As Japan faces a nuclear radiation leak, a team of researchers from Dartmouth Medical School is offering use of its radiation exposure device to assess radiation levels and determine who needs medical assistance. The offer, however, has been declined by Japanese officials, according to Harold Swartz, a radiation oncology professor at DMS and director of the project developed by Dartmouth's Physically-Based Biodosimetry Center for Medical Countermeasures Against Radiation.
The device, an electron paramagnetic resonance dosimeter, checks tooth enamel for high levels of radiation, according to Swartz. Patients bite down on a mouthpiece and rest their heads against padding while a small loop is placed painlessly over one of the patient's front tooth. Within five minutes, the 60-pound device can measure a precise level of radiation dose based on an electron paramagnetic resonance spectrum reading, Swartz said.
"Radiation from a strong nuclear source like a nuclear weapon or radioactive fallout delivers energy in a way that creates free radicals that tend to be very reactive," he said. "If there is a solid material that is reasonably well organized, the radicals can be stabilized. My research showed that if teeth were radiated they hold a permanent signal that can be detected."
In the wake of Japan's recent 9.0-magnitude earthquake and 33-foot tsunami, and the subsequent damage to major nuclear power plant reactors in the country, Swartz and his team contacted Japanese officials to offer this device for determining radiation levels in affected citizens. Government officials determined that there was not a present need for the device, Swartz said.
Despite the relevance of Japan's current events to the dosimeter, Swartz was said he was "not surprised" that the device had yet to be used for the nuclear crisis.
"If you look at the exposure levels occurring in Japan now, the radiation is a lot smaller than would be normally detected [on the dosimeter]," Swartz said. "And we would have to bring the people to the device because it's not transportable."
The center, also known as Dart-Dose CMCR, was recently contacted by the Japanese Department of Environmental Health in a March 26 email with a request for more information about the tooth dosimetry system, according to Ben Williams, radiology professor and associate director of Dart-Dose CMCR.
Dart-Dose CMCR has also reached out to international groups, such as the World Health Organization and International Atomic Health Organization, about Japan's nuclear crisis, according to Swartz.
"If the word is out there and someone thinks it's useful, we're prepared to help," Swartz said.
Using tooth enamel and other markers is a "distinct" and effective way to measure radiation exposure compared to more conventional methods, according to Williams. The process of using tooth enamel to detect radiation exposure is also not as susceptible to burns or other wounds that could affect biologically-based signals, Williams said.
Although Swartz has been researching dosimetry the study of the levels of radiation emitted by a radioactive source since 1968, interest in developing a device that would measure radiation exposure in humans has grown significantly in the past 10 years following the Chernobyl nuclear disaster in 1986, according to Swartz.
The dosimeter was designed to measure high levels of radiation that would only occur in a "major catastrophe" such as the detonation of a nuclear weapon or a severe nuclear explosion, Williams said. The dosimeter would help emergency personnel perform triages by acting as a screening device for individuals seeking medical help, Swartz said.
"There is a need to have a mechanism in case of such a large event to keep medical systems from getting overwhelmed by thousands of people who may not need to be seen if they are in fact not exposed to radiation at all," Swartz said.
Swartz also said the device may help calm a nervous public after a nuclear event.
"If there is a society that is reasonably anxious and a government that is behaving responsibly but people don't have 100 percent confidence [after a nuclear disaster], it may be a good idea to bring in independent source of measurements," he said.
Ann Barry Flood, associate director of Dart-Dose CMCR and a radiology professor at DMS, has done research evaluating the dosimeter in a greater societal context.
"What makes my work different and interesting is that most comparative effectiveness research studies are assumed to be done in normal constrained circumstances such as hospitals and doctors' offices," Flood said. "Here, there is no developed way in trying to evaluate scientifically the context of an event that is extremely rare and hopefully will never happen again."
While the device at Dartmouth remains in its research stages, a copy of the model was created and sent to the Japanese National Institute of Public Health near Tokyo two years ago, Swartz said.
"Originally, we made one clone of the instrument for a colleague in Japan to measure radiation exposure in elderly survivors of Hiroshima and Nagasaki," Swartz said.
Dart-Dose CMCR hopes to improve the design and refine the operation of the dosimeter in the future, according to Swartz.
"We want to make a device that is portable enough to take on site [of a disaster], make the measurements quickly, and have a device that is automated and can be operated within five minutes of instruction because there will not be experts on site," Swartz said.
Dart-Dose CMCR is also working on final negotiations with an unnamed federal agency in collaboration with General Electric to make tooth dosimetry technology a "fully automated instrument," according to Swartz.
The device will then go through the federal approval process and, if approved, will be ready to be manufactured and put into the National Strategic Stockpile supply.
Research at Dart-Dose CMCR aimed at making the dosimeter a portable and "deployable" device is funded by a $3.3 million five-year grant from the National Institutes of Health and additional funding from the National Institute of Allergy and Infectious Diseases, Swartz said.
In addition to using tooth enamel to measure radiation exposure, Dart-Dose CMCR is also developing dosimetry technology for fingernails, both on the finger and in clippings, according to Swartz.
