The equipment in a radiology enterprise varies by size and specialized resources of the department. Table 2.2 lists the possible types of equipment possibly present in an imaging organization, as well as relative expense. This wide variety of possible modalities, and the high cost, requires that each department must choose and optimize imaging equipment to meet the clinical needs of its community and patient population. For example, some hospitals without a breast cancer screening program will not have mammography equipment. This topic of optimizing equipment for the resources of an institution and the epidemiological needs of a community is covered in greater depth in the Radiology Readiness chapter of this text.