Positron emission tomography (PET) scanning differs from most other medical imaging techniques because it is used to look at function inside the body, rather than structure. In this video interview, Simon Cherry from UC Davis in the US explains the physics underpinning PET scans and how these machines are used in the diagnoses and monitoring of cancer. Cherry is the leader of the $15.5m EXPLORER project to develop the world’s first PET scanner that can image the entire body simultaneously. He speaks about how the technology could cut costs, improve patient experience and open new medical opportunities.
In PET scans, patients are injected with radioactive tracers, which emit positrons that annihilate upon collision with electrons in tissue. The result is the release of photon pairs, which trigger signals in external detectors – enabling medical physicists to create maps of internal biological processes. Cherry says the process is “a beautiful example of Einstein’s E = mc2 equation”, before explaining how tumours can be diagnosed from their high demand for the biological tracer.
Depending on the scale of the affected area, patients often require a sequence of scans so that clinicians can piece together 3D images of their body. Therefore, the ability to image an entire body in one scanning procedure would bring many advantages. It could reduce running costs and the time required for scans, as well as the amount of radioactive tracer material required. Cherry also speaks about how the technology could be used to monitor and diagnose other medical conditions that affect large areas of the body, including infections and inflammations.
This is the final interview in a three-part series that profiles pioneering medical physicists. Last week’s video featured Katia Parodi of Ludwig-Maximilians University in Germany speaking about using acoustic signals to track ion-beam therapy. The previous week, we profiled Bas Raaymakers from UC Utrecht, speaking about using magnetic resonance imaging (MRI) alongside radiotherapy. All three scientists are board members of Physics in Medicine & Biology, a journal published by IOP Publishing, which also publishes Physics World.