Evaluation of Thyroid Disorders During Head-and-Neck Radiotherapy by Using Functional Analysis and Ultrasonography

Journal Article · Tue May 01 04:00:00 EDT 2012 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2011.05.064· OSTI ID:22056329

Bakhshandeh, Mohsen ^[1]; Hashemi, Bijan ^[1]; Mahdavi, Seyed Rabie ^[2]; Nikoofar, Alireza ^[3]; Edraki, Hamid Reza ^[4]; Kazemnejad, Anoshirvan ^[5]

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1. Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)
2. Department of Medical Physics, Faculty of Medical Sciences, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)
3. Department of Radiation Oncology, Hafte-Tir Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)
4. Department of Radiology, Panzdahe-Khordad Hospital, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of)
5. Department of Biostatistics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

Purpose: To evaluate thyroid function and vascular changes during radiotherapy for patients with head and neck cancer. Methods and Materials: Fifty patients treated with primary or postoperative radiotherapy for various cancers in the head and neck region were prospectively evaluated. The serum samples (triiodothyronine [T3], thyroxine [T4], thyroid-stimulating hormone [TSH], free triiodothyronine [FT3], and free thyroxine [FT4]), the echo level of the thyroid gland, and color Doppler ultrasonography (CDU) parameters of the right inferior thyroid artery (RITA) of the patients were measured before and at regular intervals during radiotherapy. The thyroid gland dose-volume histograms of the patients were derived from their computed tomography-based treatment plans. Results: There was a significant fall in TSH level (p < 0.0001) but an increase in FT4 (p < 0.0001) and T4 (p < 0.022) levels during the radiotherapy course. The threshold dose required to produce significant changes was 12 Gy (Biologically Effective Dose in 2-Gy fractions, BED{sub 2}). There were significant rises in the patients' pulsatility index, resistive index, peak systolic velocity, blood volume flow levels, and RITA diameter (p < 0.0001), as detected by CDU during radiotherapy, compared to those parameters measured before the treatment. Hypoechogenicity and irregular echo patterns (p < 0.0001) were seen during radiotherapy compared to those before treatment. There was significant Pearson's correlation between the CDU parameters and T4, FT4, and TSH levels. Conclusions: Radiation-induced thyroiditis is regarded as primary damage to the thyroid gland. Thyroiditis can subsequently result in hypothyroidism or hyperthyroidism. Our results demonstrated that changes in thyroid vessels occur during radiotherapy delivered to patients. Vessel changes also can be attributed to the late effect of radiation on the thyroid gland. The hypoechogenicity and irregular echo patterns observed in patients may result from the increase in intrathyroidal flow.

• OSTI ID: 22056329
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 83; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ARTERIES
BLOOD
COMPUTERIZED TOMOGRAPHY
FUNCTIONAL ANALYSIS
HEAD
HYPERTHYROIDISM
HYPOTHYROIDISM
NECK
NEOPLASMS
PATIENTS
RADIATION INJURIES
RADIOTHERAPY
THRESHOLD DOSE
THYROID
THYROIDITIS
THYROXINE
TRIIODOTHYRONINE
TSH
ULTRASONOGRAPHY