DiffuseRT: predicting likely anatomical deformations of patients undergoing radiotherapy

Smolders, A. (author), Rivetti, Luciano (author), Vatterodt, N. (author), Korreman, S. S. (author), Lomax, A. (author), Sharma, Manju (author), Studen, Andrej (author), Weber, D. C. (author), Jeraj, Robert (author), Albertini, F. (author)

Objective. Predicting potential deformations of patients can improve radiotherapy treatment planning. Here, we introduce new deep-learning models that predict likely anatomical changes during radiotherapy for head and neck cancer patients. Approach. Denoising diffusion probabilistic models (DDPMs) were developed to generate fraction-specific anatomical changes based on a reference cone-beam CT (CBCT), the fraction number and the dose distribution delivered. Three distinct DDPMs were developed: (1) the image model was trained to directly generate likely future CBCTs, (2) the deformable vector field (DVF) model was trained to generate DVFs that deform a reference CBCT and (3) the hybrid model was trained similarly to the DVF model, but without relying on an external deformable registration algorithm. The models were trained on 9 patients with longitudinal CBCT images (224 CBCTs) and evaluated on 5 patients (152 CBCTs). Results. The generated images mainly exhibited random positioning shifts and small anatomical changes for early fractions. For later fractions, all models predicted weight losses in accordance with the training data. The distributions of volume and position changes of the body, esophagus, and parotids generated with the image and hybrid models were more similar to the ground truth distribution than the DVF model, evident from the lower Wasserstein distance achieved with the image (0.33) and hybrid model (0.30) compared to the DVF model (0.36). Generating several images for the same fraction did not yield the expected variability since the ground truth anatomical changes were only in 76% of the fractions within the 95% bounds predicted with the best model. Using the generated images for robust optimization of simplified proton therapy plans improved the worst-case clinical target volume V95 with 7% compared to optimizing with 3 mm set-up robustness while maintaining a similar integral dose. Significance. The newly developed DDPMsgenerate distributions similar to the real anatomical changes and have the potential to be used for robust anatomical optimization.

• Language: English
• Keywords: medical imaging, radiotherapy, deep learning
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 16 str.
• Numbering: Vol. 69, no. 15, art. no. 155016
• PID: 20.500.12556/RUL-166523
• UDC: 615.84
• ISSN on article: 0031-9155
• DOI: 10.1088/1361-6560/ad61b7
• COBISS.SI-ID: 222722307
• Publication date in RUL: 16.01.2025

Record is a part of a journal

• Title: Physics in Medicine & Biology
• Shortened title: Phys. Med. Biol.
• Publisher: American Institute of Physics
• ISSN: 0031-9155
• COBISS.SI-ID: 26128896

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: medicinsko slikanje, radioterapija, globoko učenje

Projects

• Funder: EC - European Commission
• Project number: 955956
• Name: Real-time Adaptive Particle Therapy of Cancer
• Acronym: RAPTOR