Table 3.
Dosimetric parameters by technique
| Structure | Mean estimate for 9-field technique (SD) | Mean estimate for segmental technique (SD) | Mean estimate for heart blocked segmental technique (SD) | Mean estimate for tangential beamlet technique (SD) |
|---|---|---|---|---|
| Normal tissues | ||||
| Right lung | ||||
| Mean dose (Gy) | 3.18 (1.27) | 0.54 (0.23) | 0.44 (0.15) | 0.72 (0.67) |
| V2 (%) | 75.32 (13.36) | 3.30 (2.58) | 2.40 (1.95) | 10.34 (13.58) |
| V5 (%) | 11.09 (21.30) | 0.28 (0.26) | 0.15 (0.20) | 1.90 (5.19) |
| V10 (%) | 1.32 (4.09) | 0.03 (0.05) | 0.03 (0.05) | 0.38 (0.98) |
| Right breast/chest wall | ||||
| Mean dose (Gy) | 2.68 (0.74) | 1.01 (0.45) | 0.84 (0.38) | 0.65 (0.33) |
| V2 (%) | 58.93 (22.01) | 11.77 (6.22) | 9.11 (5.02) | 10.55 (8.08) |
| V5 (%) | 10.56 (8.27) | 2.28 (1.40) | 1.85 (1.27) | 0.77 (0.73) |
| V10 (%) | 0.46 (0.63) | 1.09 (0.75) | 0.94 (0.70) | 0.38 (0.41) |
| Left lung | ||||
| Mean dose (Gy) | 17.95 (1.44) | 15.68 (2.30) | 13.77 (1.91) | 13.99 (2.06) |
| V2 (%) | 99.94 (0.11) | 68.23 (4.34) | 65.79 (3.98) | 75.13 (9.57) |
| V5 (%) | 93.45 (5.14) | 49.17 (4.10) | 46.17 (3.93) | 54.00 (10.28) |
| V10 (%) | 67.80 (12.07) | 38.79 (4.60) | 35.76 (4.24) | 42.48 (10.23) |
| V20 (%) | 34.46 (4.20) | 30.82 (5.17) | 27.61 (4.50) | 29.49 (4.70) |
| V30 (%) | 17.76 (3.17) | 25.76 (5.21) | 22.24 (4.43) | 20.01 (4.50) |
| V40 (%) | 7.31 (2.31) | 19.44 (4.99) | 15.10 (4.35) | 9.80 (4.99) |
| V50 (%) | 0.89 (0.79) | 8.05 (3.47) | 3.82 (1.96) | 2.06 (1.93) |
| Heart | ||||
| Mean dose (Gy) | 7.18 (1.21) | 4.10 (1.46) | 1.91 (0.33) | 2.60 (1.33) |
| V2 (%) | 99.94 (0.20) | 47.76 (14.70) | 37.63 (12.71) | 51.47 (31.87) |
| V5 (%) | 80.18 (16.63) | 12.47 (6.18) | 3.40 (1.33) | 10.15 (13.27) |
| V10 (%) | 11.49 (7.32) | 7.11 (4.10) | 0.55 (0.39) | 2.46 (3.32) |
| V20 (%) | 0.31 (0.36) | 4.84 (3.11) | 0.03 (0.06) | 0.40 (0.79) |
| V30 (%) | 0.01 (0.02) | 3.34 (2.38) | 0.005 (0.01) | 0.05 (0.17) |
| LAD artery | ||||
| Mean dose (Gy) | 11.23 (1.53) | 20.59 (8.46) | 6.00 (1.63) | 5.44 (2.38) |
| Max dose to 1% volume (Gy) | 19.32 (4.29) | 46.60 (14.50) | 14.22 (5.34) | 9.81 (5.17) |
| Targets | ||||
| Whole breast PTV | ||||
| Mean dose (Gy) | 54.65 (0.41) | 57.22 (1.94) | 54.82 (1.74) | 54.52 (1.71) |
| D95 (Gy) | 50.24 (0.88) | 51.41 (1.88) | 44.97 (3.76) | 45.86 (4.77) |
| Max dose to 1% volume (Gy) | 61.39 (1.24) | 66.00 (1.43) | 65.14 (1.14) | 63.20 (0.96) |
| V47.5 (%) | 96.77 (1.06) | 98.57 (1.19) | 93.92 (1.82) | 94.50 (2.69) |
| Internal mammary region | ||||
| Mean dose (Gy) | 53.57 (1.22) | 45.95 (11.85) | 43.88 (11.15) | 49.40 (8.46) |
| D95 (Gy) | 47.98 (2.49) | 36.03 (17.28) | 30.61 (15.61) | 43.76 (10.93) |
| Max dose to 1% volume (Gy) | 59.60 (1.46) | 53.69 (6.48) | 52.46 (6.12) | 57.47 (5.47) |
| V47.5 (%) | 95.03 (4.86) | 72.71 (29.07) | 61.55 (25.96) | 79.75 (28.33) |
| Supraclavicular region | ||||
| Mean dose (Gy) | 53.78 (0.55) | 53.88 (2.19) | 52.56 (1.38) | 53.20 (1.75) |
| D95 (Gy) | 49.37 (2.57) | 49.88 (3.73) | 48.75 (3.31) | 49.43 (2.92) |
| Max dose to 1% volume (Gy) | 58.13 (0.91) | 57.43 (2.83) | 55.85 (1.88) | 58.15 (2.59) |
| Infraclavicular region | ||||
| Mean dose (Gy) | 53.45 (0.75) | 52.46 (2.33) | 50.72 (1.86) | 52.87 (1.95) |
| D95 (Gy) | 49.51 (1.66) | 46.38 (4.50) | 44.11 (3.18) | 49.41 (2.54) |
| Max dose to 1% volume (Gy) | 57.46 (0.47) | 57.46 (2.22) | 55.44 (1.76) | 57.27 (2.01) |
| Boost volume | ||||
| Mean dose (Gy) | 60.39 (1.20) | 63.84 (1.40) | 62.90 (1.32) | 61.26 (0.85) |
| D95 (Gy) | 58.79 (0.96) | 59.34 (6.14) | 60.58 (1.39) | 59.65 (1.41) |
| Max dose to 1% volume (Gy) | 62.41 (1.61) | 66.59 (1.65) | 65.62 (1.47) | 63.72 (0.69) |
| V47.5 (%) | 99.44 (0.79) | 99.88 (0.38) | 99.95 (0.13) | 99.58 (0.85) |
Abbreviations: V2 = percentage of the volume receiving 2 Gy or more, e.g., V5 is the percentage of the volume receiving 5 Gy or more, etc.; D95 = lowest dose received by at least 95% of the volume; SD = standard deviation.