title: [Two-step radioiodine therapy in benign thyroid diseases during a single hospital visit--observations on 100 patients].
abstract: OBJECTIVE
  A two-step radioiodine therapy (RITh) is occasionally necessary in patients with benign thyroid disorders, when strong differences to the pretherapeutic radioiodine test occur. In this study, the parameters (uptake and effective half-life of I-131) of the radioiodine test are compared with those of the first and second RITh.
  
  
  METHODS
  100 patients were evaluated, who received a two-step RITh in our department between June 1992 and March 1994. Uptake and effective half-life of I-131 and the absorbed dose in the first and second therapy were compared with each other based on the daily measured activity of the thyroid.
  
  
  RESULTS
  A two-step RITh was necessary in 10% of the patients. The uptake of I-131 in the first RITh was significantly lower as compared to the test and significantly higher as compared to the second RITh. There were no significant changes between the effective half-life of I-131 in test, first and second RITh.
  
  
  CONCLUSIONS
  The importance of radioiodine test for the calculation of therapeutic doses is emphasized. The data gathered in our study concerning the diminution of uptake of I-131 in the second RITh can be useful for dose calculation.
authors.affiliation: Klinik und Poliklinik für Nuklearmedizin, Universität zu Köln, Deutschland.
authors.forename: A
authors.initials: A
authors.lastname: Khandani
authors.forename: H
authors.initials: H
authors.lastname: Schicha
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019583:Dose Fractionation, Radiation; D005260:Female; D006111:Graves Disease / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006207:Half-Life; D006801:Humans; D006980:Hyperthyroidism / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes