Custom silicon for tomographic instrumentation

This paper addresses the issues that are appropriate when considering custom silicon for tomographic instrumentation. The whole range of mask and field programmable custom silicon options are described. These embrace full custom, mask-programmable gate array, cell-based IC and field programmable logic devices. Attention is drawn to economic considerations. It is noted that there is a shortage of previous examples of the application of custom silicon technology to tomographic instruments. Most previous reports describe accelerators for image reconstruction algorithms and, consequently, utilize digital technology. Examples of some existing custom silicon devices are briefly summarized and these involve applications to positron emission and electrical impedance tomography. Attention is drawn to the fact that different techniques may share common requirements and therefore it is conceivable that, with concerted attention, custom silicon devices may be developed that are appropriate for a broad range of tomographic applications.