CAJ | 학술논문

目的比较早期乳腺癌保乳术后切线2野动态调强与非共面多野调强放疗治疗靶区和危及器官的剂量学差异.方法选取40例接受保乳术后放疗的左侧乳腺癌患者,在同一患者CT影像上,利用相同优化条件分别进行切线2野和非共面3、4、5野4种调强治疗计划设计.比较4种计划的靶区剂量分布、心脏、左肺及右侧乳腺受照剂量和体积,以及机器跳数的差异.结果非共面4、5野调强计划适形度指数(CI)和均匀性指数(HI)均优于切线2野调强计划(P＜0.05),临床靶区(PTV)最大剂量(Dmax)小于2野调强计划(P＜0.05),PTV最小剂量(Dmin)大于2野调强计划(P＜0.05).3野与2野计划间无明显差异.4种计划的右乳接受5 Gy照射的百分体积(V5)、心脏接受30 Gy照射的百分体积(V30)及平均剂量(Dmean)、左肺接受20和5 Gy照射的百分体积(V20、V5)、平均剂量(Dmean)无明显差异,而机器跳数间差异有统计学意义(F =25.63,P＜0.05),2野调强跳数最少,5野最多.结论保乳术后非共面4、5野调强计划与切线2野调强计划相比,靶区剂量分布更好,不明显增加正常组织、器官的受照射剂量,但机器跳数明显增加.
목적 비교조기유선암보유술후절선2야동태조강여비공면다야조강방료치료파구화위급기관적제량학차이.방법 선취40례접수보유술후방료적좌측유선암환자,재동일환자CT영상상,이용상동우화조건분별진행절선2야화비공면3、4、5야4충조강치료계화설계.비교4충계화적파구제량분포、심장、좌폐급우측유선수조제량화체적,이급궤기도수적차이.결과 비공면4、5야조강계화괄형도지수(CI)화균균성지수(HI)균우우절선2야조강계화(P＜0.05),림상파구(PTV)최대제량(Dmax)소우2야조강계화(P＜0.05),PTV최소제량(Dmin)대우2야조강계화(P＜0.05).3야여2야계화간무명현차이.4충계화적우유접수5 Gy조사적백분체적(V5)、심장접수30 Gy조사적백분체적(V30)급평균제량(Dmean)、좌폐접수20화5 Gy조사적백분체적(V20、V5)、평균제량(Dmean)무명현차이,이궤기도수간차이유통계학의의(F =25.63,P＜0.05),2야조강도수최소,5야최다.결론 보유술후비공면4、5야조강계화여절선2야조강계화상비,파구제량분포경호,불명현증가정상조직、기관적수조사제량,단궤기도수명현증가.
Objective To compare the dosimetric differences of target and organs at risk (OAR) induced by the tangential and non-coplanar multi-fields used in the dynamic intensity modulated radiotherapy (IMRT) plans for breast cancer patients after breast-conserving surgery.Methods Forty patients with early-stage left breast cancer after breast-conserving surgery were included.Based on the CT anatomy of the same patient,dynamic IMRT treatment plans using two tangential fields,3,4 and 5 non-coplanar fields were designed respectively utilizing the same optimization objects.The plans were compared by means of target dose distribution,the doses and irradiated volumes of heat,left lung,right breast,and total monitor units (MUs).Results The conformal index (CI) and homogeneity index (HI) of planning target volume (PTV) in the plans using 4 and 5 fields were better than that using 2 fields (P ＜ 0.05).Maximum doses (Dmax) in PTV were significantly lower in the plans of 4 and 5 fields than of 2 fields (P ＜0.05).Yet the plans of 4 and 5 fields generated significant higher minimum doses (Dmin) in PTV than that of 2 fields (P ＜ 0.05).No significant difference was observed between plans of 2 or 3 fields.Across the four plans,the differences of right breast V5 (relative volume acquired at least 5 Gy of dose),heart V30,heart mean dose (D),left lung V20,V5 and D were not significant.Yet the disparities of total MUs were statistically significant (F =25.63,P ＜ 0.05).The least MUs were used by the 2 fields and the most MUs were observed in the 5-field plans.Conclusions Comparing with IMRT plans of 2 fields,using 4 or 5 non-coplanar fields can improve the target dose distribution without increasing OAR doses.As a tradeoff,more MUs are needed for multi-fields plans.