Radiological Emergency Response: The National Biological Dosimetry Response Plan

This presentation will discuss new developments in emergency biological dosimetry and the CRTI (CBRN Research and Technology Initiative) National Biological Dosimetry Response Plan (NBDRP). Biological dosimetry is a technique used to estimate the biological consequences of a radiation exposure and is largely based on chromosome aberration detection. The NBDRP will establish a national network of laboratories to respond to a nuclear event for the purposes of rapid radiation dose estimation for crisis management and for long-term health risk assessment. In the event of a large-scale radiation accident or deliberate act of terrorism this will help guide the actions of emergency officials, emergency responders and health care personnel by providing timely biological dose estimates. The presentation will outline the research initiatives to develop modern techniques used for biological dosimetry. The overall purpose of this presentation is to provide the audience with a brief introduction to radiobiology, radiation-induced DNA damage, the health risks associated with radiation exposure, and the latest cytogenetic techniques used to estimate the risk

Acute pulmonary and splenic response in an in vivo model of whole-body low-dose X-radiation exposure

Purpose: Diagnostic radiation is an important part of patient care in the Intensive Care Unit; however, there is little data on the acute effects of exposure to these doses. We investigated pulmonary and splenic response 30 minutes, 4 hours or 24 hours after exposure to 2 mGy, 20 mGy, 200 mGy or 4 Gy whole-body X-radiation in a Sprague Dawley rat model. Materials and methods: Lung injury was assessed via respiratory mechanics, pulmonary edema, cellular, and proteinaceous fluid infiltrate and protein expression of oxidative stress markers. The radiation effect on the spleen was determined via proliferation, apoptosis and protein expression of oxidative stress markers. Results: All measurements of the lung did not differ from sham animals except for an increase in catalase after high dose exposure. Stimulated splenocyte proliferation increased after sham and low dose exposure, did not change after 200 mGy exposure and was significantly lower after 4 Gy exposure. The number of apoptotic cells increased 4 hours after 4 Gy exposure. There were fewer apoptotic cells after low dose exposure compared to sham. Both catalase and MnSOD were increased after 4 Gy exposure. Conclusion: There was no measured effect on pulmonary function while there was an impact to the spleen after low and high dose exposure.Stephanie Puukila, Stacy Muise, James McEvoy, Tara Bouchier, Antony M. Hooker, Douglas R. Boreham … et al

Relative biological effectiveness of 280 keV neutrons for apoptosis in human lymphocytes

The relative biological effectiveness (RBE) of neutrons varies from unity to greater than ten depending upon neutron energy and the biological endpoint measured. In our study, we examined apoptosis in human lymphocytes to assess the RBE of low energy 280 keV neutrons compared to Cs gamma radiation and found the RBE to be approximately one. Similar results have been observed for high energy neutrons using the same endpoint. As apoptosis is a major process that influences the consequences of radiation exposure, our results indicate that biological effect and the corresponding weighting factors for 280 keV neutrons may be lower in some cell types and tissues. Copyrigh

Canadian Cytogenetic Emergency Network (CEN) for biological dosimetry following radiological/nuclear accidents

Purpose: To test the ability of the cytogenetic emergency network (CEN) of laboratories, currently under development across Canada, to provide rapid biological dosimetry using the dicentric assay for triage assessment, that could be implemented in the event of a large-scale radiation/nuclear emergency. Materials and methods: A workshop was held in May 2004 in Toronto, Canada, to introduce the concept of CEN and recruit clinical cytogenetic laboratories at hospitals across the country. Slides were prepared for dicentric assay analysis following in vitro irradiation of blood to a range of gamma-ray doses. A minimum of 50 metaphases per slide were analyzed by 41 people at 22 different laboratories to estimate the exposure level. Results: Dose estimates were calculated based on a dose response curve generated at Health Canada. There were a total of 104 dose estimates and 96 (92.3%) of them fell within the expected range using triage scoring criteria. Half of the laboratories analyzed 50 metaphases in ≤ 1 hour and the time to score them was proportional to dose. The capacity and scoring expertise of the various participating laborat