21 Sep 2016
Combination of photoacoustic and ultrasound imagery should provide faster route to accurate diagnosis and reduce rate of ‘false positives’.
A research team from the University of Twente is heading up a new €5.1 million Horizon 2020-funded project to build a laser-based imager expected to dramatically improve screening for breast cancer.
With €4.35 million from the European Union research program and the remaining cash from the Swiss government, project leader Srirang Manohar and colleagues will design and test a clinical prototype system that combines photoacoustic and ultrasound techniques.
Known as “PAMMOTH”, Manohar describes the proposed hardware as a “dream imager”, capable of delivering simultaneous three-dimensional information from two sources, in real time.
Crucially, the photoacoustic element will use different excitation laser wavelengths to determine the level of oxygen saturation in any tumors that are discovered, and the density of blood vessels feeding a tumor. Both provide indications of whether the tumors are benign or malignant - without the need for any artificial contrast agents.
While current imaging schemes are generally good at spotting lesions in breast tissue, the major drawback is that they are much less able to indicate how likely it is that the disease will spread, or the rate at which a tumor might grow in size. It means that millions of women undergo what turn out to be unnecessary biopsies, while others are mis-diagnosed with a benign form of the disease.
Working alongside Manohar and the team from Twente’s Biomedical Photonic Imaging group will be the university’s own related spin-off company, PA Imaging, while local doctors at the Medical Spectrum Twente hospital in Enschede will conduct a pilot study on the system.
Other partners include researchers at University College London, who will develop image reconstruction methods, including quantitative image reconstruction. In Switzerland, Brno University is working on algorithms for real-time imaging, with the University of Bern contributing image analysis expertise.
Ekspla lasers to feature
Among the commercial partners are Lithuanian optics firm Ekspla, which will develop the lasers for the photoacoustic imager, and France-based Imasonic, which will design multi-element ultrasound detectors needed to pick up the tiny high-frequency noise that is generated when tissues absorb the laser excitation pulses.
Germany’s TP21, which is co-ordinating a large number of Brussels-backed translational medicine research projects – including the “FULLPHASE” effort to develop hand-held photoacoustics for point-of-care diagnostics – is overseeing the PAMMOTH project.
Manohar and the Twente team have previously tested their photoacoustic technology on breast cancer patients, and in a paper published last year they reported that their “photoacoustic mammoscope” was able to recognize three different types of tumor.
“We were able to identify lesions in suspect breasts at the expected locations in 28 of 29 cases,” they noted, with Manohar saying at the time that the Twente researchers were already working on a new kind of imager featuring a 755 nm source and computed tomography to reconstruct images from multiple projections around the breast.
The new laser wavelength is important, because it should reveal more about the nature of the tumors imaged, arising from the different absorption coefficients of hemoglobin and oxygenated hemoglobin at 755 nm and 1064 nm.
Earlier this year Alexander Oraevsky, one of the pioneers of optoacoustic imaging, told optics.org that the pace of technological development had now reached the point where effective clinical systems for human applications had become the hottest current topics in the sector.
"The laser industry is catching up, with laser manufacturers now selling components specifically labeled for optoacoustic imaging," he said, while it is hoped that a multi-center trial of Seno Medical's imaging system in the US will soon result in clearance for the technology in clinical diagnostics.
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