Welcome Physics World  August 2020

Diagnosing, tracking and studying disease

High-sensitivity detector. (Los Alamos National Laboratory)

Welcome to this Physics World Briefing dedicated to all things medical imaging. In this issue we examine recent developments in imaging modalities ranging from X-ray to optical, MRI to ultrasound, PET to SPECT, and more. And as these imaging technologies and devices evolve and progress, their potential medical uses expand alongside. We describe applications such as monitoring brain glucose to help detect Alzheimer’s disease, using 3D ultrafast ultrasound to measure coronary blood flow and even investigating the effects of space travel on astronauts’ brains.

One ongoing challenge in radiological imaging is keeping the delivered dose down. Among many research efforts to achieve this goal, a team from Los Alamos National Laboratory has developed a perovskite thin-film X-ray detector that’s 100 times more sensitive than conventional detectors, allowing a big reduction in the required imaging dose. In Australia, researchers are investigating the use of propagation-based phase-contrast CT for breast imaging. This technology can generate high-quality diagnostic images at a comparable or lower radiation dose than conventional mammography or digital breast tomosynthesis.

Another development that’s playing an increasing role in medical diagnostics is artificial intelligence (AI). We take a look at examples such as AI analysis of CT scans to diagnose disease, modelling radiomics features from MR images to help predict patient survival and using deep-learning to forecast cancer recurrence from pathology images. But there’s also a note of caution – a study headed up at the University of Cambridge showed that deep-learning tools used to create high-quality images from short scans are unreliable, producing artefacts that could affect diagnosis.

Ultrahigh-resolution imaging is another flourishing research area. A team in Australia, for example, has developed a motion-correction method for single-molecule localization microscopy that enables researchers to measure the position of individual molecules with nanometre precision. Elsewhere, a UK-led team has created a laboratory-scale coherent extreme-UV source, and used it to create high-resolution images of lab-grown neurons. These highly detailed images could find use, for example, in the study of neurodegenerative diseases.

We also speak to medical physicist and entrepreneur Maryellen Giger. She describes the events that sparked her initial interest in medical physics and explains how she went on to establish the use of artificial intelligence in breast cancer imaging.