By Daniil Nikitichev

What is the idea?

Photoacoustic imaging (PAI) is an emerging technique that can be used to image vasculature with high spatial resolution. The phenomenon of photoacoustics was discovered in 1880 by Alexander Graham Bell, who observed the production of sound by chopped sunlight. This observation led him to the invention of the “photophone” for transmitting the human voice. This project is centred on creating a PAI demonstration kit for teaching and public engagement activities within the University and at external Festivals and Conferences. Similar to the “photophone”, the demo involves the production of music/human voice using a simple LED torch based on photoacoustic sound generation.

What is the benefit of this teaching demo?

We developed a teaching demonstration tool to illustrate the photoacoustic effect to undergraduate and graduate students based on the experiment that led to its discovery.  This demo will spark the interest of the students and increase their awareness of how this physical phenomenon can be applied to medical imaging for diagnostic purposes.

Public engagement and outreach activities at UCL would benefit from further promoting science with this tool. This demo kit provides a stimulating way of teaching pupils (secondary school students) some basic concepts of physics, and a motivation to select studies across STEM (Science, Technology, Engineering and Mathematics) subjects. On the other hand, people from different backgrounds and ages can engage with state-of-the-art research for medical imaging and diagnostic applications, since PAI is currently applied in preclinical studies based on small animal experiments.

Finally, with this demo kit, scientists and researchers will improve their public speaking and teaching skills and make their presentations more stimulating and approachable to their audience.

How did we approach our project?

The project involved the design of a simple amplification circuit connected to an Apple iPod (or a similar music playing device) through a Bluetooth connection in order to modulate the LEDs of a torch for generation of the photoacoustic effect. The generated signal was detected by a stethoscope. The demo was built at the workshop of the Department of Medical Physics and Biomedical Engineering, UCL. Several engineers from the department provided assistance on technical issues that arose during the project.

Conclusion

At the moment the total cost of the demo is several hundreds pounds due to the cost of the stethoscope. Further work will be performed in reducing the cost and size of the demo. At the moment the demo is available for use to any member of the department for teaching and demonstration purposes. Furthermore, Cambridge University decided to build similar demo based on our design.

D. I. Nikitichev, W. Xia, E. Hill, C. A. Mosse, T. Perkins, K. Konyn, S. Ourselin, A. E. Desjardins, T. Vercauteren: “Music-of-Light Stethoscope: A Demonstration of the Photoacoustic Effect (Photoacoustic Stereo)”, Phys. Educ., 51, 045015, 2016