The U.S. Department of Homeland Security -- announcing its first patent -- has developed a portable device that measures radiation exposure. The so-called Citizen's Dosimeter contains radiation-sensitive material and would be read with a card reader. "The device we envision would look something like a credit card," said Gladys Klemic, a National Urban Security Technology Laboratory physicist.
Meant to supplement dosimeters that detect acute levels of high radiation in contaminated conditions, the miniature version would measure a person's long-term, cumulative radiation dose, Klemic said in an interview this week. High levels of radiation exposure present the most extreme, immediate health concerns. But lower levels of radiation can, over the long term, lead to cancer and other health problems.
The effort to develop the Citizen's Dosimeter was launched in 2003, just after the Department of Homeland Security was formed. Researchers discussed what would have happened if the September 2001 terrorist attacks had included a radiological component. "That was our initial motivation," Klemic said. According to researchers, a dirty bomb would bring social and economic disruption -- from the initial evacuation to the cleanup to the economic costs of a site that's unusable.
Klemic and chemist Paul Bailey visited Landauer, a commercial dosimetry provider in Illinois, where they were inspired by Luxel, a thin, radiation-sensitive material. Back in Manhattan, where their work is based, Klemic and her team made note of the card readers they used to move around the city's subway system. At the Laboratory Managed Research Program, about 20 blocks north of the World Trade Center site, the team set out to develop a miniature dosimeter that could be read with a card reader. (Previous iterations of the dosimeter were larger and had to be sent to a dosimetry service for processing.)
The new dosimeter could be useful to people at various radiation risk levels, Klemic said. First responders who use traditional dosimeters could also carry the smaller version to monitor their long-term radiation dose, she said. Secondary responders, who work in elevated radiation areas, and even the public moving through the contamination, could use the device.
The Citizen's Dosimeter would complement other options that are already available, Klemic said, including:
- JP Laboratories in New Jersey offers a $20 color-changing dosimeter called RADTriage, designed to identify medically-significant radiation exposures. It is currently being used in Japan.
- Alarming electronic radiation monitors ($200 and up) are applicable for first responders in high radiation areas where they have established radiation control zones and would work for limited time periods.
- States have stockpiles of personal radiation dosimeters, including the pocket ion chamber, which is designed to be clipped into a breast pocket.
- Global Dosimetry in California offers a new dosimeter called Instadose, which looks like a thumb drive and can be read using the Internet.
With the patent in hand, "our role is essentially done," Klemic said. The work is transitioning now to industry and academic partners who will focus on the engineering and development of a prototype dosimeter and its package. The device is not expected to be completed for at least a year.
Photo: Gladys Klemic