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

Abstract

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)more » 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.« less

Authors:
 [1];  [1];  [2];  [3];  [4];  [5]
  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)
Publication Date:
OSTI Identifier:
22056329
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 83; Journal Issue: 1; Other Information: Copyright (c) 2012 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:
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

Citation Formats

Bakhshandeh, Mohsen, Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir, Mahdavi, Seyed Rabie, Nikoofar, Alireza, Edraki, Hamid Reza, and Kazemnejad, Anoshirvan. Evaluation of Thyroid Disorders During Head-and-Neck Radiotherapy by Using Functional Analysis and Ultrasonography. United States: N. p., 2012. Web. doi:10.1016/J.IJROBP.2011.05.064.
Bakhshandeh, Mohsen, Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir, Mahdavi, Seyed Rabie, Nikoofar, Alireza, Edraki, Hamid Reza, & Kazemnejad, Anoshirvan. Evaluation of Thyroid Disorders During Head-and-Neck Radiotherapy by Using Functional Analysis and Ultrasonography. United States. doi:10.1016/J.IJROBP.2011.05.064.
Bakhshandeh, Mohsen, Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir, Mahdavi, Seyed Rabie, Nikoofar, Alireza, Edraki, Hamid Reza, and Kazemnejad, Anoshirvan. 2012. "Evaluation of Thyroid Disorders During Head-and-Neck Radiotherapy by Using Functional Analysis and Ultrasonography". United States. doi:10.1016/J.IJROBP.2011.05.064.
@article{osti_22056329,
title = {Evaluation of Thyroid Disorders During Head-and-Neck Radiotherapy by Using Functional Analysis and Ultrasonography},
author = {Bakhshandeh, Mohsen and Hashemi, Bijan, E-mail: bhashemi@modares.ac.ir and Mahdavi, Seyed Rabie and Nikoofar, Alireza and Edraki, Hamid Reza and Kazemnejad, Anoshirvan},
abstractNote = {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.},
doi = {10.1016/J.IJROBP.2011.05.064},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 1,
volume = 83,
place = {United States},
year = 2012,
month = 5
}
  • Purpose: To evaluate the incidence of thyroid disorders and dose distribution to the thyroid in patients treated with radiotherapy for head-and-neck carcinomas. Methods and Materials: A retrospective evaluation of data from 73 patients treated for head-and-neck cancers in our department was performed. Thyroid function was evaluated mainly by the measurement of thyrotropin (thyroid stimulating hormone [TSH]). A retrospective analysis of treatment plans was performed for 57 patients. Percentages of thyroid glandular volume absorbing 10, 30, and 50 Gy (V10, V30, and V50 respectively) were considered for statistical analysis. Results: A majority of patients (61%) had a normal thyroid function whereasmore » 19 patients (26%) had hypothyroidism. Mean thyroid volume was 30.39 cc. Point 3 (located at isthmus) absorbed lower doses compared with other points (p < 0.0001). Median values of V10, V30, and V50 were 92% (range, 57-100%), 75% (range, 28.5-100%), and 35% (range, 3-83%) respectively. Gender was associated with toxicity (presence of any kind of thyroid disorders) (p < 0.05), with females displaying higher levels of TSHr (relative TSH = patient's value/maximum value of the laboratory range) (p = 0.0005) and smaller thyroid volume (p 0.0012) compared with male population. TSHr values were associated with thyroid volume, and the presence of midline shielding block in the anterior field was associated with relative free thyroxine (FT4r = patient's value/maximum value of the laboratory range) values. Conclusions: Gender and thyroid volume seem to play an important role in the occurrence of thyroid toxicity, but further studies on dose-effect relationship for radiotherapy-induced thyroid toxicity are needed.« less
  • Purpose: To analyze changes in parotid gland dose resulting from anatomic changes throughout a course of radiotherapy in a cohort of head-and-neck cancer patients. Methods and Materials: The study population consisted of 10 head-and-neck cancer patients treated definitively with intensity-modulated radiotherapy on a helical tomotherapy unit. A total of 330 daily megavoltage computed tomography images were retrospectively processed through a deformable image registration algorithm to be registered to the planning kilovoltage computed tomography images. The process resulted in deformed parotid contours and voxel mappings for both daily and accumulated dose-volume histogram calculations. The daily and cumulative dose deviations from themore » original treatment plan were analyzed. Correlations between dosimetric variations and anatomic changes were investigated. Results: The daily parotid mean dose of the 10 patients differed from the plan dose by an average of 15%. At the end of the treatment, 3 of the 10 patients were estimated to have received a greater than 10% higher mean parotid dose than in the original plan (range, 13-42%), whereas the remaining 7 patients received doses that differed by less than 10% (range, -6-8%). The dose difference was correlated with a migration of the parotids toward the high-dose region. Conclusions: The use of deformable image registration techniques and daily megavoltage computed tomography imaging makes it possible to calculate daily and accumulated dose-volume histograms. Significant dose variations were observed as result of interfractional anatomic changes. These techniques enable the implementation of dose-adaptive radiotherapy.« less
  • Purpose: To develop a fast computational radiobiologic model for quantitative analysis of tumor volume during fractionated radiotherapy. The tumor-volume model can be useful for optimizing image-guidance protocols and four-dimensional treatment simulations in proton therapy that is highly sensitive to physiologic changes. Methods: The analysis is performed using two approximations: (1) tumor volume is a linear function of total cell number and (2) tumor-cell population is separated into four subpopulations: oxygenated viable cells, oxygenated lethally damaged cells, hypoxic viable cells, and hypoxic lethally damaged cells. An exponential decay model is used for disintegration and removal of oxygenated lethally damaged cells frommore » the tumor. Results: We tested our model on daily volumetric imaging data available for 14 head-and-neck cancer patients treated with an integrated computed tomography/linear accelerator system. A simulation based on the averaged values of radiobiologic parameters was able to describe eight cases during the entire treatment and four cases partially (50% of treatment time) with a maximum 20% error. The largest discrepancies between the model and clinical data were obtained for small tumors, which may be explained by larger errors in the manual tumor volume delineation procedure. Conclusions: Our results indicate that the change in gross tumor volume for head-and-neck cancer can be adequately described by a relatively simple radiobiologic model. In future research, we propose to study the variation of model parameters by fitting to clinical data for a cohort of patients with head-and-neck cancer and other tumors. The potential impact of other processes, like concurrent chemotherapy, on tumor volume should be evaluated.« less