Iodine deficiency and increased risk from radioactive iodine intake in nuclear medicine personnel.

Since the entity of the stable endogenous iodine pool is inversely related to the probability of thyroid uptake of radioactive iodine isotopes in subjects exposed for professional reasons to radioiodine intake, we evaluated the urinary iodine excretion, which is a reliable indicator of stable iodine daily intake, in 19 subjects of a nuclear medicine department. Seventeen out of 19 subjects showed a reduced iodine elimination < 150 mcg iodine per g of urinary creatinine, while the values of TSH and free fractions of T3 e T4 were within normal limits. Thyroglobulin levels were increased in 5 subjects only, all with reduced iodine excretion. Iodine deficiency is still present in several european areas and is responsible for several thyroid diseases including cancer; it is also responsible for increased thyroid dosimetry after accidental intake. According to Breuer, an increased radiation rate to bone marrow and ovaries is expected in subjects with a reduced endogenous iodine pool. On account of these results, we recommend to monitor the urinary iodine excretion in personnel exposed to the risk of radioiodine contamination and correct their dietary daily intake, thus reducing organ dosimetry not only in normal working conditions, but also in case of accidental internal contamination.