With the possibility that terrorists and other criminals might obtain radioactive materials for malicious use, mitigating this threat to global security has become increasingly important. In response, SRI International has been developing a diagnostic test for absorbed doses of radiation in the event of such an attack.
SRI International, a nonprofit, independent research center serving government and industry, has been awarded a $12.2 million contract from the Biomedical Advanced Research and Development Authority (BARDA) to continue the development of the diagnostic test. BARDA, a division of the Department of Health and Human Services (HSS), is dedicatedto developing medical countermeasures to protect civilians from adverse health effects resulting from exposure to chemical, biological, and radiological or radionuclide agents.
The project began more than five years ago when BARDA selected David Cooper, Ph.D., director of the Sensor Systems Laboratory, and his team at SRI to develop a radiation biodosimeter.
In an effort to prepare for an unanticipated radiological or nuclear incident in which large numbers of people may be exposed to radiation that could lead to severe health consequences, time is of the essence. To rapidly triage large numbers of people to determine who needs immediate treatment, SRI developed a new and simple screening test.
"If you have hundreds of thousands of people potentially affected, you want to screen quickly and use medical resources efficiently," Cooper said. "Our goal is to develop a quick and simple point-of-care medical device that the government, first responders, hospitals and doctors can use in the field to determine a person’s absorbed dose of ionizing radiation."
Cooper and the SRI team are researching and developing a device with subcontractors from DCN Diagnostics, Evolve Manufacturing, and Stanford University School of Medicine. Cooper stated. "At this point, there is nothing else like it that takes a sample from an individual and assesses whether they have absorbed ionizing radiation or not."
Any living tissue in the human body can be damaged by ionizing radiation. This form of radiation has sufficient energy to strip away electrons from atoms (creating two charged ions) or to break some chemical bonds. The extent of damage depends on the dose of radiation received.
According to the Environmental Protection Agency, some of the early symptoms of radiation sickness are fairly nonspecific and include nausea, weakness, hair loss, skin burns or diminished organ function (especially bone marrow)—and can eventually cause death.
Currently, a wait-and see-approach is used to determine whether a person has absorbed a significant dose of ionizing radiation. Once symptoms develop, this roughly correlates to the exposure level but it is not a definitive diagnosis. The finger-prick blood test will solve the time delay and diagnostic concerns. In less than 30 minutes, the results will show whether a person has absorbed a clinically significant dose.
The technology is based on a lateral flow immunoassay method, similar to home pregnancy test kits. Antibodies specific to a panel of radiation-responsive proteins and a proprietary phosphorescent reporter system allow for quantitative measurement of protein concentrations in the patient’s blood sample.
"Because our test actually measures biological response to radiation rather than a physical radiation dose, the information obtained is very important," Cooper explained.
Due to differences in individual sensitivities to radiation effects, each subject’s response to the same physical dose may be different, therefore the immediate medical decision may be different.
This monetary award will support verification testing of the system, which puts the device one step closer to FDA clearance. SRI also feels infectious disease diagnostic testing can benefit from the technology employed in the device, making it innovative and dual purpose. Ionized radiation and infectious disease may just be the beginning of the diagnostic testing possibilities.
