Digital radiology product guide: Digital definitions

Computed Radiography (CR)

CR systems were developed in the 1980s. The film screen combination is replaced by a photostimulable storage phosphor (PSP) that is loaded in a protective cassette. CR is the cheapest of the digital-era alternatives. CR has a broad dynamic range, excellent resolution and image manipulation algorithms that are equivalent to DR.

Digital Radiography (DR)

Digital radiography systems can be divided into direct and indirect systems. In direct DR, x-rays are directly converted to an electronic signal without a light intermediate. Semiconductors detect the x-rays and create a small charge or current that is detected and converted to an electrical signal. Indirect DR systems use a scintillation x-ray detector plate in which the x-ray information results in a light flash from the scintillation plate that is then registered from a light flash to an electrical signal. The electrical signals are then processed into an image. DR images have excellent dynamic range and resolution and are ideal for the impatient patient, as images are available within four to six seconds.

PACS

PACS (Picture Archiving and Communication System) is a system to allow for retrieval of image data, review, manipulation, interpretation and storage. A good PACS system has three key components. The first is a central storage server that is on site with dual redundant off-site back up for when the hard drive crashes. The second component is a good review workstation that includes several high-grade, high-resolution (1 to 2 megapixels) grayscale monitors. The third component is a high-quality, dependable viewing software for evaluation, review and manipulation of images.

Clifford Berry, DVM, DACVR

2010 CVC Kansas City proceedings

DICOM

DICOM (digital imaging communications in medicine) is a set of comprehensive communication standards developed to promote interoperability of digital imaging devices in medicine. DICOM is the tool that permits standardized communication among various devices. Several different types of images—e.g. JPEG, RLE, JPEG-LS, JPEG 200—can be used in DICOM files. While DICOM is ­commonly referred to as a type of image, it is not—it’s an image format. DICOM files consist of image pixel data and other precise attributes combined with services (e.g., commands for transmitting data).

Jonathan Shiroma, DVM, MS, DACVR 
MedVet

Medical Center for Pets for Veterinary Medicine, "An introduction to DICOM," December 2006