Personnel Monitoring

Federal and state regulations require the UW to monitor the radiation dose to employees who may be exposed to radiation as part of their job duties.

Employees whose job duties result in exposure to radiation may be assigned dosimeters to monitor their exposure. Depending on the source and amount of exposure, this may include whole body badges, rings or both. Individual badges are collected monthly or quarterly, and the reported doses are reviewed by an EH&S Radiation Safety team member.

Bioassays may be required of UW employees who use large amounts of radioiodine or tritium, to monitor for any uptake. The As Low as Reasonably Achievable (ALARA) principle ensures individual doses are monitored closely, and helps ensure employees are not receiving excess radiation exposure from the jobs they perform.


What you need to know

The federal government has defined annual dose limits for radiation workers as follows:

Body part Dose limit
Whole body 5,000 mrem
Lens of the eye 15,000 mrem
Extremities, shallow, any single organ 50,000 mrem
Declared pregnant worker (9 months) 500 mrem


Workers are required to wear dosimetry if they are likely to receive at least 10 percent of the annual dose limit.

EH&S is charged with enforcement of the ALARA principle. The Radiation Safety Committee and EH&S’s Radiation Safety team have determined quarterly dose levels that will trigger an ALARA investigation.

  • Level I may trigger an investigation, depending on the individual’s normal job duties and dose history.

  • Level II automatically triggers an investigation by a health physicist to determine if further action needs to be taken.

Quarterly ALARA Investigation Levels
Dose ALARA Level 1 ALARA Level 2
Category (mrem) (mrem)
Deep 125 375
Deep*  375 625
Lens 375 1125
Lens* 1125 1875
Shallow 1875 5625
Extremity 1250 3750


Dose categories with an asterisk (*) denote a higher limit for some workers as determined by the EH&S Radiation Safety team


What you can do to stay safe

Wear your dosimeter(s) properly

Whole body badges, except for fetal badges, should be worn over any protective shielding, between the collar and the belt. Fetal badges should be worn at the waist under any protective shielding. Ring badges should be worn under gloves on the hand most likely to receive the most dose.

Refer to the Dosimetry page for more information.

Return your dosimeter(s) promptly

Timely return and processing of badges assure that any concerns with a higher than expected dose can be investigated and mitigated quickly.

Report for your bioassay on time

Timely bioassay measurements assure that any abnormal readings can be addressed and investigated quickly.

Services available

EH&S provides the following services:

  • Consultation on concerns regarding occupational exposure to radiation
  • Issue dosimetry to monitor external exposure to radiation
  • Conduct bioassays for monitoring internal exposure to radioactive material

Frequently asked questions



Radiation Safety Contact

(206) 543-0463