Probabilistic dose prediction using mixture density networks for automated radiation therapy treatment planning

• Published in: Physics in medicine & biology 2021-03, Vol.66 (5), p.055003-055003
• Main Authors: Nilsson, Viktor, Gruselius, Hanna, Zhang, Tianfang, De Kerf, Geert, Claessens, Michaël
• Format: Article
• Language: English
• Subjects: Automation; deep learning; dose mimicking; dose prediction; Humans; knowledge-based planning; Male; mixture density network; Organs at Risk - radiation effects; Probability; Prostatic Neoplasms - radiotherapy; radiation therapy treatment planning; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy, Intensity-Modulated - adverse effects; Rectum - drug effects
• ISSN: 0031-9155; 1361-6560; 1361-6560
• DOI: 10.1088/1361-6560/abdd8a

We demonstrate the application of mixture density networks (MDNs) in the context of automated radiation therapy treatment planning. It is shown that an MDN can produce good predictions of dose distributions as well as reflect uncertain decision making associated with inherently conflicting clinical tradeoffs, in contrast to deterministic methods previously investigated in the literature. A two-component Gaussian MDN is trained on a set of treatment plans for postoperative prostate patients with varying extents to which rectum dose sparing was prioritized over target coverage. Examination on a test set of patients shows that the predicted modes follow their respective ground truths well, both spatially and in terms of their dose-volume histograms. A special dose mimicking method based on the MDN output is used to produce deliverable plans and thereby showcase the usability of voxel-wise predictive densities. Thus, this type of MDN may serve to support clinicians in managing clinical tradeoffs and has the potential to improve the quality of plans produced by an automated treatment planning pipeline.