Stereotactic radiotherapy is a form of radiation therapy that enables delivery of high-dose radiation to a target while sparing the surrounding normal structures. This is achieved by combining precise 3D target localization with multiple high-energy radiation beams.
There are two types of stereotactic radiotherapy:
- Stereotactic radiosurgery (SRS)
- Stereotactic body radiation therapy (SBRT)
While in SRS, the dose of radiation is delivered in a single treatment session; in SBRT the treatment course is divided in multiple fractions. Recent studies have demonstrated that SRS/SBRT is an effective alternative to surgery or conventional radiation therapy for selected diseases. In addition, SRS/SBRT allows the treatment of patients who have inoperable tumors or who were previously irradiated.
CyberKnife robotic radiosurgery is one of the most advanced forms of SRS/SBRT. The CyberKnife system is capable of delivering maximally aggressive doses of radiation with sub-millimeter accuracy anywhere in the body. This is achieved by combining sophisticated image guidance with robotically targeted radiation delivery. The procedure is non-invasive and is performed on an outpatient basis.
A typical treatment course requires one to five daily sessions, each lasting between 30 to 90 minutes. The VSITM system is the latest development in CyberKnife technology. Thanks to a faster radiation delivery and variable beam apertures, it enables considerably reduced treatment times, extending the advantages of SBRT to conventionally fractionated radiation therapy.
Cyberknife and Liver Tumors
From Accuray, the maker of Cyberknife:
"The CyberKnife® Robotic Radiosurgery System was cleared by the U.S. Food and Drug Administration in 2001 to treat tumors anywhere in the body, including the liver. Despite its name, the CyberKnife System is not a surgical procedure. In fact, there is no cutting involved. Instead, the CyberKnife System delivers high doses of radiation directly to liver tumors.
The CyberKnife System offers patients who cannot undergo liver cancer surgery due to their medical condition, or who refuse surgery, a minimally invasive alternative treatment for liver cancer. CyberKnife liver cancer treatments are typically performed on an outpatient basis in one to five days, requiring no overnight hospital stays. Most patients experience minimal to no side effects with a quick recovery time."