Table 4.
Plan parameters stratified by institute
| Institute Technique | A | B | C | D | E | ||
|---|---|---|---|---|---|---|---|
| PTVboost |
CI95 |
VMAT |
1.39 |
1.35 |
1.31 |
1.43 |
1.38 |
| IMRT |
1.43 |
1.42 |
1.37 |
1.55 |
1.47 |
||
| PTVtotal |
CI95 |
VMAT |
1.51 |
1.49 |
1.54 |
1.45 |
1.51 |
| IMRT |
1.58 |
1.63 |
1.70 |
1.55 |
1.65 |
||
| Spinal cord |
D1% (Gy) |
VMAT |
39.1 |
45.6 |
47.7 |
41.1 |
43.8 |
| IMRT |
39.7 |
46.7 |
48.0 |
42.0 |
45.5 |
||
| Brain stem |
D1% (Gy) |
VMAT |
44.1 |
45.6 |
49.4 |
35.4 |
44.6 |
| IMRT |
42.9 |
45.8 |
46.9 |
40.0 |
44.4 |
||
| Parotid gland ipsilateral |
Dmean (Gy) |
VMAT |
27.6 |
26.6 |
33.3 |
23.2 |
29.3 |
| IMRT |
28.5 |
28.4 |
34.2 |
25.3 |
39.0 |
||
| Parotid gland contralateral |
Dmean (Gy) |
VMAT |
23.9 |
21.1 |
23.4 |
20.6 |
20.8 |
| IMRT |
24.8 |
22.7 |
23.6 |
21.5 |
23.6 |
||
| Submandibular gland contralateral |
Dmean (Gy) |
VMAT |
49.4 |
58.0 |
57.4 |
47.5 |
52.6 |
| IMRT |
49.1 |
58.6 |
58.1 |
51.1 |
54.3 |
||
| Oral cavity |
Dmean (Gy) |
VMAT |
40.0 |
35.2 |
41.6 |
30.7 |
36.0 |
| IMRT |
42.5 |
40.2 |
43.6 |
33.5 |
37.4 |
||
| Larynx |
Dmean (Gy) |
VMAT |
51.4 |
44.5 |
49.4 |
43.5 |
38.6 |
| IMRT |
51.5 |
46.3 |
49.1 |
44.5 |
40.9 |
||
| Pharyngeal constrictors° |
Dmean (Gy) |
VMAT |
52.0 |
45.0 |
49.8 |
43.9 |
44.7 |
| IMRT |
49.0 |
45.7 |
48.8 |
44.2 |
46.6 |
||
| Mandible° |
Dmean (Gy) |
VMAT |
48.8 |
48.0 |
50.5 |
47.6 |
48.0 |
| IMRT |
49.7 |
49.9 |
51.1 |
49.3 |
51.3 |
||
| Effective delivery time |
(min:sec) |
VMAT |
4:51 |
6:50 |
-- |
5:15 |
6:41 |
| IMRT |
11:47 |
12:08 |
-- |
15:04 |
14:00 |
||
| MUs |
-- |
VMAT |
600 |
602 |
540 |
774 |
698 |
| IMRT | 830 | 670 | 824 | 841 | 975 |
Pairs in bold denote statistically significant differences between VMAT and IMRT.
Pairs in italic denote that the averaged plan parameter is better for IMRT.
° Not all institutes used objectives to control dose for these structures.