Label-free imaging pinpoints ovarian cancer

 

US-based researchers have combined multi-photon microscopy with computational analysis in a bid to rapidly pinpoint ovarian metastases in the operating room. 

 

Current technologies, including traditional light microscopy, which detect tumour cells can miss metabolic and structural “signatures” of small micro-metastases from parent tumours.

 

However the latest multi-photon microscopy method, developed by Professor Irene Georgakoudi from Biomedical Engineering at Tufts University and colleagues, is claimed to identify these markers with great accuracy.

 

“This is extremely high impact work,” says Dr Behrouz Shabestari, Director of the National Institute of Biomedical Imaging and Bioengineering Program in Optical Imaging and Spectroscopy.

 

“The ultimate aim of using this technology during surgery - to detect and remove routinely missed metastases - promises to significantly improve surgical outcomes for women being treated for ovarian cancer,” he adds. “Plus, the technology will also be applicable to other types of cancer.”

 

The two-photon laser scanning microscopy involves firing short bursts of laser light at the tissue to to generate fluorescence and SHG images at 755 nm and 900 nm excitation.

 

Laser light was focused on the sample using a 25x objective (0.9 NA / water-immersion), and neutral density filters were also employed to achieve a power of 25–35 mW.

 

The laser light reflects off different components of the tissue, which have different shapes and textures and therefore, emit different signals.

 

The signals are captured and analysed by automated image processing algorithms and statistical textural analysis techniques to ultimately pinpoint whether tissues are normal or cancerous.

 

As the researchers point out, combining the laser microscopy and the computations allows the identification of each type of tissue without any sort of chemical labelling or processing of the tissue.

 

This is a critical aspect of the technology because it raises the possibility of using the system in the operating room to scan tissues during surgery, where tiny metastatic areas, not visible with current technologies, could be removed along with removal of the primary ovarian tumour tissue.

 

 

The researchers have assessed the feasibility of using the microscope during a laparoscopy, imaging healthy and diseased biopsies from eight patients.

 

Remarkably, the technique correctly classified 40 of the 41 images with 11 of 11 correctly classified as metastatic and 29 of 30 classified as healthy.

 

“The results of this study are extremely encouraging,” says Dr Dimitra Pouli from Biomedical Engineering at Tufts. “The next steps include verifying our results with a larger sample from a wider variety of patients.”

 

The researchers are also hoping to integrate the microscope into the repertoire of surgical instruments to realise the ultimate goal of analysis of tissues during an operation.

 

This would allow immediate removal of formerly undetectable areas of metastatic cancer.

 

Research is published in Biomedical Optics Express.