Biodistribution of free 211At and 125I- in nude mice bearing tumors derived from anaplastic thyroid carcinoma cell lines.
Free 211At has been proposed for therapy of anaplastic thyroid carcinoma (ATC). However, no extensive biodistribution study comparing tumor-bearing and nontumor-bearing mice has previously been performed. The aim of this study was to perform a complete evaluation of the biodistribution of 211At, both for normal and ATC-bearing mice. For comparison, the biodistribution of 125I- was simultaneously studied. Dosimetric evaluations were performed to investigate if (211)At can be used for therapy of ATC.


METHODS
Athymic nude mice were subcutaneously injected with either of two human ATC cell lines, HTh83 and KAT-4. Tumor-bearing and nontumor-bearing mice were injected intravenously with 0.3 MBq 211At and 0.3 MBq 125I- simultaneously. The mice were sacrificed 4-24 hours after injection, and the activity concentrations in tissues were determined.


RESULTS
Except for the thyroid, the concentration of 211At was higher than that of 125I- in the tissues. The uptake of 211At was primarily high in NIS-expressing organs. Furthermore, the absorbed doses to these organs were higher than both tumor types.


CONCLUSIONS
The biodistribution of 211At and 125I- differed in this animal model. The higher mean absorbed dose from 211At in several organs than in tumor tissue restricts the possibility of using free 211At for therapy of ATC.
Lundh
Charlotta
C
Department of Radiation Physics, Göteborg University, Göteborg, Sweden. charlotta.lundh@radfys.gu.se
Lindencrona
Ulrika
U
Schmitt
Anneli
A
Nilsson
Mikael
M
Forssell-Aronsson
Eva
E
D000818:Animals; D001246:Astatine / Q000097:blood / Q000493:pharmacokinetics*; D045744:Cell Line, Tumor; D005260:Female; D006262:Health; D006801:Humans; D007457:Iodine Radioisotopes / Q000097:blood / Q000493:pharmacokinetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011874:Radiometry; D013964:Thyroid Neoplasms / Q000097:blood / Q000473:pathology*; D023041:Xenograft Model Antitumor Assays
D007457:Iodine Radioisotopes; D001246:Astatine