Characteristics and Clinical Application of the Octavius 4D Ionization Chamber Arrays in Dose
Verification of the RapidArc
WANG Ning1，CHEN Along2
1. Department of Radiotherapy, Zhongshan Traditional Chinese Medicine Hospital, Zhongshan Guangdong 528400, China;
2. State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou Guangdong 510060, China
Abstract：Objective To evaluate the characteristics and clinical application of the Octavius 4D ionization chamber arrays in
RapidArc dose verification. Methods The reproducibility, dose and dose rate dependence, field sizes dependence of the Octavius 729
and 1000SRS ionization chamber were measured. The results were compared with the measurement results of PTW31010 0.125 cm3
ionization chamber. Gamma rate was used to analyze the dose difference between selected 20 RapidArc plans by
the Octavius 729 and 1000SRS two-dimensional ionization chamber array respectively, which included 10 nasopharyngeal cancer
and 10 rectal cancer. Results The Octavius 729 and 1000SRS performed well for all tests. Average Gamma analysis
passing rates with 3%/3 mm for 20 RapidArc plans were nasopharyngeal cancer ( 96.2% and 99.3% ) and rectal cancer ( 98.4%
and 99.7% ) respectively, statistical significance has been found between either two of the groups (P<0.05). Conclusion Octavius
4D system (729 and 1000SRS) can meet the dose verfication for RapidArc plans of multiple cancer. The measured
plane is always rotated in a random frame and perpendicular to the beam, which hasn't directional dependence. The
complexity of VMAT plan is the main factor affecting the passing rate, 1000SRS liquid ionization chamber array has
great advantages.
王宁1，陈阿龙2. Octavius 4D电离室探头特性及在RapidArc剂量验证中的应用研究[J]. 中国医疗设备, 2019, 34(7): 65-68.
WANG Ning1，CHEN Along2. Characteristics and Clinical Application of the Octavius 4D Ionization Chamber Arrays in Dose
Verification of the RapidArc. China Medical Devices, 2019, 34(7): 65-68.
