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BioMed Research International
Volume 2015, Article ID 609607, 7 pages
Research Article

Influence of Ionizing Radiation on Two Generations of Cochlear Implants

1Department of Head and Neck Surgery, CHU Nice, 06100 Nice, France
2Department of Radiation Oncology/IBDC CNRS UMR 6543, Cancer Center Antoine-Lacassagne, University Nice Sophia-Antipolis, 06189 Nice, France
3Clinical and Scientific Research Department, Oticon Medical-Neurelec, 06220 Vallauris, France

Received 10 August 2015; Accepted 2 September 2015

Academic Editor: Christof Kolb

Copyright © 2015 Nicolas Guevara et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The purpose of the present study was to test the behavior of two different generations of cochlear implant systems subjected to a clinical radiotherapy scheme and to determine the maximal acceptable cumulative radiation levels at which the devices show out-of-specification behaviors. Using stereotactic irradiation (Cyberknife, 6 MV photon beam), three Digisonic SP and three Neuro devices were submitted to 5 Gy doses that cumulated to 60 Gy (12 sessions) and 80 Gy (16 sessions), respectively. A follow-up series of irradiation was then applied, in which Digisonic SP devices received two additional fractions of 50 Gy each, cumulating to 160 Gy, and Neuro devices three additional fractions of 20, 40, and 150 Gy, cumulating to 290 Gy. Output current values were monitored during the treatment. At clinical doses, with 60 or 80 Gy cumulative radiation exposure, no single measurement showed more than 10% divergence from the reference measure. The cochlear implants tested in this study showed high resistance to clinically relevant cumulative radiation doses and showed no out-of-bounds behavior up to cumulative doses of 140 or 160 Gy. These observations suggest that cochlear implant users can undergo radiotherapy up to cumulative doses well above those currently used in clinical situations without risk of failure.