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Title: Intensity-Modulated vs. Conformal Radiotherapy of Parotid Gland Tumors: Potential Impact on Hearing Loss

Abstract

In 3-dimensional (3D) conformal radiotherapy of parotid gland tumors, little effort is made to avoid the auditory system or the oral cavity. Damage may occur when the ear is located inside the treatment field. The purpose of this study was to design and evaluate an intensity-modulation radiotherapy (IMRT) class solution, and to compare this technique to a 3D conformal approach with respect to hearing loss. Twenty patients with parotid gland cancer were retrospectively planned with 2 different techniques using the original planning target volume (PTV). First, a conventional technique using a wedged beam pair was applied, yielding a dose distribution conformal to the shape of the PTV. Next, an IMRT technique using a fluence map optimization with predefined constraints was designed. A dose of 66 Gy in the PTV was given at the International Commission on Radiation Units and Measures (ICRU) dose prescription point. Dose-volume histograms of the PTV and organs at risk (OARs), such as auditory system, oral cavity, and spinal cord, were compared. The dose in the OARs was lower in the IMRT plans. The mean volume of the middle ear receiving a dose higher than 50 Gy decreased from 66.5% to 33.4%. The mean dose in themore » oral cavity decreased from 19.4 Gy to 16.6 Gy. The auditory system can be spared if the distance between the inner ear and the PTV is 0.6 cm or larger, and if the overlap between the middle ear and the PTV is smaller than 10%. The maximum dose in the spinal cord was below 40 Gy in all treatment plans. The mean volume of the PTV receiving less than 95% of the prescribed dose increased in the IMRT plan slightly from 3.3% to 4.3 % (p = 0.01). The mean volume receiving more than 107% increased from 0.9% to 2.5% (p = 0.02). It can be concluded that the auditory system, as well as the oral cavity, can be spared with IMRT, but at the cost of a slightly larger dose inhomogeneity in the PTV. The IMRT technique can therefore, in most cases, be recommended as the treatment of choice for the irradiation of parotid tumors.« less

Authors:
 [1]; ;  [2];  [3];  [4]
  1. Department of Radiation Oncology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands), E-mail: e.lamers@nki.nl
  2. Agenzia Provinciale per la Protonterapia, Trento (Italy)
  3. Department of Radiation Oncology, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)
  4. (Netherlands)
Publication Date:
OSTI Identifier:
21045978
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Dosimetry; Journal Volume: 32; Journal Issue: 4; Other Information: DOI: 10.1016/j.meddos.2006.12.004; PII: S0958-3947(06)00177-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; AUDITORY ORGANS; GLANDS; ICRU; IRRADIATION; NEOPLASMS; ORAL CAVITY; PLANNING; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIATION HAZARDS; RADIOTHERAPY; SPINAL CORD

Citation Formats

Lamers-Kuijper, E., Schwarz, M., Rasch, C., Mijnheer, B., and INHOLLAND University of Professional Training, Haarlem. Intensity-Modulated vs. Conformal Radiotherapy of Parotid Gland Tumors: Potential Impact on Hearing Loss. United States: N. p., 2007. Web. doi:10.1016/j.meddos.2006.12.004.
Lamers-Kuijper, E., Schwarz, M., Rasch, C., Mijnheer, B., & INHOLLAND University of Professional Training, Haarlem. Intensity-Modulated vs. Conformal Radiotherapy of Parotid Gland Tumors: Potential Impact on Hearing Loss. United States. doi:10.1016/j.meddos.2006.12.004.
Lamers-Kuijper, E., Schwarz, M., Rasch, C., Mijnheer, B., and INHOLLAND University of Professional Training, Haarlem. Mon . "Intensity-Modulated vs. Conformal Radiotherapy of Parotid Gland Tumors: Potential Impact on Hearing Loss". United States. doi:10.1016/j.meddos.2006.12.004.
@article{osti_21045978,
title = {Intensity-Modulated vs. Conformal Radiotherapy of Parotid Gland Tumors: Potential Impact on Hearing Loss},
author = {Lamers-Kuijper, E. and Schwarz, M. and Rasch, C. and Mijnheer, B. and INHOLLAND University of Professional Training, Haarlem},
abstractNote = {In 3-dimensional (3D) conformal radiotherapy of parotid gland tumors, little effort is made to avoid the auditory system or the oral cavity. Damage may occur when the ear is located inside the treatment field. The purpose of this study was to design and evaluate an intensity-modulation radiotherapy (IMRT) class solution, and to compare this technique to a 3D conformal approach with respect to hearing loss. Twenty patients with parotid gland cancer were retrospectively planned with 2 different techniques using the original planning target volume (PTV). First, a conventional technique using a wedged beam pair was applied, yielding a dose distribution conformal to the shape of the PTV. Next, an IMRT technique using a fluence map optimization with predefined constraints was designed. A dose of 66 Gy in the PTV was given at the International Commission on Radiation Units and Measures (ICRU) dose prescription point. Dose-volume histograms of the PTV and organs at risk (OARs), such as auditory system, oral cavity, and spinal cord, were compared. The dose in the OARs was lower in the IMRT plans. The mean volume of the middle ear receiving a dose higher than 50 Gy decreased from 66.5% to 33.4%. The mean dose in the oral cavity decreased from 19.4 Gy to 16.6 Gy. The auditory system can be spared if the distance between the inner ear and the PTV is 0.6 cm or larger, and if the overlap between the middle ear and the PTV is smaller than 10%. The maximum dose in the spinal cord was below 40 Gy in all treatment plans. The mean volume of the PTV receiving less than 95% of the prescribed dose increased in the IMRT plan slightly from 3.3% to 4.3 % (p = 0.01). The mean volume receiving more than 107% increased from 0.9% to 2.5% (p = 0.02). It can be concluded that the auditory system, as well as the oral cavity, can be spared with IMRT, but at the cost of a slightly larger dose inhomogeneity in the PTV. The IMRT technique can therefore, in most cases, be recommended as the treatment of choice for the irradiation of parotid tumors.},
doi = {10.1016/j.meddos.2006.12.004},
journal = {Medical Dosimetry},
number = 4,
volume = 32,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}