Radioiodine test
The radioiodine test is the examination of the thyroid function by giving a radioactive iodine isotope - usually 131 iodine or 123 iodine - and a subsequent radioactivity measurement above the thyroid gland .
Up until the 1980s, radioiodine studies to assess the metabolic status of the thyroid were common and the standard method for determining secretion performance . In diagnostics today , uptake measurements are only occasionally carried out in connection with a thyroid scintigraphy with 123 iodine and uptake measurements after 4 to 24 hours in order to distinguish diseases with high iodine uptake (e.g. Graves' disease ) from those with low iodine uptake (e.g. Thyroiditis ). In the routine, the simple measurement of the uptake during the scintigraphy with iodine or 99m technetium , combined with a highly precise determination of the thyroid hormones in the blood serum, is sufficient .
In preparation for radioiodine therapy for benign thyroid diseases, the radioiodine test is still used to determine the activity required for the individual patient . Usually about 5 MBq I-131 are administered and the uptake in the thyroid gland is measured with a special probe or the gamma camera after certain time intervals. The stored iodine content in percent and its biological half-life can be estimated from the measured values. The amount of iodine required for therapy can now be calculated using the so-called Marinelli formula (see radioiodine therapy # Determination of the appropriate therapy activity ).
swell
- Robert F. Dons, Frank H. Wians, Jr .: Endocrine and Metabolic Disorders: Clinical Lab Testing Manual, Fourth Edition . Taylor & Francis, July 13, 2009, ISBN 978-1-4200-7936-4 , p. 30.
- Torsten Kuwert: Nuclear Medicine . Georg Thieme Verlag, 2008, ISBN 978-3-13-118504-4 , p. 383.
Individual evidence
- ↑ JR Bierich: Endocrinology. In: H. Wiesener: Introduction to the developmental physiology of the child . Springer, [Sl] 1964, ISBN 978-3-642-86507-7 , p. 310.
