title: Calculation of Thyroid Dose with Planner System and Evaluation of Thyroid Function after Radiotherapy for Patients with Breast Cancer.
abstract: BACKGROUND
  Much research has widely been conducted into thyroid hormones levels following radiotherapy for breast cancer. Consequently, in this study, we evaluated to relate the rate of thyroid hormones levels with the dose distribution among breast cancer patients.
  
  
  METHODS
  Thirty patients were treated with 4-field breast cancer radiotherapy. The dose volume histograms, the volume percentage of the thyroid absorbing respectively 20, 30, 40 and 50 Gy were then estimated (V20, V30, V40 and V50) together with the individual average thyroid dose over the whole gland derived from their computed tomography-based treatment plans. Then, in serum samples triiodothyronine [T3], thyroxine [T4], thyroid-stimulating hormone [TSH] of the patients were measured before and after radiotherapy.
  
  
  RESULTS
  There were no significant differences in thyroid hormones levels before and after radiotherapy for patients with breast cancer (P value >.05).
  
  
  CONCLUSIONS
  On the balance, we understood that thyroid stimulating hormones levels did not change before and after cancer breast radiotherapy.
authors.affiliation: Radiology and Radiotherapy Department, Faculty of Paramedical, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Dorri Giv
authors.affiliation: Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: M H
authors.initials: MH
authors.lastname: Bahreini Toosi
authors.affiliation: Radiology and Radiotherapy Department, Faculty of Paramedical, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: S M R
authors.initials: SM
authors.lastname: Aghamiri
authors.affiliation: Medical Physics Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Akbari
authors.affiliation: MSc of Radiation Biology and Orotection, Shiraz University of Medical Science, Shiraz, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Taeb
keywords:  Breast Cancer ;  Radiotherapy; Thyroid 