Figure 3: 11C-PK11195 PET images in coronal and transaxial directions. (a) Images of severe clinical inflammation of the right knee (depicted at the left in both images) and no clinical inflammation of the left knee in a patient with rheumatoid arthritis (RA). (b) Images of mild inflammation of both knee joints in an RA patient. (c) Images of knees without joint disease in a control subject. The different levels of tracer uptake correspond to the colors in the color bar at the left, from van der Laken et al. (2008) [125].