Room: Exhibit Hall
Purpose: To evaluate the availability of patient-specific quality assurance(QA) using different dose verification decices.
Methods: Twenty cervical cancer patients with VMAT treatment plans delivered by Varian Trilogy machine (Varian, US) were selected. The absolute dose verification of pretreatment and the dose verification based on anatomic structure were performed respectively with different dose verification tools.respectively. And the quantitative evaluation would be analyzed. The dose verification decices include mapcheckã€?ArcCheckã€?EPID; Mobius 3D (Mobius Medical Systems, US) and SNC/3DVH(SunNuclear, US) for dose-reconstructio based on anatomical structure. Of course, the gamma analysis index is 3%/3mm, and the pass rate is 90%.
Results: Compared with the dose planed, the 2D Gamma pass rate verified by the pretreatment plan relatively, A good consistency was seen for the gamma passing rates of 2D Mapcheck and EPID showed a little difference of (97.8Â±2.55)% and(98.10Â±1.25)% for pre-treatment verification. The 3D Gamma pass rate [ArcCheck (97.10Â±1.25)% vs Mobius(97.25Â±2.32)%] shows good consistency. According to the dose verification of the anatomical structure, the maximum deviation between the cervical cancer target area and the DVH index of the organ that is at risk was -2.18Gy and 1.55%, respectively. The maximum deviation measured by Mobius was -2.45Gy and 1.37%.
Conclusion: Several different dose verification tools to effectively implement individualized quality patient, pre-treatment of validation and dose verification based on anatomical structures is complementary relationship, to fully guarantee the safety of patients during radiotherapy dose and accuracy to provide strong guarantee.
Not Applicable / None Entered.
TH- Radiation dose measurement devices: Phantoms for dosimetric measurement