Characterization of an in vivo thyroid 131I monitoring system using an imaging plate

The effects of neck diameter, thyroid volume, and prethyroid tissue thickness on a count-activity conversion coefficient and the detection limit of a thyroid 131I monitoring system with an imaging plate (IP) were estimated by using an anthropomorphic thyroid–neck phantom. The conversion coefficient and detection limit of the IP system was approximately constant for normal Japanese adults regardless of their neck diameters, thyroid volumes, and prethyroid tissue thicknesses. The IP system is a new option for thyroid 131I monitoring.