Research on Dosimetry and Clinical Impact of Leakage and Transmission Radiation
of HD120 MLC in Varian Novalis Tx Medical Linear Accelerator
DENG Yongjina, OUYANG Bina, WANG Zhenyua, XIAO Zhenhuaa, HUANG Botiana, HUANG Jingxiana, LI Honghangb, BAO Yonga
DENG Yongjina, OUYANG Bina, WANG Zhenyua, XIAO Zhenhuaa, HUANG Botiana, HUANG Jingxiana, LI Honghangb, BAO Yonga
a. Department of Radiation Oncology; b. Department of Medical Engineering, The First Affiliated Hospital of
Sun Yat-sen University, Guangzhou Guangdong 510080, China
Abstract:Objective To make research on dosimetry and clinical impact of leakage and transmission radiation of HD120 MLC in Varian
Novalis Tx medical linear accelerator. Methods The ionization chamber, electrometer, water tank and solid water were used to measure
the leakage and transmission radiation of MLC in different positions and directions in the closed field. A total of 10 cases of whole brain
radiotherapy were selected as clinical test plans, to explore the impact of leakage and transmission radiation of MLC on organ at risk
(OARs) including eyes and lens outside the field which were sensitive to radiation. Results The intraleaf transmission rate of HD120
MLC was 0.9%-1.4%, and the interleaf leakage rate was 1.3%-1.9%, while the leaf ends leakage rate was as much as 25%-35%. The
leakage and transmission rate of 15 MV photon radiation was slightly higher than that of 6 MV. The clinical test plans indicated that the
OARs was affected by leakage and transmission radiation. While meeting the dose coverage requirement of target volume, the way that
used jaws and MLC together to shelter OARs got better protection effect than used MLC only, which showed significant differences
(P<0.05). Conclusion The leakage and transmission radiation of HD120 MLC has unnegligible influence on radiation dosimetry, which
should be considered in clinical treatment plan to protect OARs and meet the dose coverage requirement of target volume at the same time.
邓永锦a,欧阳斌a,王振宇a,肖振华a,黄伯天a,黄镜先a,李宏行b,包勇a. Varian Novalis Tx医用直线加速器HD120MLC漏透射特性的测定及其临床影响研究[J]. 中国医疗设备, 2018, 33(10): 49-53.
DENG Yongjina, OUYANG Bina, WANG Zhenyua, XIAO Zhenhuaa, HUANG Botiana, HUANG Jingxiana, LI Honghangb, BAO Yonga. Research on Dosimetry and Clinical Impact of Leakage and Transmission Radiation
of HD120 MLC in Varian Novalis Tx Medical Linear Accelerator. China Medical Devices, 2018, 33(10): 49-53.