摘要
目的研究宫颈癌术后盆腔三维适形放疗（3DCRT）和调强放疗（IMRT）技术建立方法，进行三维剂量学研究，找出适合临床应用的最佳方案。方法选择宫颈癌根治性全子宫切除术及盆腔淋巴结清扫术后具有术后盆腔放疗指征的10例患者行下列研究：（1）放疗最佳体位（俯卧位或仰卧位）比较；（2）放疗时膀胱充盈状况与正常组织受照体积相关性研究；（3）放疗射野移动误差测定和靶区勾画；（4）3DCRT及IMRT计划设计及优化比较。结果采用俯卧位固定方式患者治疗中心点的摆位误差在前后、头脚及左右方向的误差均在5mm以内，而采用仰卧位误差均〉5mm，两者差异有统计学意义。俯卧位、膀胱充盈状态时膀胱受照体积百分比较之膀胱处于排空状态时为小，且小肠和结肠受照体积百分比较之膀胱处于排空状态时为小。俯卧位、膀胱充盈状态时射野片显示放疗过程中射野移动的总误差为（7．4±1．6）mm。采用95％可信区间，CTV至PTV的外放边界可定为1cm。3DCRT3、4、5和6个射野下PTV适形指数分别为0．46、0．67、0．68和0．68，4个以上射野数目的增加不再显著改善靶区分布和减少正常组织受照体积百分比。IMRT5、7、9、11和13个射野下PTV适形指数分别为0．75、0．83、0．84、0．85和0．85，9个以上增加射野数目不再显著改善靶区分布和减少正常组织受照体积百分比。结论宫颈癌术后盆腔放疗者俯卧位固定方式因摆位误差小而优于仰卧位固定方式，膀胱处于充盈状态因可使膀胱及肠道受照体积百分比减少而优于膀胱排空状态。对宫颈癌术后盆腔3DCRT和IMRT计划的三维剂量学研究表明，3DCRT以4个射野数计划为优，IMRT以9个射野数计划为优。
Objective To establish the methods of three-dimensional conformal（3DCRT） and intensity-modulated radiotherapy（IMRT） for whole pelvic irradiation in post-hysterectomy cervical carcinoma, And to optimize the methods for clinical practice. Methods Between 2004 and 2005,10 patients with cervical carcinoma who underwent hysterectomy with high risk of recurrence were selected for this study. The following observations and measurements were used for the study： Set-up errors with supine or prone position were measured to determine appropriate immobilization position. Influence of full and empty bladder on irradiated normal tissue volume was measured. Treatment errors were detected and CTV/PTV were then delineated. 3DCRT and IMRT planning and comparison were applied. Results The set-up error was within 5 nun of three dimensions in prone position and more than 5 mm in supine position,the difference of which was statistically significant. The percentage of irradiated volume of the bladder and bowel was smaller when the bladder was full comparing with empty bladder. In prone position and with full bladder, portal films showed the movement of isocenter in three directions. The total uncertainty was [7.4 ±1.6] mm. For 95% confidence interval,the margin from CTV to PTV was 1 cm. CIPTV for 3,4,5,and 6 fields 3DCRT was 0.46, 0.67,0.68, and 0.68, respectively. When beyond 4 fields, the advantage of adding fields was not significant.Four fields planning was feasible for clinical practice. CI for 5,7,9,11, and 13 fields IMRT was 0.75,0.83, 0.84,0.85, and 0.85, respectively. When beyond 9 fields, the advantage of adding fields was not significant. Nine fields planning was feasible for clinical practice. Conclusions For whole pelvic radiotherapy for post-hysterectomy cervical carcinoma, prone position was better than supine position for immobilization due to smaller set-up errors. The full bladder is recommended during radiotherapy, planning, For clinical practice, 4 fields planning is feasible in 3DCRT while 9 fields planning is feasible in IMRT.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2008年第5期372-376,共5页
Chinese Journal of Radiation Oncology
关键词
宫颈肿瘤
三维适形放疗
调强放疗
剂量学
Cervical neoplasms
Three-dimensional conformal radiotherapy
Intensity-modula- ted radiotherapy
Dosimetry
