CONCEPTS OF OPERATIONS FOR A US DOSIMETRY AND BIODOSIMETRY NETWORK.

The USA must be prepared to provide a prompt, coordinated and integrated response for radiation dose and injury assessment for suspected radiation exposure, whether it involves isolated cases or mass casualties. Dose estimation for radiation accidents typically necessitates a multiple parameter diagnostics approach that includes clinical, biological and physical dosimetry to provide an early-phase radiation dose. A US Individual Dosimetry and Biodosimetry Network (US-IDBN) will increase surge capacity for civilian and military populations in a large-scale incident. The network's goal is to leverage available resources and provide an integrated biodosimetry capability, using multiple parameter diagnostics. Initial operations will be to expand an existing functional integration of two cytogenetic biodosimetry laboratories by developing Standard Operating Procedures, cross-training laboratorians, developing common calibration curves, supporting inter-comparison exercises and obtaining certification to process clinical samples. Integration with certified commercial laboratories will increase surge capacity to meet the needs of a mass-casualty incident.

Acceptance Testing of Thermoluminescent Dosimeter Holders.

The U.S. Navy uses the Harshaw 8840/8841 dosimetric (DT-702/PD) system, which employs LiF:Mg,Cu,P thermoluminescent dosimeters (TLDs), developed and produced by Thermo Fisher Scientific (TFS). The dosimeter consists of four LiF:Mg,Cu,P elements, mounted in Teflon® on an aluminum card and placed in a plastic holder. The holder contains a unique filter for each chip made of copper, acrylonitrile butadiene styrene (ABS), Mylar®, and tin. For accredited dosimetry labs, the ISO/IEC 17025:2005(E) requires an acceptance procedure for all new equipment. The Naval Dosimetry Center (NDC) has developed and tested a new non-destructive procedure, which enables the verification and the evaluation of embedded filters in the holders. Testing is based on attenuation measurements of low-energy radiation transmitted through each filter in a representative sample group of holders to verify that the correct filter type and thickness are present. The measured response ratios are then compared with the expected response ratios. In addition, each element's measured response is compared to the mean response of the group. The test was designed and tested to identify significant nonconformities, such as missing copper or tin filters, double copper or double tin filters, or other nonconformities that may impact TLD response ratios. During the implementation of the developed procedure, testing revealed a holder with a double copper filter. To complete the evaluation, the impact of the nonconformities on proficiency testing was examined. The evaluation revealed failures in proficiency testing categories III and IV when these dosimeters were irradiated to high-energy betas.