Researchers from the Netherlands have combined SPECT/CT and fluorescence imaging for use during tumor resection, in an effort to help surgeons better visualize tumors that cannot be seen by the naked eye, and remove them more completely.

In a recent featured basic science article in The Journal of Nuclear Medicine, the researchers from Radboud University Nijmegen Medical Centre in Nijmegen, Netherlands, showed how the dual-modality imaging method helped surgeons distinguish tumor tissue from normal tissue.

The study looked at mouse models of metastatic colorectal cancer and used labetuzumab, which targets carcinoembryonic antigen, a tumor antigen that is overexpressed in colorectal cancer, as the tracer. The labetuzumab was labeled with both a near-infrared fluorescent dye and a radioactive label.

The dual-modality imaging method was able to visualize pulmonary tumor colonies less than a millimeter in size as early as the first week of growth.

“We think that using an antibody with both a radiolabel and a fluorescent label is a powerful combination in image-guided surgery,” Marlène Hekman, the study’s corresponding author, told HCB News. “Both techniques are complementary to each other. Tumors can be visualized preoperatively by SPECT/CT, next localized intraoperatively with a gamma probe and finally resected with fluorescence imaging. The radiolabel overcomes the major limitation of fluorescence imaging, the limited penetration depth in tissue.”

The method could be used for other cancer types with different imaging agents, which Hekman said may revolutionize oncological surgery.

The researchers are currently investigating a similar concept in a clinical trial with renal cell carcinoma patients, and expect to start the clinical trial in colorectal cancer patients soon, Hekman said.