How does stereotactic radiotherapy work?


In stereotactic radiotherapy, the patient receives very high doses (6 to 20 Gy per session) but only for few sessions (1 to 10). Different immobilization devices are used to limit the patient’s movements during the session in order to avoid high dose irradiation of the healthy tissues surrounding the tumor.

Stereotactic radiotherapy is a treatment technique in which the patient receives very high doses per session (6 to 20 Gy) that are delivered to a smaller tumor volume with reduced treatment margins and in fewer sessions (1 to 10). Depending on the treated area, an immobilization device can be made to limit the patient’s movements as much as possible during the sessions. To take into account the tumor motion during irradiation, different compensation techniques have been developed depending on the technique. Indeed, stereotactic radiotherapy can be delivered using different machines or treatment devices, and each has its own technological features. For instance, the movement of a lung tumor during breathing can be taken into account by evaluating the breathing cycles during the session. Then, radiation is delivered only at specific points of the cycle (gating). Alternatively, the target motion can be monitored in real-time using markers implanted in the target area before radiotherapy initiation (tracking).