Radioactive I-131 Patient Release Dose Calculator

This tool calculates the potential radiation dose others may get from a patient who has been administered I-131.

Calculations are based on Appendix B of the NRC Regulatory Guide 8.39 (issued April 2020).

Initial Activity (mCi)

Quantity of I-131 administered to patient in millicuries

Which of the following medical conditions applies to the patient?

Hyperthyroidism

Postthyroidectomy for thyroid cancer

None of these options

Medical condition of the patient

Which of the following Occupancy Factors applies to the patient during the period from 8 hours after administration until total decay?

E = 0.75 - When a physical half life, an effective half life, or a specific time period under consideration (e.g. bladder holding time) is less than 1 day.

E = 0.25 - When an effective half life is greater than 1 day if the patient has been given instructions, such as Maintain a prudent distance from others for at least the first two days. Sleep alone in a room for at least the first night. Do not travel by airplane or mass transportation for at least the first day. Do not travel on a prolonged automobile trip with others for at least the first two days. Have sole use of a bathroom for at least the first two days. Drink plenty of fluids for at least the first two days.

E = 0.125 - When an effective half life is greater than 1 day if the patient has been given instructions, such as Follow the instructions for E = 0.25 above, Live alone for at least the first two days. Have few visits by family or friends for at least the first two days.

Occupancy Factor applied to the patient