Interindividual registration and dose mapping for voxelwise population analysis of rectal toxicity in prostate cancer radiotherapy

• Published in: Medical physics (Lancaster) 2016-06, Vol.43 (6), p.2721-2730
• Main Authors: Dréan, Gaël, Acosta, Oscar, Lafond, Caroline, Simon, Antoine, de Crevoisier, Renaud, Haigron, Pascal
• Format: Article
• Language: English
• Subjects: 3D dose distribution; 60 APPLIED LIFE SCIENCES; Anatomy; biological organs; CALCULATION METHODS; cancer; Computed tomography; Dose-Response Relationship, Radiation; dosimetry; Dosimetry/exposure assessment; Humans; Imaging, Three-Dimensional - methods; interindividual registration; Laplace equations; Laplacian model; Magnetic circular dichroism spectroscopy; Male; MAPPING; Medical image segmentation; Models, Biological; NEOPLASMS; Organs at Risk - injuries; Organs at Risk - radiation effects; Precision Medicine - methods; PROSTATE; Prostatic Neoplasms - diagnostic imaging; Prostatic Neoplasms - radiotherapy; RADIATION DOSE DISTRIBUTIONS; Radiation Injuries - diagnosis; RADIATION PROTECTION AND DOSIMETRY; radiation therapy; RADIOTHERAPY; Radiotherapy - adverse effects; Radiotherapy Dosage; rectal toxicity; RECTUM; Rectum - diagnostic imaging; Rectum - injuries; Rectum - radiation effects; Scintigraphy; Spatial analysis; Therapeutic applications, including brachytherapy; Tomography, X-Ray Computed - methods; TOXICITY; toxicology; tubular structural description
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.4948501

Purpose: Recent studies revealed a trend toward voxelwise population analysis in order to understand the local dose/toxicity relationships in prostate cancer radiotherapy. Such approaches require, however, an accurate interindividual mapping of the anatomies and 3D dose distributions toward a common coordinate system. This step is challenging due to the high interindividual variability. In this paper, the authors propose a method designed for interindividual nonrigid registration of the rectum and dose mapping for population analysis. Methods: The method is based on the computation of a normalized structural description of the rectum using a Laplacian-based model. This description takes advantage of the tubular structure of the rectum and its centerline to be embedded in a nonrigid registration-based scheme. The performances of the method were evaluated on 30 individuals treated for prostate cancer in a leave-one-out cross validation. Results: Performance was measured using classical metrics (Dice score and Hausdorff distance), along with new metrics devised to better assess dose mapping in relation with structural deformation (dose-organ overlap). Considering these scores, the proposed method outperforms intensity-based and distance maps-based registration methods. Conclusions: The proposed method allows for accurately mapping interindividual 3D dose distributions toward a single anatomical template, opening the way for further voxelwise statistical analysis.