Daniel Lighter

Doctoral Researcher
Physical Sciences for Health CDT 

Thesis project - "Diffuse Optical Tomography Imaging In Rheumatoid Arthritis"

Dr Hamid Dehghani, School of Computer Science
Dr Andrew Filer, Institute of Inflammation and Ageing
Dr Iain Styles, School of Computer Science

Approximately 1% of the population are affected by Rheumatoid Arthritis (RA), an autoimmune disease where inflammation in the joints can lead to destruction of bone and eventually disability. Improvements over recent decades in anti-inflammatory therapies mean that by using an individual-tailored treatment strategy and monitoring symptoms closely, control of inflammation and resulting damage can be significantly improved. In the initial stages of the disease, there is a window of therapeutic opportunity, during the first three to four months from onset of symptoms, during which aggressive treatment leads to better long term patient outcomes. Hence a cheap, non-invasive and easy to use tool capable of diagnosing people with RA very early on is highly desired by rheumatologists.

A range of imaging tools for this goal already exist, yet each have their own drawbacks for early diagnosis. Computed Tomography and X-ray reveal little information on any early muscle or ligament changes, along with their inherent radiation risk. Magnetic Resonance Imaging is highly effective in diagnosing RA, yet its high cost and poor tolerance by many patients prevent its widespread clinical use early on. Ultrasound (US) examinations are increasingly used in early RA, where increased blood flow associated with RA is measured, however they can only be performed by trained clinicians, take around 20 minutes and results vary depending on the operator.

RA joints are known to display lower oxygen levels than healthy joints, which are thought to play an important role in stimulating inflammation. Near infrared (NIR) spectroscopy is one technique that has been widely used to measure oxygen levels in living tissue, with particular success investigating brain oxygenation and breast tumours. We aim to develop and evaluate a novel, non-invasive NIR imaging system employing a method called Diffuse Optical Tomography (DOT), where taking measurements at several locations on the hand will allow three dimensional oxygenation maps to be generated. The novel nature of our system will combine some key advantageous features from a selection of existing state of the art NIR technologies, including 1. no need for invasive probes or markers 2. will measure at several wavelengths of NIR light, allowing measurement of oxygenation 3. will provide this information in three dimensions 4. no detectors will need to be in contact with the hand and finally 5. will not be limited to specific joints, but capable of imaging the whole hand.

 Completion of this project requires an interdisciplinary approach, using knowledge from all three scientific areas in Sci-Phy. Physical Sciences are required to design equipment capable of accurately measuring light transmitted through a human hand. The collected data will need Computational techniques to process 3D data. Finally an understanding of the Biomedical Sciences is needed to interpret oxygenation maps and relate them to the mechanisms of arthritis.

 Once a system has been developed, testing will be carried out to establish performance in both healthy human subjects and RA patients, including studies over a year following patients, to establish the validity of the system. As successful development of this technology has the potential to fulfil a clinical need, it is crucial that it is low cost, easy to use (capable of being administered by technical or support staff instead of a clinician), and rapid, producing useful data in under 10 minutes. If successfully developed, this new imaging system for diagnosing RA would provide several benefits to the NHS. In addition to being lower cost, more easily tolerated by patients and faster than alternative imaging techniques, it also has the potential to be more effective at diagnosing patients at these crucial early stages of RA, meaning patients can receive treatment sooner and improve the long term outcome of their disease.