title: Micronucleus frequencies in groups receiving external or internal radiation.
abstract: OBJECTIVE
  In the current study, we aimed to explore whether there is alteration between pre- and post-treatment micronucleus (MN) frequencies induced by internal and external ionizing radiation.
  
  
  METHODS
  The study enrolled a total of 67 patients including patients admitted to our hospital for treatment of hyperthyroidism (n = 17), scanning with low-dose I-131 (n = 15), and ablative therapy with high-dose I-131 (n = 15) at Department of Nuclear Medicine as well as patients with different diagnoses receiving external radiotherapy with various doses and durations at Department of Radiation Oncology (n = 20). Thirty-two patients who received radioactive iodine and returned for a follow-up visit at 1 month.
  
  
  RESULTS
  Considering both pre- and post-treatment MN frequencies of each group, lowest MN frequencies were detected for patients undergoing screening with low-dose I-131, and highest MN frequencies were found in radiotherapy patients. Comparison of pre- and post-treatment MN frequencies among hyperthyroidism, when pre- and post-treatment MN frequencies compared among hyperthyroidism, I-131 whole body scanning, ablation, and radiotherapy patient groups differences between MN frequencies were significant for each group (P < 0.05).
  
  
  CONCLUSIONS
  Our study showed that MN analysis might be of value in determining chromosome damage that could potentially occur in patients exposed to internal and external radiation.
authors.affiliation: Department of Nuclear Medicine, Kayseri Training and Research Hospital, Kayseri 38010, Turkey.
authors.forename: Ayşegül
authors.initials: A
authors.lastname: Özdal
authors.affiliation: Department of Nuclear Medicine, School of Medicine, Cumhuriyet University, Sivas 58140, Turkey.
authors.forename: Taner
authors.initials: T
authors.lastname: Erselcan
authors.affiliation: Department of Medical Genetics, School of Medicine, Cumhuriyet University, Sivas 58140, Turkey.
authors.forename: Öztürk
authors.initials: Ö
authors.lastname: Özdemir
authors.affiliation: Department of Nuclear Medicine, Kayseri Training and Research Hospital, Kayseri 38010, Turkey.
authors.forename: Güler
authors.initials: G
authors.lastname: Silov
authors.affiliation: Department of Nuclear Medicine, Kayseri Training and Research Hospital, Kayseri 38010, Turkey.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Erdoğan
authors.affiliation: Department of Nuclear Medicine, Kayseri Training and Research Hospital, Kayseri 38010, Turkey.
authors.forename: Özgül
authors.initials: Ö
authors.lastname: Turhal
keywords: Ionizing radiation; micronucleus; radioiodine