Biomechanical quality assurance criteria for deformable image registration algorithms used in radiotherapy guidance.

Biomechanical quality assurance criteria for deformable image registration algorithms used in radiotherapy guidance. Phys Med Biol. 2019 Oct 22;: Authors: Zachiu C, Denis de Senneville B, Raaymakers BW, Ries MG Abstract Image-guided radiation therapy (IGRT) allows radiation dose deposition with a high degree of geometric accuracy. Previous studies have demonstrated that such therapies may benefit from the employment of deformable image registration (DIR) algorithms, which allow both the automatic tracking of anatomical changes and accumulation of the delivered radiation dose over time. In order to ensure patient care and safety, however, the estimated deformations must be subjected to stringent quality assurance (QA) measures. In the present study we propose to extend the state-of-the-art methodology for QA of DIR algorithms by a set of novel biomechanical criteria. The proposed biomechanical criteria imply the calculation of the normal and shear mechanical stress, which would occur within the observed tissues as a result of the estimated deformations. The calculated stress is then compared to plausible physiological limits, providing thus the anatomical plausibility of the estimated deformations. The criteria were employed for the QA of three DIR algorithms in the context of abdominal conebeam computed tomography and magnetic resonance radiotherapy guidance. An initial evaluation of organ boundary alignment capabilities indicated th...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research