1260 / 1601
7
Old School IMRT in Head and
Neck
1994
19 predefined fields optimisation overnight
Co planar fields
Test the difference between head tilted
backwards (chin-up) vs neutral/comfortable
position (chin-down) in terms of dose to the
parotid gland.
Patient position and IMRT
“Chin down”
“Chin up”
Patient position and IMRT
Dose to the parotid gland
(chin down)
0
20
40
60
80
100
0
10
20
30
40
50
60
Dose (Gy)
Vol.%
Right parotid
Left parotid
Dose to the parotid gland
(chin up)
0
20
40
60
80
100
0
10
20
30
40
50
60
Dose (Gy)
Vol.%
Right parotid
Left parotid
Patient example of interaction on
planning and setup
50.4+ 70 Gy
Lnn metastasis melanoma of the skin
High dose near the brainstem, 54 Gy (ED2)
– But with steep gradient towards more
How to deal?
– Lower the target dose
– Fractionate more
– Decrease you CTV-PTV margin
– Local guided setup