4 days ago
IISc researchers develop new imaging method to detect tumours
BENGALURU: Researchers at the Indian Institute of Science (IISc) in Bengaluru have developed a new imaging molecule that could help detect tumours accurately, at a fraction of the cost of current methods and without the risks associated with repeated radiation exposure.
The molecule, called GPc, is created by scientists from the Department of Bioengineering at IISc and designed for use with Photoacoustic (PA) Tomography, a relatively new imaging technique. Their work could open the door to safer and more affordable tumour detection, especially for tumours located close to the body's surface.
Tumour cells are far more active than healthy ones and consume a lot more glucose. PET (Positron Emission Tomography) scans — currently the gold standard in cancer imaging — take advantage of this by injecting patients with a radioactive sugar molecule called 18F-FDG. This sugar builds up in tumours, helping doctors spot them. But PET scans are expensive and repeated scans can expose patients to harmful radiation over time.
Photoacoustic Tomography uses a safer approach. A near-infrared laser beam is directed at special light-absorbing molecules, called chromophores, which slightly expand and create tiny pressure waves when heated. These waves can be detected as sound signals and processed into 3D images. The method is less costly than PET or MRI and works well for mapping superficial tumours.
At present, clinical PA imaging mostly relies on natural chromophores already found in the body, such as haemoglobin. But haemoglobin's signals, while useful, are not strong enough for certain diagnostic needs. This is where IISc's innovation comes in.
The team conducted several experiments to see whether GPc enters cells the same way glucose does and whether it competes with glucose for entry. This was important because if GPc behaved like a glucose 'agonist', entering cells and being metabolised, it might not work as a good imaging agent. The results were promising. GPc entered tumour cells easily, was not metabolised, and did not depend on GLUT1 transporters (the proteins that normally carry glucose into cells).
