Deformation driven Seq2Seq longitudinal tumor and organs-at-risk prediction for radiotherapy Journal Article


Authors: Lee, D.; Alam, S. R.; Jiang, J.; Zhang, P.; Nadeem, S.; Hu, Y. C.
Article Title: Deformation driven Seq2Seq longitudinal tumor and organs-at-risk prediction for radiotherapy
Abstract: Purpose: Radiotherapy presents unique challenges and clinical requirements for longitudinal tumor and organ-at-risk (OAR) prediction during treatment. The challenges include tumor inflammation/edema and radiation-induced changes in organ geometry, whereas the clinical requirements demand flexibility in input/output sequence timepoints to update the predictions on rolling basis and the grounding of all predictions in relationship to the pre-treatment imaging information for response and toxicity assessment in adaptive radiotherapy. Methods: To deal with the aforementioned challenges and to comply with the clinical requirements, we present a novel 3D sequence-to-sequence model based on Convolution Long Short-Term Memory (ConvLSTM) that makes use of series of deformation vector fields (DVFs) between individual timepoints and reference pre-treatment/planning CTs to predict future anatomical deformations and changes in gross tumor volume as well as critical OARs. High-quality DVF training data are created by employing hyper-parameter optimization on the subset of the training data with DICE coefficient and mutual information metric. We validated our model on two radiotherapy datasets: a publicly available head-and-neck dataset (28 patients with manually contoured pre-, mid-, and post-treatment CTs), and an internal non-small cell lung cancer dataset (63 patients with manually contoured planning CT and 6 weekly CBCTs). Results: The use of DVF representation and skip connections overcomes the blurring issue of ConvLSTM prediction with the traditional image representation. The mean and standard deviation of DICE for predictions of lung GTV at weeks 4, 5, and 6 were 0.83 ± 0.09, 0.82 ± 0.08, and 0.81 ± 0.10, respectively, and for post-treatment ipsilateral and contralateral parotids, were 0.81 ± 0.06 and 0.85 ± 0.02. Conclusion: We presented a novel DVF-based Seq2Seq model for medical images, leveraging the complete 3D imaging information of a relatively large longitudinal clinical dataset, to carry out longitudinal GTV/OAR predictions for anatomical changes in HN and lung radiotherapy patients, which has potential to improve RT outcomes. © 2021 American Association of Physicists in Medicine.
Keywords: radiotherapy; image enhancement; computerized tomography; medical imaging; tumors; forecasting; biological organs; deformation; non small cell lung cancer; adaptive radiotherapy; deformation vector field; image representations; large dataset; convlstm; longitudinal prediction; deformation vectors; hyper-parameter optimizations; imaging information; mean and standard deviations; toxicity assessment
Journal Title: Medical Physics
Volume: 48
Issue: 9
ISSN: 0094-2405
Publisher: American Association of Physicists in Medicine  
Date Published: 2021-09-01
Start Page: 4784
End Page: 4798
Language: English
DOI: 10.1002/mp.15075
PUBMED: 34245602
PROVIDER: scopus
PMCID: PMC8486948
DOI/URL:
Notes: Article -- Export Date: 1 October 2021 -- Source: Scopus
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MSK Authors
  1. Pengpeng Zhang
    157 Zhang
  2. Yu-Chi Hu
    106 Hu
  3. Jue Jiang
    59 Jiang
  4. Saad Nadeem
    47 Nadeem
  5. Donghoon Lee
    11 Lee