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Radiation Safety

Dosimetry Program (badges)

Dosimeters are used to monitor your occupational dose from radioactive material or radiation-producing equipment. The University's Radiation Safety Program strives, to the extent practicable, to maintain doses at levels that are As Low As (is) Reasonably Achievable (ALARA). Most individuals working with X-ray producing equipment in the hospital will be issued a dosimeter. For those individuals working in the research laboratory setting, dosimeters will be issued based on the nuclide and total activity that will be used.

Guidelines for Issuance of Dosimeters

The following table will be used as guidance to determine if an individual should be issued a dosimeter to monitor external dose. The guidelines are generally based on total activity used in 1 month.

Radioisotope(s) Activity (mCi) Type of Monitoring
C-14, H-3, P-33 & S-35 any amount none required
P-32 < 6 mCi none required
>= 6 mCi
< 30 mCi		 ring dosimeter
>= 30 mCi ring dosimeter & whole body dosimeter
Ca-45 < 50 mCi none required
>= 50 mCi ring dosimeter
Low Energy Gamma Ray Emitters
< 200 keV (e.g. I-123, I-125, Tc-99m, Tl-201)		 < 50 mCi none required
>= 50 mCi ring dosimeter & whole body dosimeter
High Energy Gamma Ray Emitters
>= 200 keV (e.g. Cr-51, I-131, Co-60, Cs-137) 		< 2 mCi none required
>= 2 mCi
< 5 mCi		 ring dosimeter
>= 5 mCi ring dosimeter & whole body dosimeter

 

Before a dosimeter can be issued, the applicant must:
  1. complete, and submit to EHS, a Dosimeter Application
  2. complete online radiation safety training (see Required Radiation Safety Training for Issuance of Radiation Dosimeter below);
  3. be fully informed about NRC Regulatory Guide 8.13 - Instructions Concerning Prenatal Radiation Exposure; and
  4. understand prudent practices for wearing a dosimeter (see Instructions for Use of Dosimeter below).

For dosimeter wearers who become pregnant, the Declaration of Pregnancy form provides the University (licensee) with information to "ensure that the dose equivalent to the embryo/fetus during the entire pregnancy, due to the occupational exposure of a declared pregnant woman, does not exceed 0.5 rem (5 mSv)". In addition, there is a University wide policy on the radiation worker and pregnancy which can be viewed here.

Finally, it is important to return your dosimeter each month or quarter for timely processing by Landauer. Environmental Health & Safety will charge your department for late or unreturned dosimeters. If you have additional questions, call EHS at 434-982-4911 or the UVa Dosimetrist at 434-243-3010.

Required Radiation Safety Training for Issuance of Radiation Dosimeter

 

Applicants with NO Previous Radiation Safety Training

Individuals who are issued dosimeters by EHS must first complete the appropriate online Radiation Safety Guide Lecture.

Applicants with Previous Radiation Safety Training

If you have already completed one of the following radiation safety training courses below and have documentation of such, you do not need to complete either of the above mentioned Radiation Safety Guide Lectures. Please document the course name and date of completion on the dosimeter application form. The UVa Research Compliance Database will be used to verify documentation of training completed by dosimeter applicants.

Instructions for Use of Dosimeter

Environmental Health & Safety provides individual monitoring devices to any individual who is likely to receive, in one year, from sources external to the body, a dose in excess of 10 percent of the limits listed below or who enters a high or very high radiation area. The dosimeters issued to University personnel are effective for measuring dose resulting from exposure to high energy betas, x and gamma rays (the radiation-sensitive part of the dosimeter consists of a thin layer of aluminum oxide).

Total Effective Dose Equivalent (whole body) - 5 rem per year

Lens of the eye - 15 rem per year

Skin or any extremity - 50 rem per year

The following rules should be observed by all dosimeter wearers:

  1. The dosimeter is non-transferable. All exposures to the dosimeter are added to an individual's account as indicated by the identification code.
  2. The dosimeter should not be worn outside of the work environment. It is intended to monitor your exposure to radiation at work only. They are to be worn at all times when you are working with radioactive material or radiation producing equipment.
  3. To report a lost or damaged dosimeter, contact Diane Russell at EHS immediately (434-243-3010 or drr2c@virginia.edu) so that a temporary replacement dosimeter can be issued. Return your dosimeter at the end of each wear period to the designated person in your department, and pick up your new dosimeter. An unreturned dosimeter provides no information. Your department will be charged for late or unreturned badges.
  4. The dosimeter indicates only the exposure at the position at which it is worn, and for that reason, should be worn on the part of the body most likely to receive the highest exposure. It is important that the badges are worn properly at all times. If they are worn improperly (or not worn when required), the dose recorded will not be an accurate record of the dose you actually received.

If it is likely that the body may be exposed fairly uniformly, a dosimeter should be worn on the trunk of the body since the gonads and most of the blood-forming organs that constitute the principal critical organs for whole-body exposure are located in the trunk. Suitable locations are the breast pockets, lapels, and the belt. Dosimeters should be worn so that they are visible at all times, except when they are intentionally covered by a shield. This prevents unintentional shielding by clothing or by items in a pocket. In situations where the trunk of the body is shielded but the head region is not, the dosimeter should be worn on the collar to monitor exposure to the thyroid and lens of the eyes. A whole body dosimeter should not be used to monitor radiation exposure to extremities. A ring badge will be issued to you by for this purpose if necessary.

Extremity Dosimeters - In non-uniform radiation fields where an extremity may receive a significant exposure, extremity dosimeters should be worn as near to the point of maximum exposure as possible (e.g. finger or wrist) and should not be shielded by the extremity. Ring badges may be issued for one or both hands. Ring badges are marked with right and left hand indicators. Do not interchange them. When protective gloves are being worn while handling radioactive material, the ring badge(s) should always be worn under the gloves to prevent contamination of the badge.

NOTE: The dosimeter is not an indication of authorization to use radioactive material. The authorization to use radioactive material is an independent process that is initiated by the completion of applicable training and a General or Qualified User application.

Radiation Dosimetry Program
Environmental Health & Safety
Contact: Diane Russell (drr2c@virginia.edu)
Phone: 434-243-3010, Fax: 434-982-4921