Cormack A M
Int J Radiat Oncol Biol Phys. 1987 Apr;13(4):623-30. doi: 10.1016/0360-3016(87)90082-4.
The radiation field required to produce a dose distribution in rotation therapy may, in a certain approximation, be calculated using an integral equation, that is, the solution of the equation predicts the intensities needed to produce the dose distribution. The nature of this approximation is discussed and is shown to be connected with a Radon-type problem for circles through the origin provided the beam can be continuously modified during the rotation. The lowest order approximation provides a vivid geometrical way of looking at treatment planning which may be useful in novel situations and which will persist, to some extent, in higher-order approximations. Questions of scattering, and of the extension of the problem to a full three dimensional treatment are discussed.
在旋转治疗中产生剂量分布所需的辐射场，在一定近似下，可以用一个积分方程来计算，也就是说，该方程的解能预测产生剂量分布所需的强度。讨论了这种近似的性质，并表明它与通过原点的圆的拉东型问题有关，前提是在旋转过程中光束可以连续修改。最低阶近似提供了一种直观的几何方法来审视治疗计划，这在新情况下可能有用，并且在某种程度上会在高阶近似中持续存在。还讨论了散射问题以及将该问题扩展到完整三维治疗的问题。
