Abstract:Objiective To study the application of ArcCHECK combined with 3DVH in volumetric modulated arc therapy (VMAT)
dose verification. Methods Twenty cancer cases were randomly selected, including five nasopharyngeal carcinoma cases, five
esophageal cancer and lung cancer cases respectively, and five rectal cancer cases. Double arc VMAT plans were designed with
Pinnacle3 Version 9.8 treatment planning system (TPS) and transplanted to the ArcCHECK phantom to recalculate the dose. The
ArcCHECK phantom was used to measure the beam output, and the gamma passing rate of each patient was evaluated. Then the
dose distribution of target and organs at risk were reconstructed by 3DVH software, and the deviation of dose volume parameters
were compared with that of TPS. Results The average gamma passing rates of VMAT plans in twenty patients were 98.1%±1.1%.
Except for one of the patients with nasopharyngeal carcinoma, the gamma passing rates in the remaining cases were more than 95%.
The deviations of D2%, D98%, D50%, Dmean of PTV were less than 3%. In organs at risk, the Dmax deviations of left and right crystal in one
nasopharyngeal carcinoma case were 8.63% and 7.01%,respectively. For two rectal cancer cases,the V50 deviations of left femoral
head and right femoral head were more than 5%, and the dose volume deviations of other cases were less than 5%. Conclusion
ArcCHECK combined with 3DVH in VMAT dose verification can provide more dose distribution informations, which help to
improve the safety of clinical tumor radiotherapy.