Table 5.
Comparison between IMRT and VMAT for 39 head and neck plans with a prescription of 69.3 Gy
| IMRT (n = 38) | 1A (n = 38) | 1Am (n = 38) | 2A (n = 38) | 2Am (n = 38) | |
|---|---|---|---|---|---|
|
PTV 69.3Gy |
|
|
|
|
|
| Dmax (%) |
107.6 (103.9 - 110.3) |
107.9 (104.4 - 112.7)b+ |
108.0 (105.7-111.8)ac+ |
106.8 (104.4- 109.2)a+b+ |
107.0 (104.4 - 109.9)c+ |
| V95% (%) |
93.4 (88.1 - 97.8) |
91.5 (85.3 - 99.1)a+ |
91.0 (82.9 - 98.1)a+c |
91.9 (86.1 - 99.1)a+ |
91.6 (85.4 - 98.8)a+c |
| HI |
1.10 (1.07 - 1.14) |
1.11 (1.06 - 1.15)a+b+ |
1.12 (1.07 - 1.17)a+c+ |
1.10 (1.06 - 1.14)b+ |
1.11 (1.06 - 1.14)c+ |
| CN |
0.77 (0.22 - 0.91) |
0.81 (0.26 - 0.91)a+b+ |
0.83 (0.30 - 0.92)a+c+ |
0.84 (0.29 - 0.93)a+b+ |
0.85 (0.40 - 0.93)a+c+ |
|
PTV 56.1Gy |
|
|
|
|
|
| Dmax (%) |
127.8 (124.0 - 135.1) |
122.7 (115.6 - 130.4)a+ |
123.2 (116.7-129.0)a+c+ |
122.3 (117.0 - 126.4)a+ |
122.1 (118.2-127.2)a+c+ |
| V95% (%) |
93.1 (81.7 - 97.9) |
93.3 (85.5 - 97.3)b+ |
87.6 (80.3 - 94.9)a+c+ |
96.1 (92.2 - 99.1)a+b+ |
92.0 (84.1 - 97.2)c+ |
| HI |
1.21 (1.12 - 1.31) |
1.19 (1.14 - 1.24)ab+ |
1.21 (1.14 - 1.28)c+ |
1.16 (1.10 - 1.22)a+b+ |
1.18 (1.10 - 1.25)a+c+ |
| CN |
0.67 (0.46 - 0.82) |
0.69 (0.42 - 0.83)b+ |
0.69 (0.49 - 0.81)c+ |
0.71 (0.44 - 0.85)a+b+ |
0.73 (0.50 - 0.85)a+c+ |
| D50% (%) |
101.2 (99.0 - 104.3) |
102.6 (101.1-105.9)a+b+ |
100.8 (99.5 - 102.1) |
102.2 (101.0 -104.6)a+b+ |
100.6 (98.9 - 101.9)a |
|
PTV 54Gy |
|
|
|
|
|
| Dmax (%) |
129.9 (106.5 - 136.3) |
126.8 (114.5 - 134.6)ab+ |
126.8 (112.5 - 133.0)a |
124.5 (110.7 -129.8)a+b+ |
125.6 (109.1 - 132.9)a+ |
| V95% (%) |
90.1 (85.0 - 95.3) |
94.0 (90.8 - 97.5)a+b+ |
89.0 (79.2 - 92.9) |
96.1 (92.5 - 98.7)a+b+ |
92.5 (87.3 - 97.5) |
| HI |
1.22 (1.09 - 1.28) |
1.20 (1.12 - 1.25)b+ |
1.21 (1.12 - 1.31)c+ |
1.17 (1.09 - 1.24)a+b+ |
1.19 (1.09 - 1.27)a+c+ |
| CN |
0.70 (0.57 - 0.79) |
0.73 (0.63 - 0.87)a+b+ |
0.74 (0.65 - 0.81)a+ |
0.76 (0.66 - 0.88)a+b+ |
0.76 (0.65 - 0.87)a+ |
| D50% (%) |
100.1 (98.4 - 101.5) |
102.4 (101.3-103.4)a+b+ |
100.6 (98.9 - 102.2) |
101.9 (101.1- 103.2)a+b+ |
100.5 (99.8 - 101.8) |
|
PTV 52.8Gy |
|
|
|
|
|
| Dmax (%) |
114.0 (103.9 - 134.7) |
114.9 (109.6 - 128.2)b+ |
112.9 (108.0 - 126.5) |
113.1 (109.1 - 127.3)b+ |
112.0 (106.2 - 128.3) |
|
V95% (%) |
92.7 (73.0 - 99.5) |
96.5 (91.7 - 99.3)ab+ |
91.9 (83.8 - 97.9)c+ |
97.9 (95.5 - 99.8)a+b+ |
95.1 (87.1 - 99.2)c+ |
| HI |
1.11 (1.07 - 1.21) |
1.13 (1.09 - 1.18)b+ |
1.13 (1.09 - 1.18)c+ |
1.10 (1.07 - 1.14)b+ |
1.11 (1.07 - 1.15)c+ |
| CN |
0.64 (0.47 - 0.75) |
0.71 (0.63 - 0.84)a+ |
0.72 (0.64 - 0.87)a+c |
0.72 (0.64 - 0.84)a+ |
0.74 (0.63 - 0.88)a+c |
| D50% (%) |
99.9 (98.0 - 102.7) |
102.7 (101.5-104.5)a+b+ |
100.5 (99.5 - 101.5) |
102.2 (101.0 -103.6)a+b+ |
100.5 (99.1 - 101.8) |
|
Body |
|
|
|
|
|
| Dmean (Gy) |
7.1 (3.9 - 18.2) |
6.7 (3.7 - 17.0)a+ |
6.6 (3.6 - 16.8)a+c+ |
6.7 (3.7 - 17.0)a+ |
6.6 (3.6 - 16.6)a+c+ |
| V5Gy (%) |
21.2 (10.6 - 56.6) |
21.4 (10.7 - 58.2)a+b+ |
21.4 (10.7 - 57.5)a+c+ |
21.6 (10.7 - 58.5)a+b+ |
21.5 (10.8 - 58.7)a+c+ |
|
Brain |
|
|
|
|
|
| Dmax (Gy) |
38.8 (3.7 - 62.9) |
41.5 (5.2 - 60.4)ab |
40.1 (5.1 - 58.6) |
40.1 (5.2 - 63.3)b |
39.9 (5.0 - 60.7) |
|
Brain stem |
|
|
|
|
|
| Dmax (Gy) |
39.3 (20.6 - 51.0) |
44.6 (22.2 - 51.5)a+ |
42.9 (18.9 - 52.5)a |
44.3 (15.0 - 51.6)a+ |
43.1 (17.0 - 51.0)a |
|
Lips |
|
|
|
|
|
| Dmax (Gy) |
28.6 (2.1 - 71.4) |
29.1 (2.4 - 70.4) |
28.3 (2.2 - 64.7) |
30.4 (2.2 - 70.3) |
29.8 (2.2 - 69.3) |
|
Parotid gland |
|
|
|
|
|
| Dmean (Gy) |
30.2 (7.8 - 62.7) |
30.7 (9.7 - 55.7)a+b+ |
29.5 (9.7 - 55.8) |
30.3 (9.6 - 55.7)ab+ |
29.2 (9.8 - 56.0) |
| V28Gy (%) |
48.1 (8.7 - 100.0) |
49.6 (11.0 - 92.9)a+b+ |
46.6 (12.1 - 93.0) |
48.2 (10.3 - 93.2)ab+ |
45.6 (10.4 - 93.3) |
|
Spine |
|
|
|
|
|
| Dmax (Gy) |
37.4 (33.1 - 44.3) |
36.3 (33.2 - 44.6)ab+ |
36.1 (32.7 - 44.0)ac+ |
35.1 (32.5 - 41.0)a+b+ |
35.3 (32.6 - 42.8)a+c+ |
| MU | 649.2 (458–802) | 370.5 (313–524)a+b+ | 372.9 (326–482)a+c+ | 393.1 (322–558)a+b+ | 393.6 (320–538)a+c+ |
Single and double arc plans before (1A, 2A) and after modification (1Am, 2Am) of the optimization penalties; values are expressed as the mean (range).
ap < 0.05 for Wilcoxon matched-pair signed rank test vs. IMRT; bp < 0.05 1A vs. 2A; cp < 0.05 1Am vs. 2Am; +p < 0.01.