Objective: To compare the protection for OAR( organ at risk ) of IMRT ( intensity - modulated radiation therapy ) and CRT ( conventional radiotherapy ) in the postoperation radiotherapy of cervical carcinoma. Methods : All 30 patients with cervical carcinoma who need postoperation radiotherapy were studied. Before the treatment, computed tomography scan image were transferred to an IMRT planning system, on which target area and OAR were completed. Clinical target volume( CTV ) included supravaginal portion and cuff,paracervical tissue,common iliac,internal , external iliac, obturator and sacral lymph nodes drainage region. Planning target volume( PTV ) was based on CTV,and PTV was extended 1cm in all directions. The prescription dose was 95% PTV 45Gy/l. 8Gy/25f. Every patient was designed for two plans ( IMRT and CRT ) . The comparison results were obtained by analyzing DVH map. Then 15 patients were treated with IMRT,the other patients treated with CRT. Results:Comparing the two radiotherapy technologies in the same prescription doses:The radiation volumes of marrow,small intestine,bladder and rectum in IMRT were significantly lower than in CRT. The rates of radiocystitis and radiation enterocolitis in IMRT were significantly lower than in CRT. There was no difference with the rates of bone marrow inhibition in both groups. Conclusion: To patients with cervical carcinoma who need postoperation radiotherapy, protection of IMRT for the OAR was better than CRT.%目的:比较IMRT (intensity modulated radiation therapy,调强适形放射治疗)和CRT(conventional radiotherapy,常规放疗)在宫颈癌术后放疗中,对危及器官保护方面的差异.方法:选取我院2007年1月-2010年1月30例宫颈癌术后放疗患者,均行CT模拟定位扫描并勾画靶区及危及器官,临床靶区(CTV)包括子宫、宫颈、阴道等原发肿瘤区域及髂总、髂外、髂内、闭孔、骶前淋巴结等区域和其周围组织,计划靶区(PTV)为CTV外放1cm,处方剂量为45Gy/1.8Gy/25次,95%PTV达到处方剂量要求.30例患者均做IMRT及CRT两种计划设计,对比两种照射方式下骨髓、小肠、直肠及膀胱的剂量分布、剂量、体积直方图(ova)中的多个指标.随后按患者自主意愿选取15例入IMRT组,另15例入CRT组进行放疗,对比两组副反应发生率.结果:与CRT相比,IMRT降低了30-40Gy范围内骨盆骨髓、小肠、膀胱、直肠的受照体积,有显著统计学意义.IMRT组膀胱、肠道副反应发生率明显低于CRT组,有显著统计学意义.两组在骨髓抑制方面无统计学差异.结论:对于宫颈癌术后放疗的患者,IMRT较CRT能明显降低危及器官的受量,降低并发症发生率,具有明显优势,值得临床推广应用.
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