Guidance

Radioiodine using hand-held instruments: thyroid monitoring guidance

This guidance (HPA-CRCE-044) gives a procedure for monitoring of the thyroid using mini instruments type 44 and type 42 probes.

• From: Public Health England
• Published: 1 February 2013

Documents

HPA-CRCE-044: practical guidance on thyroid monitoring for radioiodine using hand-held instruments

Ref: ISBN 978-0-85951-729-4

PDF, 248 KB, 28 pages

Details

Following an incident involving release of radioactive iodine, it may well be necessary to monitor large numbers of people for internal contamination. In the case of iodine-125 (¹²⁵I), iodine-131 (¹³¹I) and radioiodine releases from nuclear reactors (mixtures of ¹³¹I and shorter lived iodine radionuclides) screening measurements can be done with simple scintillation probe based instruments held over the thyroid.

This guidance gives a procedure for monitoring of the thyroid using Mini Instruments type 44 and type 42 probes. Factors are given to convert measured count rates to activity in thyroid, dose to the thyroid and committed effective dose for intakes by inhalation. Measurements with these instruments are capable of detecting about 2 kBq of ¹³¹I and 1 kBq of ¹²⁵I in the thyroid of an adult. For measurements made 24 hours after intake, these activities correspond to values of committed effective dose of 0.2 and 0.05 mSv for ¹³¹I and ¹²⁵I respectively, assuming stable iodine has not been administered.

Published 1 February 2013