues". [ 57 ]  The Society of Radiographers believe this copyright is owned by employer (unless the radiographer is self-employed—though even then their contract might require them to transfer ownership to the hospital). This copyright owner can grant certain permissions to whoever they wish, without giving up their ownership of the copyright. So the hospital and its employees will be given permission to use such radiographic images for the various purposes that they require for medical care. Physicians employed at the hospital will, in their contracts, be given the right to publish patient information in journal papers or books they write (providing they are made anonymous). Patients may also be granted permission to "do what they like with" their own images.


The  Cyber Law in Sweden  states: "Pictures can be protected as photographic works or as photographic pictures. The former requires a higher level of originality; the latter  protects all types of photographs, also the ones taken  by amateurs, or  within medicine  or science. The protection requires some sort of photographic technique being used, which includes digital cameras as well as holograms created by laser technique. The difference between the two types of work is the term of protection, which amounts to seventy years after the death of the author of a photographic work as opposed to fifty years, from the year in which the photographic picture was taken." [ 58 ]


Medical imaging may possibly be included in the scope of "photography", similarly to a U.S. statement that "MRI images, CT scans, and the like are analogous to photography." [ 59 ]


Nuclear Medicine and Biology  is a  peer-reviewed   medical journal  published by  Elsevier  that covers research on all aspects of  nuclear medicine , including  radiopharmacology ,  radiopharmacy  and clinical studies of targeted  radiotracers . It is the official journal of the  Society of Radiopharmaceutical Sciences . According to the  Journal Citation Reports , the journal has a 2011  impact factor  of 3.023. [ 1 ]


The journal is abstracted and indexed in:


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Nuclear Medicine Communications  ( abbreviated  Nucl. Med. Commun.)  is an official journal of the  British Nuclear Medicine Society  based in  Nottingham ,  United Kingdom . [ 1 ] [ 2 ]  The journal publishes studies based on  radionuclide   imaging  for basic, preclinical, and clinical research. Areas of interest include  radiochemistry ,  radiopharmacy ,  radiobiology ,  radiopharmacology ,  medical physics ,  computing  and  engineering , and technical and  nursing  professions involved in delivering nuclear medicine services.


Nucl. Med. Commun.  has an  impact factor  of 1.465 and currently ranks 96 among the 129 journals publishing  radiology ,  nuclear medicine , and  medical imaging  scientific studies  [ citation needed ] . It has an International Standard Serial Number ( ISSN ) 0143-3636, and an online ISSN 1473-5628. The journal publishes 12 issues each year. [ 3 ]  The journal allows scientific manuscripts to be published at no charge to the authors, however, the manuscript are not open-access. Authors can pay a fee for the accepted articles to be published as open-access material.


The  Nucl. Med. Commun.  journal published its first journal in March 1980. [ 4 ]  The website is operated from Riverwoods, IL,  United States . [ 5 ]  The current  editor-in-chief  is Professor  Jamshed Bmanji  based at the  University College Hospital , London. [ 6 ]


The history of pursuing  nuclear medicine  goes back to 1956, when the  Pakistan Atomic Energy Commission  (PAEC) was established under the executive order of the  Prime Minister of Pakistan ,  Huseyn Shaheed Suhrawardy . The PAEC, the scientific body that  is responsible for establishing the nuclear power plants in the country, has sat up a Nuclear Medicines laboratory. The PAEC also sat up the nuclear medicines lab and facilities throughout the country to fight against Cancer. Pakistan Atomic Energy Commission had provided the facilities of diagnosis and treatment of cancer and allied diseases to the patients from all over the country employing Nuclear Techniques at its Medical Centers. PAEC also sponsored the research program in the field of radiochemistry and biochemistry. PAEC also sat up the research institutes all over the country, some of them are below:


Nuclear medicine physicians , also called  nuclear   radiologists  or simply nucleologists, [ 1 ] [ 2 ]  are  medical  specialists that use tracers, usually  radiopharmaceuticals , for diagnosis and therapy.   Nuclear medicine  procedures are the major clinical applications of  molecular imaging  and molecular therapy. [ 3 ] [ 4 ] [ 5 ]  In the United States, nuclear medicine physicians are certified by the  American Board of Nuclear Medicine  and the  American Osteopathic Board of Nuclear Medicine .


In 1896,  Henri Becquerel  discovered  radioactivity . [ 6 ]   It was only a little over a quarter of a century (1925) until the first radioactive tracer study in animals was performed by  George de Hevesy , and the next year (1926) the first diagnostic tracer study in  humans  was performed by Herman Blumgart and Otto Yens. [ 7 ]


Some of the earliest applications of radioisotopes were therapy of hematologic malignancies and therapy of both benign and malignant thyroid disease.  In the 1950s  radioimmunoassay  was developed by  Solomon Berson  and  Rosalyn Yalow .  Dr. Yalow was co-winner of the 1977 Nobel Prize in Physiology or Medicine (Dr. Berson had already died so was not eligible).  Radioimmunoassay was used extensively in clinical medicine but more recently has been largely replaced by non-radioactive methods.


In 1950, human imaging of both  gamma  and  positron  emitting  radioisotopes  was performed.  Benedict Cassen 's work with a directional probe lead to the development of the first imaging with a  rectilinear scanner . [ 8 ]   Gordon Brownell developed the first  positron scanner . [ 9 ]   In the same decade (1954) the  Society of Nuclear Medicine  (SNM) was organized in Spokane, Washington (US), [ 10 ]  and (1958)  Hal Anger  developed the  gamma scintillation camera , [ 11 ]  which could image a whole region at the same time.


Initial introduction of radioisotopes into medicine required individuals to acquire of a considerable background information which was foreign to their medical training.  Often a particular application drove the introduction of radioisotopes into a health care facility.  As other applications developed the physician or group that had developed knowledge of and experience with radioisotopes usually provided the new service.  Consequently, the radioisotope service found homes in several established specialties – commonly in radiology due to an interest in imaging, in pathology ( clinical pathology ) due to an interest in radioimmunoassay, and in endocrinology due to the early application of  131 I to thyroid disease. [ 12 ]


Nuclear medicine became widespread and there was a need to develop a new specialty.  In the United States, the  American Board of Nuclear Medicine  was formed in 1972. [ 13 ]   At that time, the specialty include all of the uses of radioisotopes in medicine – radioimmunoassay, diagnostic imaging, and therapy.  As use of and experience with radioisotopes became more widespread in medicine, radioimmunoassay generally transferred from nuclear medicine to clinical pathology.  Today, nuclear medicine is based on the use of the  tracer principle  applied to diagnostic imaging and therapy.


In the United States, the  Accreditation Council for Graduate Medical Education  (ACGME) and the  American Osteopathic Association Bureau of Osteopathic Specialists  (AOABOS) accredit nuclear medicine residency programs, and the  American Board of Nuclear Medicine  (ABNM) and the  American Osteopathic Board of Nuclear Medicine  (AOBNM) certify nuclear medicine physicians. After completing  medical school , a post-graduate  clinical year  is followed by three years of nuclear medicine  residency .  A common alternate path for physicians who have completed a radiology residency is a one-year residency in nuclear medicine, leading to sub-specialty certification by the American Board of Radiology.  A less common path for physicians who have completed another residency is a two-year residency in nuclear medicine. [ 15 ]


Nuclear medicine procedures are performed by  Nuclear Medicine Radiographers , [ 16 ]  who require extensive training both in underlying principles (physics, instrumentation) but also in the clinical applications.   Nursing  support, especially in the hospital setting, is valuable, but may be shared with other services.  Nuclear medicine is a technology embedded specialty depending upon a large number of non-physician professional, including  medical physicists ,  health physicists ,  radiobiologists ,  radiochemists , and  radiopharmacists .


Residency trained nuclear medicine physicians have the most extensive training and highest level of certification, including all aspects of diagnosis and radionuclide therapy.  However, current U.S. regulations do not prohibit other physicians from interpreting nuclear medicine studies and perform radionuclide therapy.   Radiologists  who are not sub-specialty trained in the specialty, nonetheless often limit their practice to practicing nuclear medicine.  Some  cardiologists , especially non-invasive cardiologists, will interpret diagnostic cardiology studies including nuclear medicine studies.   Radiation oncologists  perform all forms of radiation therapy, sometimes including radionuclide therapy.  Some  endocrinologists  treat hyperthyroidism and thyroid cancer with  131 I.  The mix of physicians rendering nuclear medicine services varies both between different countries and within a single country.


Nuclear pharmacy , also known as  radiopharmacy , involves preparation of  radioactive  materials for patient administration that will be used to diagnose and treat specific diseases in  nuclear medicine . It generally involves the practice of combining a  radionuclide tracer  with a pharmaceutical component that determines the biological localization in the patient. [ 1 ] [ 2 ]   Radiopharmaceuticals  are generally not designed to have a therapeutic effect themselves, but there is a risk to staff from  radiation exposure  and to patients from possible contamination in production. [ 3 ]  Due to these intersecting risks, nuclear pharmacy is a heavily regulated field. [ 4 ] [ 5 ]  The majority of diagnostic nuclear medicine investigations are performed using  technetium-99m . [ 6 ]


The concept of nuclear pharmacy was first described in 1960 by Captain William H. Briner while at the  National Institutes of Health  (NIH) in  Bethesda, Maryland . Along with Mr. Briner, John E. Christian, who was a professor in the School of Pharmacy at  Purdue University , had written articles and contributed in other ways to set the stage of nuclear pharmacy. William Briner started the NIH Radiopharmacy in 1958. [ 7 ] [ 8 ]  John Christian and William Briner were both active on key national committees responsible for the development, regulation and utilization of radiopharmaceuticals. A  technetium-99m generator  was commercially available, followed by the availability of a number of Tc-99m based radiopharmaceuticals.


In the  United States  nuclear pharmacy was the first  pharmacy  specialty established in 1978 by the  Board of Pharmacy Specialties . [ 9 ]


Various models of production exist internationally. Institutional nuclear pharmacy is typically operated through large  medical centers  or  hospitals  while commercial centralized nuclear pharmacies provide their services to subscriber hospitals. They prepare and dispense radiopharmaceuticals as unit  doses  that are then delivered to the subscriber hospital by nuclear pharmacy personnel.


A few basic steps are typically involved in technetium based preparations. First the active technetium is obtained from a  radionuclide generator  on site, which is then added to a non-radioactive kit containing the pharmaceutical component. Further steps may be required depending on the materials in question to ensure full  binding  of the two components. These procedures are usually carried out in a  clean room  or isolator to provide radiation shielding and sterile conditions. [ 10 ] [ 11 ]


For  Positron Emission Tomography  (PET),  Fludeoxyglucose ( 18 F)  is the most common radiopharmaceutical, with the radioactive component usually obtained from a cyclotron. [ 11 ]  The short half life of  Fluorine-18  and many other PET  isotopes  necessitates rapid production. PET radiopharmaceuticals are now often produced by automated computer controlled systems to reduce complexity and radiation doses to staff. [ 12 ]


Radiopharmacy is a heavily regulated field, as it combines several practices and fields which may come under the purview of multiple  regulators  and legislation. These include occupational exposure of staff to  ionising radiation , preparation of medicines, patient exposure to ionising radiation, transport of radioactive materials, and environmental exposure to ionising radiation. [ 13 ]  Different regulations may cover the various stages involved in radiopharmacies, ranging from production of "cold" (non-radioactive) kits, to the marketing and distribution of final products. [ 14 ]


Staff working in nuclear pharmacies require extensive training on aspects of  good manufacturing practice ,  radiation safety  concerns and  aseptic dispensing . In the  United States  an authorised nuclear pharmacist must be a fully qualified pharmacist with evidence of additional training and qualification in nuclear pharmacy practice. [ 15 ]  Several  European Union   directives  cover radiopharmaceuticals as a special group of medicines, reflecting the wide range of types of producers and staff groups that may be involved. [ 16 ]  In the UK qualified pharmacists may be involved along with clinical scientists or technologists, with relevant training. [ 17 ]


The  oxygen enhancement ratio  (OER) or  oxygen enhancement effect  in  radiobiology  refers to the enhancement of therapeutic or detrimental effect of  ionizing radiation  due to the presence of  oxygen . This so-called  oxygen effect [ 1 ]  is most notable when cells are exposed to an ionizing radiation  dose .


The OER is traditionally defined as the ratio of radiation doses during lack of oxygen compared to no lack of oxygen for the same biological effect. This may give varying numerical values depending on the chosen biological effect.  Additionally, OER may be presented in terms of hyperoxic environments and/or with altered oxygen baseline, complicating the significance of this value.


The maximum OER depends mainly on the ionizing density or LET of the radiation. Radiation with higher  LET  and higher relative biological effectiveness (RBE) have a lower OER in mammalian cell tissues. [ 2 ]  The value of the maximum OER varies from about 1–4. The maximum OER ranges from about 2–4 for low-LET radiations such as X-rays, beta particles and gamma rays, whereas the OER is unity for high-LET radiations such as low energy alpha particles.


The effect is used in  medical physics  to increase the effect of  radiation therapy  in  oncology  treatments. Additional oxygen abundance creates additional  free radicals  and increases the damage to the target tissue.


In solid tumors the inner parts become less oxygenated than normal tissue and up to three times higher dose is needed to achieve the same  tumor control probability  as in tissue with normal oxygenation.


The best known explanation of the  oxygen effect  is the oxygen fixation hypothesis which postulates that oxygen permanently fixes radical-induced DNA damage so it becomes permanent. [ 3 ]  Recently, it has been posited that the oxygen effect involves radiation exposures of cells causing their mitochondria to produce greater amounts of reactive oxygen species. [ 4 ]


Eric J. Hall and Amato J. Giaccia: Radiobiology for the radiologist, Lippincott Williams & Wilkins, 6th Ed., 2006


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Pentetic acid  or  diethylenetriaminepentaacetic acid  ( DTPA ) is an  aminopolycarboxylic acid  consisting of a  diethylenetriamine  backbone with five carboxymethyl groups. The molecule can be viewed as an expanded version of  EDTA  and is used similarly.  It is a white solid with limited solubility in water.


The  conjugate base  of DTPA has a high affinity for metal  cations . Thus, the penta-anion DTPA 5−  is potentially an  octadentate ligand  assuming that each nitrogen centre and each –COO −  group counts as a centre for coordination. The  formation constants  for its complexes are about 100 greater than those for EDTA. [ 3 ]   As a  chelating agent , DTPA wraps around a metal ion by forming up to eight bonds. Its complexes can also have an extra water molecule that coordinates the metal ion. [ 4 ]  Transition metals, however, usually form less than eight  coordination bonds . So, after forming a complex with a metal, DTPA still has the ability to bind to other reagents, as is shown by its derivative  pendetide . For example, in its complex with copper(II), DTPA binds in a hexadentate manner utilizing the three amine centres and three of the five carboxylates. [ 5 ]


Like the more common  EDTA , DTPA is predominantly used as  chelating  agent for complexing and   sequestering  metal ions.


DTPA has been considered for treatment of radioactive materials such as  plutonium ,  americium , and other  actinides . [ 4 ]  In theory, these complexes are more apt to be eliminated in  urine . It is normally administered as the  calcium  or  zinc  salt (Ca or Zn-DTPA), since these ions are readily displaced by more highly charged cations and mainly to avoid to depleting them in the organism. DTPA forms complexes with  thorium (IV),  uranium (IV),  neptunium (IV), and  cerium (III/IV). [ 6 ]


In August, 2004 the  US Food and Drug Administration  (USFDA) determined zinc-DTPA and calcium-DTPA to be safe and effective for treatment of those who have breathed in or otherwise been contaminated internally by plutonium, americium, or curium.  The recommended treatment is for an initial dose of calcium-DTPA, as this salt of DTPA has been shown to be more effective in the first 24 hours after internal contamination by plutonium, americium, or curium.  After that time has elapsed both calcium-DTPA and zinc-DTPA are similarly effective in reducing internal contamination with  plutonium ,  americium  or  curium , and zinc-DTPA is less likely to deplete the body's normal levels of zinc and other metals essential to health. Each drug can be administered by  nebulizer  for those who have breathed in contamination, and by  intravenous injection  for those contaminated by other routes. [ 7 ]


DTPA is also used as  MRI   contrasting agent . DTPA improves the resolution of magnetic resonance imaging (MRI) by forming a soluble complex with a  gadolinium  (Gd 3+ ) ion, which alters the  magnetic resonance  behavior of the  protons  of the nearby  water molecules  and increases the images contrast. [ 8 ]


DTPA under the form of iron(II) chelate (Fe-DTPA, 10 – 11 wt. %) is also used as  aquarium plants   fertilizer . The more soluble form of iron, Fe(II), is a  micronutrient  needed by  aquatic plants . By binding to Fe 2+  ions DTPA prevents their  precipitation  as Fe(OH) 3 , or Fe 2 O 3  · n H 2 O poorly soluble oxy-hydroxides after their  oxidation  by dissolved  oxygen . It increases the  solubility  of Fe 2+  and Fe 3+  ions in water, and therefore the  bioavailability  of iron for aquatic plants. It contributes so to maintain iron under a dissolved form (probably a mix of Fe(II) and Fe(III) DTPA complexes) in the  water column . It is unclear to what extent does DTPA really contribute to protect dissolved Fe 2+  against air oxidation and if the Fe(III)-DTPA complex cannot also be directly assimilated by aquatic plants simply because of its enhanced solubility. Under natural conditions,  i.e. , in the absence of complexing DTPA, Fe 2+  is more easily assimilated by most organisms, because of its 100-fold higher solubility than that of Fe 3+ .


In  pulp and paper mills  DTPA is also used to remove dissolved ferrous and ferric ions (and other redox-active metal ions, such as  Mn  or  Cu ) that otherwise would accelerate the  catalytic  decomposition of  hydrogen peroxide  (H 2 O 2  reduction by Fe 2+  ions according to the  Fenton reaction  mechanism). [ 9 ]  This helps preserving the  oxidation  capacity of the hydrogen peroxide stock which is used as  oxidizing agent  to  bleach pulp  in the chlorine-free process of paper making. [ 10 ]  Several thousands tons of DTPA are produced annually for this purpose in order to limit the non-negligible losses of H 2 O 2  by this mechanism. [ 3 ]


DTPA chelating properties are also useful in deactivating  calcium  and  magnesium  ions in  hair products . DTPA is used in over 150 cosmetic products. [ 11 ]


DTPA is more effective than  EDTA  to deactivate redox-active metal ions such as Fe(II)/(III), Mn(II)/(IV) and Cu(I)/(II) perpetuating  oxidative damages  induced in  cells  by  superoxide  and  hydrogen peroxide . [ 12 ] [ 9 ]  DTPA is also used in  bioassays  involving redox-active metal ions.


An unexpected negative environmental impact of chelating agents, as DTPA, is their toxicity for the  activated sludges  in the treatment of  Kraft pulping  effluents. [ 13 ]  Most of the DTPA worldwide production (several thousands of tons) [ 3 ]  is intended to avoid  hydrogen peroxide  decomposition by redox-active  iron  and  manganese  ions in the chlorine-free Kraft pulping processes (total chlorine free (TCF) and environmental chlorine free (ECF) processes). DTPA decreases the  biological oxygen demand  (BOD) of activated sludges and therefore their microbial activity.


Compounds that are structurally related to DTPA are used in medicine, taking advantage of the high affinity of the triaminopentacarboxylate scaffold for metal ions.


Positron emission tomography–magnetic resonance imaging  ( PET–MRI ) is a hybrid  imaging technology  that incorporates  magnetic resonance imaging  (MRI)  soft tissue  morphological imaging and  positron emission tomography  (PET)  functional imaging . [ 1 ]


The combination of PET and MRI was mentioned in a 1991 Phd thesis by R. Raylman. [ 2 ]  Simultaneous PET/MR detection was first demonstrated in 1997, however it took another 13 years, and new detector technologies, for clinical systems to become commercially available. [ 3 ]


Presently, the main clinical fields of PET-MRI are  oncology , [ 4 ] [ 5 ] [ 6 ]   cardiology , [ 7 ]   neurology , [ 8 ] [ 9 ] [ 10 ]  and  neuroscience . [ 11 ]  Research studies are actively conducted at the moment to understand benefits of the new PET-MRI diagnostic method. The technology combines the exquisite structural and functional characterization of tissue provided by MRI with the extreme sensitivity of PET imaging of metabolism and tracking of uniquely labeled cell types or cell receptors.


Several companies offer clinical and pre-clinical combined PET-MR system; clinical systems are available from  United Imaging ,  Philips ,  Siemens , and  GE . There are varying approaches to the combination of the two technologies. Some designs are essentially separate machines, in the same room, with a bed that can transfer a patient from one scanner to another. [ 12 ] [ 13 ]  Fully integrated systems are the most technically challenging to achieve, but provide greatest benefits in terms of the ability to make simultaneous, exactly aligned, acquisitions. [ 14 ] [ 15 ]


The first two clinical  whole body  PET-MRI systems were installed by Philips at Mount Sinai Medical Centre in the United States and at Geneva University Hospital in  Switzerland , in 2010. The system featured a PET and MRI scanner separated by a revolving bed. [ 16 ] [ 17 ]


Siemens was the first company to offer simultaneous PET/MR acquisitions, with the first systems installed in 2010 based on  avalanche photodiode  detectors. [ 18 ] [ 3 ]


Currently Siemens and GE are the only companies to offer a fully integrated whole body and simultaneous acquisition PET-MRI system. The Siemens system (Biograph mMR) received a  CE mark [ 19 ]  and  FDA  approval [ 20 ]  for customer purchase in 2011.


The GE system (SIGNA PET/MR) received its 510K & CE mark in 2014. [ citation needed ]


Currently, the combination of positron emission tomography (PET) and magnetic resonance imaging (MRI) as a hybrid imaging modality is receiving great attention not only in its emerging clinical applications but also in the preclinical field. Several designs based on several different types of PET detector technology have been developed in recent years, some of which have been used for first preclinical studies. [ 21 ] [ 22 ] [ 23 ]


Several companies offer MR-compatible preclinical PET scanner inserts for use in the bore of an existing MRI, enabling simultaneous PET/MR image acquisition. [ 24 ] [ 25 ] [ 26 ] [ 27 ]


The combination of PET with X-ray  computed tomography  (CT) is the more established PET imaging technology. With both PET-CT and PET-MR the intended advantage is to combine  functional imaging  provided by PET, with structural ( anatomical ) information from CT or MRI. Although images from different modalities collected at different scanning sessions can be overlaid by  image registration , a simultaneous acquisition offers better alignment of images and direct correlation. Combining imaging modalities in one single scanning session also has the advantage of reducing the number of appointments and therefore improving patient comfort. [ 28 ] [ 29 ]


The same clinical decisions that would influence the choice between stand-alone CT or MR imaging would also determine areas where PET-CT or PET-MR would be preferred. [ 14 ]  For example, one advantage of MRI compared to CT is its superior soft tissue contrast, while CT has the advantage of being much faster than MRI.


One clear advantage of PET-MR compared to PET-CT is the lower total  ionising radiation dose  obtained. For body PET-CT applications, the CT part of the examination constitutes approximately 60-80% of the radiation dose, with the remaining radiation dose originating from the PET  radiopharmaceutical . [ 30 ]  In contrast, no ionising radiation dose is obtained from MRI. PET-MR is therefore appealing in children, in particularly for serial follow-up examinations as used in oncology or chronic inflammatory conditions. [ 31 ]


PET-MRI systems don't offer a direct way to obtain  attenuation  maps, unlike stand-alone PET or PET-CT systems. [ 32 ] [ 33 ]


Stand alone PET systems' attenuation correction (AC) is based on a transmission scan (mu - map) acquired using a  68 Ge ( Germanium-68 ) rotating rod source, which directly measures photon attenuation at 511 keV. [ 32 ] [ 34 ]  PET-CT systems use a low-dose CT scan for AC. Since X-rays have a range of energies lower than 511 keV, AC values are closely approximated from  Hounsfield units . [ 35 ]


There is no correlation between MR image intensity and electron intensity, therefore conversion of MR images into an attenuation map is difficult. [ 36 ] [ 32 ] [ 34 ]  This is an active area of research and a range of approaches have been developed. One method uses a Dixon  MRI sequence , and  segments  the resultant image into fat and water, with pre-set attenuation factors. Disadvantages of this method include a lack of bone attenuation, and loss of the true continuous range of attenuation factors. Comparisons with PET-CT attenuation maps for oncology purposes however have shown that this is a usable technique. [ 34 ]  The Dixon method can be combined with ultrashort echo time (UTE) sequences to better identify bone and increase the possible classes of tissue for segmentation. More sequences increase MRI acquisition time, and therefore the risk of motion artefacts. [ 37 ]


In areas of the body with predictable structures (e.g. the head), segmentation (where tissue is categorised using the MRI image data), or "atlas" methods can be used. In atlas methods a standard MR image, with associated CT attenuation data, can be warped to fit the actual patient anatomy. Disadvantages of this method include difficulty with unusual anatomy, a need for a suitable library of images, and the need to account for MR coil attenuation. [ 34 ]  Synthetic, or Substitute CT (sCT) methods to generate CT like data from MRI are also of interest for  radiotherapy planning , and have been primarily investigated for sites in the head. While some of these use an atlas technique, many take a  voxel  approach where actual voxel intensities (contrast data) are used in combination with machine learning (trained on MR/CT data) to assign electron density values. [ 34 ] [ 38 ] [ 39 ]


In many of the above methods,  MRI artifacts  (e.g. from physiological motion) can affect attenuation correction accuracy. [ 34 ] [ 40 ]


PET radiotracer   is a type of  radioligand  that is used for the  diagnostic purposes  via  positron emission tomography  imaging technique. [ 1 ] [ 2 ]


PET is a  functional imaging  technique that produces a three-dimensional image of functional processes in the body. The system detects pairs of  gamma rays  emitted indirectly by a  positron -emitting  radionuclide  ( tracer ), which is introduced into the body on a biologically active molecule. [ 3 ]


In  in vivo  systems it is often used to quantify the binding of a test molecule to the binding site of radioligand. The higher the affinity of the molecule the more radioligand is displaced from the binding site and the increasing radioactive decay can be measured by  scintillography . This assay is commonly used to calculate  binding constant  of molecules to receptors. Due to the probable injuries of PET-radiotracers, they could not be administered in the normal doses of the medications. Therefore, the binding affinity (P KD ) of the PET-tracers must be high. In addition, since via the PET imaging technique is desired to investigate a function accurately, the selectivity of bindings to the specific targets is very important. [ 1 ]


PET response criteria in solid tumors  ( PERCIST ) is a set of rules that define when tumors in cancer patients improve ("respond"), stay the same ("stabilize"), or worsen ("progress") during treatment, using  positron emission tomography  (PET). The criteria were published in May 2009 in the  Journal of Nuclear Medicine  (JNM). [ 1 ]  A  pooled analysis  from 2016 concluded that its application may give rather different results from  RECIST , and might be a more suitable tool for understanding tumor response to treatment. [ 2 ]


Complete metabolic response (CMR)


Partial metabolic response (PMR)


Stable metabolic disease (SMD)


Progressive metabolic disease (PMD)


Pretargeting  (imaging) is a tool for  nuclear medicine  and  radiotherapy .  Imaging  studies require a high contrast of target to background. This can be provided by using a  biomarker  which has a high affinity and specificity for its target (e.g. an  antibody ).


Owing to their high affinity and specificity, antibodies have been considered as suitable vehicles for imaging and therapeutics, since the beginning of the 20th Century. [ 1 ] [ 2 ] [ 3 ]


The first radiolabelled antibodies were used in the early 1950s and got used for cancer therapy, [ 4 ] [ 5 ]  but it took roughly two more decades before it was demonstrated that they target human tumour associated antigens in cancer patients. [ 6 ]  Due to the  hybridoma technology  in 1975, monoclonal ( murine ) antibodies could easily be produced in practical amounts, [ 7 ]  consequently the number of studies increased drastically. However, these types of antibodies turned out to be quite troublesome, due to the triggering of the human anti-murine  antibody response . [ 8 ]  Consequently  chimeric ,  humanised  and  human monoclonal antibodies  have been created, produced and get used nowadays. [ 9 ]


Owing to the high  molecular weight  of antibodies and the  Fc domain  of the antibody, [ 10 ]  a slow  clearance  from the  blood  and non-target tissue occurs, which results in low tumour-to-blood and tumour-to-muscle ratios. [ 11 ] [ 12 ]  Because of this, antibodies which are going to be used for imaging purposes need to be labelled with  radionuclides  that have a long  half-life , [ 13 ]  which increases the  radiation dose  to the patient. This consequently encouraged the development of lower  molecular weight  antibodies and resulted in the development of minibodies, diabodies,  single chain variable fragments  (scFv) and single domain fragments (Fv). [ 14 ]


To bypass the problem associated with the prolonged circulation time of radiolabelled antibodies, in the mid-1980s a strategy called pretargeted  radioimmunotherapy  was developed. [ 15 ] [ 16 ]  In short, this approach contained two important steps: 1. administration of a  macromolecular  targeting vector (usually antibody-based), and 2. a small radiolabelled molecule, which interacts with the targeting vector. Most importantly the small radiolabelled molecule gets injected after a predetermined lag period after which the macromolecule has had enough time to bind to its target and the residual unbound macromolecule to be cleared out of the system. [ 14 ]  To ensure sufficient interaction between the two components, suitable modifications with complementary species are required (like  bioorthogonal  modifications). [ 17 ]


Pretargeting strategies can lead to an improved imaging contrast, as it combines the high target specificity and affinity of an antibody with the fast pharmacokinetic properties of a small molecule. The concept of pretargeting, although existing for several decades already, was limited to a few distinct classes. Developing chemical reactions that proceed quickly within living systems, without interacting with the large variety of existing functional groups, used to be an inherent difficulty. However, there have been several advancements in this area over the past few years. [ 14 ]


The beginning of the pretargeting concept was based on  bispecific antibodies  which were able to bind a specific target  antigen  and a radiolabelled  hapten . [ 18 ] [ 19 ] [ 20 ] [ 21 ] [ 22 ] [ 23 ]  Possible was this approach because of the development of monoclonal Antibodies which could be connected to  radiometal  chelates. [ 15 ]  Also connecting two haptens via a two amino acid linker resulted in an enhancement effect of the affinity, which improved the uptake and retention of the radiolabelled compound without affecting the rapid clearance. [ 24 ]


Limiting factor of this approach were the slow  binding constant  which was rarely higher than 10 −10  M, amongst other reasons. [ 14 ]


After the discovery of the fast interaction between  Biotin  and  (Strept)Avidin , which show a high  binding affinity , this approach has been used in many different ways (e.g. for  protein purification  purposes like the  Step-tag ). [ 25 ] [ 26 ] [ 27 ] [ 28 ] [ 29 ] [ 30 ] [ 31 ]


The  radioactive iodine uptake test  is a type of scan used in the diagnosis of  thyroid  problems, particularly  hyperthyroidism . It is entirely different from  radioactive iodine therapy  (RAI therapy), which uses much higher doses to destroy cancerous cells. The RAIU test is also used as a follow-up to RAI therapy to verify that no thyroid cells survived, which could still be cancerous. [ 1 ]


The patient swallows  a radioisotope  of  iodine  in the form of capsule or fluid, and the absorption (uptake) of this  radiotracer  by the thyroid is studied after 4–6 hours and after 24 hours with the aid of a  scintillation counter . The dose is typically 0.15–0.37  MBq  (4–10  μCi ) of  131 I iodide , or 3.7–7.4 MBq (100–200 μCi) of  123 I iodide . [ 2 ]  The RAIU test is a reliable measurement when using a dedicated probe with a reproducibility of 1 percent and a 95%-least-significant-change of 3 percent. [ 3 ]


The normal uptake is between 15 and 25 percent, but this may be forced down if, in the meantime, the patient has eaten foods high in  iodine , such as dairy products and seafood. [ 4 ]  Low uptake suggests  thyroiditis , high uptake suggests  Graves' disease , [ 5 ]  and unevenness in uptake suggests the presence of a  nodule . [ citation needed ]


123 I has a shorter  half-life  than  131 I (a half day vs. 8.1 days), so use of  123 I exposes the body to less radiation, at the expense of less time to evaluate delayed scan images. [ 6 ]  Furthermore,  123 I emits  gamma radiation , while  131 I emits gamma and  beta radiation . [ 7 ]


The test is inappropriate for patients who are pregnant or breastfeeding. [ 5 ]


A  radioactive nanoparticle  is a  nanoparticle  that contains  radioactive materials .  Radioactive nanoparticles have applications in  medical diagnostics ,  medical imaging ,  toxicokinetics , and  environmental health , and are being investigated for applications in  nuclear   nanomedicine .  Radioactive nanoparticles present special challenges in  operational health physics  and  internal dosimetry  that are not present for other substances, although existing  radiation protection  measures and  hazard controls for nanoparticles  generally apply.


Engineered radioactive nanoparticles are used in  medical imaging  techniques such as  positron emission tomography  and  single-photon emission computed tomography , [ 2 ]  and an aerosol of carbon nanoparticles containing  technetium-99m  are used in a commercially available procedure for  ventilation/perfusion   scintigraphy  of the  lungs. [ 3 ] : 122–125    Engineered radioactive nanoparticles are also used as a  radiolabel  to detect the presence of the nanoparticles themselves in  environmental health  and  toxicokinetics  studies. [ 3 ] : 119–122


Engineered radioactive nanoparticles are being investigated for  therapeutic  use combining  nuclear medicine  with  nanomedicine , especially for cancer. [ 3 ] : 125–130    Neutron capture therapy  is one such potential application. [ 2 ] [ 4 ]   In addition, nanoparticles can help to sequester the toxic daughter nuclides of  alpha emitters  when used in radiotherapy. [ 1 ]


Nuclear imaging is non-invasive and has high sensitivity, and nanoparticles are useful as a platform for combining multiple copies of targeting vectors and effectors in order to selectively deliver radioisotopes to a specific region of interest. [ 5 ]   Other benefits of nanoparticles for diagnostic and therapeutic use include increased blood and tumor retention time, as well as the possibility of using their unique physical and chemical properties in treatment. [ citation needed ]   However, the nanoparticles must be engineered to avoid being recognized by the  mononuclear phagocyte system  and transported to the  liver  or  spleen , often through manipulating their surface functionalization. [ 4 ] [ 5 ]


Targeting techniques include functionalizing radioactive nanoparticles with  antibodies  to target them to a specific tissue, and using  magnetic nanoparticles  that are attracted to a magnet placed over the tumor site. [ 4 ]   Technetium-99m,  indium-111 , and  iodine-131  are common radioisotopes used for these purposes, [ 3 ] : 119–130  [ 4 ]  with many others used as well. [ 6 ] [ 7 ]   Radioactive nanoparticles can be produced by either synthesizing the nanoparticles directly from the radioactive materials, or by irradiating non-radioactive particles with  neutrons  or  accelerated ions , sometimes  in situ . [ 3 ] : 119  [ 8 ]


As with all nanoparticles, radioactive nanoparticles can also be naturally occurring or incidentally produced as a byproduct of industrial processes.  The main source of naturally occurring nanomaterials containing radionuclides is the decay of  radon  gas, whose immediate decay products are non-gaseous elements that precipitate into nanoscale particles along with atmospheric dust and vapors.  Minor natural sources include  primordial radionuclides  present in the nanoscale portion of  volcanic ash , and primordial and  cosmogenic nuclides  taken up by plants which are later burned.  Radioactive nanoparticles may be incidentally produced by procedures in the  nuclear industry  such as  nuclear reprocessing  and the cutting of contaminated objects. [ 3 ] : 16–20


Radioactive nanoparticles combine the  hazards of radioactive materials  with the  hazards of nanomaterials. [ 3 ] : 2–6    Inhalation exposure  is the most common route of exposure to airborne particles in the workplace.  Animal studies on some classes of nanoparticles indicate pulmonary effects including  inflammation ,  granulomas , and  pulmonary fibrosis , which were of similar or greater potency when compared with other known  fibrogenic  materials such as  silica ,  asbestos , and ultrafine  carbon black .  Some studies in cells or animals have shown  genotoxic  or  carcinogenic  effects, or systemic  cardiovascular  effects from pulmonary exposure. [ 9 ] [ 10 ]   The hazards of ionizing radiation depend on whether the exposure is  acute  or  chronic , and includes effects like  radiation-induced cancer  and  teratogenesis . [ 11 ] [ 12 ]   In some cases, the inherent physicochemical toxicity of the nanoparticle itself may lead to lower  exposure limits  than those associated with the radioactivity alone, which is not the case with most radioactive materials. [ 3 ] : 2–6


Radioactive nanoparticles present special challenges in  operational health physics  and  internal dosimetry  that are not present for other substances, as the nanoparticles'  toxicokinetics  depend on their physical and chemical properties including  size ,  shape , and  surface chemistry .  For example, inhaled nanoparticles will deposit in different locations in the lungs, and will be metabolized and transported through the body differently, than vapors or larger particles. [ 3 ] : 2–6    There may also be hazards from associated processes such as strong magnetic fields and  cryogens  used in imaging equipment, and handling of lab animals in experimental studies. [ 13 ]   Effective risk assessment and communication is important, as both nanotechnology and radiation have unique considerations with public perception. [ 14 ]


In general, most elements of a standard  radiation protection  program are applicable to radioactive nanomaterials, and many  hazard controls for nanomaterials  will be effective with the radioactive versions.  The  hierarchy of hazard controls  encompasses a succession of five categories of control methods to reduce the risk of illness or injury.  The two most effective are  elimination  and  substitution , for example reducing dust exposure by eliminating a  sonication  process or substituting a nanomaterial  slurry  or  suspension  in a liquid solvent instead of a dry powder.  Substitutions should consider both the radioactivity and physicochemical hazards of all the options, and also take into account that radioactive nanomaterials are easier to detect than non-radioactive substances. [ 3 ] : 2–6, 35–41


Engineering controls  should be the primary form of protection, including local exhaust systems such as  fume hoods ,  gloveboxes ,  biosafety cabinets , and  vented balance enclosures ;  radiation shielding ; and  access control  systems. [ 3 ] : 41–48    The need for  negative room pressure  to prevent contamination of outside areas can conflict with the customary use of  positive pressure  when pharmaceuticals are being handled, although this can be overcome through use of a cascade pressure system, or by handling nanomaterials in enclosures. [ 13 ]


Administrative controls  include procedures to limit radiation doses, and  contamination control  procedures including encouraging good work practices and monitoring for contamination.   Personal protective equipment  is the least effective and should be used in conjunction with other hazard controls.  In general, personal protective equipment intended for radioactive materials should be effective with radioactive nanomaterials, including impervious  laboratory coats ,  goggles ,  safety gloves , and in some cases  respirators , although the greater potential penetration through clothing and mobility in air of nanoparticles should be taken into account. [ 3 ] : 48–63


Radioimmunodetection  is an  imaging technique  using radiolabeled  antibodies . [ 1 ] [ 2 ]


This  immunology  article is a  stub . You can help Wikipedia by  expanding it .


A  radionuclide generator  is a device which provides a local supply of a short-lived  radioactive  substance from the decay of a longer-lived parent  radionuclide . They are commonly used in  nuclear medicine  to supply a  radiopharmacy . [ 1 ]  The generator provides a way to separate the desired product from the parent, typically in a process that can be repeated several times over the life of the parent. [ 2 ] [ 3 ]


Use of a generator avoids the challenge of distributing short-lived radionuclides from the original production site (typically a  nuclear reactor ) to individual users; the loss of  activity  due to decay in transit can result in too little being supplied or the need for much larger initial quantities to be sent out (incurring additional production and transport costs). [ 4 ]  An alternative to generators for on-site production of radionuclides is a  cyclotron , though it is uncommon that the same radionuclide can be provided by both methods. It is feasible to have cyclotrons at larger centres, but they are much more expensive and complex than generators. In some cases a cyclotron is used to produce the parent radionuclide for a generator. [ 5 ]


Long-lived radionuclides which are administered to a patient with a view to utilising useful properties of a daughter product have been termed  in-vivo  generators, though they are not routinely used clinically. [ 6 ]


Radionuclide therapy  ( RNT , also known as  unsealed source radiotherapy  or  molecular radiotherapy ) uses  radioactive  substances called  radiopharmaceuticals  to treat medical conditions, particularly  cancer . These are introduced into the body by various means ( injection  or  ingestion  are the two most commonplace) and localise to specific locations,  organs  or tissues depending on their properties and administration routes. This includes anything from a simple compound such as  sodium iodide  that locates to the  thyroid  via trapping the iodide ion, to complex biopharmaceuticals such as recombinant antibodies which are attached to radionuclides and seek out specific  antigens  on cell surfaces. [ 1 ] [ 2 ]


This is a type of targeted therapy which uses the physical, chemical and biological properties of the radiopharmaceutical to target areas of the body for radiation treatment. [ 3 ]  The related diagnostic modality of  nuclear medicine  employs the same principles but uses different types or quantities of radiopharmaceuticals in order to  image  or analyse functional systems within the patient.


RNT contrasts with sealed-source therapy ( brachytherapy ) where the radionuclide remains in a capsule or metal wire during treatment and needs to be physically placed precisely at the treatment position. [ 4 ]


When the radionuclides are  ligands  (such as with  Lutathera  and  Pluvicto ), the technique is also known as  radioligand therapy .
 [ 5 ]


Iodine-131  ( 131 I) is the most common RNT worldwide and uses the simple compound  sodium iodide  with a radioactive isotope of  iodine . The patient (human or animal) may ingest an oral solid or liquid amount or receive an intravenous injection of a solution of the compound. The iodide ion is selectively taken up by the  thyroid  gland. Both benign conditions like  thyrotoxicosis  and certain malignant conditions like  papillary thyroid cancer  can be treated with the radiation emitted by  radioiodine . [ 6 ]  Iodine-131 produces  beta  and  gamma  radiation. The beta radiation released damages both normal thyroid tissue and any thyroid cancer that behaves like normal thyroid in taking up iodine, so providing the therapeutic effect, whilst most of the gamma radiation escapes the patient's body. [ 7 ]


Most of the iodine not taken up by thyroid tissue is  excreted  through the  kidneys  into the  urine . After radioiodine treatment the urine will be radioactive or 'hot', and the patients themselves will also emit  gamma radiation . Depending on the amount of radioactivity administered, it can take several days for the radioactivity to reduce to the point where the patient does not pose a  radiation hazard  to bystanders. Patients are often treated as  inpatients  and there are international guidelines, as well as legislation in many countries, which govern the point at which they may return home. [ 8 ]


Radium-223  chloride,  strontium-89  chloride and  samarium-153   EDTMP  are used to treat  secondary cancer  in the bones. [ 9 ] [ 10 ]   Radium  and  strontium  mimic calcium in the body. [ 11 ]   Samarium  is bound to tetraphosphate  EDTMP , phosphates are taken up by  osteoblastic  (bone forming) repairs that occur adjacent to some metastatic lesions. [ 12 ]


Beta  emitting  phosphorus-32  ( 32 P), as sodium phosphate, is used to treat  overactive   bone marrow , in which it is otherwise naturally metabolised. [ 13 ] [ 14 ] [ 15 ]


An  yttrium-90  ( 90 Y)  colloidal  suspension is used for  radiosynovectomy  in the  knee  joint. [ 16 ]


90 Y in the form of a  resin  or glass spheres can be used to treat primary and metastatic liver cancers. [ 17 ]


131 I-mIBG ( metaiodobenzylguanidine ) is used for the treatment of  phaeochromocytoma  and  neuroblastoma . [ 18 ]


177 Lu is bound with a  DOTA   chelator  to target  neuroendocrine tumours . [ 19 ]


At the  Institute for Transuranium Elements  (ITU) work is being done on alpha-immunotherapy, this is an experimental method where antibodies bearing  alpha  isotopes are used.  Bismuth-213  is one of the isotopes which has been used. This is made by the alpha decay of  actinium-225 . The generation of one short-lived isotope from longer lived isotope is a useful method of providing a portable supply of a short-lived isotope. This is similar to the generation of  technetium-99m  by a  technetium generator . The actinium-225 is made by the irradiation of  radium-226  with a  cyclotron . [ 20 ]


Targeted alpha-particle therapy  (or  TAT ) is an in-development method of targeted  radionuclide  therapy of various  cancers . It employs  radioactive  substances which undergo  alpha decay  to treat diseased tissue at close proximity. [ 1 ]  It has the potential to provide highly targeted treatment, especially to  microscopic   tumour   cells . Targets include  leukemias ,  lymphomas ,  gliomas ,  melanoma , and  peritoneal carcinomatosis . [ 2 ]  As in diagnostic  nuclear medicine , appropriate radionuclides can be  chemically bound  to a targeting  biomolecule  which carries the combined  radiopharmaceutical  to a specific treatment point. [ 3 ]


It has been said that "α-emitters are indispensable with regard to optimisation of strategies for tumour therapy". [ 4 ]


The primary advantage of  alpha particle  (α) emitters over other types of radioactive sources is their very high  linear energy transfer  (LET) and  relative biological effectiveness  (RBE). [ 5 ]   Beta particle  (β) emitters such as  yttrium-90  can travel considerable distances beyond the immediate tissue before depositing their energy, while alpha particles deposit their energy in 70–100 μm long tracks. [ 6 ]


Alpha particles are more likely than other types of radiation to cause  double-strand breaks  to DNA molecules, which is one of several effective causes of  cell death . [ 7 ] [ 8 ]


Some α emitting isotopes such as  225 Ac  and  213 Bi  are only available in limited quantities from  229 Th  decay, although  cyclotron  production is feasible. [ 9 ] [ 10 ] [ 11 ]  Among alpha-emitting radiometals according to availability, chelation chemistry, and half-life,  212 Pb  is also a promising candidate for targeted alpha-therapy. [ 12 ] [ 13 ]


The ARRONAX cyclotron can produce  211 At  by irradiation of  209 Bi . [ 14 ] [ 9 ]


Though many α-emitters exist, useful isotopes would have a sufficient energy to cause damage to cancer cells, and a  half-life  that is long enough to provide a therapeutic  dose  without remaining long enough to damage healthy tissue.


Several radionuclides have been studied for use in  immunotherapy . Though β-emitters are more popular, in part due to their availability, trials have taken place involving  225 Ac,  211 At,  212 Pb and  213 Bi. [ 9 ]


Treatment of peritoneal carcinomas has promising early results limited by availability of α-emitters compared to β-emitters. [ 4 ]


223 Ra  was the first α-emitter approved by the  FDA  in the United States for treatment of  bone metastases  from  prostate cancer , and is a recommended treatment in the UK by  NICE . [ 3 ] [ 15 ]  In a  phase III trial  comparing  223 Ra  to a  placebo , survival was significantly improved. [ 16 ]


Early trials of  225 Ac and  213 Bi have shown evidence of anti-tumour activity in  Leukaemia  patients. [ 17 ]


Phase I trials on  melanomas  have shown  213 Bi is effective in causing tumour  regression . [ 18 ] [ 19 ]


The short  path length  of alpha particles in tissue, which makes them well suited to treatment of the above types of disease, is a negative when it comes to treatment of larger bodies of  solid tumour  by intravenous injection. [ 20 ] [ 21 ]  Potential methods to solve this problem of delivery exist, such as direct intratumoral injection [ 22 ]  and  anti-angiogenic drugs . [ 23 ] [ 3 ]  Limited treatment experience of low grade malignant  gliomas  has shown possible efficacy. [ 24 ]


The  Therac-25  is a computer-controlled  radiation therapy  machine produced by  Atomic Energy of Canada Limited  (AECL) in 1982 after the Therac-6 and Therac-20 units (the earlier units had been produced in partnership with  Compagnie générale de radiologie (CGR)  of France). [ 1 ]


The Therac-25 was involved in at least six accidents between 1985 and 1987, in which some patients were given massive  overdoses of radiation . [ 2 ] :  425    Because of  concurrent programming errors  (also known as race conditions), it sometimes gave its patients radiation doses that were hundreds of times greater than normal, resulting in death or serious injury. [ 3 ]  These accidents highlighted the dangers of software  control  of safety-critical systems.


The Therac-25 has become a standard case study in  health informatics ,  software engineering , and  computer ethics . It highlights the dangers of engineer overconfidence [ 2 ] :  428    after the engineers dismissed end-user reports, leading to severe consequences.


The French company CGR manufactured the  Neptune  and  Sagittaire  linear accelerators.


In the early 1970s, CGR and the Canadian public company  Atomic Energy of Canada Limited  (AECL) collaborated on the construction of linear accelerators controlled by a DEC  PDP-11  minicomputer: the Therac-6, which produced X-rays of up to 6 MeV, and the Therac-20, which could produce X-rays or electrons of up to 20 MeV. The computer increased ease of use because the accelerator could operate without it. CGR developed the software for the Therac-6 and reused some subroutines for the Therac-20. [ 4 ]


In 1981, the two companies ended their collaboration agreement. AECL developed a new double pass concept for electron acceleration in a more confined space, changing its energy source from  klystron  to  magnetron . In certain techniques, the electrons produced are used directly, while in others they are made to collide against a tungsten anode to produce X-ray beams. This dual accelerator concept was applied to the Therac-20 and Therac-25, with the latter being much more compact, versatile, and easy to use. It was also more economical for a hospital to have a dual machine that could apply treatments of electrons and X-rays, instead of two machines.


The Therac-25 was designed as a machine controlled by a computer, with some safety mechanisms switched from hardware to software as a result. AECL decided not to duplicate some safety mechanisms, and reused modules and code routines from the Therac-20 for the Therac-25.


The first prototype of the Therac-25 was built in 1976 and was put on the market in late 1982.


The software for the Therac-25 was developed by one person over several years using PDP-11 assembly language. It was an evolution of the Therac-6 software. In 1986, the programmer left AECL. In a subsequent lawsuit, lawyers were unable to identify the programmer or learn about his qualification and experience.


Five machines were installed in the United States and six in Canada. [ 4 ]


After the accidents, in 1988 AECL dissolved the  AECL Medical  section and the company  Theratronics International Ltd  took over the maintenance of the installed Therac-25 machines. [ 5 ]


The machine had three modes of operation, with a turntable moving some apparatus into position for each of those modes: either a light, some  scan magnets , or a tungsten target and  flattener . [ 6 ]


The patient is placed on a fixed stretcher. Above them is a turntable to which the components that modify the electron beam are fixed. The turntable has a position for the X-ray mode (photons), another position for the electron mode and a third position for making adjustments using visible light. In this position an electron beam is not expected, and a light that is reflected in a stainless steel mirror simulates the beam. In this position there is no ion chamber acting as a radiation dosimeter because the radiation beam is not expected to function.


The turntable has some  microswitches  that indicate the position to the computer. When the plate is in one of the three allowed fixed positions a plunger locks it by  interlocking . In this type of machine, electromechanical locks were traditionally used to ensure that the turntable was in the correct position before starting treatment. In the Therac-25, these were replaced by software checks. [ 6 ]


The six documented accidents occurred when the high-current electron beam generated in X-ray mode was delivered directly to patients. Two software faults were to blame. [ 6 ]  One was when the operator incorrectly selected X-ray mode before quickly changing to electron mode, which allowed the electron beam to be set for X-ray mode without the X-ray target being in place. A second fault allowed the electron beam to activate during field-light mode, during which no beam scanner was active or target was in place.


Previous models had hardware interlocks to prevent such faults, but the Therac-25 had removed them, depending instead on software checks for safety.


The high-current electron beam struck the patients with approximately 100 times the intended dose of radiation, and over a narrower area, delivering a potentially lethal dose of  beta radiation . The feeling was described by patient Ray Cox as "an intense electric shock", causing him to scream and run out of the treatment room. [ 7 ]  Several days later,  radiation burns  appeared, and the patients showed the symptoms of  radiation poisoning ; in three cases, the injured patients later died as a result of the overdose. [ 8 ]


A Therac-25 had been in operation for six months in  Marietta, Georgia  at the Kennestone Regional Oncology Center when, on June 3, 1985, applied radiation therapy treatment following a  lumpectomy  was being performed on 61-year-old woman Katie Yarbrough. She was set to receive a 10-MeV dose of electron therapy to her  clavicle . When therapy began, she stated she experienced a "tremendous force of heat...this red-hot sensation." The technician entered the room, to whom Katie stated, "you burned me." The technician assured her this was not possible. She returned home where, in the following days, she experienced reddening of the treatment area. Shortly after, her shoulder became locked in place and she experienced spasms. Within two weeks, the aforementioned redness spread from her chest to her back, indicating that the source of the burn had passed through her, which is the case with radiation burns. The staff at the treatment center did not believe it was possible for the Therac-25 to cause such an injury, and it was treated as a symptom of her  cancer . Later, the hospital physicist consulted the AECL about the incident. He calculated that the applied dose was between 15,000 and 20,000 rad (radiation absorbed dose) when she should have been dosed with 200 rad. A dose of 1000 rad can be fatal. In October 1985, Katie sued the hospital and the manufacturer of the machine. In November 1985, the AECL was notified of the lawsuit. It was not until March 1986, after another incident involving the Therac-25, that the AECL informed the FDA that it had received a complaint from the patient.


Due to the radiation overdose, her breast had to be surgically removed, an arm and shoulder were immobilized, and she was in constant pain. The treatment printout function was not activated at the time of treatment and there was no record of the applied radiation data. An out-of-court settlement was reached to resolve the lawsuit. [ 3 ]


The Therac-25 had been in operation in the clinic for six months when, on July 26, 1985, a 40-year-old patient was receiving her 24th treatment for  cervical cancer . The operator activated the treatment, but after five seconds the machine stopped with the error message "H-tilt", the treatment pause indication and the dosimeter indicating that no radiation had been applied. The operator pressed the  P  key (Proceed : continue). The machine stopped again. The operator repeated the process five times until the machine stopped the treatment. A technician was called and found no problem. The machine was used to treat six other patients on the same day.


The patient complained of burning and swelling in the area and was hospitalized on July 30. She was suspected of a radiation overdose and the machine was taken out of service. On November 3, 1985, the patient died of cancer, although the autopsy mentioned that if she had not died then, she would have had to undergo a hip replacement due to damage from the radiation overdose. A technician estimated that she received between 13,000 and 17,000 rad.


The incident was reported to the FDA and the Canadian Radiation Protection Bureau.


The AECL suspected that there might be an error with three microswitches that reported the position of the turntable. The AECL was unable to replicate a failure of the microswitches and microswitch testing was inconclusive. They then changed the method to be tolerant of one failure and modified the software to check if the turntable was moving or in the treatment position.


Afterward, the AECL claimed that the modifications represented a five-order-of-magnitude increase in safety. [ 3 ]


In December 1985 a woman developed an  erythema  with a parallel band pattern after receiving treatment from a Therac-25 unit. Hospital staff sent a letter on January 31, 1986, to the AECL about the incident. The AECL responded in two pages detailing the reasons why radiation overdose was impossible on the Therac-25, stating both machine failure and operator error were not possible.


Six months later, the patient developed chronic ulcers under the skin due to tissue necrosis. She had surgery and skin grafts were placed. The patient continued to live with minor  sequelae . [ 3 ]


Over two years, this hospital treated more than 500 patients with the Therac-25 with no incident. On March 21, 1986, a patient presented for his ninth treatment session for a tumor on his back. The treatment was set to be 22-MeV of electrons with a dose of 180 rad in an area of 10x17 cm, with an accumulated radiation in 6 weeks of 6000 rad.


The experienced operator entered the session data and realized that she had written an “x” for ‘x-ray’ instead of an “e” for ‘electron beam’ as the type of treatment. With the cursor she went up and changed the “x” to an “e” and since the rest of the parameters were correct she pressed  ↵ Enter  until she got down to the command box. All parameters were marked "Verified" and the message "Rays ready" was displayed. She hit the  B  key ("Beam on"). The machine stopped and displayed the message "Malfunction 54" (error 54). It also showed 'Treatment pause'. The manual said that the "Malfunction 54" message was a "dose input 2" error. A technician later testified that "dose input 2" meant that the radiation delivered was either too high or too low.


The radiation monitor (dosimeter) marked 6 units supplied when it had demanded 202 units. The operator pressed  P  ( Proceed : continue). The machine stopped again with the message "Malfunction 54" (error 54) and the dosimeter indicated that it had delivered fewer units than required. The surveillance camera in the radiation room was offline and the intercom had been broken that day.


With the first dose the patient felt an electric shock and heard a crackle from the machine. Since it was his ninth session, he realized that it was not normal. He started to get up from the table to ask for help. At that moment the operator pressed  P  to continue the treatment. The patient felt a shock of electricity through his arm, as if his hand was torn off. He reached the door and began to bang on it until the operator opened it. A physician was immediately called to the scene, where they observed intense  erythema  in the area, suspecting that it had been a simple electric shock. He sent the patient home. The hospital physicist checked the machine and, because it was calibrated to the correct specification, it continued to treat patients throughout the day. The technicians were unaware that the patient had received a massive dose of radiation between 16,500 and 25,000 rads in less than a second over an area of one cm 2 . The crackling of the machine had been produced by saturation of the ionization chambers, which had the consequence that they indicated that the applied radiation dose had been very low.


Over the following weeks the patient experienced paralysis of the left arm, nausea, vomiting, and ended up being hospitalized for radiation-induced  myelitis  of the spinal cord. His legs, mid-diaphragm and vocal cords ended up paralyzed. He also had recurrent herpes simplex skin infections. He died five months after the overdose.


From the day after the accident, AECL technicians checked the machine and were unable to replicate error 54. They checked the grounding of the machine to rule out electric shock as the cause. The machine was back in operation on April 7, 1986. [ 3 ]


On April 11, 1986, a patient was to receive electron treatment for skin cancer on the face. The prescription was 10 MeV for an area of 7x10 cm. The operator was the same as the one in the March incident, three weeks earlier. After filling in all the treatment data she realized that she had to change the mode from X to E. She did so and pressed  ↵ Enter  to go down to the command box. As "Beam ready" was displayed, she pressed  P  (Proceed : continue). The machine produced a loud noise, which was heard through the intercom. Error 54 was displayed. The operator entered the room and the patient described a burning sensation on his face. The patient died on May 1, 1986, just shy of 3 weeks later. The autopsy showed severe radiation damage to the right temporal lobe and brain stem.


The hospital physicist stopped the machine treatments and notified the AECL. After strenuous work, the physicist and operator were able to reproduce the error 54 message. They determined that speed in editing the data entry was a key factor in producing error 54. After much practice, he was able to reproduce the error 54 at will. The AECL stated they could not reproduce the error and they only got it after following the instructions of the physicist so that the data entry was very rapid. [ 3 ]


On January 17, 1987, a patient was to receive a treatment with two film-verification exposures of 4 and 3 rads, plus a 79-rad photon treatment for a total exposure of 86 rads. Film was placed under the patient and 4 rads were administered through a 22 cm × 18 cm opening. The machine was stopped, the aperture was opened to 35 cm × 35 cm and a dose of 3 rad was administered. The machine stopped. The operator entered the room to remove the film plates and adjust the patient's position. He used the hand control inside the room to adjust the turntable. He left the room, forgetting the film plates. In the control room, after seeing the "Beam ready" message, he pressed the  B  key to fire the beams. After 5 seconds the machine stopped and displayed a message that quickly disappeared. Since the machine was paused, the operator pressed  P  (Proceed : continue). The machine stopped, showing "Flatness" as the reason. The operator heard the patient on the intercom, but could not understand him, and entered the room. The patient had felt a severe burning sensation in his chest. The screen showed that he had only been given 7 rad. A few hours later, the patient showed burns on the skin in the area. Four days later the reddening of the area had a banded pattern similar to that produced in the incident the previous year, and for which they had not found the cause. The AECL began an investigation, but was unable to reproduce the event.


The hospital physicist conducted tests with film plates to see if he could recreate the incident, which involved two X-ray parameters with the turntable in field-light position. The film appeared to match the film that was left by mistake under the patient during the accident. It was found the patient was exposed to between 8,000 and 10,000 rad instead of the prescribed 86 rad. The patient died in April 1987 from complications due to radiation overdose. The relatives filed a lawsuit that ended with an out-of-court settlement. [ 3 ]


A commission attributed the primary cause to generally poor software design and development practices, rather than singling out specific coding errors. In particular, the software was designed so that it was realistically impossible to test it in a rigorous,  automated  way. : Safeware, [48]  [ additional citation(s) needed ]


Researchers who investigated the accidents found several contributing causes. These included the following institutional causes:


The researchers also found several  engineering  issues:


Leveson  notes that a lesson to be drawn from the incident is to not assume that reused software is safe: [ 9 ]  "A naive assumption is often made that reusing software or using commercial off-the-shelf software will increase safety because the software will have been exercised extensively. Reusing software modules does not guarantee safety in the new system to which they are transferred ..." [ 6 ]   In response to incidents like those associated with Therac-25, the  IEC 62304  standard was created, which introduces development life cycle standards for medical device software and specific guidance on using  software of unknown pedigree . [ 10 ]


VistA Imaging  is an FDA-listed Image Management system used in the  Department of Veterans Affairs healthcare facilities nationwide . It is one of the most widely used image management systems in routine healthcare use, and is used to manage many different varieties of images associated with a patient's medical record. The system was started as a research project by  Ruth Dayhoff  in 1986 and was formally launched in 1991. [ 1 ]


The VistA Imaging System uses hardware components to provide short- and long-term storage. It takes advantage of network servers for storage. It uses a  DICOM  gateway system to communicate with commercial  Picture Archiving and Communication Systems  (PACS) and modalities such as CT, MR, and Computed Radiography (x-ray) devices for image capture. It utilizes a background processor for moving the images to the proper storage device and for managing storage space.


The system not only manages radiologic images, but also is able to capture and manage  EKGs ,  pathology  images,  gastroenterology (endoscopic)  images,  laparoscopic  images, scanned paperwork, or essentially any type of health care image.


VistA Imaging is currently integrated into the  VistA EMR  (electronic medical record) system used nationwide in Department of Veterans Affairs hospitals. This integration is able to provide increased efficiency of retrieval of images. [ 2 ]  It has also been used as a separate software package and can be used with  EHRs  other than VistA.


VistA Imaging now connects to a nationwide backbone that allows clinicians to access the 350 million images stored in the VA system via Remote Image View software. [ 3 ]


The VA has developed interfaces for more than 250 medical devices in VistA Imaging, the images from which can be accessed through the desktop VistA Imaging Viewer. The Department of Defense will use the VistA Imaging Viewer to enhance its own EHR. [ 3 ]


As part of the US national mandate to co-ordinate care between Department of Defense and the VA, VistA Imaging is forming a cornerstone of the effort to exchange medical imagery between the two systems. “When soldiers come back from Iraq and Afghanistan and eventually enter the VA system, images will be able to move from DOD to VA seamlessly." Eventually, DOD and VA should be able to share all image file types from all sites. Additional enhancements to VistA Imaging include development of a central archive for all VA images (whether acquired through VistA or a commercial system) and new indexing and search capabilities. [ 4 ]


The software for VistA Imaging has been made available through the  Freedom of Information Act  so that it is in the public domain. Due to its designation as a medical device, however, it can not be designated as free open source software and therefore can not be altered or implemented without FDA approval.


Although it can be used in healthcare facilities that are outside the  Department of Veterans Affairs , this is possible only if the proprietary modules that have been integrated into it are also licensed and implementation is registered with the FDA. This has effectively limited its use to government institutions who have licensed the proprietary modules.


The source code can be downloaded from  the OSEHRA VistA-M.git tree .


VistA Imaging uses proprietary modules not in the public domain. This makes its public domain use limited.


The VistA Imaging system was robust enough to be restored after  Hurricane Katrina  damaged the data facility at the New Orleans VA. [ 5 ]  This type of backup proved superior to a paper record system.


A  well counter  is a device used for measuring  radioactivity  in small samples. It usually employs a  sodium iodide   crystal detector .
It was invented in 1951 by  Hal Anger , who is also well known for inventing the  scintillation camera . [ 1 ]  Anger filed U.S. patent #2,779,876 on March 3, 1953 for his "Radio-Activity Distribution Detector"; the patent was issued on January 29, 1957. [ 2 ]


The well counter is so called because the samples are inserted into a well within the crystal in order to maximize sensitivity by collecting as many of the emitted  gamma rays  as possible.


Modern well counters can automatically record activity in different samples sequentially. Samples in test tubes are inserted into the well, one sample at a time, and  counted  for a predetermined time. Results are presented as a  graphic , and corrected for the  decay  of the sample. [ 3 ]


Aarthi Scans and Labs  is an Indian  radiology  and pathology diagnostic provider, headquartered in  Chennai . The business has 40 diagnostic centres in India, and is accredited with the  NABL  and  NABH . [ 2 ] [ 3 ]


In 1985, V. Govindarajan and his wife made the decision to establish a  polyclinic  in the  Tamil Nadu  town of  Kovilpatti . However, they felt a lack of medical tools and technology for MRI scans and diagnostics, and thus decided to found Aarthi Scans and Labs in 2000. The business began as a single state operator and is now widespread throughout India. [ 2 ]


During the  COVID-19 pandemic , Aarthi Scans and Labs gathered 75,500 Swabs from homes. [ 4 ]  Additionally, it contributed   ₹2,500,000  to a COVID-19 Relief Fund alongside other donors [ 5 ]  and offered scans and blood tests to COVID patients during pandemic. [ 6 ]


In 2021, Aarthi Scans and Labs signed a contract with Mindray Ultrasound India [ 7 ]  and partnered with health tech firm Qure.ai. [ 8 ] [ 9 ]


In May 2022, the company partnered with Indian radiology company Synapsica to provide Spine MRI. [ 10 ]


Alliance Medical  is a radiology services company founded in 1989 by  Robert Waley-Cohen  operating across Europe.


In 2010  Lloyds Bank ,  Commerzbank  and  M&G Investments  acquired 85% of the company in a debt-for-equity swap. [ 1 ]


A consortium, called the Collaborative Network, between the company and  Christie Hospital NHS Foundation Trust  won a ten-year NHS contract to provide PET-CT scanning services across 30 locations in England in January 2015. [ 2 ]  The contract provides for investment of £87 million over 10 years to install new scanners and improve the current infrastructure. Twenty-four existing sites will remain where they are, and six new sites will be added at Maidstone Hospital;  William Harvey Hospital ;  Cumberland Infirmary ;  Lincoln County Hospital ;  Southmead Hospital ;  Royal United Hospital ; and  Royal Cornwall Hospital . [ 3 ]  The contract was awarded despite an NHS consortium bid being £7m cheaper. [ 4 ] [ 5 ]


In 2013 the company acquired IBA Molecular UK and Erigal, two of the three companies in England that produce the radioactive drug  Fludeoxyglucose (18F) , which is injected into patients as part of the imaging process.   Siemens Healthcare  is the only other UK producer. [ 6 ]


It was bought by  LIFE Healthcare Group  for about 10.4 billion rand (£584 million, €680 million, $727 million) in November 2016. [ 7 ]


It took over the running of the Taunton Diagnostic Centre, the first  community diagnostic centre  run by the independent sector in partnership with the NHS,  in November 2022 after  Rutherford Health  went into liquidation. It provides  Magnetic Resonance Imaging ,  Computed Tomography ,  Ultrasound  and  X-Ray  facilities.  [ 8 ]


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The  American Association for Women in Radiology  (or  AAWR ) is a  professional association  founded in 1981 as a resource for "professional socialization" for women in a male-dominated field of  radiology . [ 1 ] [ 2 ] [ 3 ]


AAWR’s role model is  Marie Curie . [ 1 ] [ 2 ]


The main goals of the association were to provide a forum for issues unique to women in radiology,  radiation oncology  and related professions, to sponsor programs that promote opportunities for women, and to facilitate networking among women radiologists. [ 1 ] [ 2 ]


Established in 1934, the  American Board of Radiology  ( ABR ) is an independent, not-for-profit  professional association  with headquarters in Tucson, Arizona. [ 1 ]  It oversees the certification and ongoing professional development of physician specialists in  diagnostic radiology ,  interventional radiology , and  radiation oncology , as well as  medical physicists  in  diagnostic ,  nuclear , and  therapy   medical physics . [ 2 ]


The ABR certifies its diplomates through a comprehensive process involving educational requirements, professional peer evaluation, and examination.


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The  American College of Radiology  ( ACR ), founded in 1923, is a professional medical society representing nearly 40,000 diagnostic  radiologists , radiation  oncologists , interventional radiologists, nuclear medicine  physicians  and medical  physicists .


The ACR has 54 chapters in the United States, Canada and the Council of Affiliated Regional Radiation Oncology Societies (CARROS). [ 1 ]


The ACR has accredited more than 39,000 medical imaging facilities [ 2 ]  in 10 imaging modalities since 1987, including:


The ACR provides patient information through the website Radiologyinfo.org, [ 7 ]  co-produced by the  Radiological Society of North America , to help patients understand how various radiology procedures and radiation therapy are performed.


ACR's Imaging 3.0 initiative is a roadmap to transition the practice of radiology from volume-based to value-based care. Four main focus areas of Imaging 3.0 include; [ 8 ]


The  American Osteopathic Board of Radiology  ( AOBR ) is an organization that provides  board certification  to qualified  Doctors of Osteopathic Medicine  (D.O.) who specialize in the use of  imaging  in the diagnosis and treatment of disease ( radiologists ). The board is one 18  medical specialty  certifying boards of the  American Osteopathic Association Bureau of Osteopathic Specialists  approved by the  American Osteopathic Association  (AOA), [ 4 ] [ 5 ]  and was established in 1939. [ 1 ]  The American Osteopathic Board of Radiology and the  American Board of Radiology  are the two certifying boards for radiologists in the United States. [ 6 ] [ 7 ]  As of December 2011, 732  osteopathic  radiologists held active certification with the AOBR. [ 8 ]  Radiologists board certified by the AOBR are eligible for membership in the  American College of Radiology . [ 9 ]


Initial certification is available to osteopathic radiologists who have successfully completed an AOA-approved  residency  in diagnostic radiology or radiation oncology, two years of practice, and successful completion of oral and written exams. [ 10 ] [ 11 ] [ 12 ]


Diplomates certified in  diagnostic radiology  or in  radiation oncology  prior to 2002 are eligible for voluntary recertification. Since 2002, the American Osteopathic Board of Radiology requires osteopathic radiologists to renew their certification every ten years to avoid expiration of their board certified status. [ 13 ]  Additionally, osteopathic radiologists who have completed the requirements set forth by the AOBR and completed an AOA-approved radiology residency may be eligible to pursue certification by the  American Board of Radiology . [ 14 ]


Osteopathic radiologists may also receive Certification of Added Qualifications (CAQ) in the following areas: [ 15 ]


The  American Osteopathic College of Radiology (AOCR) , founded in 1941, is a  non-profit   professional   medical association  in the  United States  representing  Doctors of Osteopathic Medicine  (D.O.) that specialize in  radiology . The AOCR is accredited by the  American Osteopathic Association  (AOA) and the  Accreditation Council for Continuing Medical Education  to oversee  continuing medical education  activities for  osteopathic  radiologists. [ 3 ] [ 4 ]  The AOCR is one of two professional organizations representing American radiologists, the other organization is the  American College of Radiology . The college publishes  The Journal of the American Osteopathic College of Radiology  ( JAOCR ). [ 5 ]


Certified fellows of the American Osteopathic College of Radiology are eligible to become senior members of the American Society of Neuroradiology in addition to their certified peers from the  American Board of Radiology  and the  Royal College of Physicians and Surgeons of Canada . [ 6 ]  Additionally, osteopathic radiologists that have completed an  ACGME  radiology residency or completed an AOA/AOCR-approved residency in  diagnostic radiology  and subsequent  board certification  by the  American Osteopathic Board of Radiology , may also apply for board certification through the  American Board of Radiology . [ 7 ]


John “Drew” Ridge, MD, PhD, Secretary
Quynh-Thu Le, MD, Treasurer


The  American Radium Society  is a medical association devoted to the study and treatment of cancer. It was founded in 1916. [ 1 ]


The Society's original mission was to further "the scientific study of radium in relation to its physical properties and therapeutic applications" distinguishing it from the  American Roentgen Ray Society  (ARRS). The society's mission was expanded in 1950 to include "the treatment of  neoplastic  and allied diseases and the study and application of  ionizing radiation ." [ 2 ]


In 1933, The ARS founded the annual Janeway Lecture in honor of  Henry Harrington Janeway , a pioneer in radium therapy. The first Janeway Lecture, "Early Experience in Radium Therapy", was given by the pathologist  James Ewing . The lecture is delivered at the society's annual general meeting with the lecturer chosen for their "outstanding scientific contributions". The 2014 Janeway Lecturer was Murray F. Brennan of the  Memorial Sloan Kettering Cancer Center . Since 1937 each Janeway Lecturer is presented with the Janeway Medal. [ 3 ]


The society's first president was the Canadian physician W. H. B. Aikins, known as the founder of  radiotherapy  in Canada. [ 4 ]  Other past presidents have included: [ 5 ]


The  American Roentgen Ray Society  ( ARRS ) is the first and oldest  radiology  society in the United States. It was founded in 1900, in the early days of  X-ray  and radiation study.


Headquartered in  Leesburg, Virginia , the society publishes a monthly peer-reviewed journal:   American Journal of Roentgenology  (previously  American Journal of Radiology ), providing a forum for advances in radiology and related fields.  It provides  scholarships , and presents awards. [ 1 ]


Its educational programs include seminars and a program of  continuing education  for  radiologic technologists . [ 2 ]


Its 9th meeting, in 1908, was held in New York City.  There, it announced that there was "no excuse whatever" for anyone being injured during medical X-rays, which "could be taken in a fraction of a second". [ 3 ]


The  Center for Radiological Research  (CRR) is a research institute in New York City. It was founded in 1916 at  Memorial Hospital  by  Gioacchino Failla  before moving to  Columbia University  in 1942. [ 1 ]  It has been described as the oldest and largest research center of its kind in the world. [ 2 ]  Achievements by the CRR under Failla include constructing the first radon generator in the US and building the first  human phantom  in the US. [ 3 ]


The  Centre for Radiation, Chemical and Environmental Hazards  (CRCE) is a British government environmental research site, run by  Public Health England  (PHE) in  Chilton, Oxfordshire  that monitors levels of toxic chemicals and background radiation in the British environment; it is largely a continuation of the former  National Radiological Protection Board  (NRPB).


The Radiation Protection Division of the  Health Protection Agency  was formed on 1 April 2005, due to the  Health Protection Agency Act 2004 , directly superseding the NRPB. This became the CRCE due to the  Health and Social Care Act 2012 , when Public Health England was formed. [ citation needed ]


It is part of PHE's Radiation Protection Adviser Services. PHE was the UK's first Radiation Protection Adviser Body, under the  Ionising Radiations Regulations  (IRR) 17 (which came from the  International Commission on Radiological Protection ). [ citation needed ]


It monitors  background radiation  in the UK. Workers exposed to radiation include workers in  dental radiography [ 1 ]  and  nuclear power stations ; exposure to radiation for workers in the UK must be  ALARP . It offers 3-day training courses around twice a month, at a national level, for workers exposed to radiation.


It produces reports on environmental background radiation in England. [ 2 ]  It works with the ICRP, the  United Nations Scientific Committee on the Effects of Atomic Radiation  (UNSCEAR), and the  International Atomic Energy Agency  (IAEA). Inside the UK, it works with the  Scottish Environment Protection Agency  (SEPA) and the  Environment Agency  (EA).


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The  College of Radiology, Academy of Medicine Malaysia  is a  non-profit organization  of clinical radiologists, clinical oncologists, and medical physicists in  Malaysia .


It was established as the Malaysian Radiological Society (MRS) following the inaugural general meeting held on November 27, 1976, at the then General Hospital,  Kuala Lumpur . [ 1 ]  On August 23, 2001, the MRS became a chapter in the  Academy of Medicine of Malaysia  and from then on is known by its current name. [ 2 ]


It has adopted  Biomedical Imaging and Intervention Journal  as its official publication. [ citation needed ]


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The  European Congress of Radiology  (Europäischer Röntgenkongress)  is an annual meeting in Europe for  radiologists  from around the world.  Founded in 1967, the Congress is run by Verein Europäischer Röntgenkongress (ECR).


When the congress was founded in 1967, it was held every four years in a different location.  However, this format did not allow for the creation of a consistent group of experienced  radiologists  responsible for the preparation of the congress. Furthermore, the radiological community in  Europe  wanted to create a common platform for European radiologists.


In 1985, a committee chaired by Josef Lissner from  Munich  ( Germany ) was established to re-organise the Congress. The committee recommended holding the congress every two years in the same location,  Vienna  ( Austria ) . The society 'Verein Europäischer Röntgenkongress' (ECR) was founded, and a congress-organising institution was established at the Medical Academy of Vienna. The first 'new' Congress opened on Saturday, September 15, 1991 under the presidency of Lissner. It attracted more than 9,000 participants.


In 1999, the ECR changed the congress to an annual event.


The Congress is the largest radiological meeting in Europe with more than 28,000 participants from around 100 countries and 4,000  scientific papers  and  exhibits . To answer growing demand, the ECR has developed EPOS, an online electronic  presentation system  and ECR Online, providing coverage of the majority of sessions via  live video streaming .


The  European Society of Radiology  ( ESR ) is an international medical society based in  Vienna ,  Austria  dedicated to the promotion and coordination of scientific, philanthropic, intellectual and professional activities of  radiology  in Europe. In addition to various other activities, the ESR serves as an umbrella organisation for European  radiologists , organises the annual  European Congress of Radiology  (ECR) and coordinates the publication of  European Radiology , a monthly peer-reviewed  medical journal . [ 1 ] [ 2 ]  Additionally, the ESR pilots the harmonisation of teaching programmes throughout Europe with various activities and initiatives.


Founded in 2005, the European Society of Radiology (ESR) was created through the merger of two established radiological societies; the European Association of Radiology (EAR), a federation of national radiological societies founded in 1962, and the European Congress of Radiology (ECR), the organising body of the eponymous congress which was first held in 1967. [ 4 ] : 30


The EAR was established on 15 December 1962 through the efforts of  Boris Rajewsky  of the  Max Planck Institute  in Frankfurt and Charles Marie Gros of the  University of Strasbourg  who would become the association's first president and first secretary-general respectively. [ 5 ]  The EAR was tasked with coordinating a European congress and establishing a European counterpart to the  Radiological Society of North America  (RSNA), which had existed since 1915. [ 4 ] : 4, 23   By the time it was formally registered, the association comprised radiological member societies from nine countries –  Belgium ,  France ,  Italy ,  Luxembourg ,  The Netherlands ,  Portugal ,  Spain ,  Switzerland , and  West Germany . The  European Congress of Radiology  was to be held every four years in a different European city, starting in 1967 which  Barcelona  with took place in conjunction with the Radiological Federation of Latin Culture (Féderation Radiologique de Culture Latine). [ 4 ] : 23


After successor congresses were held in  Amsterdam  (1971),  Edinburgh  (1975),  Hamburg  (1979),  Bordeaux  (1983) and  Lisbon  (1987), the EAR in 1985 founded a committee, chaired by  Josef Lissner  of the  University of Munich , specifically tasked with organising future congresses. An ever-changing location and the lack of a consistent group of experienced radiologists responsible for the congresses were deemed obstacles to the most effective congress possible. [ 4 ] : 25  [ 5 ]  As a result, the committee ultimately decided that the frequency of the congress should be increased to every two years and a permanent host location be selected. [ 6 ]


As the late 1980s, early 1990s was marked by the fall of the iron curtain and a call for greater European cooperation, a suitable host location was sought that could embody these ideals. Situated near the then border between eastern and western Europe,  Vienna  was chosen to host all future congresses beginning in 1991. [ 4 ] : 24   By the late 1980s, the Verein Europaeischer Roentgenkongress, or European Congress of Radiology (ECR), had been founded and a congress-organising institution was established at the  Medical University of Vienna , both in support of the biennial meeting. [ 4 ] : 24   With ECR'91, EAR remained a federation of national societies who sent delegates to the general assembly at the end of every congress. [ 5 ]  Due to the growing success of the ECR, it was decided that the congress would be held annually from 1999 on. [ citation needed ]