Shortwave IR Imaging Aids in Tumor Identification

A method combining highly detailed, real-time images within the body with shortwave infrared (SWIR) light has been used for the first time during surgery to differentiate cancerous tumors and healthy tissue.

The technique, which was already demonstrated in mice, was developed by engineers at the Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS) at University College London (UCL) and surgeons at Great Ormond Street Hospital (GOSH).

SWIR imaging holds advantages over conventional near-infrared (NIR) imaging, with reduced tissue scattering and autofluorescence. As part of the work, the researchers constructed a multispectral NIR-I/SWIR fluorescence imaging device to allow an objective comparison between the two imaging windows.

The researchers said that the development could have implications for treating neuroblastoma, which is among the most common forms of solid cancer tumors found in children. Standard treatment typically involves surgery to completely remove cancerous cells, which can be difficult to see as they look similar to the surrounding healthy tissue.

In the recent work, the UCL and GOSH scientists used molecular imaging during surgery. With this approach, fluorescent chemicals are injected into the bloodstream to act as imaging probes. These chemicals are attracted to cancerous cells in the body. Once attached, the probes light up. This in turn lights up the tumor.

The technique, used during preclinical testing in mice, successfully revealed part of a tumor that had not been removed during surgery.

Using a high-definition camera to capture SWIR fluorescence, the researchers were able to then distinguish between cancerous tumors and healthy tissue during preclinical tests.

“Surgery to remove neuroblastoma requires a delicate balance. Remove too little and the tumor might grow back, but remove too much and the surgeon risks damaging the surrounding blood vessels, nerves and other healthy organs,” said team leader Stefano Giuliani, consultant pediatric surgeon at GOSH and associate professor at UCL Great Ormond Street Institute of Child Health. “This technique effectively lights up the tumor, allowing surgeons to remove it with unprecedented precision.”

Unlike x-ray or magnetic resonance imaging, which focus on organs and bones, molecular imaging produces detailed pictures of biological processes. It can be done live during surgery, meaning clinical teams don’t have to wait for biopsy or culture results when screening for diseases. The SWIR component enhances the images in real time.

Researchers at GOSH and UCL WEISS are now working to fast track the technology into the operating theater at GOSH within the next 12 months to benefit children with cancerous tumors. The team is also exploring the use of machine vision techniques to produce a binary classification map outlining the tumor based on fluorescence spectra across the NIR-SWIR range to provide an objective, robust image segmentation to the surgeon.

The research was published in Cancer Research (www.doi.org/10.1158/0008-5472.CAN-22-2918).