KEY POINTS
- Workflow and dosimetric validation study of magnetic resonance-only simulation for prostate magnetic resonance-guided stereotactic body radiotherapy in 10 patients treated under the SMART protocol.
- The workflow reduced simulation from 3 scans to 2 scans by replacing planning computed tomography with a synthetic computed tomography generated from 3 tesla DIXON magnetic resonance imaging.
- Treatment planning used the 3 tesla magnetic resonance imaging for urethra and dominant intraprostatic lesion delineation, with delivery on a 0.35 tesla MRIdian magnetic resonance linear accelerator.
- Synthetic computed tomography versus planning computed tomography dose agreement was high: gamma pass rate 96.80 ± 1.33% at 2%/2 mm local and 99.98 ± 0.03% at 3%/2 mm global.
- Mean absolute planning target volume D95% difference was 0.06 ± 0.14 Gy; Hounsfield unit agreement showed near-zero global bias (-9.5 HU) but larger deviations in dense bone and transient air cavities.
CLINICAL TAKEAWAY
This study supports a practical magnetic resonance-only path for prostate magnetic resonance-guided stereotactic body radiotherapy when high-field magnetic resonance imaging is needed for definitive urethra and dominant intraprostatic lesion delineation. The main value is workflow efficiency: removing planning computed tomography while preserving synthetic computed tomography dose-calculation accuracy. The evidence is still technical and early, with only 10 patients in retrospective dosimetric validation and a single-volunteer end-to-end test.