Answer to Question #4938 Submitted to "Ask the Experts"

The energy of the gamma rays emitted by iridium-192 is relatively high and is very penetrating, especially compared to typically lower-energy x rays. That is why x rays work well for medical imaging of human tissue, which has a low density compared to metal components that must be imaged with the higher-energy gamma rays of iridium-192 or cobalt-60.

Considering the penetrating power of the iridium-192 gamma rays some—but not much—additional protection is provided by lead aprons, gloves, or eye-protection equipment to an "industrial radiographer" as contrasted to a medical x-ray technician who is well protected from low-energy x rays by lead aprons, gloves, and eye-protection equipment.

The requirements for personnel protection, dosimetry, survey meters, etc., for industrial radiographers can vary from state to state, so be very familiar with your state's regulations and be fully authorized by your state for any work as an industrial radiographer.

As a closing note, the most overexposures for industrial radiographers occur because the radiographer did not use or improperly used his/her handheld survey meter. So, keep your survey meter ON and calibrated, set it so it is making "clicks," listen to it, watch the readings carefully, and trust it. This should help best of all to keep your exposure as low as is reasonably achievable (ALARA) as an industrial radiographer.

John P. Hageman, MS, CHP