The New Scientist
by Sergio Pistoi, Rome
(Link to original at New Scientist.com)
It sounds too good to be true, but two independent studies appear to show that tumours can be detected by scanning people with a hand-held device similar to the metal detectors used to frisk airline passengers.The development holds the prospect of a mass-screening technology that is cheap, quick and non-invasive.
The idea for the scanner came about after physicist Clarbruno Vedruccio, at the University of Bologna, Italy, designed a detector for non-metallic landmines and plastic explosives. It occurred to him that it might also be able to locate cancerous tissues in people.
So with the help of Turin-based aerospace firm Galileo Avionica he built the slimline scanner and has been testing it in hospitals.
Called the Trimprobe – short for Tissue Resonance Interferometer – the device is a white plastic baton about the size of a Pringles tube. Inside it, an antenna produces a beam of microwaves that vary in frequency from 400 to 1350 megahertz.
The power in the signal is less than 100 milliwatts, much lower than the 2-watt peak power of a cellphone. To use it, the baton is simply swiped over the body – with no need for patients to undress.
When the Trimprobe’s electromagnetic signal hits biological tissues, Vedruccio says they resonate at certain frequencies and produce a signal that interferes with the original incoming signal. The amount of interference is then detected by a receiving antenna in the probe.
Unlike MRI scanners, Vedruccio’s system does not produce an image of an organ. Instead, a computer displays a sequence of bands showing the amount of interference at different frequencies.
Vedruccio and his colleagues found that tumours generate strong interference at around 400 megahertz. They do not yet know why this happens, but believe that the dielectric constant of tumour tissue – a measure of a material’s ability to sustain an electric field – differs from that of healthy tissue.
In clinical trials at the San Carlo Borromeo Hospital in Milan, the scanner was able to predict prostate tumours in 93 per cent of cases that were later confirmed by biopsy.
“The results are amazing. The scanner seems ideal for mass-screening of cancer because it is rapid, non-invasive and highly sensitive,” says Carlo Bellorofonte, the urologist who led the trial.
Meanwhile a separate study on 200 women carried out at the European Institute of Oncology in Milan found that the prototype scanner could detect breast cancer in 66 per cent of the cases.
Galileo Avionica says that further trials for lung, stomach, liver and colorectal cancer are now under way in other centres in Italy and it hopes to market the scanner later this year at a cost of £20,000 per unit. However, the results of the early trials have yet to appear in a peer-reviewed medical journal and must be regarded with caution until then.