Under the conditions of the UWM NRC license, the use of personnel monitoring devices (e.g. dosimeters) is required for all persons working in radionuclide use areas where they could receive, in a year from external radiation sources, a dose in excess of 10% of the dose limit as outlined in Table 2.

Table 2:   Occupational Dose Limits (in REM)

Additionally, minors (any person who is under 18 years of age) and declared pregnant workers likely to receive, in a year from external radiation sources, a dose in excess of 10% of the specified dose limits established for these populations (see Table 2) must also be monitored for external exposure.

Two types of dosimeters are issued: "whole body" badges, which measure radiation exposure to the trunk of the body; and "extremity" badges (e.g. ring badges) which measure radiation exposure to hands and/or fingers. Finally, University regulations require that all workers who use 1 mCi or more of strong beta or gamma emitting radioactive material which decays with certain product energies (see Table 3) wear dosimeters to verify that excessive exposure to ionizing radiation has not occurred.

Table 3:   Dosimetry Requirements for Strong Beta and Gamma Radiation

Whole body and extremity dosimeters are available from the Radiation Safety Program. To obtain a dosimeter complete and submit RS Form 310 (Appendix L). All persons requesting dosimeters must have successfully completed the radiation safety exam (see Section 6).

If you lose a whole body or extremity dosimeter contact the Radiation Safety Program and submit a "Lost Dosimeter Dose Estimate", RS Form 320 (Appendix M). If an estimate is not submitted to the Radiation Safety Program a maximum dose for the monitoring period may be assumed and a $25 replacement fee will be assessed.

All exposure results are received by the Radiation Safety Officer and are reviewed as soon as they are received from the vendor. You will automatically be notified of any unusual exposure levels. Note, too, that any overexposures will be immediately investigated as required under the campus ALARA program. All personal dosimetry reports for UWM employees and students will be retained indefinitely by the Radiation Safety Program. Individual exposure histories may be obtained from Radiation Safety by submitting a written request. Radiation Safety will provide an annual exposure history to each worker within the first six months of the year following the exposure.

Additionally, federal regulations (10 CFR 20.2104) require that UWM must obtain all available radiation exposure records from your previous employers or institutions where you used radioactive materials. This information is used to evaluate both your current (short-term) and long-term exposure to ionizing radiation. The Radiation Safety Program will request information regarding your previous employers or schools at the time you apply for a dosimeter. If information for the current year is not available a "maximum" dose of 1.25 rem per quarter will be assigned and the allowable dose limit for the year will be reduced by that total.

Dosimeters provide legal documentation of an individual's exposure to radiation. Dosimeters issued at UWM are for use involving UWM activities only. All individuals issued a dosimeter to monitor their radiation exposure should follow a few simple rules to ensure that the dosimeter accurately records their radiation exposure.

• Wear only your assigned dosimeter; never wear another worker's badge.
• Wear your ring badge beneath your gloves with the label on the palm side of the hand that handles the radiation source and thus has the greatest potential for exposure.
• Do not store your badge near radiation sources or heat sources.
• If you suspect contamination on your badge, return it immediately to Radiation Safety; you will be given a new, uncontaminated badge.
• Never intentionally expose your badge to any radiation.
• Do not wear your badge when receiving medical radiation exposure (e.g., x-rays, tests, nuclear medicine procedures, etc.)
• Return your badge to Radiation Safety at the end of the monitoring period. The vendor charges for lost badges and Radiation Safety passes this fee on to the laboratory.

When required by 10 CFR 20.1502, each licensee must take suitable and timely measurements of quantities of radionuclides in the body, concentrations of radioactive materials in the air in the work area, or any combination of such measurements as may be necessary for detection and assessment of individual intakes of radioactive material. Specifically, any individual who may receive, in a year, an intake in excess of 10% of the applicable Annual Limits on Intake (ALI) in Table 1, Columns 1 and 2, of Appendix B, 10 CFR Part 20, must be monitored for internal exposure. ALI values are based on inhaled or ingested activity that would expose an individual to occupational limits (ICRP 1978). ALI values are measured using bioassay procedures such as urinalysis or thyroid scans. Radioisotope types (alpha, beta or gamma), the potential for exposure, and the amounts of radioactivity received by a laboratory are determinants for scheduling bioassays. For example, workers in a lab receiving a large activity of 51Cr may not be susceptible to an internal exposure hazard while workers in a lab receiving even small quantities of 125I may need bioassays.

For radioisotopes other than iodine, routine bioassay measurements shall be required at any time the sum of the total activity of the radionuclide manipulated by the worker in an unsealed form is equal to or exceeds 200 times the ALI for that nuclide. Bioassay monitoring requirements for radioiodine compounds are discussed in Section 14.