Creating patient-specific digital phantoms with a longitudinal atlas for evaluating deformable CT-CBCT registration in adaptive lung radiotherapy Journal Article
| Authors: | Meyer, S.; Alam, S.; Kuo, L. C.; Hu, Y. C.; Liu, Y.; Lu, W.; Yorke, E.; Li, A.; Cerviño, L.; Zhang, P. |
| Article Title: | Creating patient-specific digital phantoms with a longitudinal atlas for evaluating deformable CT-CBCT registration in adaptive lung radiotherapy |
| Abstract: | Background: Quality assurance of deformable image registration (DIR) is challenging because the ground truth is often unavailable. In addition, current approaches that rely on artificial transformations do not adequately resemble clinical scenarios encountered in adaptive radiotherapy. Purpose: We developed an atlas-based method to create a variety of patient-specific serial digital phantoms with CBCT-like image quality to assess the DIR performance for longitudinal CBCT imaging data in adaptive lung radiotherapy. Methods: A library of deformations was created by extracting the longitudinal changes observed between a planning CT and weekly CBCT from an atlas of lung radiotherapy patients. The planning CT of an inquiry patient was first deformed by mapping the deformation pattern from a matched atlas patient, and subsequently appended with CBCT artifacts to imitate a weekly CBCT. Finally, a group of digital phantoms around an inquiry patient was produced to simulate a series of possible evolutions of tumor and adjacent normal structures. We validated the generated deformation vector fields (DVFs) to ensure numerically and physiologically realistic transformations. The proposed framework was applied to evaluate the performance of the DIR algorithm implemented in the commercial Eclipse treatment planning system in a retrospective study of eight inquiry patients. Results: The generated DVFs were inverse consistent within less than 3 mm and did not exhibit unrealistic folding. The deformation patterns adequately mimicked the observed longitudinal anatomical changes of the matched atlas patients. Worse Eclipse DVF accuracy was observed in regions of low image contrast or artifacts. The structure volumes exhibiting a DVF error magnitude of equal or more than 2 mm ranged from 24.5% (spinal cord) to 69.2% (heart) and the maximum DVF error exceeded 5 mm for all structures except the spinal cord. Contour-based evaluations showed a high degree of alignment with dice similarity coefficients above 0.8 in all cases, which underestimated the overall DVF accuracy within the structures. Conclusions: It is feasible to create and augment digital phantoms based on a particular patient of interest using multiple series of deformation patterns from matched patients in an atlas. This can provide a semi-automated procedure to complement the quality assurance of CT-CBCT DIR and facilitate the clinical implementation of image-guided and adaptive radiotherapy that involve longitudinal CBCT imaging studies. © 2023 American Association of Physicists in Medicine. |
| Keywords: | controlled study; major clinical study; cancer radiotherapy; comparative study; tumor volume; radiotherapy; retrospective study; computerized tomography; quality assurance; image quality; mediastinum tumor; biological organs; longitudinal study; image registration; cone beam computed tomography; non small cell lung cancer; phantoms; adaptive radiotherapy; deformable image registration; human; article; radiation oncologist; patient specific; lung radiotherapy; digital phantoms; imaging algorithm; planning ct; deformation vectors; root mean squared error; vector fields; deformable registration algorithm; longitudinal atlas; deformation pattern |
| Journal Title: | Medical Physics |
| Volume: | 51 |
| Issue: | 2 |
| ISSN: | 0094-2405 |
| Publisher: | American Association of Physicists in Medicine |
| Date Published: | 2024-02-01 |
| Start Page: | 1405 |
| End Page: | 1414 |
| Language: | English |
| DOI: | 10.1002/mp.16606 |
| PUBMED: | 37449537 |
| PROVIDER: | scopus |
| PMCID: | PMC10787815 |
| DOI/URL: | |
| Notes: | Article -- MSK Cancer Center Support Grant (P30 CA008748) acknowledged in PubMed and PDF -- MSK corresponding author is Sebastian Meyer -- Source: Scopus |
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65Kuo -
181Zhang -
452Yorke -
121Hu -
72Lu -
49Riyahi Alam -
20Liu -
142Cervino Arriba -
19Li -
7Meyer
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