Personal Radiation Dosimeter
A dosimeter is a device used for personnel monitoring to detect beta, gamma, X-Ray, and neutron radiation. Dosimeters would not protect you from radiation exposure.
Technicians and lab engineers who operate x-ray machines, fluoroscopy units, certain unsealed and sealed radioisotopes, or that are exposed to other sources of gamma or high energy beta radiation, are generally required to wear one or more dosimeters.
According to the United States Nuclear Regulatory Commission (NRC) CFR 20.1502, the following are the conditions to monitor occupational exposure:
- Adults likely to receive a dose in excess of 10 percent of the limits in CFR 20.1201(a) in one (1) year from sources external to the body,
- Declared pregnant women likely to receive during the entire pregnancy a deep dose equivalent in excess of 0.1 rem (1 mSv) from radiation sources external to the body; and
- Individuals entering a high or very high radiation area.
Requesting a Dosimeter
New personnel working with radiation sources or radiation-emitting equipment, must complete the RC-2 during the Radiation Safety Practical training, and return the form to the RSO, who will review it and order the dosimeter.
Wearing a Dosimeter
Body dosimeter should be worn on their collar or mid-torso facing out.
RAM workers may request a ring dosimeter. Ring dosimeters should be worn on the hand most likely to receive higher exposure.
When your whole body badge is not being worn, it should be kept at a location protected from radiation and heat.
Radiation Exposure Limits
The occupational limits for radiation are the following:
- 5,000 mrem per year for the whole body
- 15,000 mrem per year for the lens of the eye
- 50,000 mrem per year for skin dose
When to Swap a Dosimeter
Dosimeters are issued for two (2) time frames: monthly and quarterly. The wear dates are printed on the front of the badge, under your name, as a reminder of the start of the monitoring period. Once the wear period ends, EHS will collect them. If you are expecting dosimeters and do not receive them by the second week from the request, please contact the Radiation Safety Officer for an update.
At the end of the monitoring period (i.e., monthly or quarterly), dosimeters must be returned to Radiation Safety. EHS will be coordinating the dosimeter swap as promptly as possible to expedite the processing. To make the process smoother, badges and rings should be placed in the yellow bin provided by EHS.
Terminating a Dosimeter
When a radiation worker leaves the university or changes work locations, please complete the “Radiation Monitoring Badge Cancellation” section of the RC-2 form and submit it to the Radiation Safety Officer.
If you are no longer working with radioisotopes or operate an x-ray machine, badges and rings must be returned to EHS. You will need to complete the “Radiation Monitoring Badge Cancellation” section of the RC-2 form and submit it to the Radiation Safety Officer.