Stereotactic body radiation therapy (SBRT) – also sometimes referred to as stereotactic radiosurgery (SRS) – is one of the most advanced form of radiation therapy for cancer treatments. SBRT and SRS are techniques used in radiation therapy to destroy diseased tissue by precisely directing very high doses of radiation, while avoiding healthy surrounding tissue, critical structures and organs. SBRT commonly is used for treating tumors throughout the body, while SRS is typically used to describe treatments specific to the head and neck.

Unlike conventional radiation therapy (IMRT, IGRT and proton therapy, which can require 35 or more consecutive days of treatments), SBRT and SRS treatments are given once per day for 5 days or fewer.

Conventional radiation treatments for prostate cancer face a challenge delivering radiation to the prostate tumors because the prostate, and the tumor itself, move involuntarily in response to body functions. Leveraging its SBRT and SRS functionality, the CyberKnife System solves this problem by tracking tumor movements. Doctors use fiducial markers – tiny gold seeds inserted into the prostate with a needle – to help the CyberKnife System keep track of the tumor’s position, even as it moves.

Then, throughout the treatment process, the CyberKnife System takes digital images to ensure that each radiation beam is aimed directly at the tumor. The system also adjusts to regular movement of the tumor and patient’s body to ensure treatment remains on target, sparing healthy tissue.