Nuclear Chemist Interview Question:

Explain me what are tracers? Explain how Thyroidisis and Brain Tumour Location can be detected with the help of tracer I131.?

Submitted by: Muhammad

The element which is labelled is called as a Tracer element. In the series of chemical reactions the path of the element or a compound containing the element can be traced using the tracer element.

☛ a. Thyroidisis: The iodine plays an important role in our well-being as it controls the growth and our metabolism. Most of the iodine that we intake from our food is stored in the thyroid gland. The thyroid gland in some people may become over-active or under-active. Both these conditions are considered to be critical. The condition of thyroid in patients are understood with the help of tracer as follows: about 10 µCi of I131 in the form of NaI is given to the patient through orange juice and the counting of the γ activity emitted is started immediately. The counting is taken for several hours and then the ratio of counts D/P (dummy/patients) are plotted as a function of time. The curve obtained is compared with the curve of the normal person and thus hypothyroidisis or hyperthyroidisis is detected.

☛ b. Brain Tumour Location: Dyes like fluorescein, rose Bengal are absorbed by cancerous cells, thus in order to locate the brain tumour location the dye labelled with I131 is given to the patient. Then the entire space around the skull is scanned by the help of special counters and the place where ever I131 is accumulated is found and thus it is possible to locate the brain tumour to some extent.
Submitted by: Muhammad