A fluoroscopic examination requires 3 minutes of exposure at an exposure rate of 3 mGy/hr. What is the approximate exposure for this procedure?

To determine the approximate exposure for a fluoroscopic examination, you can use the information given regarding the exposure rate and the duration of the exposure. The exposure rate is 3 mGy/hr, and the procedure lasts for 3 minutes.

Since 1 hour equals 60 minutes, you can convert the exposure rate from an hourly rate to a per-minute rate by dividing the hourly rate by 60:

3 mGy/hr ÷ 60 minutes/hr = 0.05 mGy/min.

Now, you multiply the per-minute exposure rate by the duration of the exposure in minutes:

0.05 mGy/min × 3 minutes = 0.15 mGy.

Thus, the total approximate exposure for the fluoroscopic examination is 0.15 mGy, making this the correct choice for the question. This calculation illustrates the importance of converting units appropriately and applying them in practical situations involving radiation exposure.