Today, 3D conformal radiotherapy is the most frequently used external radiotherapy technique. It allows adapting the radiation beam shape in function of the tumor volume shape and to spare as much as possible the surrounding healthy tissue.
Conformal radiotherapy is an external radiotherapy technique that allows adapting the radiation beam shape to fit the tumor volume to be irradiated in order to limit as much as possible the exposure of healthy tissue around the tumor. Today, 3D conformal radiotherapy is the most common external radiotherapy technique.
Before treatment initiation,3D images of the area to be treated are acquired(simulation scan) to delineate in three dimensions (height, width, depth) the target tumor volume (i.e. treatment volume) and the neighboring organs at risk.
Technological progress led to the development of intensity-modulated conformal radiotherapy in which the radiation beam intensity is continuously modulated during irradiation (modification of the beam shape to adapt to the tumor shape in three dimensions) to fit the dose precisely to the tumor to limit the exposure of healthy tissues.