“Health Physics Archeology” An Overview of Dose Reconstruction Radiation Studies Branch National Center for Environmental Health Centers for Disease Control and Prevention August, 2004 Outline Overview of dose reconstruction principles Examples of CDC dose reconstruction projects
An Overview of
Radiation Studies Branch
National Center for Environmental Health
Centers for Disease Control and Prevention
Dose reconstruction is a comprehensive analysis of the exposure received by individuals in the vicinity of facilities that release contaminants to the environment (i.e., real doses to real people).
No matter how good the science, if the public does not accept the results, we fail.
1. Retrieval and assessment of data
2. Development of initial source term and pathway analysis
3. Calculation of screening doses and exposures
4. Development of methods for assessing environmental doses
5. Calculation of environmental exposures, doses, and risks
If risk = health effect, conservative
estimates of dose will be nonconservative
Scoping Study– A preliminary analysis used to determine whether a comprehensive dose reconstruction study is appropriate as the basis for a continued comprehensive epidemiological study
Conditions of the Release:
Conditions of the Environment:
Conditions of the Population:
Based on the outcome of the scoping study, the project may come to halt or proceed to a full dose reconstruction.
Ways to determine and estimate the source term:
Redundant analyses are desirable.
Data could be missing because of:
Models must be developed to extrapolate missing data.
Data may be recorded from releases that are:
Quantification of the extent of uncertainty in the model from all conceivable sources.
Involves propagation of uncertainty in the input parameters and the methodology.
Often expressed as a ‘confidence interval.’
Evaluation of the extent to which changes in values of independent variables (or model parameters) of an equation (or mathematical model) bring about changes in the results.
Allows identification of the parameters that dominate the overall uncertainty in the model.
After completion of dose reconstruction, the information can be used as input in an epidemiological study.
The study of disease in human populations
Questions used to determine objectives:
- one group with the health effect to
- one group without the health effect.
- exposed group
- not exposed group.
Many radiation-related epidemiological studies are cohort studies.
In order to determine the feasibility of an epidemiological study, the statistical power of the study must be high enough to identify an increased risk for health effects if one exists.
Probability that the study can distinguish between a true exposure-to-disease relation and a coincidence
The variables for statistical power are:
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