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.

White baton

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.

Amazing results

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 ÂŁ20,000 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.

Doctors in Italy used the technique to treat a 48-year-old man with multiple tumours in his liver. One year after the operation, which took 21 hours, the man is alive and well. His liver is functioning normally and the latest scans have not revealed any signs of tumours.

The team, which consists of surgeons at the San Matteo Hospital in Pavia and physicists from the local division of the National Institute of Nuclear Physics, is now waiting for approval to treat another six patients with multiple liver tumours. If these are successful, the technique could one day be used to tackle hard-to-treat cancers in other organs that can be transplanted, such as the lungs or pancreas.

The patient they have treated had had a colon tumour removed, but the cancer spread to his liver. Scans revealed no fewer than 14 tumours there, and many smaller ones were discovered during the operation. Such diffuse cancers are very difficult to treat by conventional means.

Neutron capture

The tumours proved resistant to chemotherapy. And there was little hope of killing such widespread growth with conventional radiotherapy – which usually involves focusing X-ray beams onto the target – without destroying the liver.

So doctors decided to try a method called boron neutron capture therapy, first attempted in the 1950s, in which boron atoms are attached to the amino acid phenylalanine and injected into a patient. Because they are growing quickly, tumours take up more of the compound than normal cells.

The team has been working on the method since 1987 and has done extensive studies to work out the optimum dose. Two to four hours after the compound is given, a low-energy neutron beam is directed at the organ, splitting the boron into high-energy particles that mainly kill the cancer cells.

But to ensure that all cancerous cells are destroyed, an even dose of neutrons has to be given to the entire organ. That’s not easy to do in the body, where obstructions such as bones block the neutron beam. And the tissues surrounding the organ inevitably receive a large dose of radiation.

Teflon bag

Instead the surgeons decided to remove the entire liver. The organ was placed in a Teflon bag that neutrons can pass through and taken to a research reactor nearby, where it was irradiated with neutrons. It was then re-implanted, just as in a normal liver transplant operation.

“By explanting the organ, we could give a high and uniform dose to all the liver, which is impossible to obtain inside the body without serious risk to the patient,” says Tazio Pinelli, a physicist who coordinated the work together with liver surgeon Aris Zonta.

“It was a bold stroke and has stirred the interest of many in the field,” says Paul Busse, a neutron radiology expert at Harvard Medical School in Boston.

The technique has been dubbed TAORMINA after the Italian for “advanced treatment of organs by means of neutron irradiation and autotransplant”. But with only one person treated so far, it is too early to judge how safe and effective it is.

Brain tumours

Even if the method proves effective against liver and other cancers, such a drastic operation would be reserved for patients with the worst outlook, and could only be carried out while they were still strong enough to survive the long operation.

It could also be used only in cases where the spreading cancer is restricted to one organ. Once cancers spread widely, there is little that can be done. Another problem is that there are few reactors capable of producing suitable neutron beams.

But the work could also help improve normal boron neutron capture therapy, Busse says, by improving our knowledge of what doses are safe and effective. The technique is currently being tested on patients with otherwise untreatable brain tumours – obviously without removing the organ in question.

Diabetics suffer from a lack of insulin, a hormone produced by the pancreas
that stimulates cells to take up glucose from the blood. To correct this
imbalance they need to monitor their blood sugar levels to know how much insulin
to inject. The most common way of doing this is to apply a pinprick of blood to
a test strip, but many find this inconvenient.

The new sensor, developed by MiniMed in California, measures glucose levels
in the fluids in the subcutaneous tissue just under the skin. It consists of a
tiny electrode attached to a pager-sized monitor that can be worn on the belt or
inside clothing.

Under normal circumstances, the device is as effective as a blood test. But
blood sampling is still required about once a day to calibrate the sensor.