Table 3.
SMART treatment planning characteristics
| Characteristic | Number (median, range) |
|---|---|
| Prescribed dose (Gy) | 24 Gy (18–50 Gy) |
| Number of fractions | 3 fractions (1–5 fractions) |
| 1 fraction | 4 (6.6%) |
| 2 fractions | 4 (6.6%) |
| 3 fractions | 45 (73.8%) |
| 4 fractions | 1 (1.6%) |
| 5 fractions | 7 (11.5%) |
| Median BED10 (Gy) | 51.3 Gy (28–100 Gy) |
| BED10 (Gy) | |
| ≤ 51.3 | 47 |
| > 51.3 | 14 |
| Median GTV diameter (mm) | 24 mm (6–74 mm) |
| Median GTV/CTV volume (cc) | 29.8 cc (5.8–794.5 cc) |
| Median PTV volume (cc) | 36.6 cc (8.6–809.5 cc) |
| PTV margin | |
| No margin | 13 (21.2%) |
| 1 mm in all directions, 0 from posterior | 9 (14.8%) |
| 1 mm in all directions | 19 (31.1%) |
| 2 mm in all directions, 0 from posterior | 1 (1.6%) |
| 2 mm | 6 (9.8%) |
| 3 mm | 13 (21.3%) |
| Median treatment time (beam on; minutes) | 15.1 min (8.6–29.9 min) |
| Median coverage compromise index (CCI) | 0.90 (0.64–0.98) |
| PTV D98% | 94.2% (80.5–101%) |
| PTV D95% | 100% (91.1–102.8%) |
| PTV D50% | 112% (103.4–119.8%) |
| PTV D2% | 118.9% (107.1–141.7%) |
PTV D98 and D2 minimum dose to 98% and 2% volumes, respectively; PTV D50 median dose, PTV D50 minimum dose delivered to 95% of the PTV; GTV gross tumor volume; CTV clinical tumor volume; PTV planning target volume; SMART stereotactic magnetic resonance-guided adaptive radiotherapy