This book was produced to answer the need expressed by Radiologists and trainee Radiology Technologists for clear and detailed description of the PACS and its uses in Radiology service. The concept of picture Archiving and Communication System (PACS) has now been in existence for over 20 years. Advances in computer hardware technology only enabled it to become a realistic clinical entity in the 1990s. PACS installations are now rising exponentially worldwide, and although most institutions with PACS have achieved a completely filmless working environment, few function in a paperless mode. PACS integrates imaging modalities, interfaces with hospital and departmental information systems, and manages the acquisition, storage, retrieval, and display of images to radiologists, hospital physicians, and remote referring physicians, specialists, clinics and imaging centers. PACS serves as a secure database for medical images, but more importantly, PACS improves the efficiency of imaging departments.