16排螺旋CT在食管癌术后放疗中的应用

Deployment of 16-Row Spiral CT in Post-Operative Radiotherapies for Esophageal Neoplasms

目的研究应用大孔径16排螺旋CT进行食管癌术后放疗模拟定位的优势及其临床价值。方法选取使用Philips PQS单排和Philips Brilliance CT Big Bore 16排螺旋CT进行模拟定位的患者各20例。患者仰卧位、双上肢上举、双手抱头,真空负压气垫固定,CT扫描后,在模拟定位工作站确定等中心,通过激光定位系统,调节激光灯并移床,做等中心体表标记。在治疗计划系统设计治疗计划,使用Varian EX直线加速器的机载影像系统(OBI)千伏级锥形束CT(kV CBCT)进行扫描和配准验证,对验证误差进行对比分析。结果大孔径16排螺旋CT有较高的时间分辨率、空间分辨率、密度分辨率,提高了食管癌术后放疗照射野与剂量分布的优化方案设计和防护的精确性,大孔径16排螺旋CT模拟定位的验证误差优于单排螺旋CT(t=-4.63,3.21,6.74;P<0.05)。结论大孔径16排螺旋CT在放疗模拟定位中的应用大大提高了放疗定位的精确性,为精确计划、精确治疗提供了保证。放疗先进设备的应用可以改善食管癌术后放疗肿瘤的局部控制率和患者的生存率。

Objective To explore the clinical effects and advantages of large-aperture 16-row spiral CT scanning in post-operative positioning-simulated radiotherapies for esophageal neoplasms. Methods Positioning simulation was performed respectively in two groups of 20 patients with Philips PQS single- row CT scanner and Philips Brilliance Big Bore 16-row spiral CT scanner. All the patients were required to take postures like the supine position, double-upper-limb uplift and double-upper-limb cross with fixation of the vacuum negative-pressure air cushion so as to receive the CT scanning. Then, location of the isocenter needed to be determined in the positioning-simulated workstation through deployment of the laser position system, adjustment of the laser lamp, bed placement and isocenter-marks-making on the physical surface. After treatment plans were generated by the treatment plan system, scanning and adjustment validation were performed with Varian EX on-board image （OBI） and cone beam CT （CBCT） system so as to compare and analyze the validation errors. Results Large-aperture 16-row spiral CT displayed the characteristics of higher time, spatial and density resolution, which improved the optimization design of the radiation field and the dose distribution as well as the accuracy of radiation protection in post-operative radiotherapies for esophageal neoplasms. In comparison of validation errors, superiority was achieved by large-aperture 16-row spiral CT over single-row spiral CT （t = -4.63, 3.21, 6.74： P〈 0.05）. Conclusion Deployment of large-aperture 16-row spiral CT in positioning-simulated radiotherapies greatly improved the accuracy of radiotherapy localization and provided the guarantee for accurate treatment plan designing and precise treatment. With the advancement of radiation equipment, it could be deployed to enhance the local control rate of radiated-tumors and the survival rate in post- operative radiotherapies for the esophageal neoplasms patients.