PACS are typically made up of the following components: Modality interfaces, a highbandwidth network, two or more tiers of image-review workstations, two or more tiers of image archives, specialized servers, and interfaces to other information systems and peripherals (e.g., film printers and paper printers). These components are composed of commercial off-the-shelf (COTS) hardware, COTS operating system software and specialized, developer/vendor-specific PACS application software. Each of these PACS components is discussed in detail below