We have constructed a general purpose optical tomographic imaging device capable of evaluating a variety of body appendages. A novel functional feature of the instrument is its use of a geometrically adaptive scanning head, in the form of a mechanical iris, about which are attached optical fibers positioned in a circular array. By adjusting the pass-through diameter of the iris, optical fibers can be brought into gentle contact with a tissue target. This serves to improve optical coupling while simultaneously stabilizing the tissue against motion artifacts. In addition, in many instances it also permits gentle deformation of the tissue to a simple circular geometry which is favorable for data analysis. The instrument also employs a rotating filter array that serves to extend the dynamic range of measurement to >1012 while retaining excellent precision (CV= 0.2-0.3%). Reconstruction results of laboratory phantoms and physiological imaging studies of the human forearm are presented.