The latest addition to the CyberKnife product family, which was released in September 2009. This review updates the previous technical reviews of the original system version published in the late 1990s. There is a clear dose response for localized prostate cancer radiotherapy and there probablyis a radiobiological rationale for hypo-fractionation. Combining the two should maximize tumor control and increase the therapeutic ratio. Technical developments over the last decade have impacted virtually every aspect of the CyberKnife System. These developments have increased the geometric accuracy of the system and have enhanced the dosimetric accuracy and quality of treatment, with advanced inverse treatment planning algorithms, rapid Monte Carlo dose calculation, and post-processing tools that allow trade-offs between treatment efficiency and dosimetric quality to be explored. The CyberKnife can produce superior DVHs for sparing of rectum and bladder and excellent DVHs for target coverage compared with IMRT, and possesses dose heterogeneities to the same degree as IMRT plans.
Keywords: CyberKnife System; Radiosurgery; Stereotactic Body Radiation Therapy; Hypofractionation; IMRT Hetrogeneities