Abstract
Feasibility for the use of the collimated NaI (Tl) scintillation spectrosurvey meter SS-γ C3475 (Hamamatsu Photonics) in the estimation of thyroidal 131I burden in patients that received emergency exposure to radioiodine (131I) is demonstrated. When the NaI (Tl) crystal probe collimated well to a neck phantom simulating the human thyroid gland, the detection limit of 131I deposited in that organ was estimated at 0.58kBq, which was well below the generally adopted screening level of 30kBq. The detection system for thyroidal 131I presented in this report is remarkably inexpensive compared to the conventional whole-body counters, and is considered to provide a satisfactorily accurate evaluation of thyroidal 131I burden.
