News of the Day ... In Perspective7/29/2005
Patients may set off airport alarms after nuclear medicine scans
Patients passing through airport security up to 30 days after a thallium scan may trigger highly sensitive radiation detectors. I-131 for thyroid scans or treatment of hyperthyroidism has an even longer half-life and could cause a false alarm up to 100 days after the procedure.
Patients have also been detained while visiting a bank vault or the White House.
Some portable instruments detect gamma dose rates as low as 0.1 – 50 microSv/hr. The sensitivity of detectors in common use cannot be determined because the information is restricted.
According to The Lancet of Jul 23, 2005, “Patient information cards could lessen the impact of such false alarms and avoid unnecessary interrogations by airport security personnel.”
The security measures are apparently a response to a “dramatic increase” in worldwide smuggling of radioactive materials (Ariz Daily Star 7/23/05).
The detectors used for interdiction purposes would be off-scale and useless in the event of use of a “dirty bomb” or nuclear weapon. The lowest dose rate that will trigger a NukAlert, a device designed to detect radiation from nuclear fallout, is 0.1 rad/hr, which is equivalent to 1 mSv/hr or 1,000 microSv/hr (see demonstration at www.knorad.com).
“U.S. Unprepared for Nuclear Terrorism,” News of the Day, May 25, 2005.