现代医药卫生
現代醫藥衛生
현대의약위생
Journal of Modern Medicine & Health
2015年
22期
3380-3381,3384
,共3页
前列腺肿瘤%放射治疗剂量%多叶准直器%位置偏移
前列腺腫瘤%放射治療劑量%多葉準直器%位置偏移
전렬선종류%방사치료제량%다협준직기%위치편이
Prostatic neoplasms%Radiotherapy dosage%Multi leaf collimator%Position offset
目的 评价高分辨多叶准直器(HDMLC)位置偏移对前列腺癌调强放射治疗(IMRT)在不同剂量率下剂量分布的影响,为多叶准直器(MLC)的日常质量控制提供参考.方法 选取2014年2月至2015年4月32例前列腺癌患者,使用9个照射野IMRT计划进行放射治疗,射野间隔40°,使用瓦里安Turebeam STX加速器HDMLC、Eclipse治疗计划系统,模拟每个计划在下列条件下引入固定数值(0.3、0.5、1.0、2.0 mm)的MLC位置偏差:(1)MLC X1X2方向同时扩大;(2)MLC X1X2方向同时缩小.每个计划结果的比较使用以下2个指标:(1)95%等剂量线适形指数(95%CI);(2)直肠最高剂量(Rectum Dmax).结果 (1)如果MLC沿X1X2准直器方向扩大偏移大于或等于0.3 mm,则95%CI下降,Rectum Dmax增加,并且这种影响与剂量率和偏移量的增大成正比;(2)如果MLC沿X1X2准直器方向缩小偏移大于或等于0.3 mm时,95%CI先增加到峰值;如果MLC缩小偏移大于或等于1.0 mm时,95%CI迅速下降,且剂量率越高下降越明显;然而, Rectum Dmax呈明显减少趋势,并且这种减少与剂量率和偏移量的增大成正比.结论 HDMLC的叶片位置误差大于0.3 mm时,前列腺癌的IMRT计划会发生大量的剂量偏差,并且这种偏差随着剂量率的增加更加明显,因此MLC日常质量保证应将MLC平均位置误差控制在0.3 mm以内.
目的 評價高分辨多葉準直器(HDMLC)位置偏移對前列腺癌調彊放射治療(IMRT)在不同劑量率下劑量分佈的影響,為多葉準直器(MLC)的日常質量控製提供參攷.方法 選取2014年2月至2015年4月32例前列腺癌患者,使用9箇照射野IMRT計劃進行放射治療,射野間隔40°,使用瓦裏安Turebeam STX加速器HDMLC、Eclipse治療計劃繫統,模擬每箇計劃在下列條件下引入固定數值(0.3、0.5、1.0、2.0 mm)的MLC位置偏差:(1)MLC X1X2方嚮同時擴大;(2)MLC X1X2方嚮同時縮小.每箇計劃結果的比較使用以下2箇指標:(1)95%等劑量線適形指數(95%CI);(2)直腸最高劑量(Rectum Dmax).結果 (1)如果MLC沿X1X2準直器方嚮擴大偏移大于或等于0.3 mm,則95%CI下降,Rectum Dmax增加,併且這種影響與劑量率和偏移量的增大成正比;(2)如果MLC沿X1X2準直器方嚮縮小偏移大于或等于0.3 mm時,95%CI先增加到峰值;如果MLC縮小偏移大于或等于1.0 mm時,95%CI迅速下降,且劑量率越高下降越明顯;然而, Rectum Dmax呈明顯減少趨勢,併且這種減少與劑量率和偏移量的增大成正比.結論 HDMLC的葉片位置誤差大于0.3 mm時,前列腺癌的IMRT計劃會髮生大量的劑量偏差,併且這種偏差隨著劑量率的增加更加明顯,因此MLC日常質量保證應將MLC平均位置誤差控製在0.3 mm以內.
목적 평개고분변다협준직기(HDMLC)위치편이대전렬선암조강방사치료(IMRT)재불동제량솔하제량분포적영향,위다협준직기(MLC)적일상질량공제제공삼고.방법 선취2014년2월지2015년4월32례전렬선암환자,사용9개조사야IMRT계화진행방사치료,사야간격40°,사용와리안Turebeam STX가속기HDMLC、Eclipse치료계화계통,모의매개계화재하렬조건하인입고정수치(0.3、0.5、1.0、2.0 mm)적MLC위치편차:(1)MLC X1X2방향동시확대;(2)MLC X1X2방향동시축소.매개계화결과적비교사용이하2개지표:(1)95%등제량선괄형지수(95%CI);(2)직장최고제량(Rectum Dmax).결과 (1)여과MLC연X1X2준직기방향확대편이대우혹등우0.3 mm,칙95%CI하강,Rectum Dmax증가,병차저충영향여제량솔화편이량적증대성정비;(2)여과MLC연X1X2준직기방향축소편이대우혹등우0.3 mm시,95%CI선증가도봉치;여과MLC축소편이대우혹등우1.0 mm시,95%CI신속하강,차제량솔월고하강월명현;연이, Rectum Dmax정명현감소추세,병차저충감소여제량솔화편이량적증대성정비.결론 HDMLC적협편위치오차대우0.3 mm시,전렬선암적IMRT계화회발생대량적제량편차,병차저충편차수착제량솔적증가경가명현,인차MLC일상질량보증응장MLC평균위치오차공제재0.3 mm이내.
Objective To evaluate the influence of position deviation of high definition multi leaf collimator (HDMLC) on the dose distribution under different dose rates in the intensity modulated radiotherapy (IMRT) of prostate cancer. Methods 32 pa-tients with prostate cancer from February 2014 to April 2015 were selected and performed the radiotherapy by using the IMRT plan-ning with 9 irradiation fields,the irradiation interval of 40°,Varian Truebeam accelerator HDMLC,Eclipse treatment planning sys-tem,the MLC position deviation of introduced fixed numerical values (0.3,0.5,1.0,2.0 mm) for each planning was under the follow-ing conditions:(1)simultaneous enlargement of MLC X1 and X2 directions;(2)simultaneous shrink of MLC X1 and X2 directions. The two indexes were used for the comparison of each planning results:(1)the 95%isodose line conformal index(95%CI);(2) the rectum maximum dose(rectum Dmax). Results (1) If MLC amplified deviation at the MLC X1X2 collimator directions≥0.3 mm, 95%CI was decreased,while rectum Dmax was increased,moreover this influence was directly proportional to the enlargement of dose rate and deviation amount;(2)if the MLC shrunk deviation at the MLC X1X2 collimator directions≥0.3 mm,95%CI was firstly increased to the peak value;if MLC shrunk deviation≥1.0 mm,95%CI was rapidly dropped,moreover the higher the dose,the more obvious the drop;however,rectum Dmax showed a obviously decreasing trend and this reduce was directly proportional to the dose rate and deviation amount. Conclusion If the leaf deviation of HDMLC is more than 0.3 mm,a large number of dose deviation could occur in the IMRT planning of prostate cancer,moreover this deviation could be more obvious with the increase of dose rate, therefore the MLC daily quality assurance should control the average MLC position deviation within 0.3 mm.
