Bioassay Requirements
Radioactive material may enter one’s body via four different pathways: inhalation, ingestion, absorption, or by injection or puncture. Under certain conditions a researcher may need to undergo a bioassay to determine if there was an internal uptake of material. If the bioassay results indicate that the Nuclear Regulatory Commission’s (NRC) Annual Limits on Intake (ALI) is exceeded, work shall be suspended immediately until the cause of exposure has been identified and corrected. Below there are guidelines of when certain bioassays must be performed when working with a specific quantity of a radioisotope. However, if a researcher is exposed to any quantity of a radioisotope, the researcher may need to undergo a bioassay if they suspect that there was an intake.
Thyroid Scan:
If a researcher is working with 1 mCi or more of volatile radioiodine they will need to have a thyroid scan performed before and after the procedure. A thyroid scan will inform the researcher if they accidentally inhaled or ingested radioiodine, which accumulates in the thyroid. Thyroid scans are performed in the Environmental Health & Safety office located in Forchheimer 800 and only take a few minutes to complete.
The researcher should contact the Radiation Safety Officer and schedule an appointment at least 24 hours prior to their experiment to establish a baseline. The researcher should then schedule the post-procedure thyroid scan for no sooner than 6 hours and no later than 72 hours after performing the iodination.
This type of bioassay is for radioisotopes such as: I-123, 1-124, I-125 or I-131.
Note: Solutions containing iodide ions should not be made acidic nor stored frozen; both lead to the formation of volatile elemental iodine.
Urinalysis:
The concentration of radioactivity in urine can be used to determine the amount of activity in one’s body. Urine samples should be taken within 4 - 72 hours of exposure. Multiple urine samples may need to be taken depending on the radioisotope, its chemical form, and the amount of activity.
This type of bioassay is required when working with 100 mCi or more of C-14, H-3, P-32, or S-35.
Who to Contact:
Individuals who have been contaminated by radioactive material or involved in a radioactive material spill should immediately contact their Principal Investigator and the Radiation Safety Officer at 718-430-2243, or x4111 after hours and during holidays and weekends.