90Sr-90Y敷贴治疗的EBT3胶片剂量验证方法  

EBT3 film dose verification method for 90Sr-90Y applicator

作　　者：杨涛 胡强 周云泷 金晓峰 明慧 余辉[3] Yang Tao;Hu Qiang;Zhou Yunlong;Jin Xiaofeng;Ming Hui;Yu Hui(Radiotherapy Center,Huangshi Central Hospital,Edong Healthcare Group,Huangshi 435000,China;Department of Oncology,the Second People's Hospital of Jiangyou,Mianyang 621700,China;Department of Nuclear Medicine,Huangshi Central Hospital,Edong Healthcare Group,Huangshi 435000,China)

机构地区：[1]鄂东医疗集团黄石市中心医院放疗中心,湖北省黄石市435000 [2]江油市第二人民医院肿瘤科,四川省绵阳市621700 [3]鄂东医疗集团黄石市中心医院核医学科,湖北省黄石市435000

出　　处：《国际放射医学核医学杂志》2021年第10期642-647,共6页International Journal of Radiation Medicine and Nuclear Medicine

摘　　要：目的对90Sr-90Y敷贴治疗进行EBT3胶片剂量的测量, 为临床应用提供一种快捷的剂量验证方法。方法选用能量响应较好的辐射直接显影EBT3胶片, 并与固体水模进行比较, 通过直线加速器建立0~500 cGy的胶片灰度-剂量标准曲线并检测其组织等效性。将20片6 cm×6 cm的EBT3胶片(每张胶片厚0.28 mm)重叠放置, 将90Sr-90Y敷贴器放置在胶片最顶层, 辐照4 min。通过灰度-剂量标准曲线计算出每张胶片中心轴附近的平均吸收剂量, 根据胶片厚度计算距离敷贴器不同深度处的辐射剂量及等剂量线分布。采用非参数独立样本U检验比较不同能量的电子线照射前后所测得的吸收剂量的差异。结果胶片替换等厚度固体水模后测量结果略高于纯固体水模, 但差异无统计学意义(Z=-0.31, P=0.84)。不同深度处胶片对应的中心区域随着灰度值的降低吸收剂量迅速下降, 在0.5 cm深度处, 剂量仅为7.0 cGy。4 min照射后, 距离敷贴器不同深度处的吸收剂量满足拟合曲线y=739.07e-0.56x-44.8, 等剂量线范围随深度的增加呈先增大后减小。结论 EBT3胶片验证能够很好地满足90Sr-90Y敷贴治疗的剂量验证, 具有简单、易行、准确的特点, 适合基层医疗机构应用。Objective To measure the EBT3 film dose of brachytherapy with 90 Sr-90 Y applicator to provide a rapid dose verification method for clinical application.Methods EBT3 films with good energy response were selected and compared with a solid water phantom.The gray scale dose curve of 0–500 cGy film was established using a linear accelerator,and its tissue equivalence was detected.Twenty 6 cm×6 cm EBT3 films(0.28 mm thickness)were overlapped,and a 90 Sr-90 Y applicator was placed on the top and irradiated for 4 min.The absorbed dose near the central axis of each film was calculated using the gray scale dose curve.The radiation dose and isodose distributions at different distances from the applicator were calculated according to film thickness.Non-parametric independent sample U-test was used to compare the differences in absorbed doses measured before and after exposure to electron rays with different energies.Results The measurement results of film replacement with equal thickness solid water molds were slightly higher than those of pure solid water molds,but the difference was not statistically significant(Z=−0.31,P=0.84).The absorbed dose in the central region corresponding to different film depths decreased rapidly with decreasing gray values,and the dose at a depth of 0.5 cm was only 7.0 cGy.After irradiation for 4 min,the absorbed dose at different depths from the applicator met the fitting curve,y=739.07e−0.56x−44.8,and the range of isodose line initially increased and then decreased with the increasing depth.Conclusion EBT3 film verification can well meet the dose verification of 90 Sr-90 Y applicator,which is simple,easy,and accurate and is suitable of primary medical institutions.

关 键 词：胶片辐射剂量测定法 90Sr-90Y敷贴器 EBT3胶片 剂量验证 

分 类 号：R815[医药卫生—放射医学]