VALIDATION OF A DOSE-POINT KERNEL CONVOLUTION TECHNIQUE FOR INTERNAL DOSIMETRY
VALIDATION OF A DOSE-POINT KERNEL CONVOLUTION TECHNIQUE FOR INTERNAL DOSIMETRY
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DOI：
10.1088/0031-9155/40/3/003
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发表时间：
1995-03-01
影响因子：
3.5
通讯作者：
BOYER, AL
中科院分区：
文献类型：
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作者：
GIAP, HB;MACEY, DJ;BOYER, AL
本研究的目的是验证剂量点核卷积技术，提供了一个三维（3D）分布的吸收剂量从放射性核素I-131的三维分布。通过蒙特卡罗模拟计算穿透辐射的剂量点核，并将其投射到3D矩形矩阵中。将该矩阵与定量单光子发射计算机断层扫描（SPECT）提供的3D活性图进行卷积，以提供吸收剂量的3D分布。卷积计算使用3D快速傅里叶变换（FFT）技术进行，该技术在Intel 486 DX 2（66 MHz）个人计算机上对于128 x 128 x 16矩阵花费少于40 s。将计算的光子吸收剂量与沿I-131的22 cm直径环形源的直径沿着插入的热释光剂量计（TLD）测量的值进行比较。测量值和计算值之间百分比差异的平均值和标准差分别等于-1%和3.6%。该卷积方法也用于计算Alderson腹部体模中的3D剂量分布，该体模包含肝脏、脾脏和装载有各种浓度I-131的球形肿瘤体积。通过对整个肝脏、脾脏和肿瘤计算的剂量取平均值，将剂量点核方法与使用MIRD形式主义得出的值进行比较，发现一致性优于15%。
The objective of this study was to validate a dose-point kernel convolution technique that provides a three-dimensional (3D) distribution of absorbed dose from a 3D distribution of the radionuclide I-131. A dose-point kernel for the penetrating radiations was calculated by a Monte Carlo simulation and cast in a 3D rectangular matrix. This matrix was convolved with the 3D activity map furnished by quantitative single-photon-emission computed tomography (SPECT) to provide a 3D distribution of absorbed dose. The convolution calculation was performed using a 3D fast Fourier transform (FFT) technique, which takes less than 40 s for a 128 x 128 x 16 matrix on an Intel 486 DX2 (66 MHz) personal computer. The calculated photon absorbed dose was compared with values measured by thermoluminescent dosimeters (TLDs) inserted along the diameter of a 22 cm diameter annular source of I-131. The mean and standard deviation of the percentage difference between the measurements and the calculations were equal to -1% and 3.6%, respectively. This convolution method was also used to calculate the 3D dose distribution in an Alderson abdominal phantom containing a liver, a spleen, and a spherical tumour volume loaded with various concentrations of I-131. By averaging the dose calculated throughout the liver, spleen, and tumour the dose-point kernel approach was compared with values derived using the MIRD formalism, and found to agree to better than 15%.