Biomechanical modeling of radiation dose-induced volumetric changes of the parotid glands for deformable image registration.

Biomechanical modeling of radiation dose-induced volumetric changes of the parotid glands for deformable image registration. Phys Med Biol. 2020 Apr 22;: Authors: McCulloch M, Cazoulat G, Ford A, Elgohari BA, Bahig H, Kim AD, Elhalawani HM, He R, Wang J, Ding Y, Mohamed ASR, Polan DF, King J, Peterson CB, Ohrt AN, Fuller CD, Lai SY, Brock KK Abstract Early animal studies suggest that parotid gland (PG) toxicity prediction could be improved by an accurate estimation of the radiation dose to sub-regions of the PG. Translation to clinical investigation requires voxel-level dose accumulation in this organ that responds volumetrically throughout treatment. To date, deformable image registration (DIR) has been evaluated for the PG using only surface alignment. We sought to develop and evaluate an advanced DIR technique capable of modeling these complex PG volume changes over the course of radiation therapy. Planning and mid-treatment magnetic resonance images from 19 patients and computed tomography images from nine patients who underwent radiation therapy for head and neck cancer were retrospectively evaluated. A finite element model (FEM)-based DIR algorithm was applied between the corresponding pairs of images, based on boundary conditions on the PG surfaces only (Morfeus-spatial). To investigate an anticipated improvement in accuracy, we added a population model-based thermal expansion coefficient to simulate the dose distribution effe...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research