What is the exposure rate constant for the brachytherapy source of 192Ir?

The exposure rate constant for the brachytherapy source of Iridium-192 (192Ir) is approximately 4. This constant is a measure of the amount of ionizing radiation emitted by the source, specifically how much exposure to radiation can be expected at a distance from the source.

In brachytherapy, where radioactive sources are placed near or within tumors, the exposure rate constant allows dosimetrists to accurately calculate the dose delivered to the target tissue as well as ensure that surrounding healthy tissues receive minimal exposure. The specific value of approximately 4 R cm²/mCi hr (or a similar unit) is widely accepted for 192Ir, making it essential for treatment planning and dose calculations.

Understanding this constant helps in the effective planning of brachytherapy treatments, ensuring accurate dosimetry and optimizing patient safety.