ALARA
Radiation workers on campus are expected to follow the As Low As Reasonably Achievable (ALARA) principle during work. Simply put, this is an ideal that recognizes the risks of radiation, and takes all feasible measures to protect against any unnecessary exposures. In the work place, there are three primary methods used to implement this practice:
- Time – Decrease the amount of time spent near sources of radiation, whether that be a material or radiation generating machine;
- Distance – Increase the distance between yourself and the source of radiation. This reduces the radiation field your body is exposed to, and decreases the dose you receive;
- Shielding – When appropriate, use shielding to block the radiation from reaching you.
PPE
Personal Protective Equipment (PPE) is used to minimize the potential for any contamination of radioactive material, which can lead to external and internal exposure hazards to yourself as well as others around you. In radiochemical laboratories, lab coats/gloves, safety glasses, long pants, and closed toed shoes are required. Additional items of PPE may be required in special/non-routine work settings, and should be discussed with a Health Physicist in EHS.
Dosimetry Monitoring/Bioassays
The State of Utah Division of Waste Management and Radiation Control (UDWMRC) imposes limits for occupational radiation workers on the amount of radiation they may receive in a calendar year (shown below). For workers expected to receive up to 10% of these limits, individual monitoring is required. The University utilizes a number of personnel monitors across campus, including Thermoluminescent Dosimeters, Optically Stimulated Luminescent Dosimeters, Electronic Personal Dosimeters, etc. to monitor exposure levels of workers and areas of the general public.
Location |
Annual Limit |
Whole Body |
5 rem |
Extremity |
50 rem |
Individual Organ |
50 rem |
Lens of the Eye |
15 rem |
For workers wishing to declare a pregnancy, an additional limit is imposed by the UDWMRC on the dose to the fetus through the duration of gestation. This limit is set at 0.5 rem, and if the pregnancy is declared, an additional dosimeter will be issued to monitor this dose. For any questions on the declaration process, risks, or monitoring, please contact EHS.
Bioassays may be used in the event of an expected intake of radioactive material into the body through an inhalation, ingestion, or entry through skin wounds/absorption. In-vivo or in-vitro measurements can be performed depending on the isotope(s) of interest. In-vivo measurements are often done for thyroid counting, and can identify an uptake of radioiodine, whereas in-vitro measurements are generally done through urine collections to measure the concentration of material present. Depending on the type of material you are working with, you may be asked to perform routine bioassays at a predetermined frequency, as well as unscheduled bioassays in the event of a contamination event or suspected intake.
Questions on best practices, monitoring procedures, limits, etc. may be directed to Environmental Health and Safety’s Radiation Safety at (801) 581-6590 or to questions@ehs.utah.edu.
Resources
UDWMRC R313-15 – Standards for Protection
https://www.mirion.com/about/medical/dosimetry-services