Reduzierung der Unsicherheiten bei der klinischen Dosimetrie und bei der Dosisberechnung für Ionenstrahlen mit Hilfe von Monte Carlo Simulationen

德国第一家以医院为基地的重离子放射治疗设施将于2007年在海德堡开始运营。为了在治疗计划中达到与常规放射治疗中常见标准相同的辐射剂量和剂量计算的准确性，需要更好地描述离子与物质的基本相互作用。由于海德堡设施将提供各种不同的离子物种(从质子到氧气)，在GSI的试点项目中获得的碳离子与水相互作用的基本知识必须扩展到其他离子，但也必须扩展到水以外的目标材料。在蒙特卡罗模拟的帮助下，将详细模拟离子束通过物质的传输，并考虑电子和核的相互作用。讨论的问题包括核碎裂对不同剂量计(强调电离室)的响应的影响、剂量计的特定校正因子、不同人体组织中离子相互作用的差异、基于CT的射程计算的改进以及用于治疗计划的完全基于蒙特卡罗的剂量计算。

The first German hospital based facility for heavy ion radiotherapy will start its operation in 2007 in Heidelberg. In order to reach the same level of accuracy in radiation dosimetry and dose calculations for treatment planning as is common standard in conventional radiation therapy, a better description of the basic interactions of ions with matter is needed. Since the Heidelberg facility will offer a variety of different ion species (from protons up to oxygen), the basic knowledge gained in the pilot project at GSI for carbon ions interacting with water has to be extended to other ions, but also to target materials other than water. With the help of Monte Carlo simulations, the transport of ion beams through matter will be simulated in detail, taking in to account electronic and nuclear interactions. The questions addressed include the effects of nuclear fragmentation on the response of various dosimeters (emphasizing ionization chambers), dosimeter specific correction factors, differences of ion interactions in various body tissues, improvements in the CT based range calculation and finally a full Monte Carlo based dose calculation for treatment planning.