In this open-label monocentric explorative pilot trial the objective is to show the
biodistribution of TNFα by administration of radiolabeled anti-TNFα in patients with active
rheumatoid arthritis and spondylarthropathy. The anti-TNFα used in this trial is certolizumab
pegol (Cimzia®), a pegylated Fab'-fragment of a monoclonal antibody with high specificity for
TNFα. Certolizumab pegol will be radiolabeled with 99mTechnetium. The aim of this study is to
show the TNFα triggered inflammation process in the inflamed joints, especially in patients
who have very early joint damage where currently other imaging methods such as X-rays are not
sensitive enough for detection.