Introduction
Materials and methods
CCR-VMAT delivery in the TrueBeam developer mode
CCR-VMAT planning based on a C-shaped phantom and prostate cancer data
QA of CCR-VMAT
Coincidence of mechanical and radiation isocenters during CCR-VMAT by the Winston–Lutz test
Mechanical accuracy
Dosimetric accuracy
Results
Coincidence of mechanical and radiation isocenters during CCR-VMAT
Mechanical accuracy
Criteria | Trajectory | ||||||||
---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | |||
C-shaped phantom | |||||||||
PTV | D95% (Gy) | ≥ 50 Gy (100%) | 50.0 | 50.0 | 50.1 | 50.2 | 50.0 | 50.0 | 50.0 |
PTV | Dmax (Gy) | ≤ 55 Gy (110%) | 54.9 | 54.9 | 55.0 | 54.9 | 55.0 | 54.9 | 55.0 |
Core | D2cc (Gy) | ≤ 30 Gy (60%) | 29.6 | 29.7 | 30.0 | 29.2 | 28.9 | 29.4 | 28.7 |
Prostate (n = 5) | |||||||||
PTV | Dmean (Gy) | > 75.2 Gy (99%) | 76.0 [76.0–76.0] | 76.0 [76.0–76.0] | 76.0 [76.0–76.0] | 76.0 [76.0–76.0] | 76.0 [76.0–76.0] | 76.0 [76.0–76.0] | 76.0 [76.0–76.4] |
D95% (Gy) | > 68.4 Gy (90%) | 71.6 [71.2–72.7] | 71.5 [71.3–72.7] | 71.4 [71.1–72.9] | 71.7 [71.6–72.5] | 72.5 [71.9–73.1] | 71.3 [70.0–72.9] | 71.8 [71.1–72.9] | |
V90% (%) | > 95% | 99.8 [99.2–100.0] | 99.8 [99.4–100.0] | 99.7 [99.2–99.9] | 99.8 [99.6–100.0] | 99.9 [99.7–100.0] | 99.1 [98.3–99.9] | 99.7 [99.2–100.0] | |
Dmax (Gy) | ≤ 83.6 Gy (110%) | 80.6 [78.7–82.1] | 80.9 [79.1–81.6] | 81.0 [80.4–81.8] | 80.7 [80.4–81.5] | 81.1 [79.5–83.0] | 81.5 [79.8–81.8] | 81.0 [80.6–83.6] | |
Bladder wall | V40Gy (%) | < 65% | 22.0 [11.8–31.4] | 22.9 [11.8–28.8] | 21.2 [13.3–32.5] | 22.0 [11.5–27.7] | 24.9 [11.8–29.6] | 26.0 [13.2–30.5] | 25.3 [13.7–32.0] |
V70Gy (%) | < 35% | 12.1 [5.5–17.0] | 12.1 [5.6–17.5] | 11.3 [5.6–17.0] | 12.1 [5.5–16.7] | 12.3 [5.7–17.0] | 12.2 [6.1–16.9] | 12.2 [6.0–16.6] | |
Rectal wall | V40Gy (%) | < 65% | 40.3 [27.6–41.0] | 40.4 [28.5–42.0] | 40.3 [27.6–43.9] | 39.3 [29.2–41.6] | 37.0 [29.9–42.7] | 40.7 [28.1–43.3] | 40.9 [28.8–43.1] |
V60Gy (%) | < 35% | 24.8 [12.5–26.0] | 23.8 [12.1–26.8] | 23.7 [12.5–26.7] | 23.6 [13.7–25.8] | 21.2 [13.1–24.8] | 24.7 [12.3–25.5] | 23.6 [12.9–25.9] | |
V70Gy (%) | < 25% | 9.2 [3.7–13.6] | 9.5 [3.4–14.0] | 9.6 [2.7–14.2] | 9.2 [4.0–11.8] | 11.6 [4.6–11.7] | 9.1 [3.3–12.1] | 11.4 [3.7–12.4] | |
V76Gy (%) | < 1% | 0.0 [0.0–0.0] | 0.0 [0.0–0.0] | 0.0 [0.0–0.0] | 0.0 [0.0–0.0] | 0.0 [0.0–0.0] | 0.0 [0.0–0.0] | 0.0 [0.0–0.0] |
Trajectory | C-shaped phantom | Prostate cancers (n = 5) | ||||||
---|---|---|---|---|---|---|---|---|
Gantry [°] | Couch [°] | MLC [mm] | Beam output [MU] | Gantry [°] | Couch [°] | MLC [mm] | Beam output [MU] | |
1 | 0.04 ± 0.01 | 0.01 ± 0.01 | 0.03 ± 0.04 | 0.01 ± 0.02 | 0.04 ± 0.03 | 0.04 ± 0.02 | 0.02 ± 0.03 | 0.01 ± 0.01 |
2 | 0.04 ± 0.02 | 0.03 ± 0.06 | 0.03 ± 0.05 | 0.01 ± 0.02 | 0.04 ± 0.04 | 0.05 ± 0.08 | 0.02 ± 0.03 | 0.01 ± 0.02 |
3 | 0.04 ± 0.02 | 0.04 ± 0.09 | 0.03 ± 0.05 | 0.01 ± 0.01 | 0.04 ± 0.02 | 0.03 ± 0.06 | 0.02 ± 0.03 | 0.01 ± 0.01 |
4 | 0.04 ± 0.01 | 0.03 ± 0.03 | 0.03 ± 0.04 | 0.01 ± 0.02 | 0.04 ± 0.03 | 0.07 ± 0.05 | 0.02 ± 0.04 | 0.01 ± 0.01 |
5 | 0.04 ± 0.02 | 0.04 ± 0.08 | 0.03 ± 0.05 | 0.01 ± 0.01 | 0.04 ± 0.04 | 0.06 ± 0.09 | 0.02 ± 0.03 | 0.01 ± 0.01 |
6 | 0.04 ± 0.01 | 0.02 ± 0.01 | 0.02 ± 0.03 | 0.01 ± 0.02 | 0.04 ± 0.03 | 0.08 ± 0.03 | 0.02 ± 0.04 | 0.01 ± 0.01 |
7 | 0.04 ± 0.02 | 0.04 ± 0.01 | 0.03 ± 0.04 | 0.01 ± 0.02 | 0.04 ± 0.03 | 0.06 ± 0.02 | 0.02 ± 0.04 | 0.01 ± 0.01 |
Dosimetric accuracy
Trajectory | C-shaped phantom | Prostate cancers (n = 5) | ||||
---|---|---|---|---|---|---|
3%/3 mm [%] | 3%/1 mm [%] | 5%/1 mm [%] | 3%/3 mm [%] | 3%/1 mm [%] | 5%/1 mm [%] | |
1 | 98.0 | 91.5 | 97.5 | 98.3 ± 1.7 | 86.5 ± 2.8 | 95.9 ± 1.4 |
2 | 99.1 | 92.1 | 98.6 | 98.2 ± 0.5 | 84.9 ± 0.5 | 95.9 ± 2.2 |
3 | 99.2 | 92.0 | 98.5 | 98.4 ± 1.9 | 85.8 ± 1.8 | 95.8 ± 0.9 |
4 | 99.6 | 96.7 | 99.6 | 98.5 ± 0.8 | 88.2 ± 4.8 | 96.5 ± 2.8 |
5 | 99.0 | 92.5 | 98.3 | 97.8 ± 1.0 | 86.0 ± 3.8 | 96.0 ± 2.5 |
6 | 98.9 | 90.2 | 98.1 | 97.5 ± 1.6 | 85.8 ± 3.6 | 95.9 ± 2.4 |
7 | 99.5 | 95.8 | 99.2 | 97.2 ± 2.3 | 87.1 ± 5.7 | 95.8 ± 1.8 |