Feasibility of artificial-intelligence-based synthetic computed tomography in a magnetic resonance-only radiotherapy workflow for brain radiotherapy: Two-way dose validation and 2D/2D kV-image-based positioning.
Phys Imaging Radiat Oncol
; 24: 111-117, 2022 Oct.
Article
in En
| MEDLINE
| ID: mdl-36405564
ABSTRACT
Background and purpose:
Magnetic Resonance Imaging (MRI)-only workflow eliminates the MRI-computed tomography (CT) registration inaccuracy, which degrades radiotherapy (RT) treatment accuracy. For an MRI-only workflow MRI sequences need to be converted to synthetic-CT (sCT). The purpose of this study was to evaluate a commercially available artificial intelligence (AI)-based sCT generation for dose calculation and 2D/2D kV-image daily positioning for brain RT workflow. Materials andmethods:
T1-VIBE DIXON was acquired at the 1.5â¯T MRI for 26 patients in RT setup for sCTs generation. For each patient, a volumetric modulated arc therapy (VMAT) plan was optimized on the CT, then recalculated on the sCT; and vice versa. sCT-based digitally reconstructed radiographs (DRRs) were fused with stereoscopic X-ray images recorded as image guidance for clinical treatments. Dosimetric differences between planned/recalculated doses and the differences between the calculated and recorded clinical couch shift/rotation were evaluated.Results:
Mean ΔD50 between planned/recalculated doses for target volumes ranged between -0.2â¯% and 0.2â¯%; mean ΔD50 and ΔD0.01ccm were -0.6â¯% and 1.6â¯% and -1.4â¯% and 1.0â¯% for organ-at-risks, respectively. Differences were tested for clinical equivalence using intervals ±2â¯% (dose), ±1mm (translation), and ±1° (rotation). Dose equivalence was found using ±2â¯% interval (pâ¯<â¯0.001). The median differences between lat./long./vert. couch shift between CT-based/sCT-based DRRs were 0.3â¯mm/0.2â¯mm/0.3â¯mm (pâ¯<â¯0.05); median differences between lat./long./vert. couch rotation were -1.5°/0.1°/0.1° (after improvement of RT setup -0.4°/-0.1°/-0.4°, pâ¯<â¯0.05).Conclusions:
This in-silico study showed that the AI-based sCT provided equivalent results to the CT for dose calculation and daily stereoscopic X-ray positioning when using an optimal RT setup during MRI acquisition.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Type of study:
Guideline
Language:
En
Journal:
Phys Imaging Radiat Oncol
Year:
2022
Document type:
Article
Affiliation country:
Alemania