ABSTRACT
Objective To develop the method for testing the consistency of irradiation field produced by the active spot scanning proton and heavy ion accelerator.Methods Calibration of the EBT3 films were carried out with the calibrated ion beam to establish the dose calibration curve.According to the different proton and carbon ion energies (proton:94.29,150.68,212.62 McV;carbon ion:175.99,283.43,412.54 MeV/u),EBT3 films were located in the solid water phantoms in each therapy room,respectively.Finally,the irradiated EBT3 films were scanned and the radiation field size's deviation and flatness were analyzed.Results In different conditions,radiation field size's deviations were all less than 2 mm and the flatness parameters were all controlled below the 5％.Conclusions EBT3 films can be used to test the active spot scanning proton and heavy ion accelerator's radiation field uniformity.
ABSTRACT
Objective To study the quality testing of dose delivery system of the active spot scanning proton and heavy ion accelerator,in order to provide the reference for the quality control of related equipment.Methods In the four therapy rooms,both 0.6 cc chambers and Gafchromic EBT3 films were used,respectively,to test the accelerator for dose reproducibility,dose linearity,dose stability,depth dose distribution,beam scanning position deviation and radiation field uniformity in each therapy room.Results Dose reproducibility variation coefficients are all less than 1.5％,dose linearity's maximum deviations less than 2％,dose stability's deviations less than 2％,depth dose distribution stability within 2％,beam scanning position deviation less than 1 mm,consistency of irradiation field's deviation less than 2 mm,and flatness within ± 5％.Conclusions The indicators about quality testing for the active spot scanning proton and heavy ion accelerator are all in line with the requirements of IEC standards draft.