TY - JOUR ID - 2865 TI - Assessment of Olfactory Threshold in Patients Undergoing Radiotherapy for Head and Neck Malignancies JO - Iranian Journal of Otorhinolaryngology JA - IJORL LA - en SN - 2251-7251 AU - Jalali, Mir Mohammad AU - Gerami, Hooshang AU - Rahimi, Abbas AU - Jafari, Manizheh AD - Department of Otorhinolaryngology, Nose and Sinus Diseases Research Center, Guilan University of Medical Sciences, Rasht, Iran. AD - Department of Radiotherapy, Razi Hospital, Guilan University of Medical Sciences, Guilan, Iran. Y1 - 2014 PY - 2014 VL - 26 IS - 4 SP - 211 EP - 217 KW - Olfactory perception KW - Radiotherapy KW - Thermoluminescent Dosimetry DO - 10.22038/ijorl.2014.2865 N2 - Introduction: Radiotherapy is a common treatment modality for patients with head and neck malignancies. As the nose lies within the field of radiotherapy of the head and neck, the olfactory fibers and olfactory receptors may be affected by radiation. The aim of this study was to evaluate changes in olfactory threshold in patients with head and neck malignancies who have received radiation to the head and neck.   Materials and Methods: The olfactory threshold of patients with head and neck malignancies was assessed prospectively before radiation therapy and serially for up to 6 months after radiotherapy using sniff bottles. In vivo dosimetry was performed using 82 LiF (MCP) chips and a thermoluminescent dosimeter (TLD) system.   Results: Sixty-one patients were recruited before radiotherapy was commenced. Seven patients did not return for evaluation after radiation. Fifty-four patients were available for follow-up assessment (28 women, 26 men; age, 22–86 years; median, 49 years). Total radiation dose was 50.1 Gy (range, 30–66 Gy). Mean olfactory threshold scores were found to deteriorate significantly at various timepoints after radiotherapy (11.7 before radiotherapy versus 4.0 at Month 6, general linear model, P<0.0001). With in vivo dosimetry, we found that the median measured dose to the olfactory area was 334 µC. We also identified a cutoff point according to the dose to the olfactory epithelium. Olfactory threshold was significantly decreased 2–6 weeks after initiation of therapy, with cumulative local radiation >135 µC (Mann-Whitney U test, P=0.01).   Conclusion:  Deterioration in olfactory threshold scores was found at 6 months after initiation of radiation therapy. Provided that these results are reproducible, an evaluation of olfactory functioning in patients with head and neck malignancies using in vivo dosimetry may be useful for determining the optimal dose for patients treated with conformal radiotherapy techniques while avoiding the side effects of radiation. UR - https://ijorl.mums.ac.ir/article_2865.html L1 - https://ijorl.mums.ac.ir/article_2865_256057074b72624744c455d5ecc308b3.pdf ER -