How to Correctly Wear a Dosimeter
Wearing a dosimeter correctly – and every time – is a vital part of working with ionizing radiation. Regular exposure to ionizing radiation can be hazardous without proper dose tracking and monitoring. Medical device operators need to be proactive and diligent about wearing their dosimeter correctly.
Based on the type of equipment and shielding being used, there are specific locations on the body where a dosimeter is worn. If you’re not sure where to wear yours, check with your Radiation Safety Officer!
Chest Dosimeter
This is the most common wear location for a dosimeter.
- Without apron: midway on the torso between shoulders and waist on either side of the chest
- With apron: outside the lead apron at shoulder level on either side of the chest
Collar Dosimeter
Collar dosimeters are typically worn by personnel working in occupations utilizing high levels of radiation.
- Without apron: on either side of a collar facing the radiation source
- With apron: outside the apron at collar level facing the radiation source
Collar or Chest & Waist Dosimeters
Some radiation environments require two dosimeters. In that situation, one is worn at the collar and one at the waist.
- With apron:
- Collar: outside the apron at collar level facing the radiation source
- Chest: outside the lead apron at shoulder level on either side of the chest
- Waist: on either side of the waist, under the apron
Fetal Dosimeter
If an employee is pregnant, they should wear their regular chest or collar dosimeter as normal PLUS a fetal dosimeter. It is important to note that, even if the chest/collar dosimeter is exchanged quarterly, the fetal dosimeter must be exchanged monthly.
- Without apron
- Fetal: centered at waist level
- With apron:
- Fetal: centered on the waist, under the apron
Ring Dosimeter
The LANDAUER Saturn® Ring can be worn for dose monitoring when providing radiation services on the extremities.
- On one hand or both hands
- Label facing the radiation source
- Under gloves, if worn
Note: Ring dosimeters are labeled for either right or left-hand use. Be sure to check before wearing!
Why Does Correct Dosimeter Placement Matter?
The correct placement of dosimeters is essential for the accurate measurement of radiation exposure, personal safety, regulatory compliance, data integrity, and reliable research outcomes. Correct dosimeter placement provides radiation workers and management with accurate information about radiation exposure levels, allowing for appropriate safety measures to be implemented and potential risks to be minimized.
Regulatory requirements in your state may dictate the types and placement of dosimeters.
To comply with 10 CFR 20.1201(c), the Nuclear Regulatory Commission states that “The assigned deep-dose equivalent must be for the part of the body receiving the highest exposure.”
Therefore, the dosimeter monitoring the whole body dose, eye dose, skin dose, or extremity dose shall be placed near the location expected to receive the highest dose during the year. When the whole body is exposed fairly uniformly, the individual monitoring device is typically worn on the front of the upper torso. When handling radioactive materials, the Ring dosimeter is worn under protective gloves on both hands or the hand closest to the radiation source.
NOTE: State regulations typically echo the above placement requirements. However, your Radiation Safety Officer and/or the dosimetry program manager will advise you concerning dosimeter placement and order dosimeters based on the radiation sources in use.
Accurate Measurement
Correct placement of dosimeters ensures that they are positioned in the most appropriate location to accurately measure the radiation dose. Improper placement or improper wearing of dosimeters (e.g., wearing a Collar dosimeter under the lead apron when both a Collar dosimeter and Whole Body or Waist dosimeter are issued) can lead to inaccurate readings, which can underestimate or overestimate the radiation dose. The decision to place the Whole Body dosimeter at the waist or chest should be based on the location expected to receive the highest dose.
Personal Safety
Dosimeters are typically used, and may be required, in occupational settings where workers are likely to be exposed to ionizing radiation. Wearing them correctly will result in the accurate measurement of radiation dose. This information is crucial for personal safety, as it allows individuals to modify their workplace practices to reduce radiation dose. For those managing personnel safety, it allows them to modify policies and procedures to affect those similarly exposed. Inadequate protection measures or unnecessary concerns can result if dosimeters are not worn correctly.
Regulatory Compliance
Federal and state regulations and guidelines are in place to limit radiation exposure and ensure the safety of workers. These regulations often require the use of dosimeters and adherence to specific dosimetry practices. Wearing dosimeters correctly demonstrates regulatory compliance and helps your organization, especially during inspections, meet its legal obligations.
Data Integrity
When dosimeters are worn correctly and consistently, it results in reliable and consistent dose data, which is essential for monitoring radiation exposure trends over time. Monitoring exposure trends is necessary to ensure that radiation exposures are maintained as low as is reasonably achievable (ALARA).
Accurate dosimetry data allows organizations to assess potential risks, identify areas for improvement in radiation protection practices, and make informed decisions regarding radiation safety measures. Trend graphs are typically depicted by dosimeter type (e.g., Whole Body, Collar, Ring) and by department (e.g., Radiology, Orthopedics, Surgery, Nuclear Medicine, etc.). An example trend graph is pictured below.
Research and Analysis
Dosimeters can also be used in research studies or epidemiological investigations to gather data on radiation exposure in specific populations or locations. Wearing dosimeters correctly ensures that the collected data is reliable and the analysis of the data is valid. Reliable and valid dose measurements provide researchers with valuable insights into radiation-related risks and assist them in developing appropriate safety guidelines.
If you aren’t sure where your dosimeter should be worn, please contact us for assistance.
Frank has accumulated extensive expertise in radiation safety policies and procedures by working as a Radiologic Technologist, Army Radiation Safety Officer, instructor, and inspector. Frank's 35+ years of experience include managing radiation safety programs, conducting radiation surveys/inspections, and implementing safety measures to minimize radiation exposure. Frank worked as a radiographer before obtaining a degree in Radiologic Sciences and a commission in the US Army as a Nuclear Medical Science Officer, retiring as a Lieutenant Colonel.