Background
Methods
Patient collective
Case | Patient | Age at treatment | PTV | Prescription | Imaging |
---|---|---|---|---|---|
1 | 1 | 16 | 1st series: right lung; 2nd series: right lung and infraclavicular/pectoral/ mediastinal lymphatics | 1st series: 3x100cGy; 2nd series: 11 × 100 cGy; 11x166cGy | 1 x 6MV axes 11 x IBL axes |
2 | 2 | 15 | bilateral neck cervical, supra- and infraclavicular lymphatics and mediastinum | 11x180cGy | 1 x 6MV axes 3 x IBL axes |
3 | 3 | 17 | Right cervical/mediastinal lymphatics | 11x180cGy | 4 x 6MV axes 1 x 6MV CBCT (7.2 MU) |
4 | 4 | 16 | 1st series: Mediastinum 2nd series: Boost Mediastinum | 1st series: 11x180cGy; 2nd series: 5x200cGy | 1 x 6MV axes 4 x IBL axes |
5 | 4 | 16 | Spleen | 11x180cGy | 1 x 6MV axes 4 x IBL axes |
6 | 5 | 16 | 1st series: Mediastinum; 2nd series: Boost macroscopic residual disease (Mediastinum) | 1st series: 11x180cGy; 2nd series: 5x200cGy | 6 x kV axes 1 x kV CBCT (414 mAs) |
7 | 5 | 16 | Spleen | 11x180cGy | 1 x 6MV/IBL axes 1 x kV axes 1 x kV CBCT (621 mAs) |
8 | 6 | 5 | bilateral neck, supra-infraclavicular, mediastinal and paraaortic lymphatics, spleen | 11x180cGy | 3 x 6MV axes 5 x 6MV CBCT (54 MU in total) |
9 | 6 | 5 | Os ileum | 11x180cGy | 5 x 6MV portal images |
10 | 7 | 13 | Left cervical lymphatics | 11x180cGy | 1 x kV axes 2 x kV CBCT (458 mAs in total) |
11 | 7 | 13 | Spleen | 11x180cGy | 2 x kV axes 3 x kV CBCT (1103 mAs in total) 1 x IBL CBCT (11 MU) |
Dose calculation and secondary cancer risk model
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Scenario 2: treatment plan with real imaging performed for the patient, with imaging device and frequency differing between the individual patients (details listed in Table 1)
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Scenario 3: treatment plan with daily 121 kV 200° CBCT
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Scenario 4: treatment plan with daily 121 kV 360° CBCT
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Scenario 5: treatment plan with daily 6 MV planar imaging
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Scenario 6: treatment plan with daily 360° 6 MV CBCT.
Model parameter | Female breast | Lung |
---|---|---|
α in Gy−1 | 0.044 | 0.042 |
R | 0.15 | 0.83 |
βorg in excess cases per 10,000 PY Gy | 8.2 | 8.0 |
γ
e
| −0.037 | 0.002 |
γ
a
| 1.7 | 4.23 |
Results
Visualization of dose distributions – Example
Dose to organs at risk – DVH analysis
Organ | Criteria | Scenario1 | Scenario 2 | Scenario 3 | Scenario 4 | Scenario 5 | Scenario 6 |
---|---|---|---|---|---|---|---|
Lung le | D mean [Gy] | 9.13 ± 4.88 (2.62–17.43) | 9.27 ± 4.90 (2.74–17.54) | 9.17 ± 4.90 (2.65–17.53) | 9.28 ± 4.96 (2.74–17.80) | 9.39 ± 5.01 (2.81–17.98) | 10.46 ± 5.62 (3.59–20.25) |
V20Gy [%] | 9.72 ± 12.07 (0.00–32.26) | 11.04 ± 12.55 (0.00–32.55) | 9.91 ± 12.20 (0.00–32.54) | 10.33 ± 12.52 (0.00–33.34) | 10.73 ± 12.74 (0.00–33.84) | 14.63 ± 15.05 (0.00–40.55) | |
V10Gy [%] | 39.27 ± 27.78 (2.33–88.37) | 40.03 ± 27.99 (2.44–88.88) | 39.46 ± 27.92 (2.35–88.85) | 39.89 ± 28.27 (2.43–90.16) | 40.36 ± 28.54 (2.49–91.08) | 44.55 ± 30.80 (3.20–98.92) | |
V5Gy [%] | 59.29 ± 29.06 (11.03–100) | 60.2 ± 29.24 (11.92–100) | 59.46 ± 29.06 (11.23–100) | 59.9 ± 28.97 (11.92–100) | 60.38 ± 29.01 (12.38–100) | 67.28 ± 30.31 (20.45–100) | |
D 2% [Gy] | 20.81 ± 6.98 (3.33–31.78) | 20.96 ± 6.96 (3.43–31.84) | 20.85 ± 6.99 (3.37–31.84) | 20.98 ± 7.03 (3.45–32.05) | 21.14 ± 7.07 (3.47–32.11) | 22.12 ± 7.39 (4.33–34.14) | |
Lung ri | D mean [Gy] | 9.2 ± 6.10 (1.58–18.66) | 9.33 ± 6.12 (1.65–18.72) | 9.24 ± 6.12 (1.61–18.74) | 9.29 ± 6.08 (1.68–18.60) | 9.38 ± 6.18 (1.65–18.99) | 10.43 ± 6.62 (2.26–20.98) |
V20Gy [%] | 10.1 ± 13.08 (0.00–38.70) | 10.6 ± 13.14 (0.00–38.89) | 10.2 ± 13.68 (0.00–38.92) | 10.62 ± 13.44 (0.00–39.56) | 10.9 ± 13.52 (0.00–39.67) | 15.32 ± 16.26 (0.00–46.67) | |
V10Gy [%] | 41.13 ± 35.44 (0.00–98.93) | 41.86 ± 35.30 (0.00–98.94) | 41.26 ± 35.47 (0.00–98.93) | 41.52 ± 35.55 (0.00–98.95) | 41.70 ± 35.51 (0.00–98.96) | 45.4 ± 36.36 (0.00–99.12) | |
V5Gy [%] | 56.29 ± 35.96 (0.00–100) | 57.13 ± 36.30 (0.00–100) | 56.45 ± 35.96 (0.00–100) | 56.8 ± 35.90 (0.00–100) | 57.03 ± 35.95 (0.00–100) | 62.4 ± 36.23 (0.00–100) | |
D 2% [Gy] | 20.5 ± 8.66 (3.33–31.78) | 20.64 ± 8.65 (3.43–31.84) | 20.54 ± 8.67 (3.37–31.48) | 20.65 ± 8.70 (3.45–32.05) | 20.72 ± 8.73 (3.47–32.11) | 21.72 ± 9.24 (4.33–34.14) | |
Breast le | D mean [Gy] | 3.10 ± 2.84 (0.74–7.06) | 3.19 ± 2.81 (0.87–7.10) | 3.13 ± 2.86 (0.76–7.11) | 3.29 ± 2.95 (0.89–7.44) | 3.38 ± 3.01 (0.94–7.62) | 4.27 ± 3.53 (1.60–9.34) |
D 2% [Gy] | 12.60 ± 5.65 (8.85–20.89) | 12.67 ± 5.53 (9.01–20.75) | 12.56 ± 5.59 (8.86–20.75) | 12.76 ± 5.66 (9.02–21.05) | 12.86 ± 5.70 (9.08–21.21) | 13.93 ± 6.12 (9.90–22.89) | |
Breast ri | D mean [Gy] | 5.81 ± 4.80 (1.37–11.53) | 5.89 ± 4.82 (1.41–11.67) | 5.83 ± 4.81 (1.38–11.56) | 6.0 ± 4.85 (1.49–11.73) | 6.01 ± 4.86 (1.50–11.75) | 6.97 ± 5.13 (2.16–12.82) |
D 2% [Gy] | 16.08 ± 6.12 (9.84–21.41) | 16.18 ± 6.12 (9.90–21.43) | 16.09 ± 6.12 (9.85–21.43) | 16.28 ± 6.17 (9.99–21.43) | 16.34 ± 6.19 (10.03–21.70) | 17.41 ± 6.46 (10.83–23.31) | |
Parotid le | D mean [Gy] | 5.25 ± 7.94 (0.17–18.71) | 5.29 ± 7.92 (0.20–18.75) | 5.28 ± 7.93 (0.20–18.71) | 5.36 ± 7.91 (0.27–18.72) | 5.38 ± 7.92 (0.21–18.72) | 5.98 ± 7.82 (0.55–18.78) |
D 2% [Gy] | 6.68 ± 9.76 (0.24–21.78) | 6.74 ± 9.53 (0.36–21.82) | 6.71 ± 9.75 (0.28–21.78) | 6.66 ± 9.70 (0.40–21.78) | 6.86 ± 9.71 (0.41–21.79) | 7.62 ± 9.52 (1.20–21.86) | |
Parotid ri | D mean [Gy] | 3.77 ± 5.96 (0.39–16.50) | 3.81 ± 5.95 (0.43–16.53) | 3.80 ± 5.95 (0.42–16.50) | 3.89 ± 5.92 (0.50–16.51) | 3.90 ± 5.92 (0.45–16.51) | 4.51 ± 5.74 (0.77–16.57) |
D 2% [Gy] | 5.50 ± 7.92 (0.62–21.41) | 5.48 ± 7.92 (0.73–21.46) | 5.48 ± 7.91 (0.66–21.42) | 5.58 ± 7.88 (0.78–21.43) | 5.59 ± 7.87 (0.79–21.43) | 6.37 ± 7.60 (1.59–21.49) | |
OED | 0.79 ± 0.82 (0.14–2.20) | 0.81 ± 0.81 (0.20–2.20) | 0.81 ± 0.82 (0.16–2.20) | 0.84 ± 0.80 (0.22–2.20) | 0.84 ± 0.80 (0.22–2.20) | 1.05 ± 0.70 (0.36–2.20) | |
EAR | 0.43 ± 0.47 (0.08–1.31) | 0.43 ± 0.47 (0.09–1.31) | 0.43 ± 0.47 (0.09–1.28) | 0.45 ± 0.46 (0.11–1.31) | 0.45 ± 0.46 (0.10–1.31) | 0.55 ± 0.42 (0.16–1.31) | |
Pharynx | D mean [Gy] | 6.51 ± 7.52 (0.72–19.34) | 6.56 ± 7.50 (0.84–19.38) | 6.53 ± 7.49 (0.75–19.34) | 6.62 ± 7.49 (0.87–19.35) | 6.66 ± 7.48 (0.93–19.36) | 7.38 ± 7.28 (2.05–19.43) |
D 2% [Gy] | 12.28 ± 7.29 (1.06–21.05) | 12.37 ± 7.24 (1.18–21.11) | 12.31 ± 7.28 (1.09–21.06) | 12.48 ± 7.25 (1.22–21.06) | 12.39 ± 7.19 (1.27–21.07) | 13.33 ± 6.95 (2.41–21.15) | |
Spinal cord | D 2% [Gy] | 19.66 ± 7.97 (6.36–29.53) | 19.8 ± 7.97 (6.46–29.60) | 19.71 ± 7.99 (6.40–29.61) | 19.81 ± 8.02 (6.48–29.80) | 19.89 ± 8.05 (6.50–29.90) | 21.17 ± 8.43 (7.41–31.67) |
Imaging effect on secondary cancer risk
Scenario 1 (original) | Scenario 2 (real) | Scenario 3 (200° kV-CBCT) | Scenario 4 (360° kV-CBCT) | Scenario 5 (6MV axes) | Scenario 6 (6MV CBCT) | |
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Left lung | 5.58 ± 2.5 (2.1–9.6) | 5.66 ± 2,5 (2.2–9.6) | 6.25 ± 2.7 (2.6–10.6) | 5.72 ± 2.6 (2.2–9.9) | 5.65 ± 2.5 (2.2–9.7) | 5.60 ± 2.5 (2.1–9.6) |
Right lung | 5.54 ± 3.2 (1.3–10.0) | 5.62 ± 3,2 (1.4–10.0) | 6.17 ± 3.3 (1.9–10.8) | 5.64 ± 3.2 (1.4–10.1) | 5.62 ± 3.2 (1.4–10.1) | 5.56 ± 3.2 (1.3–10.0) |
Left breast | 8.73 ± 6.9 (2.4–17.9) | 9.03 ± 6,8 (2.8–18.0) | 11.87 ± 7.7 (5.3–22.7) | 9.53 ± 7.1 (3.0–19.2) | 9.30 ± 7.0 (2.9–18.8) | 8.81 ± 6.9 (2.4–18.0) |
Right breast | 14.12 ± 10.3 (4.8–26.0) | 14.29 ± 10.2 (5.0–26.2) | 16.63 ± 10.0 (7.7–27.5) | 14.56 ± 10.2 (5.3–26.3) | 14.57 ± 10.2 (5.3–26.3) | 14.19 ± 10.2 (4.9–26.1) |
Organ | Scenario 2 (real) | Scenario 3 (200° kV-CBCT) | Scenario 4 (360° kV-CBCT) | Scenario 5 (6MV axes) | Scenario 6 (6MV CBCT) |
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Left lung | 0.08 ± 0.09 (0.00–0.30) | 0.02 ± 0.01 (0.00–0.04) | 0.08 ± 0.04 (0.02–0.14) | 0.13 ± 0.07 (0.01–0.24) | 0.67 ± 0.34 (0.08–1.19) |
Right lung | 0.07 ± 0.11 (0.00–0.07) | 0.02 ± 0.01 (0.00–0.04) | 0.08 ± 0.05 (0.02–0.16) | 0.1 ± 0.06 (0.01–0.21) | 0.75 ± 0.66 (0.08–2.31) |
Left breast | 0.29 ± 0.16 (0.11–0.46) | 0.08 ± 0.03 (0.06–0.12) | 0.57 ± 0.22 (0.38–0.88) | 0.8 ± 0.33 (0.55–1.29) | 3.14 ± 1.19 (1.99–4.81) |
Right breast | 0.18 ± 0.09 (0.09–0.31) | 0.07 ± 0.02 (0.04–0.09) | 0.44 ± 0.16 (0.25–0.64) | 0.43 ± 0.13 (0.27–0.58) | 2.51 ± 0.77 (1.50–3.33) |
Discussion
Influence of assumed age at secondary cancer incidence
Influence of modelling approach
Scenario 2 (real) | Scenario 3 (200° kV-CBCT) | Scenario 4 (360° kV-CBCT) | Scenario 5 (6 MV axes) | Scenario 6 (6MV CBCT) | |
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Left lung | 0.26 ± 0.34 (0–5.25) | 0.08 ± 0.59 (0–5.25) | 0.29 ± 0.21 (0.06–5.25) | 0.48 ± 0.31 (0.04–5.25) | 2.48 ± 1.62 (0.26–5.25) |
Right lung | 0.25 ± 0.34 (0–1.07) | 0.07 ± 0.48 (0–0.15) | 0.18 ± 0.17 (0–0.48) | 0.34 ± 0.21 (0.04–0.63) | 2.28 ± 1.38 (0.24–4.32) |
Left breast | 0.89 ± 0.57 (0.31–1.41) | 0.24 ± 0.10 (0.16–0.39) | 1.74 ± 0.83 (1.05–2.96) | 2.51 ± 1.27 (1.45–4.35) | 10.27 ± 5.08 (6.37–17.7) |
Right breast | 0.78 ± 0.61 (0.23–1.52) | 0.23 ± 0.11 (0.08–0.33) | 1.71 ± 0.65 (0.97–2.33) | 1.80 ± 0.70 (1.05–2.41) | 10.60 ± 3.68 (6.37–13.98) |