[A simple dose-effect model for the optimization of IMRT]

Optimization of percutaneous photon beams with intensity modulation was investigated in terms of the influence of different dose-effect functions for lung tissue on the resulting dose distributions. The fluence profiles were optimized for a cylindrical phantom with a L-shaped target, the spinal cord and lung presenting the critical organs. Concurrent criteria were a minimum dose constraint for the target and a maximum dose constraint for the spinal cord. The dose effect in the lung was minimized using different approaches. All tested approaches were able to control the dose distribution in the lung. The mean dose remained constant, where as the volume of low dose could be changed. Due to the simplicity of functions and parameters, these models are suitable for clinical implementation.