[In vivo X-ray fluorescent analysis of iodine concentration in the thyroid (author's transl)]

A simple apparatus was made for the X-ray fluorescent analysis of iodine concentration of the thyroid. The apparatus consists of 241Am gamma-ray source of 300mCi and pure Ge detector of 50mm2X5mm. Diverging collimator was designed to achieve a full view of the thyroid. The detectable concentration was 0.2mg iodine/g tissue assuming the coefficient of variance of 30% and the counting time of 5 minutes. Measurement was performed for autopsied 10 thyroids and the results were in good correlation with those by neutron activation analysis (r=0.93). Iodine concentration ranged 0.3-1.2mg/g (mean 0.6mg/g) and compared well with the data in literatures. This technique is useful for the in vivo measurement of thyroidal iodine content in patients.