Particle Number Optimization Using the BFGS Method in Heavy-Ion Therapy

In the GSI therapy pilot project from 1997 until 2008 about 440 cancer patients were successfully treated with carbon ions. Due to the promising healing rates the clinical radiotherapy facility HIT was launched and opened in 2009. Nevertheless, research and improvements of heavyion therapy are still in progress at GSI. For patient treatment planning the software TRiP [1, 2] is used. An essential part of treatment planning is the particle number optimization in order to achieve a target dose distribution as close as possible to the prescribed biological dose distribution by an appropriate sparing of healthy tissue, especially critical structures like the brainstem.