Effect of recombinant TSH (rTSH) on iodine-131 residence time on thyroid gland: An experimental study in rats
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2004
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BRAZILIAN CONGRESS OF NUCLEAR MEDICINE, 22
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Patients with total thyroidectomy are strongly depended on hormone
reposition therapy to maintain a normal metabolic status. The hormone
therapy is mandatory for serum TSH levels suppression and for avoiding
undesirable symptoms of hypothyroidism such as tiredness and slowness.
However, patients with differentiated thyroid carcinoma need routine whole
body iodine-131 survey within the first 2 years of total thyroidectomy, which
requires increased levels of serum TSH to stimulate residual thyroid tissue
or even metastases. Recombinant human thyrotropin (FTSH) was
developed to avoid the interruption on hormone therapy, which brings
comfort and safety to the patient.
Our purpose was to estimate the effect of rTSH on thyroid-absorbed dose
and total glandular residence time after an oral administration of iodine131. In this experimental model, 13 Wistar rats, 200 g of weight each,
received 11,1 MBq of I-131 orally. Seven of these animals received rTSH
(IPEN-CNEN) on the day before. 24 hours urine was collected for each
animal. The urine was collected in metabolic cages and the tube collectors
that contained the urine were verified on hourly basis. A CRC-15R
Capintec dose calibrator was used to determinate their activities. The
accumulated activity in thyroid and the residence time was calculated by
MIRD standards.
The accumulated activity of 10 rats who received 1-131 without rTSH
stimulus was: A = 5.13 + 0.33 MBq.h and the average residence time was:
RT = 0.46 + 0.22 h. The rats who ingested |-131 preceded by rTSH
presented with higher accumulated activity on thyroid: A = 6.90 + 0.42
MBq.h. The residence time was also a little be longer in comparison with
the group of rats without rTSH stimuli: RT = 0.61 + 0.39 h. These preliminary data suggest that rTSH promotes higher rates of accumulated
activity of iodine-131 in the thyroid gland and also prolongs the residence
time of iodine in normal glands, in this case about 32,6%. These findings
might have significant impact on dosimetric studies on iodine-131 therapy
preceded by rTSH administration in humans.
Como referenciar
GUIMARAES, M.I.C.C.; SILVA, M.A.; OKAMOTO, M.R.Y.; YORIYAZ, H.; BUCHPIGUEL, C.A.; OKAZAKI, K.; BARTOLINI, P. Effect of recombinant TSH (rTSH) on iodine-131 residence time on thyroid gland: An experimental study in rats. In: BRAZILIAN CONGRESS OF NUCLEAR MEDICINE, 22, 9-12 Oct, 2004, Aracaju, PE. Abstract... Disponível em: http://repositorio.ipen.br/handle/123456789/19919. Acesso em: 20 Mar 2026.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.