Laser-ultrasound technique detects prostate cancer earlier

Nov. 9, 2007
November 9, 2007, St. Ingbert, Germany--A novel diagnostic technique combines laser imaging and ultrasound to improve early diagnosis of prostate cancer.

November 9, 2007, St. Ingbert, Germany--Treating prostate cancer is a race against time. By the time the patient can feel the first symptoms, the disease has usually spread too far. A novel diagnostic technique combines optical imaging with ultrasound to improve early diagnosis.

By the time the first symptoms of prostate cancer become apparent, the tumor has usually spread too far and curing it is less likely. Early diagnosis can help to save lives. While CAT scans, X-rays, and magnetic resonance devices can frequently detect tumors in time, the cost of routine examinations is often too high, and the devices are not always sensitive enough. Ultrasound is a cost-efficient alternative, but is not very reliable.

A novel, cost-efficient, and sensitive device will soon increase the number of early diagnoses of prostate cancer and offer more patients the prospect of recovery. This diagnostic device was developed by researchers at the Fraunhofer Institute for Biomedical Technology (IBMT; St. Ingbert, Germany) in collaboration with partners from five European countries. The European Commission is funding the project to the tune of 2.2 million euros. "We use a combination of two different imaging techniques: optical imaging and ultrasound," says IBMT department manager Dr. Robert Lemor. "We shine laser light into the tissue, causing it to heat up and expand. This generates pressure in the form of a sound wave, which spreads through the tissue in much the same way as ultrasound and is also detected in the same way." The researchers thus combine the good contrast of light with the good spatial resolution of sound, using the advantages of both systems.

To detect cancer cells at an early stage, however, the researchers require an even stronger contrast between cancerous and healthy cells. "We achieve this by using gold particles just a few nanometers in size. Gold absorbs the laser's infrared light much better than the cells, and therefore appears brighter in the picture," says Lemor. The researchers attach antibodies to the gold particles, and these antibodies bond with specific proteins. These occur several thousand times more frequently in cancer cells than in healthy tissue. "This means that the gold accumulates specifically around the cancer cells, while hardly any gold is found on healthy cells," explains Lemor.

The gold particles not only serve diagnostic purposes, they can also be used for therapy. If the laser output is increased and the tissue is irradiated for a longer period, the gold heats up and the generated heat destroys the cancer cells. Healthy tissue is not affected, as hardly any gold accumulates in it. The researchers will present the prototype of this diagnostic and therapeutic device at the Medica trade fair (Hall 10, Stand F05) in Düsseldorf from November 14 to 17. If all goes well, says Lemor, the clinical study could begin in about two to three years.

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