CAJ | 학술논문

目的探讨直肠癌术后螺旋断层放疗(HT)、静态调强放疗(IMRT)及三维适形放疗(3D-CRT)的剂量学特点,为临床选择直肠癌术后放疗方法提供依据.方法回顾性选取10例Ⅱ、Ⅲ期中低位直肠癌切除术(Dixon手术)后患者,在其CT定位图像上勾画靶区及危及器官,并进行HT、IMRT及3D-CRT计划设计.要求至少95％的PTV达到处方剂量为50 Gy.结果 3种治疗计划均能满足处方剂量要求；除3D-CRT计划外,HT计划与IMRT计划均能较好地满足各危及器官剂量限制要求.HT、IMRT、3D-CRT计划的适形度指数CI分别为0.86、0.82和0.62(F=206.81,P＜0.001),剂量均匀性指数(HI)分别为0.001、0.157和0.205(x2 =15.8,P＜0.001).3D-CRT计划骨盆V50、膀胱V40、小肠V50、股骨头D5明显高于IMRT与HT计划(P＜0.05),而后两者差别无统计学意义.HT计划小肠V15大于IMRT计划与3D-CRT计划(71.1％ vs.63.3％、67.7％),差异无统计学意义.结论 HT、IM RT及3D-CRT3种治疗计划均可满足直肠癌靶区处方剂量要求.HT计划适形度和均匀性最好,其次为IMRT计划,3D-CRT计划最差.HT计划满足所有危及器官的剂量限制,对正常组织的保护略优于IMRT计划.3D-CRT计划简便、实用性强,但对危及器官的保护较差.
목적 탐토직장암술후라선단층방료(HT)、정태조강방료(IMRT)급삼유괄형방료(3D-CRT)적제량학특점,위림상선택직장암술후방료방법제공의거.방법 회고성선취10례Ⅱ、Ⅲ기중저위직장암절제술(Dixon수술)후환자,재기CT정위도상상구화파구급위급기관,병진행HT、IMRT급3D-CRT계화설계.요구지소95％적PTV체도처방제량위50 Gy.결과 3충치료계화균능만족처방제량요구；제3D-CRT계화외,HT계화여IMRT계화균능교호지만족각위급기관제량한제요구.HT、IMRT、3D-CRT계화적괄형도지수CI분별위0.86、0.82화0.62(F=206.81,P＜0.001),제량균균성지수(HI)분별위0.001、0.157화0.205(x2 =15.8,P＜0.001).3D-CRT계화골분V50、방광V40、소장V50、고골두D5명현고우IMRT여HT계화(P＜0.05),이후량자차별무통계학의의.HT계화소장V15대우IMRT계화여3D-CRT계화(71.1％ vs.63.3％、67.7％),차이무통계학의의.결론 HT、IM RT급3D-CRT3충치료계화균가만족직장암파구처방제량요구.HT계화괄형도화균균성최호,기차위IMRT계화,3D-CRT계화최차.HT계화만족소유위급기관적제량한제,대정상조직적보호략우우IMRT계화.3D-CRT계화간편、실용성강,단대위급기관적보호교차.
Objective To evaluate the dosimetric characteristics of helical tomotherapy (HT),intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D-CRT) for postoperative radiotherapy of rectal cancer.Methods Ten male patients with stage Ⅱ or Ⅲ middle or low position rectal cancer were selected retrospectively.All of the 10 patients underwent Dixon surgery and CT simulation orientation.The target volumes and normal organs were drawn in the CT images and the plans for HT,IMRT and 3D-CRT were designed.The prescribed dose was given 50 Gy in 25 fractions,covering at least 95％ of the planning target volume.Results All plans met the needs of the prescribed doses.The HT and IMRT plans met the needs of dose limit to organs at risk,however,the 3D-CRT plans failed to do that.The conformity indexes of HT,IMRT and 3D-CRT plans were 0.86,0.82 and 0.62,respectively (F =206.81,P ＜ 0.001),and the homogeneity indexes were 0.001,0.157,and 0.205,respectively (x2 =15.8,P ＜ 0.001).The 3D-CRT plans had larger volumes than the HT plans and IMRT plans in the high-dose regions such as pelvic V50,bladder V40,bowel V50 and femoral head D5 (P ＜ 0.05),but the differences between the HT plans and IMRT plans were not statistically significant (P ＞0.05).The V15 value of bowel of HT plans were higher than those of the IMRT and 3D-CRT plans (71.1％ vs.63.3％ and 67.7％,respectively).However,there was no significantly difference.Conclusions All of the HT,IMRT and 3D-CRT plans are able to meet the prescription dose requirement of the target regions of rectal cancer.The HT plans show the best dose homogeneity and target conformity,followed by the IMRT plans,and then the 3D-CRT plans.The HT plans meet the needs of all OARs slightly better than the IMRT plans.3D-CRT plans are simple and practical with poor protective ability toward the OARs.