Radiobiology of nuclear terrorism: report on an interagency workshop (Bethesda, MD, December 17-18, 2001).

The diagnosis, prophylaxis, and treatment of normal tissue injuries after exposure to ionizing radiation are of great importance to patients with cancer, to populations potentially subject to accidental or intentional radiation exposure, to workers in the nuclear power industry, and to members of the military. In these populations, partial or whole body exposure in the range of 1–10 Sievert (Sv) is possible (1–3). In the United States, exposure to doses of 10 Sv has been the subject of research by the National Cancer Institute (NCI); and exposure to radiation doses 1 Sv, such as that from nuclear fallout or space exploration, has been researched by the Department of Energy and the National Aeronautics and Space Administration. Except for research by the Department of Defense and the Armed Forces Radiobiology Research Institute that is aimed at protecting members of the armed forces and research aimed at the consequences of the total body irradiation used in conditioning regimens for bone marrow transplantation (4), the intervening dose range of roughly 1–10 Sv has received relatively little attention. The events of September 11, 2001 focused attention on the possibility of nuclear terrorism (5), and 1–10 Sv is arguably the dose range of biologic interest, because doses in this range pose a risk of acute effects, but are also potentially survivable (1–3). Because of this interest, a coalition of U.S. government agencies (NCI, Department of Defense/Armed Forces Radiobiology Research Institute, and Department of Energy) and the Radiation Research Society convened an interdisciplinary workshop in December 2001 “to focus on molecular, cellular and tissue changes that occur [at 1–10 Sv] and potential mechanisms of radioprotection” (6). The Workshop was also intended to “determine the research opportunities and resources required [and] develop a research-action plan for further discussion and implementation” (7). A “draft” report on this workshop was posted on the NCI web site in mid-February (7), but it appears that a “final” report may never be published. A summary of the workshop discussions and recommendations was published in Radiation Research in July 2002 (8). The purpose of this commentary is to bring the issue to the attention of the radiation oncology community. Participants in the Workshop came from academia, as well as from government agencies, and covered fields ranging from molecular biology to animal physiology to clinical trials. The summary that follows is based on personal notes taken by the author (a presenter at the Workshop and a member of the “writing committee”), on the summary published in Radiation Research (8) and on the draft posted on the NCI web site (7). The Workshop discussions were wideranging and included the basic radiobiology relevant to injuries caused by doses of 1–10 Sv; biodosimetry problems and issues; and what resources were available now, and what could be made available within 1–5 years, for prophylaxis and treatment of radiation injuries caused by doses of 1–10 Sv. (The Workshop made an important distinction between prophylactic approaches, which begin therapy before radiation exposure, and treatment strategies, which begin therapy after exposure.) Finally, the group made some specific recommendations concerning research, technology, prophylaxis and treatment strategies, and personnel expertise issues.