Sensing and Imaging for Healthcare

Modern healthcare has been transformed by sensing and imaging technology. In the Centre for Quantum Technology we are developing new optical cameras that could be the successors to existing MRI and endoscopy equipment. 

Quantum science is being applied to the continual improvement of existing technologies in this sphere. But it also provides the foundation for new imaging systems and devices that will underpin the next revolutionary steps in healthcare.    

Imaging through the body 

We are working on seeing through the human body using optical imaging technologies. 

Although light can be transmitted through thick layers of human tissue, the way this light is scattered had made it unsuitable for capturing an image. 

However, various quantum imaging techniques - structured illumination, single photon detection, precise time for flight measurement – have been combined with machine learning approaches to reconstruct images from this previously ‘unsuitable’ scattered light.  

Time for flight measurement uses ultra-fast, ultra-sensitive detectors to record the time between a photon being emitted from a laser and hitting a separate detector. This enables the distances to objects to be calculated, which allows imaging in 3D.  

Using these approaches, we are working to obtain images of objects buried in these high-scattering tissues and even through bone.  

We are exploring how light alone might be able to record images of the outer layer of the brain corresponding to what traditionally is akin to MRI. 

Eventually, we’d like to take these techniques out of the lab and develop them into wearable optical technologies. These new medical devices could start to replace some of the functionality of X-ray machines or MRI machines. 

The ratio of MRI machines to people is still very low, even in developed economies. If these wearable optical technologies could fill some of the uses for a conventional MRI machine, the wait times for these bigger devices then decreases. 

For example, when someone suffers a stroke, that person needs to get to an MRI machine to diagnose which type of stroke it is. In this case, we can imagine a wearable helmet which is made available in an ambulance to quickly diagnose which type of stroke it is, to ensure the correct treatment is given as quickly as possible. A hospital MRI machine could then manage more scheduled scans. 

There is also potential for these optical imaging technologies to become personal health monitoring devices. Potentially, these imaging through the body technologies will lead to very cheap devices made of silicon which are able to be mass manufactured. There is potential for the equivalent of a personal heart monitor for your brain. This could potentially monitor your mental activity and mental state, helping us improve our lifestyle. 

For research into the brain, these devices would allow neuroscientists to examine the effect of motor and visual stimuli without the inconvenience and interference of confining subjects to an MRI machine.  

Quantum enhanced microscopy 

We are developing microscopes with improved resolution, spectral coverage and noise rejection (the removal of unwanted pixels). These are imaging systems that beat the fundamental performance limits of classical physics.  

Whereas a classical source generates photons one by one, a quantum source generates photons in pairs so that each probe photon has an identical reference against which it can be compared or combined to improve the quality of the image.  

We have demonstrated world-first approaches showing the potential of the quantum approach.  

Quantum 3D endoscope  

In applications like endoscopy, imaging is traditionally achieved by using a bundle of optical fibres, one fibre for every pixel in the image, resulting in devices the thickness of a finger. 

As an alternative, we are developing a new technique for imaging through a single fibre the width of a human hair. Our ambition is to create a new generation of single-fibre imaging devices. 

This ultra-thin endoscope camera could enable minimally invasive medical imaging. 

Replacing a traditional fibre bundle endoscope with a single multi-mode fibre endoscope has some challenges though.  

The problem with single multi-mode fibres is that light passing through them is completely scrambled, which makes any image it generates unrecognisable.  

To overcome this, we have developed beam shaping techniques to change the way the light passes out of the fibre. The scrambling effect is reduced as the light is turned into a focal spot instead. 

That spot of light then scans over the scene and the system measures the intensity of the backscattered light into another fibre - giving the brightness of each pixel in the image. 

By using a pulsed laser, we can also measure the time of flight of the light and hence the range of every pixel in the image. These 3D images can be recorded at distances from a few tens of millimetres to several metres away from the fibre end with millimetric distance resolution and frame rates high enough to perceive motion at close to video quality. 

Our current system works at video rates in real time. It can create images of objects or humans up to three meters away.   

In order to develop the technology into an endoscopic device for medical healthcare imaging, we are working to improve the resolution of our system and its reliability when the fibre is required to bend.