A multiphase direct aperture optimization for inverse planning in radiotherapy

Optimization of the inverse planning becomes critical because it follows the invention of intensity modulated radiotherapy (IMRT) to shorten the previous "trial-and-error" treatment process and increase efficiency. In this paper, the inverse planning is used to direct aperture optimization in the ARTS (Accurate/Advanced Radiotherapy System). The objective function was quadratic, both tolerance and dose-volume constraint types are supported. The memory efficient conjugate gradient algorithm is used to cope with its large data. Furthermore, to fully exploit the solution space, a shortest path sub-procedure is coupled into the whole algorithm, thus giving further possibility decreasing the objective function. Two clinical cases are tested, indicating that the applicability of this algorithm is promising to clinical usage.