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Nano technology
A sensor made with gold nanoparticles can detect lung cancer in
a patient's breath and may offer a diagnosis before tumours show up
on an x-ray, Israeli scientists said.
The device, which the developers say would be cheap enough for
everyday use by family doctors, detected lung cancer with 86%
accuracy and may offer a way to screen for a disease not usually
diagnosed until it has spread and is no longer curable.
It uses sensors based on gold nanoparticles to detect specific
compounds - volatile organic compounds (VOC) - that lung cancer
patients have in high levels in exhaled breath.
Breath testing is already recognised as a way of linking specific
VOCs in exhaled breath to a certain medical conditions.
In 2006, researchers found dogs could be trained to smell cancer
on the breath of patients with 99% accuracy.
Hossam Haick, one of the scientists working on the sensor, said he
hoped it could soon allow doctors to have a simple test at hand to
screen people during routine appointments.
"Conventional diagnostic methods for lung cancer are unsuitable for
widespread screening because they are expensive and occasionally
miss tumours," Haick and colleagues wrote in Nature
Nanotechnology.
"This device is not at all expensive. The whole idea in this
development was to devise something very sensitive, and very cheap
and very portable," Haick, of the Technion-Israel Institute of
Technology in Haifa, said.
Lung cancer kills 1.3 million people a year and is the leading
cause of cancer death across the world.
Only 15% of patients live more than five years, in part because
the disease is usually diagnosed so late.
The device developed by Haick and his colleagues is a nine-sensor
array consisting of gold nanoparticles combined with different
organic groups that respond to various VOCs released by lung
tumours.
They tested 56 healthy people and 40 patients who had been
diagnosed with lung cancer using conventional methods.
They found the sensor could distinguish the breath of lung cancer
patients from the of the control group with more than 86%
accuracy.
Haick said the patented device needed to be more rigorously tested
and obtain approval from drug licensing authorities before it could
go into production.
"I would say that could take three to five years," he said.
Various other methods exist to measure VOCs, including a breath
test using colour spots, but existing techniques are often
expensive, slow and sometimes require the breath to be concentrated
or dehumidified first.
