The XNAT Gateway is used to query XNAT for DICOM images from a DICOM viewing workstation, making it function similar to a PACS. You can install the Gateway locally and connect to it as to any other DICOM server. DICOM requests are translated into XNAT requests, and the result is returned over DICOM networking protocol.
Consult the XNAT/DICOM Gateway User Manual for more details on features and capabilities.
After following the standard installation and configuration instructions for the XNAT Gateway, you'll need to follow these instructions on getting Osirix configured to speak with the XNAT Gateway.