Translational research on understanding the interaction of light with biological tissues and how such knowledge can be used for the detection, diagnosis and treatment of human disease. Pioneer of minimally invasive treatments for a range of cancers using thermal lasers and photodynamic therapy (PDT, a treatment involving sensitising tissue with photosensitising drugs which are then activated by laser light). Leader of translational research group that has pioneered PDT for treatment of cancers of the mouth, oesophagus, pancreas, bile duct, prostate. Developer of optical techniques, particularly elastic scattering spectroscopy, that can detect pre-cancerous changes in tissue without the need for conventional biopsy and before they are visible directly.