el-Khatib E, Podgorsak E B, Pla C
McGill University, Department of Radiation Oncology, Montréal, Québec, Canada.
Med Phys. 1988 Mar-Apr;15(2):145-50. doi: 10.1118/1.596167.
Measured and calculated dose distributions under attenuators, which are of smaller cross-sectional dimensions than the radiation field, are presented. The study was performed on a 4-MV linac at a source-surface distance of 120 cm on the beam central axis in a water phantom for several thickness and cross sections of lead attenuators. Dose correction factors, which are used to multiply the open beam data to get dose distributions under partial attenuators, depend strongly on attenuator parameters and on depths in phantom. A method to calculate dose correction factors for any combination of attenuator parameters and any phantom depth is presented. The calculated dose distributions under partial attenuators agree well with measured data, which indicates that the method can be applied in clinical situations.
给出了在横截面尺寸小于辐射野的衰减器下测量和计算的剂量分布。该研究是在一台4兆伏直线加速器上进行的，源皮距为120厘米，在水模体的射束中心轴上，针对几种厚度和横截面的铅衰减器进行。用于乘以开放射束数据以获得部分衰减器下剂量分布的剂量校正因子，强烈依赖于衰减器参数和模体中的深度。提出了一种针对衰减器参数的任何组合和任何模体深度计算剂量校正因子的方法。部分衰减器下计算得到的剂量分布与测量数据吻合良好，这表明该方法可应用于临床情况。
