Table 5.
Mean dose for the (a) parotid and (b) larynx
|
(a) |
|
||||
|---|---|---|---|---|---|
|
Parotid mean dose (cGy) |
|||||
|
Mean dose constraint 2400 cGy | |||||
| PPC: PPC* | PPD: PPD† | PPRT: PPRT†† | PPC: PPRT | PPD: PPRT | |
| Mean |
2179.6 |
1965.5 |
1820.3 |
2233.8 |
1992.4 |
| Number of patients which exceed the dose constraint |
0 |
0 |
0 |
5 |
5 |
|
(b) |
|
|
|
|
|
| |
Larynx mean dose (cGy) |
||||
|
Mean dose constraint 4000 cGy | |||||
|
PPC: PPC |
PPD: PPD |
PPRT: PPRT |
PPC: PPRT |
PPD: PPRT |
|
| Mean |
3979.6 |
3892.3 |
3613.2 |
4108.8 |
4020.6 |
| Number of patients which exceed the dose constraint | 4 | 3 | 1 | 5 | 5 |
Where there was overlap between a parotid and the PTV the parotid dose was not included in the mean parotid dose. PP left of the colon indicates the patient position protocol for which the VMAT plan was optimized and right of the colon indicated the patient position protocol under examination.
* Patient position protocol: CT and diagnostic MRI scan viewed separately.
† Patient position protocol: CT registered with the diagnostic MRI.
†† Patient position protocol: CT registered with radiotherapy positioned MRI.