What You Need to Know About Biodosimetry:
- What is the difference between radiation biodosimetry and radiation bioassay?
- Why is biodosimetry needed?
- What is physical dosimetry?
- What is dose reconstruction?
- What clinical clues help provide estimates of radiation dose?
- How do you use the REMM Dose Estimator for Exposure?
- What should you do when there are conflicting dose estimates?
- Use of biodosimetry in long term surveillance studies after radiation exposure
- See REMM Biodosimetry Reference List
What is the difference between radiation biodosimetry and radiation bioassay?
- Radiation biodosimetry: definition
- Radiation bioassays measure
- Whether internal contamination has occurred
- What isotopes are detected
- How much internal contamination has occurred
- Bioassays measure radioactivity directly in biological specimens
- Examples: blood, urine, feces, sweat
- Bioassay results can be used to
- Estimate radiation dose (to the whole body or specific organs) expected to be accumulated in the future over a specified period of time
- Measure the ongoing effectiveness of treatments for internal contamination
- Examples of units of measure for radiation exposure from internal contamination
Why is biodosimetry needed?
- Since most victims of large mass casualty radiation emergencies would not be wearing personal dosimeters, other methods must be used to estimate the dose they received
- Biodosimetry helps to
- Predict the time course and severity of the phases of the Acute Radiation Syndrome
- Facilitate short term triage, including where the patient should be treated
- Suggest countermeasure that will be needed to treat ARS, especially acutely
- Assess the risk of long term consequences from radiation exposure.
What is physical dosimetry?
- Actual measurements of radiation exposure made by detection equipment including
- Personal dosimeters
- Worn on outside of clothing by workers in an actual or potential radiation environment to track exposure
- Measure the radiation dose received by the device
- Knowing the location of the device on the wearer's person helps interpret the significance of the dosimetry reading for the wearer
- Many different kinds of devices are available
- Survey meters
- Measure radiation levels in the environment
- Can be used to estimate dose that may have been received by workers or victims in the area assessed by the meter
- Different kinds of devices are used for specific tasks.
- Personal dosimeters
What is dose reconstruction?
- Matching a victim's geographic location(s) during an incident to radiation exposure maps for the incident created from
- Actual measurements in the field and/or
- Computer modeling data
- Computerized 2D or 3D models of radiation levels in the environment
- Can be generated from data acquired in an actual incident or from theoretical models of events, including in specific venues
- Can be overlain on maps of affected areas to track changes in radiation levels over time.
- Detailed mapping of radiation levels can help provide
- Data for protective action recommendations
- Dose estimates for individuals or groups of victims in specific locations
- See details about Dose Reconstruction
- See illustration of radiation protection factors that would affect dose reconstruction: Time Distance, Shielding
- See Time Sequenced Size of Dangerous Fallout Zone and 0.01 R/Hour Boundary after a Hypothetical 10kT Nuclear Detonation at Ground Level
What clinical clues help provide estimates of radiation dose?
- Evaluate subsyndrome severity scores for the 4 ARS subsyndromes
- A higher severity score for any of the subsyndromes is generally correlated with higher absorbed dose
- A targeted physical exam is also useful.
How do you use the REMM Dose Estimator for Exposure?
- The REMM Dose Estimator for Exposure provides information that can help responders assess, triage, and manage victims.
- Providers should
- Collect and consider all the physical, clinical and laboratory information and observe how data change over time.
- Correlate information from victim's history and physical, including signs and symptoms, with specific radiation effects expected at various doses.
- Use physical dosimetry information if and when it is available.
- Was the victim wearing a personal radiation dosimeter? This would be unlikely in a terrorist event but likely for an occupational radiation worker.
- Do incident managers have information about radiation dose in the geographic area where the victim was at the time of the incident?
- Register the victim in the incident data base using the best biodosimetry and clinical information available.
What should you do when there are conflicting dose estimates?
- Initially, use the highest whole body dose estimate to plan treatment.
- Modify the treatment plan as additional clinical and laboratory data are obtained over time.
Use of biodosimetry in long term surveillance studies after radiation exposure
- Simon SL, Bouville A, Kleinerman R. Current use and future needs of biodosimetry in studies of long-term health risk following radiation exposure. Health Phys 2010 Feb; 98(2): 109-17. [PubMed Citation]
See Biodosimetry Reference List