New Optical Biopsy System That Detects Liver Cancer Could Help Surgeons Pinpoint Best Place for Biopsy

Researchers have developed an optical biopsy system that can distinguish between cancerous and healthy liver tissue.

The new technology developed by a research team from Orel State University (Oryol, Russia) could make it easier to diagnose liver cancer, which is the sixth most common cancer globally. The optical biopsy system can reliably distinguish between cancerous and healthy cells in mouse models. The system also showed promise in preliminary tests conducted in people with suspected liver cancer.

The researchers designed the new device after the surgeons with which they were collaborating noted how difficult it is to perform needle biopsies in exactly the right location. Early-stage tumors can be hard to pinpoint when inserting a tiny hollow needle into the liver to acquire a tissue sample. If the needle is placed incorrectly and misses the tumor, it could lead to an incorrect diagnosis.

The new optical biopsy system combines diffuse reflectance spectroscopy and lifetime fluorescence measurements to evaluate markers related to cellular metabolism, which differs between healthy and cancerous cells. This could help surgeons see, in real time, where the cancer is so that they can identify the best place to acquire a tissue sample. Diffuse reflectance spectroscopy reveals tissue properties based on how they reflect light. Fluorescence lifetime analysis exposes tissues to a wavelength of light that induces fluorescence and then measures how long that fluorescence takes to fade. The timing of the fluorescence decay depends on the presence of molecules that are important in metabolism.

With a focus on using the new instrument to guide future biopsies in the clinic, the researchers selected compact, modern components for the device. The 1-millimeter-diameter probe is compatible with a standard 17.5G biopsy needle and has separate optical channels for diffuse reflectance spectroscopy and fluorescence lifetime measurements. To assess the sensitivity of the assembled system, the researchers first measured known solutions of molecules that play key roles in metabolism. Once they obtained satisfactory results, they then performed experiments in a mouse model with liver cancer and preliminary measurements in patients with suspected liver cancer. The researchers found that their instrument and the parameters they measured could reliably distinguish liver cancer tissue, healthy liver tissue and the metabolically changed liver tissues that surround a tumor.

The researchers plan to continue measuring fluorescence lifetime parameters in patients with different types of tumors at different stages to generate real-time diagnostic classifiers. This will also make it possible to apply advanced machine learning methods that could help surgeons make clinical decisions during a biopsy procedure.

“The instrument is designed to be compatible with the needles currently used for liver biopsies,” said Evgenii Zherebtsov, a member of the research team. “It could thus one day help surgeons more precisely navigate the biopsy instrument to decrease the number of errors in taking tissue samples that are used for diagnosis.”

“Optical biopsy methods like the one we developed make it possible to differentiate healthy and tumor tissues with a high degree of accuracy,” said Elena V. Potapova, who assisted Zherebtsov. “Although our system was specifically designed for use in abdominal surgery, our results show that similar technologies could be useful for other medical applications.”

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Orel State University