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Oregon State University

Dosimetry

 

External Exposure Monitoring

Internal Exposure Monitoring
Proper Badge Wear
Badge Care

Badge exchange
Badge processing
Lost or damaged badges
Fetal Monitoring
Exposure Records
Annual Exposure reports

External Exposure Monitoring

OSU employees who work with radiation sources or radioactive materials may be required to wear one or more personnel dosimeters (badges).  Dosimeters are devices used to measure occupational exposure to radiation.  Under OSU policy, dosimeters are issued under the potential exposure guidelines noted in the Radiation Safety Manual section 6.8.1.  In general, people who use high-energy beta emitters (e.g. 32P), gamma emitters, or x-ray machines need to wear dosimeters. The type of potential exposure also determines the training that must be completed before dosimeters can be issued. The need for badges is usually determined by the Radiation Safety Officer at the time of the initial radiation safety training. If you have a question about whether or not you need a dosimeter, please contact Radiation Safety at (541) 737-72227 or by email.

Proper Badge Wear

Body badges should be worn on the part of the body between your neck and waist most likely to be exposed to the source of radiation. Wear the badge so that the name tag faces toward the source of radiation. If you wear a lead apron, wear the badge at the collar level on the outside of the apron.  If you wear a lead apron and two badges are issued, wear one badge on the collar and one under the lead apron.

Wear your ring badge so that the label is facing out from the side of the hand most likely to receive an exposure. In most cases, this means that the label will face out from the palm side of your hand. Rings are hand-specific. The inner label will contain either the initials URE (right hand) or ULE (left hand). Ring badges should be worn under gloves. Be careful not to dispose of the ring in the trash when you remove your gloves.

Badge Care

Do not remove the badges from your immediate work area.  Do not take badges home, or wear them for non-work exposures such as a dentist’s office. 

Do not wear someone else’s badge or loan your badge to another person.  It is a legal requirement that doses be tracked for the worker to whom the dosimeter is assigned.

Store badges in a safe location when not in use, away from sun, heat, sources of radiation or potential damage.  Protect badges from impact, puncture, or compression. 

Do not wear the dosimeter if you have received or will be receiving medical treatments involving radiopharmaceuticals.  Notify your Program Director and Radiation Safety.

Badge exchange

Dosimeters are exchanged quarterly for most users, and in some locations, monthly. Each user is responsible for seeing that a current badge is in use and for exchanging the badges on schedule.  Delay in processing may invalidate the results (badges expire after a given time), and increases the chance of badges being lost or damaged. 

Each program requiring dosimeters has a person designated as a Badge Coordinator, often the Program Director or Lab Contact. This person orders dosimeters, distributes them to staff, collects them at the end of the month for processing, and receives dosimetry reports for program records.

The badge coordinator for each location will receive new badges a few days before the new calendar quarter (or month for some locations).  Make sure that your old badges are returned to the coordinator by the first working day of each new wear period. Badges should never be sent to Radiation Safety by campus or USPS mail.  Radiation Safety personnel will collect the badges from specific exchange locations, usually on the third working day of the month.  Late badges will need to be hand-delivered to Radiation Safety.

When terminating your employment or study at OSU, be sure to return your badges to the badge coordinator for your location to remain in regulatory compliance.

Badge processing

After Radiation Safety has collected the used badges, the badges are sent out to the badge service company for processing. Radiation Safety receives the dose reports several weeks after the vendor receives the badges and reviews the dose reports.  

OSU has established investigational levels at 1% of the federal and state dose limits. If a dose is reported that exceeds the investigational level, Radiation Safety will contact you to determine whether the reported dose is likely to be accurate and to investigate the causes of the dose in an effort to minimize dose in the future. The exposure will be reported to the user and the Program Director using form RSC167-ADRI (Abnormal Dose Reading Investigation). Any measurable exposure that does not reach OSU investigational levels will be reported to the user and the user’s program director with form RSC167B (Report of Dosimeter Reading). The user should still self-investigate to ensure exposures are As Low As Reasonably Achievable (ALARA).

Lost or damaged badges

If you lose your badge, call Radiation Safety immediately for a replacement.  You can generally be provided with a replacement badge within 24 hours of your request. Do not borrow anyone else's badge. Do not work without a badge if you have been issued one.

If a vendor is unable to process a damaged badge, or if a badge is lost or expired, an estimate of exposure must be submitted to Radiation Safety. The exposure estimate form (RSC116)  must be completed and signed by the badge user or the Program Director, indicating whether or not the exposure during the indicated wear period was typical.  The exposure estimate is a regulatory requirement, and authorization may be revoked for failure to submit the estimate.

Fetal Monitoring

Pregnant radiation workers have the option to reduce the occupational doses to the fetus by submitting a declaration of pregnancy.  This declaration is voluntary. A gestational dose limit of .5 rem applies to declared pregnant workers.  Declared pregnant workers will be on a monthly badge exchange for the fetus.   Separate badges are issued for the pregnant woman and the fetus.  See section 5.5 of the Radiation Safety Manual and US NRC Regulatory Guide 8.13 for more information on dose to embryo or fetus.

Internal Monitoring

Requirements for internal monitoring are found in section 6.9 of the Radiation Safety Manual. Contact the Radiation Safety Department for information on bioassays.

Exposure Records

Radiation Safety maintains all exposure records indefinitely.  Your radiation exposure history will be provided to you or your subsequent employers on request.  A signed release statement must be submitted with the history request.  Mail exposure requests to:

Radiation Safety Officer
Oregon State University
100 Oak Creek Building
Corvallis, OR 97331-7404 

Annual Exposure reports

During the spring of each year, the badge vendor generates annual reports equivalent to NRC Form 5 for each individual monitored during the previous calendar year if the individual’s occupational dose exceeds 100 mrem deep dose equivalent. Individuals monitored during the calendar who did not meet the criteria for receiving a Form 5 will be notified of this by email and provided with instructions for registering for online access to their exposure history.  Upon canceling dosimetry, users may also request a termination exposure report.

A summary of individual dosimetry results is also sent to the Program Director responsible for supervising the work requiring dosimetry.