CT/PET-CT imaging in radiation therapy
The success of radiation therapy is closely related to the ability to accurately define, plan, and deliver radiation treatment to the tumor, while limiting the dose to normal tissue.
Computed tomography scans (CT scans) in the treatment position form the basis for treatment planning with contouring the target tumor volumes, and defining the organs at risk. The CT scan is required for precise dose calculation with the treatment planning system.
The location of the treatment isocenter is defined based on target volume and treatment area. As soon as the treatment isocenter is determined, or “marked”, these coordinates become part of the treatment plan and are the reference for subsequent dose calculations.
External laser systems are essential to patient marking: projecting the coordinates and marking them on the patient’s skin is required for precise positioning in the linear accelerator.