An accredited dose monitoring program is usually required to demonstrate compliance with state and/or federal regulations. Dosimetry Badge’s OSL Dosimetry Service is designed to provide valuable dose information for a facility’s personnel monitoring program. To obtain accurate and meaningful data from our service, it is important to observe the following:
- The dosimeter should always be worn when there is a potential for occupational exposure to ionizing radiation.
- Dosimeters not in use should be stored in an area without radiation to prevent exposure that is not work-related.
- Remember to return the control dosimeter with the rest of the dosimeters for the same wear period. The control is used to monitor background radiation and any dose received by the dosimeters in transit. Any dose recorded by the control is subtracted from the other dosimeters, so the control should not be used for any other purpose.
- Dosimeters should be worn at the body location indicated on the dosimeter label and should never be cut, covered, blocked, or written on. When a protective garment is worn, the dosimeter should be worn at the collar and outside the protective garment.
- Care should be taken to use only the dosimeter marked with the proper individual’s identification. If it is necessary to use an unassigned dosimeter or to reassign a dosimeter, please provide the necessary information and call our office at (321) 234 – 4141 or email info@dosimetrybadge.com.
- Replacement dosimeters for the next monitoring period will be sent before the beginning of the next monitoring period. Begin wearing the dosimeters on the date printed on the dosimeter label. Return worn dosimeters from the previous monitoring period, along with the control, in the pre-addressed mailing envelope or box provided. PLEASE REMEMBER TO APPLY APPROPRIATE POSTAGE TO AVOID SHIPPING DELAYS.
- To avoid unreturned dosimeter charges, return dosimeters promptly after each wear period.
- For dosimeters with a detachable clip, please remember to detach the clip strap during the dosimeter change out and transfer it to your replacement dosimeter. Return only the dosimeter (less the strap) worn in the previous monitoring period for processing.
Control dosimeters are used to measure exposure from non-occupational sources such as cosmic radiation, irradiation that may occur during badge shipment and natural radioactive material found in building materials and soil.
A complimentary control dosimeter is provided for each type of whole-body badge (OSL, neutron, extremity) for each account. If all of your group badges are stored in the same area, one control for each whole badge type and wear period will suffice. However, if your account is split into groups, and badges are re-shipped to other locations, it is appropriate to have control dosimeters accompany those badges. Not having control dosimeters (for dosimeters that are re-shipped) may result in doses that do not represent the actual dose received by the individual(s) being monitored. For this purpose, additional control dosimeters may be purchased.
Control dosimeters should be stored in a location away from the radiation at your facility. Break rooms or reception areas are good examples of areas that are typically appropriate. Never store the control dosimeter in a lead box or safe. Never issue a control dosimeter to an individual or use one as an area monitor.
The control dosimeter should be returned along with the dosimeters for the same wear period. Unreturned badges are subject to a fee of $20/badge.
Proper use of the control badge is crucial for the accurate analysis of your personnel dosimeters and for assigning accurate dose results.
Below are the answers to frequently asked questions regarding control dosimeters.
What does it mean when my control dosimeter records a dose?
It is normal to receive dose on the control dosimeter. It represents the background and transit dose received on the badge from the time it left our facility and until it was returned. The dose recorded on a control dosimeter is usually low, and relatively constant from report to report. A control dosimeter will usually record a small dose (5 – 20 mrem per month).
What is the role of the measurement recorded on the control dosimeter in calculating occupational dose?
The dose recorded by a control dosimeter is a measurement of the background dose received during shipment and storage. To obtain the occupational dose, the measurement recorded on the control dosimeter is subtracted from the doses recorded on the other badges in the group. The difference is the occupational dose.
What happens if I return my badges without the control dosimeter?
For badges returned without a control, the reported dose will include background and transit dose along with the occupational dose received by the individuals. You can mail any unreturned badges in a padded envelope to:
If sent via USPS:
Mirion Technologies (GDS), Inc.
PO BOX 801
Oak Ridge, TN 37830
If sent via FedEx/UPS:
Mirion Technologies (GDS), Inc.
104 Union Valley Rd
Oak Ridge, TN 37830
We strongly suggest purchasing tracking to ensure your shipment is received.
Upon receipt, I split up my badge shipment and send them to different facilities. What do I need to do regarding control dosimeters for these badges?
In these cases, it is suggested you purchase an additional control dosimeter for each group of badges that will be sent elsewhere and include a control dosimeter with each group of badges when they are shipped.
Personnel monitoring of occupational exposure to radiation is required by regulations when the employees may be receiving greater than ten percent of any applicable radiation dose limit. Personnel monitoring normally means the issuing of a dosimeter to an employee to track the dose received. It is often difficult to ensure that an employee has not exceeded the ten percent level under any foreseeable circumstances, therefore, dosimeters are widely used. OSL dosimeters are a device commonly used for monitoring exposure. This device, if worn and processed properly, can provide an accurate assessment of the dose received from a variety of radiation sources.
Annual occupational dose limits (reference 10 CFR 20.1201, 20.1207, 20.1208) are established for different parts of the body as follows:
(All doses are in units of millirems (mrem) of dose that may be received in a calendar year)
| Whole Body (Deep Dose Equivalent or DDE) | 5,000 mrem |
| Lens of the Eye (Eye Dose Equivalent or EDE) | 15,000 mrem |
| Skin (Shallow Dose Equivalent or SDE) | 50,000 mrem |
| Extremities (Shallow Dose Equivalent or SDE) | 50,000 mrem |
| Fetus of a Declared Pregnant Radiation Worker | 500 mrem (for the entire pregnancy) |
| Dose Limits for Minors | 10% of adults limits |
The “whole body” refers to the head and trunk of the body; including the arms above the elbows, the legs above the knees, and the reproductive organs. The “skin” refers to the skin anywhere on the body. The “extremities” refer to the arms below the elbow and legs below the knees. (Reference 10 CFR 20.1003)
Dosimetry reports provided by Dosimetry Badge provide the doses in units of millirem. When the dosimeter is worn on the body, a deep, shallow, and eye dose will be reported.
| Dosage | Tissue Depth | Column on dosage report |
|---|---|---|
| Deep | 1.0 cm | 10 & 11 |
| Shallow | 0.007 cm | 13 |
| Lens of the Eye | 0.3 cm | 12 |
Extremity dose is monitored using ring or wrist dosimeters.
Organizations using radiation sources are also required to control those sources so that no member of the public receives more than 100 millirem per year. Also, radiation doses in unrestricted areas may not exceed 2 mrem in any one hour. Dosimeters can be helpful in demonstrating compliance with these limits. Dosimeters used as “area monitors” are posted at fixed locations to monitor local area doses. Environmental dosimeters are sealed in weather-resistant packaging so they can be posted outside. (Reference 10 CFR 20. 1302) Occupational dose does not include the dose from natural background, medical or dental diagnosis, or medical therapy. For comparison, NCRP Report 93, 1987 shows that the average annual exposure to individuals to be 360 mrem from natural and manmade sources, including routine medical procedures. An individual will typically receive approximately 5 mrem of radiation exposure on a coast-to-coast airline flight, 8 to 20 mrem from a chest x-ray, 10 mrem from a dental x-ray, or 22 mrem from a cervical spine x-ray.
For information on regulatory requirements, refer to the Nuclear Regulatory Commission regulations in Title 10 of the Code of Federal Regulations, Part 20, of the radiation protection regulations of your state.