Data Used in Dose Reconstructions

Certain information is needed to estimate an individual’s exposure to radiation. Below are the types of data NIOSH uses to complete dose reconstructions. 

Demographic Information

• Gender
• Date of birth
• Date of death 

Employment History

• Job title, by year
• Work locations: site names, building numbers, and technical areas
• Duration of relevant employment or tasks (start and end dates) 

Medical Information

• Date of cancer diagnosis
• Age at time of diagnosis
• Description of the cancer
• Type of cancer: primary (where it began) or secondary metastatic (where it spread) 

Exposure Monitoring Data

The quantities and types of monitoring data available for a dose reconstruction can vary widely. Below is the general hierarchy of data sources used for dose reconstruction under the Act/EEOICPA.

NIOSH uses data sources in this order:

1. Personal monitoring data
2. Co-worker monitoring data
3. Area monitoring
4. Work area (source term) data
5. Surrogate data

Personal Monitoring Data

In general, personal monitoring data are considered to be the most representative of the worker’s individual exposure situation. NIOSH uses personal exposure information to complete dose reconstructions whenever possible.

Listed below are examples of sources for this type of information:

• Film badges (worn by the worker to monitor external radiation exposure)
• X-rays (required as a condition of employment)
• Incident reports (describe a worker’s potential radiation exposure during particular events)
• In-vivo and in-vitro analysis (measurement of radioactive materials inside the body)
• Breathing zone air samples (for detecting radioactivity in the air near the worker’s nose and mouth)

We understand the claimant may also have information that can help us estimate radiation dose. Each claimant can speak with us about the worker’s employment history (see Work History Phone Calls).

Co-worker Monitoring Data

If personal monitoring data are unavailable or insufficient, then co-worker monitoring data are the next best source of information. In this case, data on similar workers’ exposure is used for the dose reconstruction. Co-workers are workers at a site (potentially grouped by work location, job description, or other category) whose radiation exposures are considered to be similar to those of workers for whom there is not enough monitoring data. Co-worker models can be used to reconstruct doses for unmonitored workers if the data are from the highest exposure group or a representative sampling of the exposed workers.

Co-worker information may be used for dose reconstruction if the:

• Worker was unmonitored and potentially exposed
• Worker was monitored but
  • the data were lost or destroyed
  • the monitoring methods were not reliable
• Data are insufficient

Area Monitoring Data

The next source of information that can be used in a reconstruction is area monitoring, such as:

• Work area air sampling (provides information on airborne radioactivity) found in a particular work area)
• Breathing zone air sampling (provides information on airborne radioactivity found in the air near the worker’s nose and mouth)
• Surface contamination surveys (provides information on radioactive material found on surfaces such as floors, desks, and equipment)

Work Area (Source Term) and Processing Data

If the area monitoring data are lacking, it may be possible to reconstruct an exposure with source term information on the particular operation or process. Such data includes:

• Type, quantity, and composition of the radioactive substances handled in the workplace (the source term)
• Level of containment (likelihood of it getting out)
• Source strength, distance from source, duration of exposure, and shielding (protection from the radiation source)

Surrogate Data

When facility-specific information is inadequate for dose reconstruction, then it may be possible to use surrogate data. This is information from a facility that is similar to the worker’s in any of the following ways:

• Processes (for example, data from an operation that involves grinding, welding, or cutting—with a high potential for generating airborne particulate—would not be used as surrogate data for solvent extraction operations)
• Facility design (such as physical environment, facility size, layout, and ventilation system)
• Source term (such as types and general quantities of material being processed)
• Period of operation
• Health physics practices (such as time, distance, shielding, and housekeeping)