Physical characteristics research of OPEN stereotactic body gamma knife

Abstract

Objective To study the physical characteristics of the OPEN stereotactic body radiotherapy system for the clinical application. Methods The 0.125cc ioniztion chamber, 160 mm polystyrene sphere model, Gafchromic EBT2 films and IBA film analysis software were used to evaluated the focus position tolerance, dose rate, repeatability, linear relation, penumbra and composite error of the OPEN stereotactic body gamma knife. We used the DTA method to verify the accuracy of dose distribution between the plans and measured value. Resualts The focus error was 0.36 mm, max dose rate tolerance 3%, linear relation error 2%, repeatability error 0.3%, composited error 2.5 mm. There was 90% pass rate when the distance away from test point was less than 2 mm and the dose error was set less than 5%. Conclusions Parts of the test resualts were similar to the head gamma knife national protocal of OPEN stereotatic body gamma knife. The deliver dose distribution can meet the clinic need. Key words: Stereotatic radiotherapy; Body gamma knife; Dosimetry