Real-time 2D MR cine from beam eye’s view with tumor-volume projection to ensure beam-to-tumor conformality for MR-guided radiotherapy of lung cancer Journal Article
| Authors: | Nie, X.; Li, G. |
| Article Title: | Real-time 2D MR cine from beam eye’s view with tumor-volume projection to ensure beam-to-tumor conformality for MR-guided radiotherapy of lung cancer |
| Abstract: | Purpose: To minimize computation latency using a predictive strategy to retrieve and project tumor volume onto 2D MR beam eye’s view (BEV) cine from time-resolved four-dimensional magnetic resonance imaging (TR-4DMRI) libraries (inhalation/exhalation) for personalized MR-guided intensity-modulated radiotherapy (IMRT) or volumetric-modulated arc therapy (VMAT). Methods: Two time-series forecasting algorithms, autoregressive (AR) modeling and deep-learning-based long short-term memory (LSTM), were applied to predict the diaphragm position in the next 2D BEV cine to identify a motion-matched and hysteresis-accounted image to retrieve the tumor volume from the inhalation/exhalation TR-4DMRI libraries. Three 40-s TR-4DMRI (2 Hz, 3 × 80 images) per patient of eight lung cancer patients were used to create patient-specific inhalation/exhalation 4DMRI libraries, extract diaphragmatic waveforms, and interpolate them to f = 4 and 8 Hz to match 2D cine frame rates. Along a (40•f)-timepoint waveform, 30•f training timepoints were moved forward to produce 3×(10•f-1) predictions. The accuracy of position prediction was assessed against the waveform ground truth. The accuracy of tumor volume projections was evaluated using the center-of-mass difference (∆COM) and Dice similarity index against the TR-4DMRI ground truth for both IMRT (six beam angles, 30° interval) and VMAT (240/480 beam angles, 1.5°/0.75° interval, at 4/8 Hz, respectively). Results: The accuracy of the first-timepoint prediction is 0.36 ± 0.10 mm (AR) and 0.62 ± 0.21 mm (LSTM) at 4 Hz and 0.06 ± 0.02 mm (AR) and 0.18 ± 0.06 mm (LSTM) at 8 Hz. A 10%–20% random error in prediction-library matching increases the overall uncertainty slightly. For both IMRT and VMAT, the accuracy of projected tumor volume contours on 2D BEV cine is ∆COM = 0.39 ± 0.13 mm and DICE = 0.97 ± 0.02 at 4 Hz and ∆COM = 0.10 ± 0.04 mm and DICE = 1.00 ± 0.00 at 8Hz. Conclusion: This study demonstrates the feasibility of accurately predicting respiratory motion during 2D BEV cine imaging, identifying a motion-matched and hysteresis-accounted tumor volume, and projecting tumor volume contour on 2D BEV cine for real-time assessment of beam-to-tumor conformality, promising for optimal personalized MR-guided radiotherapy. Copyright © 2022 Nie and Li. |
| Keywords: | latency; motion management; beam-to-tumor conformality; mr-bev-cine-guided radiotherapy; real-time motion prediction |
| Journal Title: | Frontiers in Oncology |
| Volume: | 12 |
| ISSN: | 2234-943X |
| Publisher: | Frontiers Media S.A. |
| Date Published: | 2022-06-01 |
| Start Page: | 898771 |
| Language: | English |
| DOI: | 10.3389/fonc.2022.898771 |
| PROVIDER: | scopus |
| PMCID: | PMC9277147 |
| PUBMED: | 35847879 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 1 August 2022 -- Source: Scopus |
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