Feasibility of MR-guided radiotherapy using beam-eye-view 2D-cine with tumor-volume projection Journal Article
| Authors: | Nie, X.; Rimner, A.; Li, G. |
| Article Title: | Feasibility of MR-guided radiotherapy using beam-eye-view 2D-cine with tumor-volume projection |
| Abstract: | Purpose. Current magnetic resonance imaging (MRI) guided radiotherapy (MRgRT) applies sagittal/coronal 2D-cine to monitor major tumor motions, however, the beam eye's view (BEV) with volumetric tumor projection would be the best measure for radiation beam conformality, independent of tumor through-plane motion. The goal is to assess the feasibility, accuracy, and performance of the BEV approach. Methods. Beam-specific BEV 2D-cine with volume-projected tumor contours were simulated to establish a 2D/3D tumor match against a tumor-motion library based on multi-breath time-resolved (TR) 4DMRI images. Two BEV-library-matching methods were developed: (1) fast screening with tumor center-of-mass (COM), in-plane area ratio, and DICE similarity, and finalizing with the highest DICE score and (2) DICE screening for top-3 candidates and finalizing with rigid registration. A 4D-XCAT digital phantom and 8 lung-cancer patients were used for assessment. For each patient, 3 sets of 40 s TR-4DMRI were acquired at 2 Hz and 6 representative BEV were created with the isocenter set at tumor COM in mid-respiration. One TR-4DMRI set (40 × 2 = 80-images) was used to simulate BEV 2D-cine and the other two (160-images) were used to create a library. The matching result was validated against the ground truth within the test set. Using a leave-one-out strategy, the success rate, accuracy, and speed of tumor matching were assessed for volume-projected tumors over 11520 time-points (=8patients•3sets•80images•6BEVs). Results. Volume-projected tumor contour area on the 6 BEVs varies by 60% ± 8% and (in-plane/volume-projected) varies by 82% ± 9%. The changes with tumor shape, orientation, and through-plane motion. Method-1 produces 96% matching success (ΔCOM = 0.7 ± 0.2 mm,=1.01 ± 0.02, Dice=0.92 ± 0.02) with the computational time of 15 ± 1 ms/match, while method-2 produces 94% ± 1% success (ΔCOM = 0.2 ± 0.1 mm, =1.00 ± 0.01, Dice = 0.94 ± 0.02) with 223 ± 13 ms/match. Conclusion. This study has demonstrated the feasibility, accuracy, and benefits of BEV 2D-cine imaging with tumor-volume projection, allowing real-time tumor motion monitoring and beam conformality checking. Further clinical evaluation is necessary before MRgRT applications. © 2021 Institute of Physics and Engineering in Medicine. |
| Keywords: | magnetic resonance imaging; radiotherapy; tumors; diagnosis; clinical evaluation; rigid registration; digital phantoms; mr-guided radiotherapy; beam eye's view (bev); mrlinac; radiation beam conformality; real-time tumor motion monitoring; center of mass; computational time; fast screening; matching methods; radiation beams; time and motion study |
| Journal Title: | Physics in Medicine and Biology |
| Volume: | 66 |
| Issue: | 4 |
| ISSN: | 0031-9155 |
| Publisher: | IOP Publishing Ltd |
| Date Published: | 2021-02-08 |
| Start Page: | 045020 |
| Language: | English |
| DOI: | 10.1088/1361-6560/abd66a |
| PROVIDER: | scopus |
| PUBMED: | 33361569 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 1 April 2021 -- Source: Scopus |
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