Texas Industrial Radiography Gamma Practice Test

If a radiographer may not receive a personal dose in excess of 104 mrem per week, how many hours can they work in a field of 5 mr/hr?

1. 1.9 hours

2. 20.8 hours

3. 31.2 hours

4. 40 hours

The correct answer is: 20.8 hours

To determine how many hours a radiographer can work in a field where the radiation exposure is 5 mR/hr while not exceeding a personal dose of 104 mrem per week, it is essential to understand the relationship between radiation dose, exposure rate, and time. To find the maximum allowable exposure time: 1. The weekly dose limit is 104 mrem. Convert this limit to millirems to match the exposure rate. Since 1 mrem = 1 mR, the dose limit remains 104 mR. 2. The exposure rate is given as 5 mR/hr. 3. Using the formula for dose (Dose = Rate × Time), we can rearrange this to find Time: Time = Dose ÷ Rate 4. Plugging in the numbers: Time = 104 mR ÷ 5 mR/hr = 20.8 hours This calculation shows that the radiographer can work for a maximum of 20.8 hours at the exposure rate of 5 mR/hr without exceeding the 104 mrem dose limit. Understanding the units and calculations reinforces the importance of being aware of both the exposure rate and the weekly dose limits when planning for safe work hours in radiographic