ABSTRACT
Objective Objective To verify the accuracy of dose calculation and the precision of beam modeling in a Pinnacle three-dimension treatment planning system(TPS).Methods Based on the photon beam model data of a Varian 600C Linac,output factor verification and 12 tests were carried out ac- cording to the recommendation of Netherlands Commission on Radiation Dosimetry(NCS).The results of ion chamber measurement and TPS calculation at selected points were compared.Deviation and confidence limit were used to evaluate dose calculation accuracy.Results The Pinnacle TPS had a high precision of dose calculation when compared with the measurement data.Deviation of calculated output factors was＜1% on all opening patrols,and was＜3% on wedged portal except one with the size of 15 cm?40 cm and angled 60?.The results of 12 tests were in accordance with the criteria of NCS recommendation,with maximum av- erage deviation＜1%.The overall accuracy is better than those of other TPS reported in the literature. Conclusions Dose verification is a prerequisite before a three-dimension treatment planning system is used in the clinical practice.Pinnacle treatment planning system installed in our institute is reasonably acceptable and satisfactory.