JV Yong-jian, WANG Gao-ren, CAO Li-yuan, LI Ke-xin, WU Di-jun, TANG Ya-hong
Objective To analyze the dosimetric differences between the results calculated from the PBC algorithm and AAA algorithm respectively in the intensity-modulated radiotherapy(IMRT) treatment planning design for the prostate cancer patients. Methods For 13 postoperative prostate cancer patients, when the IMRT treatment plan was designed, the dose parameters were calculated with PBC algorithm and AAA algorithm respectively which was provided by the treatment planning system(Eclipse Version 8.10), then the dosimetric parameters, such as HI,CI,PTVDP,PTVmean,and the V50 of bladder and rectum were obtained and compared respectively. We also do the dose verification measurement with the two-dimensional ionization chamber array, and the actual measured dose distribution will be compared with that calculated from the AAA and PBC algorithm respectively to obtain the γ value, the dose difference in measurement chamber matrix point, DDmax and DD mean. Results The average difference of HI,CI,PTVDP and PTVmean between the results calculated with PBC and AAA algorithm separately are 0.003、0.004、2.2%、10 cGy respectively, and the average difference of bladder V50 and rectum V50 are 0.3% and 1.3%. Compared the dosimetric result calculated from the above mentioned two algorithms with the measurement result, the average difference of γ value, DDmax and DDmean are 0.9%、1.2% (2.4 cGy) and 0.85% (1.7 cGy) respectively. So the dose parameters calculated from the AAA and PBC algorithms are trivial. Conclusion For the prostate cancer patients IMRT treatment planning design, the PBC algorithm and AAA algorithm can all be used.
