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目的 介绍和探讨调强适形放射治疗的质量保证和质量控制方法。方法 (1)通过体模移植的方法分别用电离室在水模体中测量 4 2例病人的IMRT治疗计划某点的绝对剂量 ,验证逆向计划系统剂量计算的准确性 ,进一步修正它的计算校正因子。 (2 )为验证MIMiC纵向的对称性、叶片横向的可靠性、稳定性 ,把剂量胶片放在两块有机玻璃板之间每周拍摄验证片。结果 (1)测量所得的相对误差均在 3%以内 ,故逆向计划系统计算校正因子不需进行修正。 (2 )每周胶片验证的结果偏差均小于 1mm ,则无需对其进行机械调整。结论 近一年的IMRT工作实践证明所采用的质量保证和剂量验证措施是可行。
Objective To introduce and discuss the methods of quality assurance and quality control of intensity modulated radiotherapy. Methods (1) The absolute dose of a certain point of IMRT treatment plan of 42 patients in the water phantom was measured by phantom transplantation respectively by ionization chamber to verify the accuracy of the dose calculation in the reverse-planned system and to further correct its calculation Correction factor. (2) To verify the longitudinal symmetry of the MIMiC, the reliability and stability of the transverse cross-section of the blade, a dose of film was placed between two sheets of plexiglass to take a verification film each week. Results (1) The relative errors of the measurement are all within 3%, so the correction factor calculated by the reverse planning system need not be corrected. (2) weekly film verification results are less than 1mm deviation, there is no need for mechanical adjustment. Conclusions Nearly a year of IMRT work proved that the quality assurance and dose verification measures adopted were feasible.