DECOMPOSITION OF PENCIL BEAM KERNELS FOR FAST DOSE CALCULATIONS IN 3-DIMENSIONAL TREATMENT PLANNING
DECOMPOSITION OF PENCIL BEAM KERNELS FOR FAST DOSE CALCULATIONS IN 3-DIMENSIONAL TREATMENT PLANNING
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DOI：
10.1118/1.597070
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发表时间：
1993-03-01
期刊：
影响因子：
3.8
通讯作者：
RHEIN, B
中科院分区：
文献类型：
--
作者：
BORTFELD, T;SCHLEGEL, W;RHEIN, B
提出了一种计算高能光子束三维剂量分布的方法。其主要特点是：(I)计算速度足够快，可以进行交互式三维治疗计划；(Ii)充分考虑了将三维剂量分布与目标体积相匹配所需的不规则形状或补偿场。该方法以铅笔束卷积技术为基础，具有精度高的特点。通过将铅笔束核分解成三个单独的项，从而减少了所需的二维卷积次数，从而获得了相当大的速度增益。通过快速Hartley变换在频域中执行卷积。利用这些技巧，在DEC VAX STATION 3100上计算卷积的时间仅为8 S左右。这是光线跟踪通过三维CT数据集的计算时间的四分之一到三分之一，这在任何情况下都必须执行。将计算结果与均匀体模中15 mV光子的测量结果进行了比较。考虑了用多叶准直器整形的两个不规则场。绝对剂量实测值与计算值的偏差小于+/-2%。
A method for the calculation of three-dimensional dose distributions for high-energy photon beams is presented. The main features are (i) the calculation is fast enough to allow interactive three-dimensional treatment planning, and (ii) irregularly shaped or compensated fields, which are required to fit three-dimensional dose distributions to target volumes, are adequately taken into consideration. The method is based on the pencil beam convolution technique and shares its features concerning accuracy. A considerable gain in speed is achieved by decomposing the pencil beam kernel into three separated terms, thus reducing the required number of two-dimensional convolutions. The convolutions are performed in the frequency domain via the fast Hartley transform. Using these techniques, the calculation time for the convolutions is only about 8 s on a DEC VAX station 3100. This is one-fourth to one-third of the calculation time for the ray tracing through the three-dimensional CT data set, which has to be performed in any case. Results of the calculation are compared with measurements in a homogeneous phantom for 15 MV photons. Two irregular fields shaped with a multileaf collimator are considered. The deviations between measured and calculated absolute dose values are smaller than +/- 2%.