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Development and application of a multimodality inverse treatment planning system (in English)
Author(s) -
Nill Simeon
Publication year - 2002
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1446103
Subject(s) - radiation treatment planning , dosimetry , proton therapy , computer science , voxel , nuclear medicine , medical physics , inverse , radiation therapy , range (aeronautics) , medical imaging , mathematical optimization , beam (structure) , physics , mathematics , artificial intelligence , medicine , optics , radiology , materials science , geometry , composite material
The introduction of intensity‐modulated radiation therapy (IMRT) opened new possibilities for the treatment planning process. Most of the existing treatment planning (TP) tools for IMRT are limited to photon treatments. To achieve a very high computational speed, simplified dose calculation algorithms are often used. Furthermore, approximations are made in the calculation of the fluence matrix. In this thesis an IMRT planning tool is developed that can be used with any available radiation modality and makes use of improved dose calculation algorithms. For the dose calculation engine, a method was implemented in which the dose deposited in every voxel by all beams is precalculated and, for later use, stored in a dose matrix. This enables the use of advanced dose calculation algorithms and the simultaneous optimization of different radiation modalities. The new TP system was applied to clinical patient data for proton and photon IMRT plans. For the delivery of the proton IMRT plans, two promising delivery techniques, “distal edge tracking” (DET) and a fully three‐dimensional (3D) technique, were compared with each other. By using the DET technique dose distributions as good as for the 3D technique were achieved but the optimization time and the expected delivery time were reduced by a factor 10. No significant differences in the effect of organ motion and particle range uncertainties were observed for the techniques. The effect of the number of beams on the proton IMRT dose distribution was also studied. It was found that even with only five evenly spaced beams the DET dose distribution is significantly better than the photon distribution, and almost indistinguishable from the seven‐beam DET plan.