The new 256-slice CT machine takes large numbers of X-ray pictures, and combines them using computer technology to produce the final detailed images.

It also generates images in a fraction of the time of other scanners: a full body scan takes less than a minute.

The Philips machine was unveiled at the Radiological Society of North America.

Because the images are 3D they can be rotated and viewed from different directions - giving doctors the greatest possible help in looking for signs of abnormalities or disease.

All images also can be accessed on any computer in a hospital or by colleagues and researchers remotely, to make it easier for the whole team to share information.

The test identifies changes in a handful of proteins that cells use to convey messages to one another.

The US researchers found it could indicate who had Alzheimer's, as well as who was likely to develop the condition, with 90% accuracy.

The work, led by Stanford University, features in Nature Medicine.

One of the most distressing aspects of Alzheimer's disease is the difficulty in determining whether mild memory problems are the beginning of an inevitable mental decline.

The researchers believe that measuring RBP4 would potentially be an effective way to assess body fat, and that treatment to cut levels of the protein might also have health benefits.

In previous work, they showed that cutting RBP4 levels in obese mice helped the animals to make better use of the hormone insulin - and thus reduce their risk of diabetes.

They also showed that measures to improve insulin sensitivity in human subjects resulted in a drop in RPB4 levels.

Researcher Dr Matthias Bluher said: "We believe that in the near future, measurements of RBP4 serum concentrations might serve as a novel biomarker for visceral obesity and increased risk for type 2 diabetes and other adverse outcomes of visceral obesity.

"In addition, pharmacological interventions that reduce RBP4 levels might be a new approach in the treatment of metabolic syndrome and visceral obesity."

The only known function of RBP4 is to carry vitamin A in the blood.

An experimental ultrasound technique that measures how easily breast lumps compress and bounce back could enable doctors to determine instantly whether a woman has cancer or not without doing a biopsy.

In a small study of 80 women, the technique -- called "elastography" -- distinguished harmless lumps from malignant ones with nearly 100 percent accuracy.

If the results hold up in a larger study, elastography could save thousands of women from the waiting, cost, discomfort and anxiety of a biopsy, in which cells are removed from the breast -- sometimes with a needle, sometimes with a scalpel -- and examined under a microscope.

"There's a lot of anxiety, a lot of stress, a lot of fear involved" with biopsies, said Susan Brown, manager of health education for the Susan G. Komen Breast Cancer Foundation. "And there's the cost of leaving work to make a second appointment. If this can be done instead of a biopsy, there would be a real cost reduction."

To explain elastography, Ophir likens the body to a box-spring mattress, but "a crazy mattress made out of millions of small springs and each one is a little different. Each is moving around at a different rate, depending on their individual stiffness." Cancerous tumors are like stiff springs. Normal tissue and benign lesions compress more easily.

Setting One year's (2005) diagnostic cases published in the case records of the New England Journal of Medicine.

Cases 26 cases from the New England Journal of Medicine; management cases were excluded.

Main outcome measure Percentage of correct diagnoses from Google searches (compared with the diagnoses as published in the New England Journal of Medicine).

Results Google searches revealed the correct diagnosis in 15 (58%, 95% confidence interval 38% to 77%) cases.

Conclusion As internet access becomes more readily available in outpatient clinics and hospital wards, the web is rapidly becoming an important clinical tool for doctors. The use of web based searching may help doctors to diagnose difficult cases.

This isn't a GE product - but it's fascinating. Anyone who's ever gotten an IV knows how unpleasant the process can be. The Veinviewer is fast (no waiting for a scan) and uses simple near-infrared light, a digital video camera, and a digital video projector (using DLP technology from Texas Instruments) to project onto your skin an image of the vein structure below. It's tough to overstate how simple and easy this is.

The VeinViewer by Luminetx uses a combination of near-infrared light and patented technologies to image vascular structures, thus allowing physicians, nurses and other healthcare professionals to clearly see accessible vasculature (or lack thereof) in real time, directly on the surface of the skin.

The test zeroes in on two forms of an enzyme involved in the degradation of amyloid, the protein that accumulates in the brain of someone with Alzheimer's, said Alkon, scientific director of the Blanchette Rockefeller Neurosciences Institute at the West Virginia University Health Sciences Center.

The presence of Alzheimer's disease is indicated by a steep imbalance in the ratio of the two forms of the enzyme, MAP kinase Erk, in skin cells that are exposed to bradykinin, an inflammation-related molecule, Alkon said. That imbalance is not seen in cells of people without dementia or those with other forms of dementia, he said.

The test produced good results when run on 60 tissue samples: 30 from a tissue bank, 30 from autopsy samples of people diagnosed with Alzheimer's disease, Alkon said.

"We have seen a correlation with the duration of the disease," he said. "The earlier it is done in the course of the disease, the larger is the abnormality."

During the trial, a brief pulse of infrared light into the eyes of four mice with Alzheimer's and four without accurately identified which had the condition.

Dr Goldstein and his team envisage the test could be used to detect the disease at its earliest stages as well as to track disease progression and monitor how people respond to Alzheimer's treatments.

Currently there is no simple test to make a diagnosis of dementia and it can only be confirmed with certainty by looking at someone's brain in a post-mortem examination.

The scientists believe the technology, known as quasi-elastic light scattering, may detect the very earliest stages of amyloid deposits in the lens, even when they appear completely clear to the naked eye.

The research makes use of gold nanoparticles that are only 16 nanometres in diameter - roughly 1/5000th the width of a human hair.

Earlier work by Professor Russell's team has refined manufacturing methods so relatively large amounts of the particles can be made quickly.

Once made, the particles are coated with sugars tailored to detect different biological substances.

When mixed with a weak solution of the sugar-coated nanoparticles, the target substance, be it a poison such as ricin or a bug like E.coli, binds to the sugar. This changes the properties of the solution and makes it change colour.

The radio pill, part of the CorTemp Physiological Monitoring System manufactured by Palmetto, Fla. based HQ Inc., relies on a temperature-sensitive quartz crystal oscillator whose vibration frequencies are well known for temperatures ranging from ­60 °C to 150 °C. For instance, the crystal oscillates at 262.25 kilohertz at the normal body temperature of 37 °C. The electronic components calculate the temperature and transmit the data as a digital signal. Power comes from a silver oxide hearing aid battery that holds enough energy for nine days of temperature readings. The capsule remains in the body for only 24 to 36 hours before it is eliminated.

The temperature readings are transmitted wirelessly to a handheld receiver­data recorder. As the digital signal induces a voltage on the pill's communication coils, this voltage creates a quasistatic magnetic field with a radius of about a meter. When a coach or trainer holds the receiver to the small of a player's back, a magnetic coupling between the pill and the receiver induces a voltage in the handheld device's antenna, which is then demodulated to retrieve the original temperature data.

Because magnetic communication does not generate a propagating wave and there is strong attenuation of the signal with distance, the data are hard to intercept and virtually free from interference-even if there are dozens of other players running around the practice field with radio pills in their guts. Creating such a magnetic communication bubble also requires very little power, which allowed the radio pill's designers to use the tiniest of commercial batteries.

An individual would be able to tell within 20 minutes whether they had the infection or not, in the privacy of their own home.

Many have expressed fears that people who find out in this way may kill themselves and hence testing should be supervised and counselled face to face.

Home HIV testing kits are banned in the UK for such reasons. However, some buy unapproved kits over the internet.

Getting a quick result is important for hospital screening and isolating infected patients to prevent disease outbreaks.

The e-nose gives a result within minutes, which is much faster than the current way of analysing ear, nose and throat swabs, which involves sending samples off to the lab and waiting 72 hours for a result.

Tests on hospital patients showed it could correctly detect three strains of Staph aureus, including MRSA, with more than 99% accuracy.

However, it cannot yet distinguish MRSA from its close cousin MSSA (methicillin-sensitive Staph aureus), which does respond to convetional antibiotics unlike MRSA.

Experts caution, however, that while breath tests are a promising diagnostic technique, it does not appear that they will completely replace trusted methods such as biopsies and CT scans.

In the meantime, Phillips is looking to license a company to produce and market his Heartsbreath test to doctors and hospitals, since such a nationwide effort cannot be undertaken by his four-person firm.

Analyzing breath to diagnose disease is a concept that dates back two millennia, Phillips said, noting that ancient physicians found that a diabetic's breath smelled like rotten apples. And while a police Breathalyzer is designed to detect just one substance — alcohol — the acetone that causes diabetic breath is among the 200 compounds that the Heartsbreath technology can identify.

In addition, Phillips said, his technology can determine the levels of each compound, being about a billion times more sensitive than police machines.

Still, the discovery may provide leads to scientists searching for therapies to at least delay the onset of the degenerative brain disease. It already affects 4.5 million people in the U.S. and is predicted to strike 14 million by 2050 as the population ages.

Moreover, researchers are honing in on lifestyle choices that may help protect the brain in the first place.

"It's exciting that we can even talk about prevention," said William Thies, scientific director of the Alzheimer's Association. He noted that just 10 years ago there was hardly any research into that possibility.