Teflon cylindrical phantom for delivery quality assurance of SBRT

摘要: At our institution the standard delivery quality assurance (DQA) procedure for tomotherapy plans is accomplished with a water equivalent phantom, EDR2 film, and ion chamber point-dose measurements. Most deliver at most 5 Gy to dose plane; however, recently stereotactic body radiotherapy (SBRT) protocol has produced delivering upwards of 12 film plane. saturates ~ 7 Gy, requiring modification DQA SBRT plans. To reduce plane accommodate possible move using Varian RapidArc, Teflon phantom been constructed tested. Our cylindrical in shape similar design phantom. The was MVCT scanned on TomoTherapy system images imported into Eclipse planning systems. Phantom were smoothed artifacts treatment purposes. Verification delivered benchmarked against procedure. tolerance criteria 3% difference measurements gamma pass rate > 90% (criteria: 3 mm DTA, difference, 10% threshold). sufficiently reduced Both systems calculated accurate point doses largest differences being 2.4% 4.4% Rapid Arc Measured distributions correlated well calculations (γ 95%). These results comparable appears be potential option DQA. Preliminary data show that are capable calculating Teflon, allow direct measured without need rescaling.