应用CBCT研究膀胱体积大小对直肠癌术后放疗剂量学的影响  

Application of CBCT to Research The Influence of Bladder Volume Size on Postoperative rectal Cancer Radiotherapy Dosimetry

作　　者：吴虹[1] 翟福山[1] 刘明[1] 王安峰[1] 徐袁秋[1] 包超恩[1] 周庆祥[1] 

机构地区：[1]河北医科大学第三医院放疗科,河北石家庄050051

出　　处：《中国医学物理学杂志》2013年第4期4253-4256,4306,共5页Chinese Journal of Medical Physics

摘　　要：目的:应用图像引导放射治疗技术,研究患者仰卧位热塑体膜固定下,膀胱大小对直肠癌术后放疗靶区和周围正常组织剂量学的影响。方法:收集行直肠癌术后盆腔预防性照射患者12例,共行CBCT扫描119次,将CBCT图像与定位CT融合配准,分析治疗过程中膀胱体积变化与靶区大小、正常组织受照剂量间的关系。结果:患者仰卧位、热塑体膜固定下,膀胱体积与临床靶体积之间呈负相关性,P<0.05。12例患者的膀胱体积与结肠、小肠、膀胱受照剂量间的相关性不同,表现为负相关、正相关和无相关性。定位时排空膀胱正常组织受量均在其耐受范围内。结论:直肠癌患者采取仰卧位,热塑体模固定方式时,随着膀胱充盈程度不同,导致主观上勾画的临床靶区体积不同。膀胱排空状态淋巴引流区显露较好,且容易控制。制定调强计划正常组织受量均在耐受范围内。因此,直肠癌术后预防照射患者采取仰卧位时,可以排空膀胱进行治疗。Objective： Analyze the effects of bladder size to postoperative radiotherapy target volume of rectal cancer and the dosimetry of surrounding normal tissues in supine position fixed by thermoplastic film using image-guided radiotherapy. Methods： 12 patients with rectal cancer who received pelvic prophylactic postoperatiVe radiotherapy in our hospital were included in this study. 119 CBCT scanning was totally carded out. Fusion CBCT images and the images of simulation CT. Analyze the influence of the size of bladder volume on the size of target area and the illuminated dose of normal tissue in the process of treatment. Results： The correlation between bladder volume and clinical target volume is negative, P〈0.05. The correlations between bladder volume and the illuminated dose of colon, small intestine, bladder in 12 patients are different, including negative correlation, positive correlation and no correlation. Positioning with empty bladder the illuminated dose of normal tissue is in the tolerance range. Conclusions： Rectal cancer patients are fixed by thermoplastic film in supine position, with the different bladder volume the prevention target volume delineated subjectively is difference. In bladder emptying condition the lymphatic drainage area shows well and the bladder volume is easy to control, intensity-modulated radiotherapy plan can ensure the surrounding normal tissue in their tolerance dose. Therefore, patients With rectal cancer who need to prophylactic postoperative radiotherapy in the supine position can empty bladder for treatment.

关 键 词：直肠癌 放射治疗 膀胱体积 临床靶区 剂量学 

分 类 号：R737.31[医药卫生—肿瘤]