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How do you demonstrate gamma imaging practically to students, without a radiation hazard?

Adam PGibson10 January 2017

By Rebecca Yerworth

This was the challenge set to 3rd year project student Nicola Wolf. The outcome? Gamma Anna, and a paper in Physics Education. The interactive demonstration that Nicola developed is applicable to medical students, secondary school lessons, and younger children when used with an appropriate age specific work sheet.

What is Gamma Imaging? It is a medical diagnostic technique which involves injecting small amount of radioactive material (tracer) in to a patient and looking to see where it goes using a radiation detector, known as a gamma camera.  The tracer is designed to be selectively absorbed into tissues of interest – e.g. radioactive glucose will accumulate in those parts of the body that are using the most energy…. Tumours have a high energy demand, so they will show up bright in the image. This is a useful tool for doctors if they want to see if a cancer has spread.

Why produce a teaching demo? It is common knowledge that well designed interactive activities increase understanding of the subject and retention of knowledge, as well as student engagement and enjoyment. However you can’t safely demonstrate real gamma imaging to students, because of the radiation hazard, quite apart from the logistics: Gamma cameras are large (room sized) and expensive. The Gamma Anna demo uses a series of analogies to explained key concepts of the imaging technique: heat, from an exothermic reaction represents the gamma radiation; tumours are represented by plaster of Paris; saline the radioactive tracer and a thermal imaging camera represents the Gamma camera. ‘Anna’ herself is a ragdoll into which the ‘tumours’ can be placed.gammaanna

Who is the demo for? Nicola tested the demo with GCSE grade students, where it served to explain principles of radiation and showed applications of physics to medicine and engineering – a topic with the potential to motivate students, including girls, to choose STEM subjects at A’ level and beyond. She also tested it with medical students, where the focus was on improving their ability to accurately advise future patients. Gamma Anna could also be used with younger children, either at an outreach event or as play-therapy if they, or a relative, need to undergo gamma imaging.  In each case age/course appropriate work sheets should be used; examples are available for download from the link above.

In conclusion… Gamma Anna is cheap, safe and easy to make and use. The largest expense being a thermal imaging camera, but mobile phone adapters are suitable, can be bought for less than £200, and are a useful resource for other demos too.

Music of Light stethoscope

Adam PGibson13 July 2016

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.

Daniil demonstrating his photoacoustic stethoscope

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