title: Cytogenetic effects of radioiodine therapy: a 20-year follow-up study.
abstract: The purpose of this study was to compare cytogenetic data in a patient before and after treatment with radioiodine to evaluate the assays in the context of biological dosimetry. We studied a 34-year-old male patient who underwent a total thyroidectomy followed by ablation therapy with (131)I (19.28 GBq) for a papillary thyroid carcinoma. The patient provided blood samples before treatment and then serial samples at monthly intervals during the first year period and quarterly intervals for 5 years and finally 20 years after treatment. A micronucleus assay, dicentric assay, FISH method and G-banding were used to detect and measure DNA damage in circulating peripheral blood lymphocytes of the patient. The results showed that radiation-induced cytogenetic effects persisted for many years after treatment as shown by elevated micronuclei and chromosome aberrations as a result of exposure to (131)I. At 5 years after treatment, the micronucleus count was tenfold higher than the pre-exposure frequency. Shortly after the treatment, micronucleus counts produced a dose estimate of 0.47 ± 0.09 Gy. The dose to the patient evaluated retrospectively using FISH-measured translocations was 0.70 ± 0.16 Gy. Overall, our results show that the micronucleus assay is a retrospective biomarker of low-dose radiation exposure. However, this method is not able to determine local dose to the target tissue which in this case was any residual thyroid cells plus metastases of thyroidal origin.
authors.affiliation: Radiation Emergency Assistance Center/Training Site, Oak Ridge Institute for Science and Education, Oak Ridge, TN, 37831-0117, USA.
authors.forename: Gordon K
authors.initials: GK
authors.lastname: Livingston
authors.affiliation: Medical Radiological Research Center, Koroliova str. 4, Obninsk, Kaluga Region, Russia, 249036. igor.khvostunov@gmail.com.
authors.forename: Igor K
authors.identifier: http://orcid.org/0000-0002-3319-0109
authors.initials: IK
authors.lastname: Khvostunov
authors.affiliation: PRP-HOM/SRBE/LDB, Institut de Radioprotection et de Sureté Nucléaire, BP 17, 92262, Fontenay aux roses Cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Gregoire
authors.affiliation: Facultat de Biociències, Universtitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Spain.
authors.forename: Joan-Francesc
authors.initials: JF
authors.lastname: Barquinero
authors.affiliation: Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
authors.forename: Lin
authors.initials: L
authors.lastname: Shi
authors.affiliation: Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tashiro
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000235:genetics / Q000532:radiotherapy / Q000601:surgery; D002291:Carcinoma, Papillary; D002869:Chromosome Aberrations / Q000528:radiation effects; D020732:Cytogenetic Analysis; D005500:Follow-Up Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D059785:Karyotype; D008297:Male; D015162:Micronucleus Tests; D011832:Radiation Injuries / Q000235:genetics*; D018570:Risk Assessment; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D007457:Iodine Radioisotopes
keywords: Biological dosimetry; Cytogenetic damage in lymphocytes; Micronucleus assay; Radioiodine therapy