Medical
scans can render people radioactive enough to trigger false
security alarms at airports for up to a month, a Lancet piece
warns. Over 18 million scans using radioactive versions of common
elements are carried out in the UK each year.
They include tests of the thyroid gland, bone, and blood flow
to the heart muscle.
Professor Richard Underwood, of London's Royal Brompton Hospital,
said the side effects should be made clear.
"Patient
information cards could lessen the impact of such false alarms
and avoid unnecessary interrogations by airport security personnel"
--- Professor Richard Underwood
He called
for patients to be issued with standard information cards about
their scan if it made use of radioisotopes.
The Lancet piece highlights the case of a 55-year-old commercial
pilot referred for cardiac investigation.
Doctors carried out a scan using a radioisotope of the element
thallium.
Two days after the scan the patient travelled to Moscow as a
crew member.
While passing through customs, the radiation detector alarms
were triggered, and the patient was detained for questioning.
After extensive interrogation, he was released, but experienced
the same problem at the same airport four days later.
Eventually the airport security officials gave him a card to
carry while travelling that explained his scan was to blame.
More sensitive systems
Professor Underwood said: "Stricter measures, and more sensitive
radiation detection systems, are being deployed at airports
worldwide.
"It is important to warn patients having had a thallium scan
that they may trigger radiation detectors for up to 30 days.
"It should be standard practice to issue patients with an information
card after diagnostic or therapeutic procedures involving radioisotopes."
Professor Underwood said the card should state the date and
place of the procedure, the radioisotope used and its half-life,
potential duration of radioactive emissions from the patient,
and details on who to contact for verification if necessary.
"Patient information cards could lessen the impact of such false
alarms and avoid unnecessary interrogations by airport security
personnel."
Professor Adrian Dixon, of the Royal College of Radiologists,
said many cardiac units had switched from using thallium, which
has a relatively long half life, to another element, technetium,
which does not linger so long in the body.
Professor Dixon said many units made patients aware the possible
side effects following a scan.
But he added: "It is good that this paper will make people more
aware of the issue."
Medical
scans can render people radioactive enough to trigger false
security alarms at airports for up to a month, a Lancet piece
warns. Over 18 million scans using radioactive versions of common
elements are carried out in the UK each year. 
