HPS N13.39:2001-(RN:2011)

In the past, internal dosimetry standards have focused on providing guidance for detection and dose assessment for specific radionuclides or groups of radionuclides (e.g., tritium, uranium, and fission and activation products). Frequently, however, these standards provided conflicting or uneven treatment of the programmatic elements that are basic to monitoring for and assessing the dose from any radionuclide. Therefore, this standard was developed to provide uniform and consistent guidance on programmatic issues that are universally applicable to all radionuclides and all occupational intake pathways.
This standard contains the essential elements of the internal dosimetry component of a radiation protection program. It provides general policies and the framework for the design and implementation of an acceptable internal dosimetry program. The topics included herein are definitions, organization, staffing and training, program documentation, quality assurance, personnel participation, internal dose assessment, incident response, and records and reports.
Other than those examples necessary for clarification, this standard does not address bioassay or internal dose assessment methodologies for specific radionuclides.(a) It is intended that the development and implementation of radionuclide-specific dosimetry programs be consistent with the broad-scoped guidance provided herein.
By its very nature, internal dosimetry is a complex task with varying degrees of difficulty, depending upon the radionuclide and the means by which the radionuclide is metabolized. For some radionuclides, such as tritium, it is relatively easy to monitor for and assess intakes that result in small doses. For others, such as 239Pu, the task is significantly more difficult. Therefore, while this standard provides the minimal acceptable elements of an internal dosimetry program regardless of the radionuclide, it should not be used to restrict the level of excellence readily achievable for some radionuclides.
This standard provides guidance for programs where monitoring for possible intakes by workers is part of the radiation protection program.
Engineered containment and administrative controls are used to minimize the probability of an intake due to normal operations and accident releases. Workplace surveillance practices identify that the containment and administrative controls are effective. Routine bioassay monitoring provides verification that radiological controls are being maintained and work effectively. Special bioassay is performed in response to indications of an abnormal condition that might have resulted in an intake.This standard focuses on establishing intake monitoring programs, identifying intakes, and assessing internal dose. It does not address equally important aspects of radiation protection involving minimizing intakes or implementing aslow- as-reasonably-achievable total dose control programs.
A graded approach is presented to account for programs involving only a small risk of intake through programs with a risk of intake that might result in an exposure above regulatory limits or even potential radiation-induced health effects. Although most of the standard addresses details relevant to programs with known or substantial risks of intakes, it is recognized that one important purpose of internal dosimetry programs is to document that workplace controls are adequate and no recordable intakes are occurring. Therefore, some guidance is provided for programs (or a part of a program) that would not be expected to involve dose assessment.
(a) Also excluded is information on dosimetric quantities and units, regulatory interactions, regulatory or administrative dose limits, methods of and recommendations on decorporation therapy, performance requirements for bioassay methodologies, bioassay frequencies, and uncertainties in assessment results. The reader is referred to the References for information on these and related topics.