CAJ | 학술논문

目的调查放射治疗计划系统(TPS)计算的多叶光栅(MLC)小野输出因子,研究用0.015 cc电离室验证小野输出因子的测量方法.方法在河南省选择8台可开展调强放射治疗的医用加速器,调查TPS计算的小野输出因子并与国际原子能机构(IAEA)推荐的出版值进行比较.如果2 cm×2 cm照射野相对偏差超出IAEA要求的±3％,3 cm×3 cm、4 cm×4 cm、6 cm×6 cm照射野相对偏差超出IAEA要求的±2％,则用0.015 cc电离室和Unidos剂量仪进行测量验证.结果 8台医用加速器的TPS计算小野输出因子与出版值比较,5台相对偏差符合IAEA要求,占调查总台数的62.5％,3台相对偏差超过IAEA要求,占调查总台数的37.5％.用针尖电离室测量验证,3台测量结果均符合IAEA要求.结论河南省部分医用加速器TPS计算的MLC小野输出因子,需要现场实施小电离室测量修正,测量值作为制定放射治疗计划的依据.
목적 조사방사치료계화계통(TPS)계산적다협광책(MLC)소야수출인자,연구용0.015 cc전리실험증소야수출인자적측량방법.방법 재하남성선택8태가개전조강방사치료적의용가속기,조사TPS계산적소야수출인자병여국제원자능궤구(IAEA)추천적출판치진행비교.여과2 cm×2 cm조사야상대편차초출IAEA요구적±3％,3 cm×3 cm、4 cm×4 cm、6 cm×6 cm조사야상대편차초출IAEA요구적±2％,칙용0.015 cc전리실화Unidos제량의진행측량험증.결과 8태의용가속기적TPS계산소야수출인자여출판치비교,5태상대편차부합IAEA요구,점조사총태수적62.5％,3태상대편차초과IAEA요구,점조사총태수적37.5％.용침첨전리실측량험증,3태측량결과균부합IAEA요구.결론 하남성부분의용가속기TPS계산적MLC소야수출인자,수요현장실시소전리실측량수정,측량치작위제정방사치료계화적의거.
Objective To investigate muli-leaf collimator (MLC)-defined small field output factors calculated by the treatment planning system (TPS), and to study the measuring method of small field output factors verified by 0.015 cc PinPoint ionization chamber.Methods Eight medical accelerators for intensity-modulated radiation therapy (IMRT) were investigated in Henan province, and TPS-calculated output factors for various small fields (6 cm ×6 cm,4 cm ×4 cm,3 cm ×3 cm and 2 cm ×2 cm) were compared with published values recommended by IAEA.If the relative deviation was more than ± 3％ for the 2 cm ×2 cm field size and ±2％ for the fields of 6 cm ×6 cm, 4 cm ×4 cm and 3 cm ×3 cm, which was beyond the scope of IAEA allowed, the output factors will be measured and verified using 0.015 cc PinPoint ionization chamber and Unidos electrometer.Results TPS-calculated small field output factors for eight medical accelerators were compared with published values.The relative deviation of small field output factors for five pieces of equipment, which accounted for 62.5％ of the total, met the IAEA's requirement, while the other three, which accounted for 37.5％ of the total, did not.After measuring with PinPoint ionization chamber, the results from only three pieces of equipment met minimum IAEA's requirement.Conclusions MLC-defined small field output factors calculated by TPS for some medical accelerators in Henan need to be measured and corrected using micro-ionization chamber, and the measured values could be taken as the basis of radiation treatment planning.