The influence of MRI scan position on patients with oropharyngeal cancer undergoing radical radiotherapy

Radiation Oncology

Table 5 Mean dose for the (a) parotid and (b) larynx

(a)
	Parotid mean dose (cGy)
	Mean dose constraint 2400 cGy
	PP_C: PP_C*	PP_D: PP_D†	PP_RT: PP_RT††	PP_C: PP_RT	PP_D: PP_RT
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
	PP _C : PP _C	PP _D : PP _D	PP _RT : PP _RT	PP _C : PP _RT	PP _D : PP _RT
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.

ISSN: 1748-717X