Background
Methods
Formula
Systematic study with 1-D hypothetical dose distribution
2-D systematic study using clinical cases
Application for comparing calculated with measured data for clinical cases
Active area (cm × cm) | 40 × 40 | 40 × 30 |
---|---|---|
Calculated matrix / Pixel pitch (mm) | 1024 × 1024 / 0.393 | 512 × 384 / 0.786 |
Measured matrix / Pixel pitch (mm) | 1190 × 1190 / 0.336 | 1024 × 768 / 0.392 |
EPID model | a-Si 1200 | a-Si 1000 |
Head and Neck (cases) | 21 | 9 |
Prostate (cases) | 13 | 17 |
Results
Systematic study with 1-D hypothetical dose distribution
Intentional Dose Error => | 0% | + 1% | + 2% | + 3% | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Intentional Spatial Error | Model => | A | B | C | A | B | C | A | B | C | A | B | C | ||||
0 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |||||
rate (%) | 2%/2 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 56.9 | 32.1 | 90.8 | ||||
1%/1 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 0 | 30.5 | 0 | 0 | 30.5 | 0 | |||||
IOA | Value | 1.000 | 1.000 | 1.000 | 1.010 | 1.010 | 1.010 | 1.020 | 1.020 | 1.020 | 1.030 | 1.030 | 1.030 | ||||
Rank | 1 | 1 | 1 | 2 | 2 | 2 | 5 | 3 | 5 | 9 | 6 | 7 | |||||
1 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 99.5 | 99.2 | 99.2 | |||||
rate (%) | 2%/2 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 71.6 | 99.2 | 54.2 | 28.9 | 32.1 | 45.8 | ||||
1%/1 mm | 100.0 | 100.0 | 100.0 | 71.6 | 84.7 | 54.2 | 28.4 | 16.0 | 45.8 | 28.0 | 16.0 | 45.0 | |||||
IOA | Value | 1.013 | 1.028 | 1.016 | 1.016 | 1.029 | 1.019 | 1.024 | 1.034 | 1.026 | 1.033 | 1.041 | 1.034 | ||||
Rank | 3 | 4 | 3 | 4 | 5 | 4 | 6 | 7 | 6 | 11 | 8 | 10 | |||||
2 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 71.1 | 98.5 | 54.2 | |||||
rate (%) | 2%/2 mm | 100.0 | 100.0 | 100.0 | 71.6 | 84.7 | 55.0 | 71.1 | 84.0 | 54.2 | 29.4 | 17.6 | 46.6 | ||||
1%/1 mm | 43.1 | 69.5 | 9.2 | 43.1 | 68.7 | 9.2 | 28.9 | 1.5 | 45.8 | 28.4 | 1.5 | 45.0 | |||||
IOA | Value | 1.025 | 1.055 | 1.032 | 1.027 | 1.056 | 1.033 | 1.032 | 1.058 | 1.038 | 1.039 | 1.062 | 1.044 | ||||
Rank | 7 | 9 | 8 | 8 | 10 | 9 | 10 | 11 | 11 | 14 | 12 | 12 | |||||
3 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 71.6 | 99.2 | 55.7 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 72.0 | 84.7 | 55.7 | 71.6 | 84.7 | 55.7 | 70.6 | 83.2 | 54.2 | |||||
rate (%) | 2%/2 mm | 44.1 | 69.5 | 10.7 | 43.1 | 68.7 | 9.9 | 70.6 | 67.7 | 53.4 | 29.9 | 3.8 | 46.6 | ||||
1%/1 mm | 42.2 | 67.9 | 9.2 | 42.2 | 67.2 | 8.4 | 1.4 | 1.5 | 1.5 | 1.4 | 1.5 | 1.5 | |||||
IOA | Value | 1.037 | 1.081 | 1.047 | 1.039 | 1.082 | 1.048 | 1.042 | 1.084 | 1.051 | 1.048 | 1.086 | 1.056 | ||||
Rank | 12 | 13 | 13 | 13 | 14 | 14 | 15 | 15 | 15 | 16 | 16 | 16 |
Intentional Dose Error => | 0% | + 1% | + 2% | + 3% | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Intentional Spatial Error | Model => | A | B | C | A | B | C | A | B | C | A | B | C | ||||
0 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 99.0 | 100.0 | 98.3 | 99.0 | 100.0 | 98.3 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 99.0 | 100.0 | 98.3 | 99.0 | 100.0 | 98.3 | |||||
rate (%) | 2%/2 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 99.0 | 100.0 | 98.3 | 59.3 | 35.3 | 98.3 | ||||
1%/1 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 0 | 33.6 | 0 | 0 | 33.6 | 0 | |||||
IOA | Value | 1.000 | 1.000 | 1.000 | 1.077 | 1.034 | 1.099 | 1.154 | 1.068 | 1.199 | 1.231 | 1.101 | 1.298 | ||||
Rank | 1 | 1 | 1 | 2 | 2 | 2 | 5 | 3 | 5 | 8 | 4 | 8 | |||||
1 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 99.0 | 100.0 | 98.3 | 99.0 | 100.0 | 98.3 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 99.0 | 100.0 | 98.3 | 99.0 | 100.0 | 98.3 | |||||
rate (%) | 2%/2 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 69.8 | 100.0 | 49.6 | 30.2 | 35.3 | 49.6 | ||||
1%/1 mm | 100.0 | 100.0 | 100.0 | 70.4 | 84.0 | 50.4 | 29.6 | 17.6 | 49.6 | 29.6 | 17.6 | 49.6 | |||||
IOA | Value | 1.128 | 1.164 | 1.165 | 1.149 | 1.167 | 1.193 | 1.200 | 1.177 | 1.258 | 1.264 | 1.192 | 1.341 | ||||
Rank | 3 | 5 | 3 | 4 | 6 | 4 | 6 | 7 | 6 | 10 | 8 | 10 | |||||
2 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 99.0 | 100.0 | 98.3 | 99.0 | 100.0 | 98.3 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 72.9 | 100.0 | 54.6 | 69.8 | 100.0 | 50.4 | |||||
rate (%) | 2%/2 mm | 100.0 | 100.0 | 100.0 | 70.4 | 84.0 | 51.3 | 69.8 | 84.0 | 50.4 | 30.7 | 19.3 | 50.4 | ||||
1%/1 mm | 40.2 | 67.2 | 0.8 | 40.2 | 67.2 | 0.8 | 30.2 | 1.7 | 49.6 | 30.2 | 1.7 | 49.6 | |||||
IOA | Value | 1.225 | 1.286 | 1.290 | 1.250 | 1.294 | 1.323 | 1.294 | 1.305 | 1.379 | 1.349 | 1.320 | 1.451 | ||||
Rank | 7 | 9 | 7 | 9 | 10 | 9 | 11 | 11 | 11 | 14 | 12 | 14 | |||||
3 mm | Gamma pass | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 77.4 | 100.0 | 62.2 | 69.8 | 100.0 | 51.3 | |||
3%/3 mm | 100.0 | 100.0 | 100.0 | 70.9 | 84.0 | 52.1 | 69.8 | 84.0 | 51.3 | 69.8 | 84.0 | 51.3 | |||||
rate (%) | 2%/2 mm | 40.7 | 67.2 | 1.7 | 40.2 | 67.2 | 1.7 | 69.8 | 67.2 | 50.4 | 31.2 | 3.4 | 50.4 | ||||
1%/1 mm | 39.7 | 66.4 | 1.7 | 39.7 | 66.4 | 0.8 | 1.0 | 1.7 | 0.8 | 1.0 | 1.7 | 0.8 | |||||
IOA | Value | 1.318 | 1.404 | 1.411 | 1.347 | 1.415 | 1.448 | 1.389 | 1.428 | 1.503 | 1.441 | 1.443 | 1.570 | ||||
Rank | 12 | 13 | 12 | 13 | 14 | 13 | 15 | 15 | 15 | 16 | 16 | 16 |
2-D systematic study using clinical cases
Intentional Dose Error | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
−3% | −2% | −1% | 0 | + 1% | + 2% | + 3% | ||||
Intentional Spatial Error | -3 mm | Gamma pass rate (%) | 4%/4 mm | 92.7 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 92.6 |
3%/3 mm | 69.9 | 81.5 | 88.6 | 100.0 | 89.2 | 82.6 | 69.5 | |||
2%/2 mm | 45.7 | 55.4 | 63.5 | 66.1 | 62.7 | 53.0 | 43.5 | |||
1%/1 mm | 13.3 | 17.4 | 22.2 | 23.3 | 20.2 | 15.9 | 12.1 | |||
IOA | 1.060 | 1.056 | 1.052 | 1.051 | 1.052 | 1.055 | 1.059 | |||
IOH | 1.022 | 1.025 | 1.029 | 1.034 | 1.039 | 1.045 | 1.052 | |||
IOC | 0.936 | 0.942 | 0.948 | 0.953 | 0.958 | 0.962 | 0.966 | |||
-2 mm | Gamma pass rate (%) | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |
3%/3 mm | 79.4 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 76.9 | |||
2%/2 mm | 47.6 | 65.4 | 79.4 | 100.0 | 78.8 | 62.6 | 46.9 | |||
1%/1 mm | 11.8 | 17.5 | 29.0 | 35.1 | 27.1 | 17.0 | 11.4 | |||
IOA | 1.049 | 1.043 | 1.039 | 1.038 | 1.039 | 1.042 | 1.048 | |||
IOH | 1.014 | 1.017 | 1.020 | 1.024 | 1.030 | 1.036 | 1.044 | |||
IOC | 0.948 | 0.955 | 0.961 | 0.966 | 0.971 | 0.975 | 0.978 | |||
-1 mm | Gamma pass rate (%) | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |
3%/3 mm | 94.6 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 92.9 | |||
2%/2 mm | 47.6 | 81.4 | 100.0 | 100.0 | 100.0 | 79.1 | 47.0 | |||
1%/1 mm | 8.2 | 16.1 | 40.7 | 100.0 | 37.2 | 16.0 | 7.4 | |||
IOA | 1.036 | 1.029 | 1.023 | 1.020 | 1.022 | 1.028 | 1.036 | |||
IOH | 1.005 | 1.007 | 1.009 | 1.013 | 1.019 | 1.026 | 1.035 | |||
IOC | 0.962 | 0.970 | 0.976 | 0.982 | 0.986 | 0.989 | 0.992 | |||
0 | Gamma pass rate (%) | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |
3%/3 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |||
2%/2 mm | 55.3 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 55.8 | |||
1%/1 mm | 0 | 0.1 | 100.0 | 100.0 | 100.0 | 0.1 | 0 | |||
IOA | 1.030 | 1.020 | 1.010 | 1.000 | 1.010 | 1.020 | 1.030 | |||
IOH | 1.000 | 1.000 | 1.000 | 1.000 | 1.010 | 1.020 | 1.030 | |||
IOC | 0.970 | 0.980 | 0.990 | 1.000 | 1.000 | 1.000 | 1.000 | |||
+ 1 mm | Gamma pass rate (%) | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |
3%/3 mm | 92.8 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 95.0 | |||
2%/2 mm | 45.7 | 78.4 | 100.0 | 100.0 | 100.0 | 82.2 | 48.5 | |||
1%/1 mm | 7.1 | 15.4 | 36.5 | 100.0 | 41.3 | 16.6 | 8.4 | |||
IOA | 1.036 | 1.029 | 1.023 | 1.020 | 1.023 | 1.028 | 1.036 | |||
IOH | 1.005 | 1.007 | 1.010 | 1.014 | 1.019 | 1.027 | 1.035 | |||
IOC | 0.962 | 0.971 | 0.978 | 0.984 | 0.989 | 0.992 | 0.995 | |||
+ 2 mm | Gamma pass rate (%) | 4%/4 mm | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | |
3%/3 mm | 75.6 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 81.6 | |||
2%/2 mm | 44.3 | 60.7 | 78.5 | 100.0 | 79.9 | 67.0 | 49.9 | |||
1%/1 mm | 10.6 | 16.3 | 26.3 | 35.1 | 29.8 | 18.2 | 12.5 | |||
IOA | 1.049 | 1.043 | 1.039 | 1.038 | 1.039 | 1.042 | 1.048 | |||
IOH | 1.015 | 1.018 | 1.022 | 1.026 | 1.031 | 1.037 | 1.045 | |||
IOC | 0.950 | 0.958 | 0.964 | 0.970 | 0.976 | 0.980 | 0.984 | |||
+ 3 mm | Gamma pass rate (%) | 4%/4 mm | 91.5 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 94.3 | |
3%/3 mm | 66.4 | 80.1 | 88.1 | 100.0 | 89.9 | 84.4 | 74.1 | |||
2%/2 mm | 41.4 | 51.1 | 61.7 | 66.0 | 64.6 | 57.6 | 47.9 | |||
1%/1 mm | 11.1 | 14.9 | 19.5 | 23.3 | 23.0 | 18.2 | 14.1 | |||
IOA | 1.060 | 1.056 | 1.053 | 1.051 | 1.052 | 1.055 | 1.059 | |||
IOH | 1.024 | 1.028 | 1.032 | 1.036 | 1.041 | 1.047 | 1.054 | |||
IOC | 0.940 | 0.947 | 0.954 | 0.960 | 0.966 | 0.970 | 0.975 |
Intentional Dose Error | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
-3% | -2% | -1% | 0 | + 1% | + 2% | + 3% | ||||
Intentional Spatial Error | -3 mm | Gamma pass rate (%) | 4%/4 mm | 71.1 | 83.6 | 95.2 | 100.0 | 94.2 | 81.3 | 68.6 |
3%/3 mm | 52.8 | 63.7 | 73.0 | 100.0 | 72.7 | 62.6 | 52.0 | |||
2%/2 mm | 30.8 | 37.5 | 45.1 | 45.9 | 42.1 | 35.1 | 28.8 | |||
1%/1 mm | 6.0 | 6.9 | 9.0 | 8.0 | 8.0 | 5.7 | 4.8 | |||
IOA | 1.210 | 1.189 | 1.176 | 1.171 | 1.177 | 1.191 | 1.212 | |||
IOH | 1.083 | 1.095 | 1.109 | 1.127 | 1.148 | 1.173 | 1.202 | |||
IOC | 0.807 | 0.836 | 0.863 | 0.885 | 0.904 | 0.920 | 0.933 | |||
-2 mm | Gamma pass rate (%) | 4%/4 mm | 79.5 | 90.9 | 98.2 | 100.0 | 98.0 | 89.1 | 76.5 | |
3%/3 mm | 56.2 | 72.9 | 90.8 | 100.0 | 89.4 | 70.3 | 54.5 | |||
2%/2 mm | 30.8 | 41.9 | 56.6 | 100.0 | 54.3 | 41.3 | 30.3 | |||
1%/1 mm | 4.9 | 6.8 | 11.1 | 12.3 | 10.0 | 6.5 | 4.8 | |||
IOA | 1.175 | 1.148 | 1.130 | 1.124 | 1.131 | 1.149 | 1.176 | |||
IOH | 1.052 | 1.062 | 1.075 | 1.091 | 1.112 | 1.139 | 1.170 | |||
IOC | 0.833 | 0.865 | 0.893 | 0.916 | 0.933 | 0.946 | 0.957 | |||
-1 mm | Gamma pass rate (%) | 4%/4 mm | 82.7 | 93.2 | 99.1 | 100.0 | 99.0 | 91.9 | 80.2 | |
3%/3 mm | 63.4 | 81.4 | 95.6 | 100.0 | 95.1 | 79.8 | 61.7 | |||
2%/2 mm | 26.6 | 44.6 | 74.1 | 100.0 | 72.2 | 44.0 | 26.6 | |||
1%/1 mm | 3.6 | 6.5 | 14.6 | 100.0 | 13.7 | 6.5 | 3.3 | |||
IOA | 1.140 | 1.106 | 1.078 | 1.067 | 1.078 | 1.106 | 1.141 | |||
IOH | 1.018 | 1.024 | 1.033 | 1.048 | 1.071 | 1.104 | 1.140 | |||
IOC | 0.861 | 0.897 | 0.929 | 0.954 | 0.969 | 0.978 | 0.985 | |||
0 | Gamma pass rate (%) | 4%/4 mm | 83.1 | 93.4 | 99.3 | 100.0 | 99.3 | 93.1 | 81.8 | |
3%/3 mm | 64.5 | 82.7 | 96.3 | 100.0 | 96.2 | 82.5 | 64.5 | |||
2%/2 mm | 28.0 | 50.5 | 79.9 | 100.0 | 80.2 | 51.4 | 29.0 | |||
1%/1 mm | 0 | 0 | 0.1 | 100.0 | 0.1 | 0 | 0 | |||
IOA | 1.124 | 1.083 | 1.041 | 1.000 | 1.041 | 1.083 | 1.124 | |||
IOH | 1.000 | 1.000 | 1.000 | 1.000 | 1.041 | 1.083 | 1.124 | |||
IOC | 0.876 | 0.917 | 0.959 | 1.000 | 1.000 | 1.000 | 1.000 | |||
+ 1 mm | Gamma pass rate (%) | 4%/4 mm | 81.7 | 92.4 | 99.1 | 100.0 | 99.1 | 93.1 | 81.8 | |
3%/3 mm | 61.7 | 80.1 | 95.1 | 100.0 | 95.5 | 81.5 | 63.4 | |||
2%/2 mm | 24.9 | 42.8 | 72.1 | 100.0 | 74.0 | 45.5 | 28.1 | |||
1%/1 mm | 3.1 | 6.1 | 13.3 | 100.0 | 14.9 | 6.8 | 3.9 | |||
IOA | 1.140 | 1.106 | 1.078 | 1.067 | 1.079 | 1.107 | 1.141 | |||
IOH | 1.018 | 1.025 | 1.034 | 1.049 | 1.072 | 1.105 | 1.141 | |||
IOC | 0.861 | 0.897 | 0.930 | 0.954 | 0.969 | 0.978 | 0.985 | |||
+ 2 mm | Gamma pass rate (%) | 4%/4 mm | 77.7 | 89.7 | 98.2 | 100.0 | 98.3 | 91.1 | 79.7 | |
3%/3 mm | 53.6 | 69.8 | 89.7 | 100.0 | 90.9 | 74.5 | 57.9 | |||
2%/2 mm | 27.8 | 39.1 | 53.5 | 100.0 | 57.7 | 43.8 | 32.9 | |||
1%/1 mm | 4.4 | 6.2 | 9.6 | 12.3 | 11.5 | 7.3 | 5.3 | |||
IOA | 1.174 | 1.149 | 1.131 | 1.125 | 1.132 | 1.151 | 1.178 | |||
IOH | 1.054 | 1.064 | 1.077 | 1.093 | 1.115 | 1.141 | 1.172 | |||
IOC | 0.834 | 0.866 | 0.894 | 0.917 | 0.934 | 0.947 | 0.957 | |||
+ 3 mm | Gamma pass rate (%) | 4%/4 mm | 67.8 | 81.0 | 94.6 | 100.0 | 95.7 | 84.6 | 73.5 | |
3%/3 mm | 50.1 | 60.1 | 71.6 | 100.0 | 75.0 | 67.3 | 55.8 | |||
2%/2 mm | 27.5 | 34.1 | 41.6 | 46.5 | 45.7 | 38.8 | 32.1 | |||
1%/1 mm | 4.4 | 5.3 | 7.7 | 8.0 | 9.4 | 7.3 | 6.4 | |||
IOA | 1.211 | 1.191 | 1.178 | 1.174 | 1.179 | 1.194 | 1.216 | |||
IOH | 1.087 | 1.099 | 1.114 | 1.131 | 1.152 | 1.177 | 1.205 | |||
IOC | 0.808 | 0.837 | 0.864 | 0.886 | 0.905 | 0.921 | 0.934 |