应用CBCT研究膀胱边界运动及其对直肠癌术后放疗剂量学的影响

发布时间：2018-03-14 21:08

本文选题：直肠癌　切入点：膀胱体积　出处：《河北医科大学》2013年硕士论文　论文类型：学位论文

【摘要】：目的：应用图像引导放射治疗技术，观察直肠癌患者仰卧位热塑体膜固定下膀胱边界的运动，研究放射治疗中膀胱的体积大小和形状变化特征，及对直肠癌术后放疗靶区和周围正常组织剂量学的影响。材料与方法：收集2010年5月至2012年10月期间在我科行直肠癌术后同步放化疗或单纯术后预防照射的患者12例。12例患者均采用仰卧位热塑体模固定，大孔径螺旋CT扫描定位，将定位扫描图像传至CMS Xio4.4治疗计划系统，然后在定位CT图像上勾画临床靶区及正常组织，并制定5野调强计划。12例患者均于精确摆位后，实施放射治疗前行KV级CBCT扫描，每周2-3次，共获取119幅CBCT图像。将收集的CBCT图像与定位CT图像进行融合配准，并在CBCT图像上勾画正常组织和靶区。依照CBCT图像的组织轮廓，在CT图像上制定与原始治疗计划相同射野角度和优化条件的新计划。观察膀胱在不同充盈状态下各壁形状及位置的变化，分析治疗过程中膀胱体积和形状的变化与靶区大小、正常组织受照剂量间的关系。结果：患者采用仰卧位、热塑体膜固定方式下，膀胱上壁、前壁、左壁、右壁、300后壁(后上方)、00后壁(正后方)、-300后壁(后下方)的移动范围分别为1.039±1.0038cm、0.281±0.2373cm、0.350±0.3151cm、0.622±0.4440cm、0.592±0.4974cm、0.615±0.4964cm、0.247±0.2527cm。12例患者膀胱体积与临床靶体积之间均呈负相关性，P0.05。研究膀胱体积大小与周围正常组织受照剂量之间的关系，发现5例患者膀胱体积与结肠V35呈负相关，2例患者膀胱体积与结肠V40呈负相关，5例患者膀胱体积与结肠平均受照剂量呈负相关，P0.05；7例患者膀胱体积与小肠V35呈负相关，7例患者膀胱体积与小肠V40呈负相关，6例患者膀胱体积与小肠平均受照剂量呈负相关，P0.05；3例患者膀胱体积与膀胱V35呈正相关，7例患者膀胱体积与膀胱V40呈正相关，3例患者膀胱体积大小与膀胱平均受照剂量呈正相关，P0.05。在分次治疗中膀胱体积比定位膀胱体积增大时，12例患者的膀胱受照剂量均较原治疗计划增加。结论: 1直肠癌患者放射治疗采取仰卧位、热塑体模固定方式，膀胱前壁移动度较小，上壁、后壁及右壁移动度较大； 2膀胱充盈程度不同勾画的直肠癌术后预防靶区也不同，膀胱排空状态下淋巴引流区显露较好，勾画的临床靶区体积较大，反之，勾画的临床靶区体积减小。 3膀胱体积大小与结肠、小肠受照剂量间存在负相关性；随着膀胱体积一定程度的增加，膀胱V40体积增加。 4若定位时排空膀胱，，调强放射治疗计划能够保证周围正常组织在其耐受剂量范围内，分次治疗间膀胱充盈程度增加时，膀胱受照剂量会增加。
[Abstract]:Objective:. The motion of bladder boundary was observed under supine thermoplastic membrane fixation in rectal cancer patients by image-guided radiotherapy, and the changes of bladder volume and shape during radiotherapy were studied. And its effect on postoperative radiotherapy target area and normal tissue around rectal cancer. Materials and methods:. From May 2010 to October 2012, 12 patients with rectal cancer received simultaneous radiotherapy and chemotherapy or only postoperative prophylactic irradiation were treated with supine thermoplastic mode fixation and large aperture spiral CT scanning. The localization scanning image was transferred to the CMS Xio4.4 treatment planning system, and then the clinical target area and normal tissue were drawn up on the location CT image, and the 5 field intensity modulation plan was made. After accurate placement, KV grade CBCT scan was performed before radiotherapy. A total of 119 CBCT images were obtained 2-3 times a week. The collected CBCT images were fused with the localized CT images, and the normal tissues and target areas were drawn on the CBCT images. According to the tissue contours of the CBCT images, A new plan with the same projection angle and optimized conditions as the original treatment plan was made on CT images. The changes of the shape and position of each wall of bladder under different filling conditions were observed, and the changes of bladder volume and shape and the size of the target area were analyzed during the treatment. The relationship between radiation doses in normal tissues. Results:. Supine position, thermoplastic membrane fixation, upper wall of bladder, anterior wall, left wall, The moving range of the posterior wall of the right wall was 1.039 卤1.0038 cm-1 0.281 卤0.3151 cm-1 0.350 卤0.3151 cm-1 0.592 卤0.4974 cm0.62 卤0.4964cm0.247 卤0.2527 cm.12 cases of clinical target volume and bladder volume were negatively correlated with the clinical target volume (P0.05). The relationship between exposure doses, It was found that there was a negative correlation between bladder volume and colon V35 in 5 patients and a negative correlation between bladder volume and colon V40 in 2 patients and a negative correlation between bladder volume and average irradiation dose in colon in 5 patients and a negative phase between bladder volume and V35 in small intestine in 7 patients. There was a negative correlation between bladder volume and small intestine V40 in 7 patients and a negative correlation between bladder volume and mean dose of small intestine in 6 patients. There was a positive correlation between bladder volume and bladder V35 in 3 patients and a positive correlation between bladder volume and bladder V40 in 7 patients. There was a positive correlation between bladder volume and average dose of bladder irradiation in 3 patients (P 0.05). When the volume of bladder was larger than that of fixed bladder, the dose of bladder exposure in 12 patients was higher than that of the original treatment plan. Conclusion:. 1 the patients with rectal cancer were treated with supine position, thermoplastic mod fixation, lower movement degree of the anterior wall of bladder, greater degree of movement of the upper wall, posterior wall and right wall; 2the prevention target area of rectal cancer with different bladder filling degree was different. The lymph drainage area was better exposed under bladder emptying, and the volume of clinical target area was larger, whereas the volume of clinical target area was decreased. (3) there was a negative correlation between the volume of bladder and the dose of colon and small intestine, and the volume of bladder V40 increased with the increase of volume of bladder to some extent. (4) if bladder was emptied during localization, the intensity modulated radiotherapy plan could ensure that the bladder irradiation dose would increase when the bladder filling degree increased in the range of tolerance dose of the surrounding normal tissue.
【学位授予单位】：河北医科大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R735.37;R730.55

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