Measurement of 131I in the human thyroid gland using a NaI(Tl) scintillation survey meter

As a method of prompt and rapid estimation of thyroidal 131I burden of the public (and nuclear workers) in emergency exposure to radioiodine, feasibility of a use of a scintillation survey meter with a NaI(Tl) crystal was demonstrated using phantoms simulating the thyroid gland of Japanese. Age dependency in the efficiency of detection was found. From the obtained detection limit, a possibility of the practical application of this method was proven. The present method may be safely used in rapid screening and measurement to a first approximation of the thyroidal 131I burden and consequently approximation of absorbed dose to the thyroid gland in emergency situations. (auth.)