CAJ | 학술논문

目的探讨食管癌简化调强放疗(sIMRT)中解剖学动态变化规律和靶体积变化,以及这些变化对初始计划剂量学分布影响,评价重新修改放疗计划的必要性和时机.方法 29例接受单纯放疗的食管癌患者常规模拟CT扫描,其中11例在放疗开始后每2周扫描(每例4次),18例在放疗第4周进行第2次扫描(每例2次).将CT模拟图像与初始计划CT图像融合后由同一医生重新勾画靶区及正常器官,将初始计划导入新勾画的靶区,得出靶区及正常器官剂量学参数后与初始计划比较.结果每2周扫描的11例忠者疗前和疗后第2、4、6周胸部轮廓体积变化平均值分别为13948cm3和13245、12789、11837 cm3(6周时t=2.07,P=0.043),每2周体积缩小平均值为425 cm3.0～6周中大体肿瘤体积平均值逐渐降低,其中0周与4、6周比较下降最明显(47.22 cm3:37.78 cm3,t=2.44,P=0.035;47.22 cm3:33.55 cm3,t=2.55,P=0.029),而4周和6周变化不明显(t=-0.75,P=0.261).0～6周靶区适行指数逐渐降低和不均匀指数依次增加,分别为0.70、0.68、0.67、0.61(4周时t=3.20,P=0.013)和1.13、1.22、1.23、1.27(4周时t=-4.56,P=0.001).全组患者sIMRT 4周时100%大体肿瘤受照剂量增加至62.57 Gy(t=-2.93,P=0.007),99%临床靶体积受照剂量和95%计划靶体积受照剂量分别下降至58.24 Gy(t=1.49,P=0.147;2例＜54 Gy)和57.44 Gy(t=2.07,P=0.048);正常组织中只有脊髓最大剂量和双肺V30的增加有统计学意义(41.52 Gy∶43.53Gy,t=-2.42,P=0.022;11.4%∶12.2%,t=-2.26,P=0.032).结论食管癌sIMRT4周时肿瘤体积变化最明显,是CT-CT融合观察靶体积变化的最佳时机.部分患者需要做二次计划的修改使肿瘤靶区获得合理剂量.
목적 탐토식관암간화조강방료(sIMRT)중해부학동태변화규률화파체적변화,이급저사변화대초시계화제량학분포영향,평개중신수개방료계화적필요성화시궤.방법 29례접수단순방료적식관암환자상규모의CT소묘,기중11례재방료개시후매2주소묘(매례4차),18례재방료제4주진행제2차소묘(매례2차).장CT모의도상여초시계화CT도상융합후유동일의생중신구화파구급정상기관,장초시계화도입신구화적파구,득출파구급정상기관제량학삼수후여초시계화비교.결과 매2주소묘적11례충자료전화료후제2、4、6주흉부륜곽체적변화평균치분별위13948cm3화13245、12789、11837 cm3(6주시t=2.07,P=0.043),매2주체적축소평균치위425 cm3.0～6주중대체종류체적평균치축점강저,기중0주여4、6주비교하강최명현(47.22 cm3:37.78 cm3,t=2.44,P=0.035;47.22 cm3:33.55 cm3,t=2.55,P=0.029),이4주화6주변화불명현(t=-0.75,P=0.261).0～6주파구괄행지수축점강저화불균균지수의차증가,분별위0.70、0.68、0.67、0.61(4주시t=3.20,P=0.013)화1.13、1.22、1.23、1.27(4주시t=-4.56,P=0.001).전조환자sIMRT 4주시100%대체종류수조제량증가지62.57 Gy(t=-2.93,P=0.007),99%림상파체적수조제량화95%계화파체적수조제량분별하강지58.24 Gy(t=1.49,P=0.147;2례＜54 Gy)화57.44 Gy(t=2.07,P=0.048);정상조직중지유척수최대제량화쌍폐V30적증가유통계학의의(41.52 Gy∶43.53Gy,t=-2.42,P=0.022;11.4%∶12.2%,t=-2.26,P=0.032).결론 식관암sIMRT4주시종류체적변화최명현,시CT-CT융합관찰파체적변화적최가시궤.부분환자수요주이차계화적수개사종류파구획득합리제량.
Objective To study the dynamic changes of anatomy and the dosimeter distribution those changes influenced. Methods Initially simplified intensity modulated radiation therapy (sIMRT)were performed to twenty-nine patients with phase Ⅲ - Ⅳa esophageal carcinoma from January 2007 to March 2009. The target volumes and involving organs were contoured on the primary spiral CT pictures.After sIMRT planning being finished, secondary CT scan was acquired to rectify the treatment center. For eleven patients at every other week and eighteen patients at the fourth week, spiral CT images were acquired according to the same treatment center, and thereafter fused with the first CT images. Firstly, the law of change and the best time of replanning were searched:the changed gross tumor volume (GTV), gross node volume (GTVnd), plan target volume (PTV) and normal organs (lung, spinal cord, heart and outline) on the fusion interface were modified by a single physician, the changes for each structure throughout treatment were measured by system software. Secondly, dose distributions were computed and evaluated for replanning CT using the same beams arrangement as the initial plan. Cumulative dose was estimated using weighted average and compared with the original plan. Results For eleven patients, The law of change:the volume of outlines and GTV gradually decreased, and the change come to peak in the fourth week. The conformal index for PTV gradually decreased, whereas the heterogeneous index gradually increased. For twenty-nine patients on the fourth week, the dose of GTV were more than 60 Gy. The dose of PTV-D95 and CTV-D99 decreased ( t = 1.49, P = 0. 147 and t = 2. 07, P = 0. 048 respectively). The dose of CTV-D99 in two patients deceased to 54 Gy or less. The cord-Dmax and lung V30 increased significantly ( t = - 2. 42, P = 0. 022 and t = -2. 26,P =0. 032). Conclusions During the course of sIMRT for esophageal cancer, the volume of GTV decreased and the change come to peak in the fourth week. It is the best time for evaluating the change of dose of target volume using CT-CT fusion. For some patients, revise of the treatment plan is needed to ensure adequate target volume dosage and safety of normal tissues.