Stanford Researchers develop new imaging technique to detect miniature tumours deep inside the body

Mumbai: A team of Stanford University researchers, led by Dr Sanjiv Gambhir, director of the molecular imaging system and head of nuclear medicine at Stanford, has developed a new imaging technique that can illuminate tiny molecules deep inside the human body, which helps doctors view minuscule tumours, 1,000 times smaller than previously possible.

The Stanford researchers say they have reason to believe that this is the first such development in diagnostic imaging.

This non-invasive molecular imaging of small subjects is called the Raman spectroscopy, which  uses tiny nano particles injected into the body to serve as scientific beacons as they attach themselves to different tumour molecules.

According to the Raman spectroscopy phenomenon, when a tiny object such as a molecule is illuminated with a laser beam, the light causes roughly one in 10 million photons to bounce off the  molecules with an increase or decrease in energy, called Raman scattering. The shift in energy gives information about the photon modes in the system and forms a unique measurable pattern, called a spectral fingerprint, for each type of molecule.

The patterns can be converted into a visible indicator of their location in the body. These strong, long-lived signals can simultaneously transmit information about multiple molecular targets.

Dr Gambhir said, ''Usually we can measure one or two things at a time. With this, we can now likely see 10, 20, 30 things at once.

''This imaging holds significant potential for biomedical imaging of living subjects,'' Gambhir wrote in the study published in the Proceedings of the National Academy of Sciences.

This technique could be useful during tumour surgeries in the removal of even the most microscopic bits of cancerous tissue, the researchers said.

Gambhir's lab is further studying these Raman nano particles, including optimising their size and dosage and evaluating possible toxicity. A clinical trial using gold nano particles in humans in conjunction with a colonoscopy to indicate early-stage colorectal cancer is being planned.