Answer to Question #9823 Submitted to "Ask the Experts"

Category: Security Screening — Airport Screening

The following question was answered by an expert in the appropriate field:

I am a security screener in an airport and am daily working around metal detectors and x-ray scanners.

I would like to know if there is any risk from walking through a metal detector 20 times a day, seven days a week.

I also stand next to an x-ray machine seven days a week, eight hours per day.

Thank you for your question. The metal detector does not emit ionizing radiation (x rays), so the only items from which you may be exposed to radiation are backscatter security screeners used for passenger screening (if you have them where you work) or x-ray machines used to check passenger luggage (a cabinet x-ray unit).

In the United States, there are restrictions on the amount of scattered radiation that can be emitted through the shielding of each device (the backscatter screener and the cabinet x-ray unit). This is to assure that operators or other bystanders who are close to the units for any length of time do not exceed 1 mSv per year total radiation dose (mSv = millisievert, a unit of effective radiation dose).

It has been calculated that the dose to the operator (standing or sitting at a distance of 30 cm from the device) of a backscatter screening system doing 180 scans per hour would be about 0.01 mSv per year, one one-hundredth of the U.S. regulatory limit.

In either case, whether the total dose is 0.01 mSv or 1.0 mSv per year, any risk (of radiation-related effects) is negligible.

Kelly Classic
Certified Medical Health Physicist

American National Standards Institute. Radiation safety for personnel security screening systems using x-ray or gamma radiation. ANSI/HPS N43.17; 2009.

Answer posted on 22 July 2011. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.