[Mechanical accuracy of a stereotactic irradiation system using a micro multi-leaf collimator].
Mechanical accuracy of a stereotactic irradiation system using a micro multi-leaf collimator (mMLC), Elekta DMLC, has been evaluated. Measurements were made to obtain transmission, leakage, penumbra, and positioning accuracy of the DMLC leaf for a 6 MV photon beam. Mechanical accuracy and long term stability of a linac isocenter was also evaluated. The resulting transmission, along a line perpendicular to the leaf movement, was 0.31±0.01%, and the leakage from the closed opposing leaf pairs was 0.39±0.01%. The measured penumbra, at a depth incurring maximum dose, was 2.37±0.16 mm toward the leaf end and 2.14±0.18 mm toward the leaf side for various field sizes. The leaf gap width error, of 0.10±0.08 mm, was obtained by analyzing picket fence test results. The maximum leaf positioning error, of 0.14±0.06 mm, was obtained by analyzing the log file for a various gantry angles during an arc delivery. The isocenter accuracy was within a radius of 1 mm, without any recalibration for two years. In conclusion, our stereotactic irradiation system using DMLC was capable of providing accurate stereotactic treatment.
Department of Radiology, Osaka City University Hospital.
Daisaku
D
Tatsumi
Ryosei
R
Nakada
Shinichi
S
Tsutsumi
Mariko
M
Sakamoto
Makoto
M
Inoue
Takao
T
Ichida
Masako
M
Hosono
D004867:Equipment Design; D010315:Particle Accelerators / Q000295:instrumentation*; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation*; D061106:Radiotherapy Setup Errors; D020266:Radiotherapy, Conformal / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D013238:Stereotaxic Techniques / Q000295:instrumentation*