New study reports first known use of positron emission particle tracking in a living animal

Researchers from the School of Biomedical Engineering and Imaging Sciences have published for the first time a new study exploring the use of positron emission particle tracking (PEPT) in a living subject.

PEPT technology enables 3D localization and tracking of a single radioactive particle within large, dense and/or optically opaque systems that are difficult to study using other methodologies. The technology is currently used to study flows within complex mechanical systems such as large motors, industrial mixers, etc., but has not yet been translated for use in biomedical applications.

PEPT was previously an unexplored area in biomedical imaging due to the lack of methods to isolate and radiolabel a single particle of small enough size and sufficient radioactivity to allow its injection and detection in a living subject.

In this new study published in the journal Nature Nanotechnologylead author Dr. Juan Pellico and a multidisciplinary team led by Dr. Rafael TM de Rosales were able to synthesize, radiolabel and isolate a single submicrometer particle of silica with sufficient radioactivity to allow detection with standard PET imaging and PEPT for the first time. .

“Our ambition is to further expand on these findings and develop improved PEPT tracers that will allow us to fully explore the potential of PEPT in biomedicine to provide whole-body insights into blood flow dynamics in different settings, with unique applications such as the study of complex multiphasic blood flow, crucial in clinical physiology and drug delivery,” explains Dr. Rafael TM de Rosales, reader in imaging chemistry at the School of Biomedical Engineering and imaging sciences.

“Other potential applications include the use of single particles for radiotherapy or high-precision PEPT-guided surgery. Additionally, in vivo PEPT with single radiolabeled cells should enable assessment of movement and migration of individual cells, as well as their interaction with blood vessels and tissues. PEPT allows you to triangulate the position of a single particle inside the body with high precision and in real time.

“In current PET imaging methods, we inject billions or even trillions of radiolabeled molecules into patients and the resulting images depict their average distribution after a period of time, typically 10 to 30 minutes.

“It doesn’t give you information about the speed of these molecules or where exactly they are in the body in real time, which could be useful for studying hemodynamics or how blood flows through your body. vessels.

“PEPT, by tracking single particles in real time, should enable the study of the velocity, density and overall dynamics of blood flow that are currently impossible to study by any other imaging modality. The study of hemodynamics at a whole-body level is particularly timely as clinical whole-body PET scanners are now available, one of which will soon be installed here at King’s.

In vivo PEPT has the potential to make significant advances in the assessment of abnormal events in cardiovascular disease or cancer where blood flow has a significant impact.

Future clinical applications could include detailed analysis of blood flow and pressure gradients within lesions such as tumors or vascular lesions, where blood flow is abnormal, which could be used to guide treatment options for the patients.