Table 1.
Mean percent volumes of organs at risk receiving 30, 25, 20, or 5 Gy and mean dose to organs at risk via anteroposterior-posteroanterior (AP-PA) or butterfly intensity-modulated radiation therapy (IMRT) techniques
| Organ at risk | IMRT | AP-PA | Difference | P value* | |
|---|---|---|---|---|---|
| Right breast |
V30 |
0.5% |
1.9% |
−1.4% |
0.01 |
| V25 |
1.9% |
3.1% |
−1.2% |
0.03 |
|
| V20 |
3.8% |
3.7% |
0.1% |
0.44 |
|
| V5 |
13.7% |
7.5% |
6.2% |
0.01 |
|
| Mean Dose, Gy |
2.28 |
1.92 |
0.36 |
0.26 |
|
| Left breast |
V30 |
1.2% |
2.9% |
−1.7% |
0.02 |
| V25 |
2.8% |
4.2% |
−1.4% |
0.01 |
|
| V20 |
4.0% |
4.9% |
−0.9% |
0.01 |
|
| V5 |
11.2% |
8.4% |
2.8% |
0.01 |
|
| Mean Dose, Gy |
2.42 |
2.38 |
0.04 |
0.41 |
|
| Right ventricle |
V30 |
12.3% |
28.7% |
−16.4% |
0.01 |
| V25 |
21.7% |
33.4% |
−11.7% |
0.01 |
|
| V20 |
27.4% |
35.8% |
−8.4% |
0.01 |
|
| V5 |
41.2% |
42.7% |
−1.5% |
0.17 |
|
| Mean Dose, Gy |
10.25 |
12.16 |
−1.91 |
0.09 |
|
| Left ventricle |
V30 |
7.3% |
9.7% |
−2.4% |
0.28 |
| V25 |
2.6% |
15.8% |
−13.2% |
0.01 |
|
| V20 |
4.6% |
18.8% |
−14.2% |
0.01 |
|
| V5 |
21.5% |
29.7% |
−8.2% |
0.21 |
|
| Mean Dose, Gy |
4.13 |
7.72 |
−3.59 |
0.02 |
|
| Left anterior descending artery |
V30 |
21.5% |
28.5% |
−7.0% |
0.28 |
| V25 |
26.4% |
38.2% |
−11.8% |
0.01 |
|
| V20 |
28% |
42.2% |
−14.2% |
0.01 |
|
| V5 |
51.8% |
51.7% |
0.1% |
0.55 |
|
| Mean Dose, Gy |
10.44 |
14.46 |
−4.02 |
0.02 |
|
| Heart |
V30 |
16.8% |
29% |
−12.2% |
0.01 |
| V25 |
23.8% |
35.7% |
−11.9% |
0.01 |
|
| V20 |
28.3% |
38.8% |
−10.5% |
0.01 |
|
| V5 |
42.5% |
46.0% |
−3.5% |
0.34 |
|
| Mean Dose, Gy |
11.52 |
14.26 |
−2.74 |
0.01 |
|
| Total lung |
V30 |
4.8% |
19.5% |
−14.6% |
0.01 |
| V25 |
15.4% |
26.5% |
−11.1% |
0.01 |
|
| V20 |
22.2% |
29.9% |
−7.7% |
0.01 |
|
| V5 |
54.0% |
41.1% |
12.9% |
0.17 |
|
| Mean Dose, Gy |
9.25 |
11.31 |
−2.06 |
0.01 |
|
| Spinal cord | V30 |
5.6% |
57.8% |
−52.2% |
0.01 |
| V25 |
35.3% |
61.7% |
−25.4% |
0.01 |
|
| V20 |
50.4% |
63.8% |
−13.4% |
0.01 |
|
| V5 |
75.6% |
75.7% |
−0.1% |
0.86 |
|
| Mean Dose, Gy | 17.16 | 21.93 | −4.77 | 0.01 |
*P values generated by the Wilcoxon match-pairs signed-rank test for non-parametric comparisons.