{
  "schema": "medimageosworld-public-task-v1",
  "task_id": "L4_long_axis_pair",
  "modality": "MR",
  "level": "L3",
  "goal_text": "The orthogonal scouts have been acquired. Accurately prescribe both the two-chamber and four-chamber long-axis localizers. The two-chamber row is initially open. Acquire the submitted two-chamber localizer before submitting the four-chamber localizer.\n\nANATOMICAL CRITERIA:\nThe plane should contain the LV apex and midpoint of the LV–LA junction and show the LV and left atrium without foreshortening. Where available, a four-chamber view provides a long-axis reference. Where a ventricular SAX stack is available, the intersection should follow the LV anterior/inferior-wall orientation, approximately parallel to the lateral wall where identifiable, while remaining outside RV tissue at the relevant LV-containing levels. The long-axis plane should be approximately perpendicular to the SAX planes. Consistency across reference views matters more than an appealing appearance in one image.\n\nBoth ventricles and both atria should be represented in one long-axis plane without foreshortening the LV apex. The LV apex and midpoint of the LV–LA junction should be in plane. Where available, basal ventricular SAX anatomy should support a four-chamber orientation across the interventricular septum toward the RV free wall, rather than an oblique two-chamber or outflow-tract view. The plane should be approximately perpendicular to the SAX planes and consistent with any acquired long-axis references.\nThese XCAT reference images are diastolic; valve leaflets may not be visible. Use the midpoint of the LV–LA junction and the LV apex to define the LV long axis. A short-axis plane is perpendicular to that long axis.\n\nENDPOINT: The two-chamber localizer acquisition is complete and the final four-chamber prescription has been submitted. Completion of the final four-chamber acquisition is not required. Then return done; unrelated workline rows are outside this task.",
  "budgets": {
    "max_steps": 120,
    "wall_budget_s": 7200.0
  },
  "observation": {
    "mode": "pixels_only",
    "viewport_px": [
      1600,
      1000
    ],
    "notes": "Screenshot of the console each step plus one history image and a compact text history of the last four actions; the full text operator manual; geometry tasks also get reference images of a correctly planned view from a different phantom. The model may request zoomed crops of the current screenshot."
  },
  "allowed_actions": [
    "click",
    "double_click",
    "drag",
    "move",
    "scroll",
    "key",
    "type",
    "wait",
    "done",
    "abstain"
  ],
  "initial_setup": "Localizer and sagittal/transverse/coronal scout acquisitions are complete; the 2-Chamber Localizer row is open in the editor. Any editable draft prescription starts from a per-episode randomised position and orientation.",
  "visualization": {
    "start_png": true,
    "success_png": false,
    "success_gif": false,
    "note": "success visualization pending: scoring this task requires private reference geometry that does not exist for the public development phantom",
    "status": "start only"
  }
}