Table 1. Tumor characteristics and planning parameters for the first 3-fr and the third 10-fr stereotactic radiosurgery with the biological effective dose of ≥80 Gy.
*Dosimetric goals of treatment planning.
**The BED10 for absolute doses of 36.3 Gy in 3 fr, 53 Gy in 10 fr, 26.7 Gy in 3 fr, and 42.5 Gy in 10 fr are 80.2 Gy, 81.1 Gy, 50.5 Gy, and 60.6 Gy, respectively.
***The %IDS of D98%, relative to Dmax.
SRS, stereotactic radiosurgery; fr, fraction; Rt, right; GTV, gross tumor volume; Dmax, maximum dose; BED10, a biologically effective dose based on the linear-quadratic formula with an alpha/beta ratio of 10; D98%, a minimum dose encompassing at least 98% of the target volume; IDS, isodose surface
| Session | First | Third | ||||||
| Fraction | 3 fr | 10 fr (re-SRS) | 10 fr (re-SRS) | 10 fr (re-SRS) | 10 fr | 10 fr | ||
| Tumor location | Rt cerebellar | Lt parietal | Rt frontal | Rt cerebellar | Lt temporal | Rt cerebellar | ||
| GTV | Volume | 0.13 cm3 | 1.24 cm3 | 0.69 cm3 | 1.02 cm3 | 1.55 cm3 | 1.69 cm3 | |
| Dmax (BED10) | BED10 ≥120 Gy* | 47.7 Gy (123.5 Gy) | 74.4 Gy (129.8 Gy) | 72.0 Gy (123.8 Gy) | 73.0 Gy (126.3 Gy) | 76.7 Gy (135.5 Gy) | 75.6 Gy (132.8 Gy) | |
| BED10 80 Gy: Dose (coverage)** | ≥98%* | 36.3 Gy (99.6%) | 53 Gy (98.9%) | 53 Gy (99.4%) | 53 Gy (97.4%) | 53 Gy (99.0%) | 53 Gy (99.2%) | |
| D98% (BED10) | BED10 ≥80 Gy* | 37.4 Gy (84.0 Gy) | 53.3 Gy (81.7 Gy) | 54.0 Gy (83.2 Gy) | 52.8 Gy (80.7 Gy) | 53.8 Gy (82.7 Gy) | 53.8 Gy (82.7 Gy) | |
| %IDS*** | ≤77/75% (3 fr/10 fr)* | 78.4% | 71.6% | 75.0% | 72.3% | 70.1% | 71.2% | |
| GTV + 2 mm | D98% (BED10) | BED10 ≥50/60 Gy (3 fr/10 fr)* | 25.7 Gy (47.7 Gy) | 43.0 Gy (61.5 Gy) | 44.5 Gy (64.3 Gy) | 43.6 Gy (62.6 Gy) | 43.9 Gy (63.2 Gy) | 44.9 Gy (65.1 Gy) |
| BED10 50/60 Gy: Dose (coverage)** | ≥95%* | 26.7 Gy (95.0%) | 42.5 Gy (98.8%) | 42.5 Gy (99.8%) | 42.5 Gy (99.3%) | 42.5 Gy (99.7%) | 42.5 Gy (99.9%) | |