3D dose computation algorithms

9th International Conference on 3D Radiation Dosimetry

Knöös, T.^1,2

Department of Haematology, Oncology and Radiation Physics, Skane University Hospital, Malmö

SE-205 02, Sweden^1

Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund

SE-221 85, Sweden^2

关键词: Collapsed cones;    Computation algorithm;    Density change;    Dose calculation;    Electron fluences;    Flattening filters;    Model-based OPC;    Radiation source;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/847/1/012037/pdf
DOI  :  10.1088/1742-6596/847/1/012037

来源: IOP

【 摘 要 】

The calculation of absorbed dose within patients during external photon beam radiotherapy is reviewed. This includes the modelling of the radiation source i.e. in most cases a linear accelerator (beam modelling) and examples of dose calculation algorithms applied within the patient i.e. the dose engine. For the first part - the beam modelling, the different sources in the treatment head as target, filters and collimators etc are discussed as well as their importance for the photon and electron fluence reaching the patient. The consequences of removing the flattening filter, which several vendors now have made commercially available, is also shown. The pros and cons regarding different dose engines ability to consider density changes within the patient will is covered (type a and b models). Engines covered are, for example, pencil-beam models, collapsed cone superposition/-convolution models and combinations of these, as well as a glimpse on Monte Carlo methods for radiotherapy. The different models' ability to calculate dose to medium (tissue) and or water is. Finally, the role of commissioning data especially measurements in today's model based dose calculation is presented.