New-generation CT scanners promise better diagnosis
An EU-funded project has made a breakthrough in medical imaging. By developing a photon-counting detector for CT scanners, higher-resolution images with lower radiation doses can be produced for accurate non-invasive screening and diagnosis of diseases.
© Eric Le Roux/ Université de Lyon, 2019
Computed tomography (CT) is the most widely used medical whole-body imaging technology. The key challenge now is to find higher-resolution methods that can deliver earlier and more accurate disease diagnoses, bringing further major healthcare benefits.
The EU-funded SPCCT project is developing imaging technology for accurate early detection, characterisation and monitoring of cardio- and neuro-vascular disease, MSK disease and lung cancer. Its big innovation is to detect photons and resolve spectral information for specific elements in body tissues, for improved non-invasive diagnosis.
I think it is a very important evolution for medical imaging, says project manager Philippe Douek, of the University of Lyon in France. We are developing a new type of detector, a photocounting detector, that should reduce the radiation dose for the patient and increase the detectability of lesions because of higher spatial resolution, in the very near future.
The longer-term aim, he says, is to combine the development of the CT technology with a new type of contrast agent. These imaging biomarkers will better distinguish diseased from healthy tissue and provide new clinically relevant information.
Less radiation, better images
CT scans combine x-ray images to create 3D pictures from inside the body. This exposes patients to x-ray radiation. The photon-counting detector enables scanners to use lower radiation doses, because it operates with less electronic noise. Lower radiation doses tend to give noisier images, but reduced detector noise compensates to give a much better signal.
The innovative Spatial Photon Counting CT (SPCCT) technology detects smaller things in the human body at a much higher resolution. It represents a breakthrough in the early detection of pathologies and the diagnosis of illnesses such as coronary artery disease.
Project partners in Italy and France are developing contrast agents to obtain colour images with additional information for clinicians. These are being tested by academia partners on animals, before the first toxicological studies.
Now, if you do CT you have a black-and-white image, which can distinguish the extent of an attenuation lesion, says Douek. This is essentially a visualisation of tissue density that highlights various pathologic conditions. If you inject two compounds you will not be able to discriminate between them. We have a detector that counts each photon and, with the technology we are developing, assesses a wide range of photon energies. Combined with K-edge technology, you will see the photo-attenuation of each of the compounds.
K-edge refers to the element-specific spike in x-ray absorption at a particular energy. By setting the CT scanner for a series of adjustable energy bins for K-edge imaging, multiple contrast agents injected into patients can be simultaneously imaged. The behaviour of contrast agents, such as iodine, gadolinium and barium, will provide valuable new information for early detection, screening and diagnostic purposes.
A widely accessible technology
The first prototype CT scanner fitted with a photon-counting detector is being used on patients in Lyon on an experimental basis. CT technology is used in many hospitals, even in small cities, which would enable the new technology to be accessible everywhere in Europe.
We will give a very high-end technology to all types of hospitals and clinics in Europe to provide for better diagnosis, says Douek. Therefore, we think the impact on healthcare will be very important. Patients will not need to travel to large hospitals with high-end nuclear technology to get disease screening or a precise diagnosis.
The project brings together the necessary engineering and clinical expertise, with academic researchers and industry experts from SMEs and large companies. The system is to be developed and sold by Philips.