Surgeons need to determine exactly where the cancerous cells lie before they exorcise a tumour.
The dual-mode imager combines two systems-near-infrared fluorescent imaging to detect marked cancer cells and visible light reflectance imaging to see the contours of the tissue itself-into one small, lightweight package approximately the size of a quarter in diameter, just 25 millimetre across.
"Dual modality is the path forward because it has significant advantages over single modality," said Rongguang Liang, an associate professor of optical sciences at University of Arizona in the US.
"By combining different modalities together, you get a much better picture of the tissue," which could help surgeons make sure they remove every last bit of the tumour and as small amount of healthy tissue as possible, said Brian Applegate of Texas A&M University in the US.
People have realised that in order to better diagnose diseases like cancer, he noted, you need information from a variety of sources, whether it is fluorescence imaging, optical imaging or biochemical markers.
The findings appeared in the journal Optics Letters.