This is the second part which highlights the role that various imaging techniques play and/or might be able to play in detecting markers of disease. Cancer is often used as the example disease, but tumors exhibit many properties in common with other tissue, so it is possible to see how the techniques could be used in the diagnosis and management of other disease. There are also examples of the reverse of this flow of hypothesis and knowledge from one discipline to another. Magnetic resonance spectroscopy can be used to detect the chemical milieu of the nucleus being focused on, be it phosphorus-31 (Arias-Mendoza) or protons (He). Phosphorus is intimately involved in carbohydrate, phospholipid metabolism and energy transfer. The brain has been the testing ground for ideas in MRI and MRS; it continues to be so today, with extension to tumor diagnosis as insights are reached and assimilated. This issue contains three techniques that rely solely or partially on optical characteristics of tissue. The supplement, in 2 issues, has mostly emphasized possibilities rather than clinically available techniques. The final chapter attempts to draw together the modalities of medical imaging and push the frontiers yet further to show how imaging and markers can be used together in the screening, diagnosis, and management of patients' disease.