Table 1.

Classification of Thyroid Ultrasound Examination Results in the Screening Program in Fukushima Prefecture

Examination result	Definition	Recommended action
A
A1	No nodules or cysts	Participation in the next scheduled screening
A2	Nodules ≤5.0 mm or cysts ≤20.0 mm	Watchful waiting until the next scheduled screening
B	Nodules ≥5.1 mm or cysts ≥20.1 mm	Confirmatory examination by health insurance
C	Suspicious finding other than A2 or B	Immediate need for confirmatory examination