The Measurement of Thyroid Absorbed dose by Gafchromic™ EBT2 Film and Changes in Thyroid Hormone Levels Following Radiotherapy in Patients with Breast Cancer

Leyla Ansari; Neda Nasiri; Fahimeh Aminolroayaei; Karim Ghazikhanlou Sani; Masoumeh Dorri-Giv; Razzagh Abedi-Firouzjah; Dariush Sardari

doi:10.4103/jmss.JMSS_10_19

The Measurement of Thyroid Absorbed dose by Gafchromic™ EBT2 Film and Changes in Thyroid Hormone Levels Following Radiotherapy in Patients with Breast Cancer

J Med Signals Sens. 2020 Feb 6;10(1):42-47. doi: 10.4103/jmss.JMSS_10_19. eCollection 2020 Jan-Mar.

Authors

Leyla Ansari¹, Neda Nasiri², Fahimeh Aminolroayaei³, Karim Ghazikhanlou Sani⁴, Masoumeh Dorri-Giv⁵, Razzagh Abedi-Firouzjah⁶, Dariush Sardari²

Affiliations

¹ Department of Radiation Sciences, Faculty of Paramedicine, Yasuj University of Medical Science, Yasuj, Iran.
² Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
³ Department of Medical Physics and Radiology, School of Allied Medicine, Kashan University of Medical Sciences, Kashan, Iran.
⁴ Department of Radiology, Paramedical School, Hamadan University of Medical Sciences, Hamadan, Iran.
⁵ Department of Paramedical, Shahid Beheshti University of Medical Science, Tehran, Iran.
⁶ Department of Medical Physics Radiobiology and Radiation Protection, School of Medicine, Babol University of Medical Sciences, Babol, Iran.

Abstract

Background: Radiotherapy is a main method for the treatment of breast cancer. This study aimed to measure the absorbed dose of thyroid gland using Gafchromic EBT2 film during breast cancer radiotherapy. In addition, the relationship between the absorbed dose and thyroid hormone levels was evaluated.

Methods: Forty-six breast cancer patients, with the age ranged between 25 and 35 years, undergoing external radiotherapy were studied. The patients were treated with 6 and 18 MV X-ray beams, and the absorbed thyroid dose was measured by EBT2 film. Thyroid hormone levels, thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxin (T4), were measured before and after the radiotherapy. Pearson's, Spearman's, and Chi-square tests were performed to evaluate the correlation between the thyroid dose and hormone levels.

Results: The mean thyroid dose was 26 ± 9.45 cGy with the range of 7.85-48.35 cGy. There were not any significant differences at thyroid hormone levels between preradiotherapy and postradiotherapy (P > 0.05). There was a significant relationship between increased thyroid absorbed dose and changes in TSH and T4 levels (P < 0.05), but it was not significant in T3 level (P = 0.1).

Conclusion: Regarding the results, the thyroid absorbed dose can have an effect on its function. Therefore, the thyroid gland should be considered as an organ at risk in breast cancer radiotherapy.

Keywords: Breast cancer; Gafchromic film; radiotherapy; thyroid gland.