Newman Francis, Asadi-Zeydabadi Masoud
Department of Radiation Oncology, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA.
Med Phys. 2008 Jan;35(1):171-80. doi: 10.1118/1.2818955.
In radiation shielding design, one is usually faced with a set of conflicting goals that are navigated by an experienced physicist. If one has abundant space, the task is simplified because concrete is relatively inexpensive and will provide adequate shielding for high energy photons and neutrons, when applicable. However, if space is constrained (which is usually the case), the design becomes more difficult since one will likely have to employ combinations of steel, lead, and concrete, or other new materials--each with different properties and costs. Very experienced shielding designers can draw upon previous plans, but they do not know if their design is optimal in any sense. We have constructed a linear program that minimizes the cost of the shielding materials and minimizes the dose at the protection point or the shielding thickness subject to space constraints and to Federal or State regulations regarding the allowable exposure to individuals adjacent to the radiotherapy vault. In spite of what appears to be a simple model, the solution may require iterations of the optimization to arrive at the optimal solution.
在辐射屏蔽设计中，人们通常会面临一系列相互冲突的目标，这些目标由经验丰富的物理学家来权衡。如果有足够的空间，任务就会简化，因为混凝土相对便宜，并且在适用的情况下，能为高能光子和中子提供足够的屏蔽。然而，如果空间受限（通常情况如此），设计就会变得更加困难，因为人们可能不得不使用钢、铅和混凝土的组合，或者其他新材料——每种材料都有不同的特性和成本。经验非常丰富的屏蔽设计师可以借鉴以前的方案，但他们不知道自己的设计在任何意义上是否是最优的。我们构建了一个线性规划，在满足空间限制以及联邦或州关于放疗室相邻人员允许照射剂量的法规要求的条件下，使屏蔽材料成本最小化，并使保护点的剂量或屏蔽厚度最小化。尽管这个模型看似简单，但可能需要对优化进行迭代才能得到最优解。
