UCI study compares image-guided radiotherapy technologies
A study by researchers from the University of California, Irvine (UCI) Medical Center suggests that image-guided RapidArc radiotherapy has clinical advantages over fixed-beam approaches to stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) for treating cancer.

Daniel C. Schiffner, MD, chief resident in UCI's department of radiation oncology, and colleagues reported on their study during a presentation at the 2009 American Society for Radiation Oncology (ASTRO) meeting in Chicago earlier this month. It compared the two treatment approaches for eight patients with a total of 13 lesions. RapidArc treatments were found to conform to the shape and size of a targeted tumor at least as well as fixed-beam approaches to intensity modulated radiation therapy (IMRT), SRS, and SRT with the capability to vary the dose delivery rate and the speed of rotation, the report stated.

According to Palo Alto, Calif.-based Varian, developers of the technology, RapidArc delivers volumetric modulated arc therapy (VMAT) and enables clinicians to process image-guided intensity-modulated treatments.

Schiffner said the device's capabilities allow for speedier results with an average of 76 percent less “beam on” time and the use of 31 percent fewer monitor units. Fewer monitor units limit the degree to which patients are exposed to radiation leakage from the treatment machine, Schiffner said.