During fluoroscopy, if the radiation exposure level is 4 mGya/hr, what is the maximum time a patient can be exposed based on a daily allowance of 0.5 mGya?

To determine the maximum time a patient can be exposed to a radiation level of 4 mGya/hr based on a daily allowable dose of 0.5 mGya, you must evaluate how this rate of exposure relates to the allowable limit.

First, you need to convert the radiation exposure rate from mGya per hour to a per-minute basis, which is necessary to align it with the daily allowance. The rate of exposure is 4 mGya/hr, and since there are 60 minutes in an hour, the exposure can be calculated as follows:

4 mGya/hr ÷ 60 minutes = 0.0667 mGya/minute.

Next, knowing the daily allowance is 0.5 mGya, you can determine the maximum number of minutes a patient can be safely exposed by dividing the daily allowance by the per-minute exposure rate:

0.5 mGya ÷ 0.0667 mGya/minute ≈ 7.5 minutes.

This calculation shows that the maximum exposure time without exceeding the daily allowance of 0.5 mGya is approximately 7.5 minutes. Therefore, this amount of time is the correct maximum limit for patient exposure to ensure safety and