As solid state device technology continues to progress, solid state x-ray imaging devices will assume an ever-increasing role in medical x-ray systems. This evolution will result in a significant number of premarket (510(k)) submissions for devices that utilize various forms of this technology. This document is intended to provide guidance on the type of data needed by the Center for Devices and Radiological Health (CDRH) to establish the substantial equivalence of an SSXI to a previously cleared conventional radiographic film/screen system, fluoroscopic image intensified imaging system, SSXI or similar device.