Most people – especially pregnant women – have been examined with a medical ultrasound scanner. It’s an accepted and standard tool for monitoring various physiological conditions inside the body. Its great advantage is that unlike computerized tomography (CT) scans and x-rays, it is not based on ionizing radiation, which is considered dangerous in high doses. 

The main component of ultrasound systems is the transducer. This electro-mechanical device transmits and receives ultrasound waves and converts signals in one form of energy to a signal in another. Produces sound waves that bounce off body tissues and make echoes. The transducer also receives the echoes and sends them to a computer that uses them to create a sonogram picture. 

However, the resolution of the ultrasound imaging system is usually lower than that of CT systems, so there is much room for improvement in these devices.  

One of the technological challenges in the world of ultrasound is the development of endoscopic transducers – miniature transducers inserted through a tiny hole in the skin or from one of the body’s natural orifices in a minimally invasive procedure. Such transducers are essential because the scan of deep tissue regions often requires a small transducer that comes close to the target tissue.

For higher resolutions, a microscopy approach is preferred, in which a single focused ultrasound transducer images the object point-by-point, but the bulky apparatus and long acquisition time of this approach limit clinical applications.

Now, a new technology developed at the Technion-Israel Institute of Technology in Haifa will make possible the miniaturization of ultrasound transducers and produce much better images. It is expected to lead to the development of tiny and effective ultrasound systems and other medical applications.

The innovative technology, called SPADE (Silicon-Photonics Acoustic Detector), is based on research led by Prof. Amir Rosenthal and doctoral student Yoav Hazan of the Technion’s Viterbi Faculty of Electrical and Computer Engineering at the Technion-Israel Institute of Technology. Their findings were published in the prestigious journal Nature Communications, “Silicon-photonics acoustic detector for optoacoustic micro-tomography.” 

The challenge in developing these transducers stems partly from the fact that miniaturization impairs their sensitivity, making it difficult to create high-quality images. The SPACE technology developed by the Technion researchers is based on optical components instead of electrical components that alter the image. It makes it possible to perform ultrasound tests in resolutions not previously achieved through this method. 

The researchers believe that the new technology will dramatically improve the resolution of additional diagnostic methods such as vascular imaging using Opto-acoustics. They present the mapping of blood vessels in a mouse’s ear at an unprecedented resolution (about 10 microns).