Progress makes laser based imaging simpler and more three-dimensional

a. b. Schematic diagram of PACTER system calibration and imaging program. BT, beam trap; DAQ, data acquisition unit; HWP, half wave plate; PBS, polarization beam splitter; ER, traverse the relay. The difference between the two modes is highlighted by a black dashed box.

c. Schematic diagram of a single component ultrasonic transducer manufactured on ER.

d. The ultrasound transducer detected 1D PATTER signals 0, t1, and tN. e at time instance t, and reconstructed a 4D image of the human palm blood vessel based on the signals in d.

Sometimes, scientific progress appears in the form of discovering new things. At other times, progress boils down to doing better, faster, or easier. The new research by Professor Li Hong Wang, a professor of medical and electrical engineering at the California Institute of Technology and Professor Bren Wang's laboratory, is the latter.

In a paper published in the journal Nature Biomedical Engineering titled "Ultrafast longitudinal imaging of biomedical via single shot volumetric photoacoustic tomography with a single element detector," Wang and postdoctoral scholar Yide Zhang demonstrated how they simplified and improved the imaging technology they first announced in 2020.

This technology is a photoacoustic imaging technique called PATER, which is the expertise of the Wang team.
In photoacoustic imaging, the laser is pulsed into the tissue, where it is absorbed by the molecules of the tissue, causing them to vibrate. Each vibrating molecule serves as a source of ultrasound and can be used to image internal structures in a manner similar to ultrasound imaging.

However, photoacoustic imaging is technically challenging as it can generate all imaging information in a short period of time. In order to capture this information, early versions of Wang's photoacoustic imaging technology required pressing arrays of hundreds of sensors onto the surface of the imaged tissue, making the technology complex and expensive.

Wang and Zhang reduced the required number of transducers by using a device called a traversal relay, which slows down the speed of information flowing into the transducers. As explained in the previous story about PATER: "In computing, there are two main ways to transmit data: serial and parallel. In serial transmission, data is sent in a single stream form through a communication channel. In parallel transmission, multiple communication channels are used to send multiple data simultaneously.".

Source: Laser Net