New photoacoustic imaging technique could improve endoscopy
Researchers have developed a flexible photoacoustic imaging technique that uses fiber-optic ultrasound to detect acoustic effects of laser pulses.
Long Jin, the lead researcher from the Institute of Photonics Technology at Jinan University in Guangzhou, China, presented his team’s findings Monday, Sept. 17, at the OSA Frontiers in Optics + Laser Science APS/DLS conference in Washington, D.C.
The sensors, designed specifically for medical applications, deliver improved sensitivity when compared to conventional fiber optic sensors, which have difficulty detecting low-frequency acoustic waves. The researchers designed the system to include a compact laser inside the core of a single-mode optical fiber.
Jin et al. placed the sensor near a mouse to detect optically induced ultrasound waves.
"By raster scanning the laser spot, we can obtain a photoacoustic image of the vessels and capillaries of a mouse's ear," Jin said. "This method can also be used to structurally image other tissues and functionally image oxygen distribution by using other excitation wavelengths—which takes advantage of the characteristic absorption spectra of different target tissues."
Optical fibers are useful because they are tiny, lightweight, and intrinsically flexible, Jin added.
"The development of our laser sensor is very encouraging because of its potential for endoscopes and wearable applications," Jin said. "But current commercial endoscopic products are typically millimeters in dimension, which can cause pain, and they don't work well within hollow organs with limited space."
The researchers believe the new technique could be used in wearable devices, endoscopes and other instrumentation.