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Superior Cochlear and Parotid Sparing and Conformality
by Intensity-Modulated Radiation Therapy (IMRT) over
Wedge Pair Technique (WP) for Unilateral Treatment of
Tonsil Carcinoma
U. Parvathaneni*, T. Yu, B. E. Mason, A. Ahamad, A. S. Garden,
I. Rosenthal
*University of Washington Medical Center, Seattle, WA
M.D. Anderson Cancer Center, Houston, TX
D.
Key points
 The prognosis of early stage tonsil carcinoma is excellent.
 Minimizing morbidity is therefore an important goal.
 Both IMRT and wedge pair techniques provided target volume cover with 98%
of prescribed dose.
 However, IMRT provided the most conformal and homogenous plans.
 With IMRT there was significant sparing of cochlea and ipsilateral parotid gland.
 IMRT did not contribute a significantly greater dose to the contra lateral half of
the head.
 We recommend IMRT for unilateral treatments of early tonsil carcinoma.
IMRT spared the Cochlea and Middle ear
Cochlea DVH IMRT
Cochlea DVH WP
Middle ear DVH IMRT
Middle ear DVH WP
IMRT spared the ipsilateral parotid gland
IMRT parotid
IMRT sub mandibular gland
WP sub mandibular gland
WP parotid
IMRT provided the most conformal and homogenous plans
105%
98%
98%
105%
110%
Wedge pair plan
7 beam IMRT plan
IMRT did not contribute a significantly greater dose to the contra
lateral half of the head
Wedge pair plan
20 Gy
6 beam IMRT
20 Gy