Washington: Cancer surgeons are virtually groping in the dark in determining whether they have removed all of the diseased tissue - the key to successful surgery. But a new imaging technique developed by researchers enables surgeons to more readily see and remove cancerous tissues, minimising damage to normal tissue.

"This technique is really the first time that cancer surgeons can see structures that are otherwise invisible, providing true image-guided surgery," said project director John Frangioni, of Beth Israel Deaconess Medical Centre (BIDMC), Boston.

The system is called FLARE or Fluorescence-Assisted Resection and Exploration. Developed over the past decade, the portable system comprises a near-infrared (NIR) imaging system, a video monitor and a computer.

"The system has no moving parts, uses LEDs instead of lasers for excitation, makes no contact with the patient, and is sterile," Frangioni added. The findings were presented Sunday at the 236th National Meeting of the American Chemical Society (ACS).

The system uses chemical dyes, NIR fluorophores, designed to target specific cancer cells when injected into patients. Exposed to NIR light, invisible to the human eye, dyes or contrast agents light up the cancer cells which are shown on a video monitor.

Images of these "glowing" cells are then superimposed over images of the normal surgical field, allowing surgeons to easily see the cancer cells even in a background crowded by blood and other anatomical structures, the researchers informed.

Frangioni compared the system to the old colour-by-number paint sets. Instead of colouring by numbers, it will provide surgeons with a means of "cutting by colour", he said.

The computerised technique also gives physicians the power to control multiple viewing angles and different magnification levels through the use of a foot switch.

In preliminary studies, Frangioni and colleagues used the FLARE to successfully visualise organs and body fluids of mice and map the lymph nodes of pigs, all in real-time.

The first human clinical trials, slated this summer, involve mapping the lymph nodes of a small group of patients with breast cancer. Broader clinical use of the device could occur within five years, the researchers estimate.

In the future, fluorophores could be developed to highlight nerves and blood vessels in one colour while visualising cancer cells in a different colour, allowing multiple structures to be viewed easily and even simultaneously, he said. IANS