Maughan R L, Kruger D G, Blosser G F, Blosser H G
Gershenson Radiation Oncology Center, Harper Hospital, Wayne State University, Detroit, Michigan 48201, USA.
Med Phys. 1995 Apr;22(4):427-33. doi: 10.1118/1.597468.
Multirod arrays can be used to produce irregularly shaped irradiation fields for use in external beam photon and neutron radiation therapy. Two prototype multirod collimators have been built for use with high energy photon beams. A practical multirod collimator is in routine use with the fast neutron beam at a superconducting cyclotron based neutron therapy facility. A simple computer program has been written for calculating the transmission of photon and neutron beams through multirod arrays. The results of calculations for both close packed and spaced rod arrays are presented, and compared with available photon and neutron transmission data. The transmission through a regularly packed array exhibits a pattern of maxima and minima which occur with a spacing corresponding to the rod radius. The program predicts the positions and magnitudes of the transmission peaks. The rod diameter and spacing, the source size, and the position of the multirod collimator and the measurement plane relative to the source, all effect the exact nature of the measured transmission pattern. The transmission of 15-MV photons through close packed and spaced rod arrays was calculated using the program and compared with measurements made in a close packed tungsten rod array and with a prototype multirod collimator. Calculations for the transmission of a p(42)-Be neutron beam through a close packed tungsten rod array were compared with previously published data. Good agreement between calculations and measured data was obtained in all cases. The program was used to design a practical multirod collimator for a d(50)- Be fast neutron beam.(ABSTRACT TRUNCATED AT 250 WORDS)
多棒阵列可用于产生不规则形状的照射野，用于外照射光子和中子放射治疗。已经制造了两个用于高能光子束的多棒准直仪原型。一种实用的多棒准直仪正在一个基于超导回旋加速器的中子治疗设施中与快中子束常规使用。已编写了一个简单的计算机程序，用于计算光子和中子束通过多棒阵列的透射率。给出了紧密排列和间隔排列的棒阵列的计算结果，并与现有的光子和中子透射数据进行了比较。通过规则排列阵列的透射率呈现出最大值和最小值的模式，其出现的间距与棒的半径相对应。该程序预测了透射峰的位置和大小。棒的直径和间距、源的大小以及多棒准直仪和测量平面相对于源的位置，都会影响测量的透射模式的精确性质。使用该程序计算了15兆电子伏特光子通过紧密排列和间隔排列的棒阵列的透射率，并与在紧密排列的钨棒阵列和一个多棒准直仪原型中进行的测量结果进行了比较。将p(42)-Be中子束通过紧密排列的钨棒阵列的透射率计算结果与先前发表的数据进行了比较。在所有情况下，计算结果与测量数据都取得了良好的一致性。该程序被用于为d(50)-Be快中子束设计一种实用的多棒准直仪。（摘要截取自250词）
