Handheld Probe Combines Photoacoustics, Ultrasound

A new handheld imaging system that combines photoacoustics and ultrasound produces detailed, real-time images of blood vessels, internal organs and body parts.

Researchers from the University of Twente’s Biomedical Photonic Imaging Group, in collaboration with Esaote Europe, Quantel and Silios Technologies, developed the probe, which uses a customized laser diode stack that emits 130-ns, 0.56 mJ pulses at 805 nm, with a repetition rate of up to 10 kHz. A customized laser driver can be triggered externally “with a high temporal stability” that is necessary to synchronize ultrasound detection and laser pulsing.

According to the researchers, the emitted beam is “collimated with cylindrical microlenses and shaped using a diffractive optical element,” which delivers standard rectangular light intensity distribution.

“Photoacoustics provides optical contrast and functional information while ultrasound provides structural and anatomical information,” the researchers wrote in the study, noting that existing photoacoustic imaging relies on large and expensive systems that limits its clinical application and makes its combination with ultrasound costly and impracticable.

“Our research aimed to break through these hindering factors,” said Twente postdoctoral fellow Khalid Daoudi.

The researchers next plan to expand the design of the imaging system to multiwavelength imaging in the near-infrared; it currently operates at a single wavelength. Applications targeted at a number of different medical issues could be assessed with the new system, they said, including rheumatoid arthritis in finger joints, oncology, cardiovascular disease and burns.

The research was published in Optics Express (doi: 10.1364/OE.22.026365).

For more information, visit www.utwente.nl.