An investigation of the impact of variations of DVH calculation algorithms on DVH dependant radiation therapy plan evaluation metrics

17th International Conference on the Use of Computers in Radiation Therapy

物理学;计算机科学

Kennedy, A.M.^1 ; Lane, J.^1 ; Ebert, M.A.^1,2

Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Australia^1

School of Physics, University of Western Australia, Perth, Australia^2

关键词: Calculation algorithms;    Dose-volume histograms;    Evaluation metrics;    Extreme conditions;    Normal tissue complication probabilitIES;    Planning systems;    Quality assurance process;    Sampling resolution;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012093/pdf
DOI  :  10.1088/1742-6596/489/1/012093

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

Plan review systems often allow dose volume histogram (DVH) recalculation as part of a quality assurance process for trials. A review of the algorithms provided by a number of systems indicated that they are often very similar. One notable point of variation between implementations is in the location and frequency of dose sampling. This study explored the impact such variations can have on DVH based plan evaluation metrics (Normal Tissue Complication Probability (NTCP), min, mean and max dose), for a plan with small structures placed over areas of high dose gradient. Dose grids considered were exported from the original planning system at a range of resolutions. We found that for the CT based resolutions used in all but one plan review systems (CT and CT with guaranteed minimum number of sampling voxels in the x and y direction) results were very similar and changed in a similar manner with changes in the dose grid resolution despite the extreme conditions. Differences became noticeable however when resolution was increased in the axial (z) direction. Evaluation metrics also varied differently with changing dose grid for CT based resolutions compared to dose grid based resolutions. This suggests that if DVHs are being compared between systems that use a different basis for selecting sampling resolution it may become important to confirm that a similar resolution was used during calculation.