Background
Methods
Patient selection
Treatment planning
Dose volume optimization
Structures | Constraints | ||
---|---|---|---|
Mean dose | Dose volume | ||
PTV | - | At least 95% volume of PTV to receive the prescribed dose | |
OAR | Rectum | <35 Gy | Less than 40% volume to exceed 40 Gy |
Bladder | <35 Gy | Less than 40% volume to exceed 40 Gy | |
Femur-heads | <25 Gy | Less than 5% volume to exceed 40 Gy |
Structures | Constraints | Parameters | |
---|---|---|---|
PTV | Min dose | 54 Gy | |
Dose/volume | V97 > 54.5 Gy | ||
Dose/volume | V3 < 57.5 Gy | ||
Max dose | 58 Gy | ||
OAR | Rectum | Dose/volume | V40 < 35 Gy, and two extra dose/volume constraints for reducing the mean dose |
Bladder | Dose/volume | V40 < 35 Gy, and two extra dose/volume constraints for reducing the mean dose | |
Femur-heads | Dose/volume | V5 < 35Gy, and two extra dose/volume constraints for reducing the mean dose | |
B-Pa
| Max dose | 50 Gy |
Biological model optimization
Structures | Model or constraints | Parameters | |
---|---|---|---|
PTV | TCP Poisson-LQ |
\( {D}_{50} \) =77.6Gy, \( \gamma \) =1.2, \( \alpha /\beta \) =10Gy | |
Target EUD | D = 54Gy, a = 0.1 | ||
Max Dose | D = 58Gy | ||
Uniformity constraint | Std. dev = 2% | ||
OARs | Rectum | NTCP LKBar
|
\( {D}_{50} \) =80Gy, \( \gamma \) =3.9, n = 0.06, m = 0.15 |
NTCP LKBbr
|
\( {D}_{50} \) =81.8Gy, \( \gamma \) =3, n = 0.29, m = 0.22 | ||
NTCP Poisson-LQcr
|
\( {D}_{50} \) =80Gy, \( \gamma \) =2.2, \( \alpha /\beta \) =3Gy, s = 1 | ||
Max EUD | D (variable), a = 1 | ||
Bladder | NTCP LKBab
|
\( {D}_{50} \) =62Gy, \( \gamma \) =6, n = 0.13, m = 0.11 | |
NTCP Poisson-LQbb
|
\( {D}_{50} \) =80Gy, \( \gamma \) =3, \( \alpha /\beta \) =3Gy, s = 0.18 | ||
Max EUD | D (variable), a = 1 | ||
Femur-heads | NTCP Poisson-LQ |
\( {D}_{50} \) =65Gy, \( \gamma \) =2.7, \( \alpha /\beta \) =3Gy, s = 1 | |
Max EUD | D (variable), a = 1 | ||
Small bowela
| NTCP Poisson-LQ |
\( {D}_{50} \) =53.6Gy, \( \gamma \) =2.3, \( \alpha /\beta \) =3Gy, s = 1.5 | |
B-P | Max Dose | D = 50Gy |
Integrated strategy optimization
Plan evaluation and statistics analysis
Results
Comparison between DVO plans and BMO plans
Structures | Parameters | DVO | BMO | ISO | P1 | P2 | P3 | |
---|---|---|---|---|---|---|---|---|
PTV | D98 (Gy) | 54.57 ± 0.46 | 53.42 ± 0.36 | 54.18 ± 0.38 | <0.01 | <0.01 | <0.01 | |
D2 (Gy) | 58.82 ± 0.22 | 58.72 ± 0.28 | 58.89 ± 0.26 | 0.27 | 0.12 | 0.18 | ||
V95 (%) | 99.13 ± 0.82 | 96.79 ± 0.81 | 98.31 ± 0.91 | <0.01 | <0.01 | <0.01 | ||
HI | 0.08 ± 0.01 | 0.10 ± 0.01 | 0.09 ± 0.01 | <0.01 | <0.01 | <0.01 | ||
CI | 0.82 ± 0.04 | 0.71 ± 0.05 | 0.76 ± 0.04 | <0.01 | <0.01 | <0.01 | ||
TCP | 15.39 ± 0.06 | 15.55 ± 0.58 | 15.39 ± 0.05 | 0.22 | 0.23 | 0.97 | ||
OAR | Rectum | V20 (%) | 97.55 ± 3.41 | 95.21 ± 6.98 | 92.66 ± 6.36 | 0.10 | <0.01 | <0.01 |
V30 (%) | 63.43 ± 10.06 | 69.67 ± 12.80 | 60.29 ± 12.76 | 0.01 | <0.01 | 0.17 | ||
V40 (%) | 26.46 ± 10.90 | 24.35 ± 12.44 | 24.24 ± 10.14 | 0.13 | 0.93 | 0.07 | ||
V50 (%) | 6.16 ± 5.63 | 4.35 ± 5.82 | 7.62 ± 10.66 | <0.01 | 0.02 | 0.31 | ||
Dmax (Gy) | 56.55 ± 2.06 | 54.29 ± 2.93 | 56.00 ± 2.01 | <0.01 | <0.01 | 0.13 | ||
Dmean (Gy) | 34.62 ± 2.81 | 34.49 ± 2.68 | 33.49 ± 2.59 | 0.66 | <0.01 | <0.01 | ||
NTCP | 0.19 ± 0.17ar
| 0.11 ± 0.12ar
| 0.14 ± 0.13ar
| <0.01 | <0.01 | <0.01 | ||
Bladder | V20 (%) | 95.35 ± 4.50 | 93.90 ± 7.13 | 91.29 ± 7.79 | 0.35 | <0.01 | 0.03 | |
V30 (%) | 62.10 ± 8.71 | 63.32 ± 8.90 | 58.06 ± 8.12 | 0.47 | <0.01 | <0.01 | ||
V40 (%) | 29.08 ± 7.07 | 30.27 ± 7.29 | 29.68 ± 6.71 | 0.25 | 0.28 | 0.54 | ||
V50 (%) | 9.79 ± 5.96 | 8.86 ± 6.44 | 9.83 ± 6.80 | 0.07 | 0.02 | 0.93 | ||
Dmax (Gy) | 58.95 ± 1.38 | 58.22 ± 1.75 | 58.63 ± 1.72 | <0.01 | 0.09 | 0.09 | ||
Dmean (Gy) | 34.29 ± 2.19 | 34.65 ± 2.22 | 33.92 ± 2.13 | 0.15 | <0.01 | 0.12 | ||
NTCP | 0.18 ± 0.20ab
| 0.14 ± 0.19 ab
| 0.16 ± 0.20ab
| 0.03 | 0.15 | <0.01 | ||
Small bowel | V20 (%) | 52.02 ± 8.45 | 51.37 ± 9.77 | 51.77 ± 8.90 | 0.44 | 0.35 | 0.41 | |
V45 (%) | 0.87 ± 1.48 | 0.83 ± 1.62 | 0.84 ± 1.79 | 0.32 | 0.26 | 0.30 | ||
NTCP | 0.94 ± 1.53 | 0.89 ± 1.74 | 0.90 ± 1.88 | 0.39 | 0.23 | 0.28 | ||
B-P | Dmax (Gy) | 57.59 ± 3.05 | 58.39 ± 1.88 | 58.04 ± 2.41 | 0.17 | 0.27 | 0.36 |
Different biological models
Biological comparison | Structures | NTCP value | NTCP value | Paired t-test p |
---|---|---|---|---|
Rectum: ar VS. br | Rectum | 0.11 ± 0.12ar
| 0.33 ± 0.19br
| <0.01 |
Bladder | 0.14 ± 0.19ab
| 0.14 ± 0.19ab
| - | |
Rectum: ar VS. cr | Rectum | 0.11 ± 0.12ar
| 0.01 ± 0.02cr
| <0.01 |
Bladder | 0.14 ± 0.19ab
| 0.14 ± 0.19ab
| - | |
Bladder: ab VS. bb | Rectum | 0.11 ± 0.12ar
| 0.11 ± 0.12ar
| - |
Bladder | 0.14 ± 0.19ab
| 0.00 ± 0.00bb
| <0.01 |