Minimum requirements for commissioning and long-term quality assurance of Elekta multi-leaf collimator for volumetric modulated arc therapy.
We have proposed minimum requirements for commissioning and long-term quality assurance (QA) of an Elekta multi-leaf collimator (MLC) for volumetric modulated arc therapy (VMAT). The MLC leaf position accuracy during VMAT delivery was evaluated with the use of three different QA test plans: (1) a leaf gap-width test between opposing leaves by measurement of the isocenter dose during constant-gap sliding-window delivery with varied dose rates, MLC leaf speeds, and gantry angles; (2) a leaf position test by picket-fence delivery with and without gantry rotation; and (3) a leaf-bank symmetry test by measurement of the field geometry with different collimator angles at a fixed gantry position. All the QA test plans were created using an ERGO++ treatment-planning system. The leaf gap-width deviation was within 0.2 mm, the leaf position deviation was within 0.5 mm, and the leaf-bank symmetry error was within 0.5 mm under all the test conditions. MLC leaf position accuracy and long-term stability were confirmed by the proposed procedures.
Department of Radiology, Osaka City University Hospital, 1-5-7 Asahimachi, Abenoku, Osaka 545-8586, Japan. t-dai@u01.gate01.com
Daisaku
D
Tatsumi
Ryosei
R
Nakada
Akane
A
Yomoda
Kentaro
K
Ishii
Shinichi
S
Tsutsumi
Makoto
M
Inoue
Takao
T
Ichida
Masako N
MN
Hosono
Yukio
Y
Miki
D011786:Quality Control; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation* / Q000592:standards; D013997:Time Factors