Measurement of Radioactivity in Breast Milk Following Administration of TC99m to the Thyroid Gland

This study was conducted at Al Nelain diagnostic center during the period from November 2016 to April 2017. The main objective of the study was to measureand calculate the amount of radioactivity excreted in breast milk after administration of 185 MBq of 99m TcO-4 to thyroid scan patients as well as estimation of the dose received by the baby from the ingestion of the milk. The study came out with many results including the average activity per 140ml of milk for 15 patients at 12 hours which was 0.65 MBq and it decreased monoexponentially to reach 0.07 MBq after 24 hours with an effective half life of 4.8 hours. Using these data, the effective dose equivalent to the babies for the administered activity were found between 0.183 And 0.498 mSv. The results, as well, showed that there was no need for breast feeding interruption more than 12 hours to achieve less than 1 mSv effective dose equivalent to the baby as this rate was compatible with the ICRP standard (less than 1 mSv per year). In case of greater activities the percentage of activity excreted can be applied to calculate the excreted activity and estimation of the interruption of breast feeding period. The results showed an inverse relationship between the thyroid uptake and the excreted activity was established.