Elimination of Intravenously Injected 125I‐Toluidine Blue into Rabbits

: The elimination of intravenously injected 125I‐toluidine blue was studied in rabbits. Within 5 minutes after the injection, approximately 80% of the dye had been metabolized, being present in the plasma and urine in a colourless state. As much as 99% of the label was recovered in the urine and faeces within 3 days. It is therefore assumed that in future clinical parathyroid scintigraphy, the absorbed radiation dose with radioiodinated dye will be smaller than with 75Se‐selenomethionine, the currently used radiopharmaceutic compound for the parathyroids.