Department of Energy (DOE) Radiological Control Manual

Chapter 5. - Radiological Health Support Operations

Part 2 - Internal Dosimetry

Table of Contents (Articles 52x)

• 521 Requirements
• 522 Technical Requirements for Internal Dosimetry
• 523 Technical Requirements for Dose Assessment

Article 521 - Requirements

1. The following personnel shall participate in an internal dosimetry program:

2. Personnel entering Radiological Buffer Areas who have the potential to receive intakes resulting in a committed effective dose equivalent of 100 mrem or more in a year
3. Declared pregnant workers likely to receive intakes resulting in a dose equivalent to the embryo/fetus of 50 mrem or more during the gestation period
4. Minors and students, visitors and public likely to receive intakes resulting in a committed effective dose equivalent of 50 mrem or more in a year.

• The estimation of internal dose shall be based on bioassay data rather than air concentration values unless bioassay data are:

• unavailable
• inadequate
• internal dose estimates based on representative air concentration values are demonstrated to be as or more accurate.

• Personnel shall participate in followup bioassay monitoring when their routine bioassay results indicate an intake in the current year with a committed effective dose equivalent of 100 mrem or more.

• Personnel whose routine duties may involve exposure to surface or airborne contamination or to radionuclides readily absorbed through the skin, such as tritium, should be considered for participation in the bioassay program.

• Personnel shall submit bioassay samples, such as urine or fecal samples, and participate in bioassay monitoring, such as whole body or lung counting, at the frequency required by the bioassay program.

• Personnel shall be notified promptly of positive bioassay results and the results of dose assessments and subsequent refinements. Dose assessment results shall be provided in terms of rem or mrem. Return to Chapter 5, Part 2 Table of Contents

Article 522 - Technical Requirements for Internal Dosimetry

DOE plans to implement accreditation programs for bioassay measurements and internal dose assessment and to provide supplemental technical guidance on the implementation of internal dosimetry programs. Until these accreditation programs are available, this Manual provides the technical guidance to implement the internal dosimetry programs.

1. A technical basis document shall be developed for the internal dosimetry program.

2. Baseline bioassay monitoring of personnel who are likely to receive intakes resulting in a committed effective dose equivalent greater than 100 mrem shall be conducted before they begin work that may expose them to internal radiation exposure.

3. Routine bioassay monitoring methods and frequencies shall be established for personnel who are likely to receive intakes resulting in a committed effective dose equivalent greater than 100 mrem. The technical basis for the methods and frequency of bioassay monitoring should be documented.

4. Management shall require termination bioassay monitoring when a person who participated in the bioassay program terminates employment or concludes work involving the potential for internal exposure. The number of persons failing to achieve this monitoring should be reviewed periodically and should be used to determine whether further efforts to get cooperation are warranted.

5. Bioassay analyses shall also be performed when any of the following occurs:

6. Facial or nasal contamination is detected that indicates a potential for internal contamination
7. Airborne monitoring indicates the potential for intakes exceeding 100 mrem committed effective dose equivalent
8. Upon direction of the Radiological Control Organization when an intake is suspected.

• Levels of intakes that warrant the consideration of medical intervention shall be established for site-specific radionuclides. The effectiveness of medical intervention, such as blocking or chelating agents, shall be documented using bioassay results.

• A preliminary assessment of any intakes detected should be conducted prior to permitting an employee to return to radiological work.

• Internal dosimetry program personnel should use radionuclide standards from or traceable to the National Institute of Standards and Technology (NIST).

• Internal dosimetry program personnel should participate in the conduct of intercomparison studies and should use the "DOE Phantom Library." Return to Chapter 5, Part 2 Table of Contents

Article 523 - Technical Requirements for Dose Assessment

Interpretations of bioassay results and subsequent dose assessments should include the following:

1. Characteristics of the radionuclide, such as chemical and physical form

2. Bioassay results and the person's previous exposure history

3. Exposure information, such as route of intake and time and duration of exposure

4. Biological models used for dosimetry of radionuclides

5. Models to estimate intake or deposition and to assess dose

6. Intradepartmental coordination between the Radiological Control Organization and the medical organization for doses that may require medical intervention.