Is a quasi-3D dosimeter better than a 2D dosimeter for Tomotherapy delivery quality assurance?

8th International Conference on 3D Radiation Dosimetry

Xing, Aitang^1 ; Deshpande, Shrikant^1,3 ; Arumugam, Sankar^1 ; George, Armia^1 ; Holloway, Lois^1,2,3,4 ; Vial, Philip^1,2 ; Goozee, Gary^1,4

Liverpool and Macarthur Cancer Therapy Centres, Ingham Institute, Liverpool Hospital, NSW, Australia^1

Institute of Medical Physics, School of Physics, University of Sydney, NSW, Australia^2

Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia^3

South West Clinical School, University of New South Wales, NSW, Australia^4

关键词: 2D detector;    Chest wall;    Mean values;    Patient specific;    Standard deviation;    Statistical dependence;    Tomotherapy;    Treatment sites;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/573/1/012077/pdf
DOI  :  10.1088/1742-6596/573/1/012077

来源: IOP

【 摘 要 】

Delivery quality assurance (DQA) has been performed for each Tomotherapy patient either using ArcCHECK or MatriXX Evolution in our clinic since 2012. ArcCHECK is a quasi-3D dosimeter whereas MatriXX is a 2D detector. A review of DQA results was performed for all patients in the last three years, a total of 221 DQA plans. These DQA plans came from 215 patients with a variety of treatment sites including head-neck, pelvis, and chest wall. The acceptable Gamma pass rate in our clinic is over 95% using 3mm and 3% of maximum planned dose with 10% dose threshold. The mean value and standard deviation of Gamma pass rates were 98.2% ± 1.98(1SD) for MatriXX and 98.5%±1.88 (1SD) for ArcCHECK. A paired t-test was also performed for the groups of patients whose DQA was performed with both the ArcCHECK and MatriXX. No statistical dependence was found in terms of the Gamma pass rate for ArcCHECK and MatriXX. The considered 3D and 2D dosimeters have achieved similar results in performing routine patient-specific DQA for patients treated on a TomoTherapy unit.