Souha Aouadi1, Ana Vasic2, Satheesh Paloor3, Tarraf Torfeh4, Maeve McGarry5, Primoz Petric6, Mohamed Riyas7, Rabih Hammoud8, Noora Al-Hammadi9. 1. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: saouadi@hamad.qa. 2. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: avasic@hamad.qa. 3. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: spaloor@hamad.qa. 4. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: ttorfeh@hamad.qa. 5. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: maevemcgarry@gmail.com. 6. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: ppetric@hamad.qa. 7. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: mriyas@hamad.qa. 8. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: rhammoud2@hamad.qa. 9. Department of Radiation Oncology, National Centre for Cancer Care and Research, Hamad Medical Corporation, Doha PO BOX 3050, Qatar. Electronic address: nalhammadi1@hamad.qa.
Abstract
PURPOSE: To create a synthetic CT (sCT) from conventional brain MRI using a patch-based method for MRI-only radiotherapy planning and verification. METHODS: Conventional T1 and T2-weighted MRI and CT datasets from 13 patients who underwent brain radiotherapy were included in a retrospective study whereas 6 patients were tested prospectively. A new contribution to the Non-local Means Patch-Based Method (NMPBM) framework was done with the use of novel multi-scale and dual-contrast patches. Furthermore, the training dataset was improved by pre-selecting the closest database patients to the target patient for computation time/accuracy balance. sCT and derived DRRs were assessed visually and quantitatively. VMAT planning was performed on CT and sCT for hypothetical PTVs in homogeneous and heterogeneous regions. Dosimetric analysis was done by comparing Dose Volume Histogram (DVH) parameters of PTVs and organs at risk (OARs). Positional accuracy of MRI-only image-guided radiation therapy based on CBCT or kV images was evaluated. RESULTS: The retrospective (respectively prospective) evaluation of the proposed Multi-scale and Dual-contrast Patch-Based Method (MDPBM) gave a mean absolute error MAE=99.69±11.07HU (98.95±8.35HU), and a Dice in bones DIbone=83±0.03 (0.82±0.03). Good agreement with conventional planning techniques was obtained; the highest percentage of DVH metric deviations was 0.43% (0.53%) for PTVs and 0.59% (0.75%) for OARs. The accuracy of sCT/CBCT or DRRsCT/kV images registration parameters was <2mm and <2°. Improvements with MDPBM, compared to NMPBM, were significant. CONCLUSION: We presented a novel method for sCT generation from T1 and T2-weighted MRI potentially suitable for MRI-only external beam radiotherapy in brain sites.
PURPOSE: To create a synthetic CT (sCT) from conventional brain MRI using a patch-based method for MRI-only radiotherapy planning and verification. METHODS: Conventional T1 and T2-weighted MRI and CT datasets from 13 patients who underwent brain radiotherapy were included in a retrospective study whereas 6 patients were tested prospectively. A new contribution to the Non-local Means Patch-Based Method (NMPBM) framework was done with the use of novel multi-scale and dual-contrast patches. Furthermore, the training dataset was improved by pre-selecting the closest database patients to the target patient for computation time/accuracy balance. sCT and derived DRRs were assessed visually and quantitatively. VMAT planning was performed on CT and sCT for hypothetical PTVs in homogeneous and heterogeneous regions. Dosimetric analysis was done by comparing Dose Volume Histogram (DVH) parameters of PTVs and organs at risk (OARs). Positional accuracy of MRI-only image-guided radiation therapy based on CBCT or kV images was evaluated. RESULTS: The retrospective (respectively prospective) evaluation of the proposed Multi-scale and Dual-contrast Patch-Based Method (MDPBM) gave a mean absolute error MAE=99.69±11.07HU (98.95±8.35HU), and a Dice in bones DIbone=83±0.03 (0.82±0.03). Good agreement with conventional planning techniques was obtained; the highest percentage of DVH metric deviations was 0.43% (0.53%) for PTVs and 0.59% (0.75%) for OARs. The accuracy of sCT/CBCT or DRRsCT/kV images registration parameters was <2mm and <2°. Improvements with MDPBM, compared to NMPBM, were significant. CONCLUSION: We presented a novel method for sCT generation from T1 and T2-weighted MRI potentially suitable for MRI-only external beam radiotherapy in brain sites.
Authors: Domen Močnik; Bulat Ibragimov; Lei Xing; Primož Strojan; Boštjan Likar; Franjo Pernuš; Tomaž Vrtovec Journal: Phys Med Date: 2018-06-19 Impact factor: 2.685
Authors: Yang Lei; Joseph Harms; Tonghe Wang; Sibo Tian; Jun Zhou; Hui-Kuo Shu; Jim Zhong; Hui Mao; Walter J Curran; Tian Liu; Xiaofeng Yang Journal: Phys Med Biol Date: 2019-04-05 Impact factor: 3.609