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Local anatomic changes in parotid and submandibular glands during radiotherapy for oropharynx cancer and correlation with dose, studied in detail with nonrigid registration.

Authors :
Vásquez Osorio EM
Hoogeman MS
Al-Mamgani A
Teguh DN
Levendag PC
Heijmen BJ
Source :
International journal of radiation oncology, biology, physics [Int J Radiat Oncol Biol Phys] 2008 Mar 01; Vol. 70 (3), pp. 875-82.
Publication Year :
2008

Abstract

Purpose: To quantify the anatomic changes caused by external beam radiotherapy in head-and-neck cancer patients in full three dimensions and to relate the local anatomic changes to the planned mean dose.<br />Methods and Materials: A nonrigid registration method was adapted for RT image registration. The method was applied in 10 head-and-neck cancer patients, who each underwent a planning and a repeat computed tomography scan. Contoured structures (parotid, submandibular glands, and tumor) were registered in a nonrigid manner. The accuracy of the transformation was determined. The transformation results were used to summarize the anatomic changes on a local scale for the irradiated and spared glands. The volume reduction of the glands was related to the planned mean dose.<br />Results: Transformation was accurate with a mean error of 0.6 +/- 0.5 mm. The volume of all glands and the primary tumor decreased. The lateral regions of the irradiated parotid glands moved inward (average, 3 mm), and the medial regions tended to remain in the same position. The irradiated submandibular glands shrank and moved upward. The spared glands showed only a small deformation ( approximately 1 mm in most regions). Overall, the primary tumors shrank. The volume loss of the parotid glands correlated significantly with the planned mean dose (p <0.001).<br />Conclusion: General shrinkage and deformation of irradiated glands was seen. The spared glands showed few changes. These changes were assessed by a nonrigid registration method, which effectively described the local changes occurring in the head-and-neck region after external beam radiotherapy.

Details

Language :
English
ISSN :
0360-3016
Volume :
70
Issue :
3
Database :
MEDLINE
Journal :
International journal of radiation oncology, biology, physics
Publication Type :
Academic Journal
Accession number :
18262099
Full Text :
https://doi.org/10.1016/j.ijrobp.2007.10.063