SPADnet looks to improve PET imaging

Technology commonly used to fabricate microchips could be employed to make medical-imaging devices that expose patients to less radiation.

This is the belief of researchers involved in the SPADnet – ’Fully Networked, Digital Components for Photon-starved Biomedical Imaging Systems’ – project.

The EU-funded project is co-ordinated by Swiss university EPFL and includes seven European experts in image sensors, medical imaging and photonics.

SPADnet will focus on improving positron emission tomography (PET), which is used for imaging biological processes, helping doctors to spot tumours.

A patient is injected with a radioactive ’tracer’ material that mimics a biologically active molecule in the body such as glucose.

When the tumour metabolises the tracer, it will emit positrons. These then emit secondary gamma rays that will affect a scintillator material, which converts the gamma rays into photons.

“The developments could enable better-quality images with lower doses of radiotracers”

EPFL research co-ordinator Claudio Bruschini said these methods often produce only rare, single bursts of photons and existing sensors are not well adapted for capturing these events.

The aim of SPADnet is to create a scalable photonic component for large-format, rare-event imaging in biomedical applications that are ’photon starved’. The core of the part will be a SPAD array implemented in a complementary metal oxide semiconductor (CMOS) – a fabrication technology used in microchips.

The proposed developments will potentially enable better-quality images with lower doses of radiotracers,’ said Bruschini. ’Other applications are also photon starved in the biomedical sector, such as those based on fluorescence lifetime imaging, which can also be tackled by the proposed sensor.’