AE Title - an Application Entity (AE) Title is the human-readable name of a entity or service on a network, such as a PACS or modality, that can speak DICOM.
Analog Signal - An analog or analogue signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.e analogous to another time varying signal. It differs from a digital signal in that small fluctuations in the signal are meaningful. Analog is usually thought of in an electrical context; however, mechanical, pneumatic, hydraulic, and other systems may also convey analog signals.
Archive - a repository for digital medical images in a PACS, typically with a specific purpose of providing a finite long-term storage of images.
Bandwidth - In computer networking and computer science, digital bandwidth, network bandwidth or just bandwidth is a measure of available or consumed data communication resources expressed in bits per second or multiples of it (kilobit/sec, Megabit/sec, etc). Bandwidth may refer to bandwidth capacity or available bandwidth in bits/sec, which typically means the net bit rate, channel capacity or the maximum throughput of a logical or physical communication path in a digital communication system.
Bit (Binary Digit) - In computing and telecommunications a bit is a basic unit of information storage and communication; it is the maximum amount of information that can be stored by a device or other physical system that can normally exist in only two distinct states. These states are often interpreted (especially in the storage of numerical data) as the binary digits 0 and 1. They may be interpreted also as logical values, either "true" or "false"; or two settings of a flag or switch, either "on" or "off".
Bit depth - Color depth or bit depth, is a computer graphics term describing the number of bits used to represent the color of a single pixel in a bitmapped image or video frame buffer. This concept is also known as bits per pixel (bpp), particularly when specified along with the number of bits used. Higher color depth gives a broader range of distinct colors.
Bits per second - see Throughput or Baud rate.
Byte - A byte is an ordered collection of bits, with each bit denoting a single binary value of 1 or 0. A byte most often consists of 8 bits in modern computer systems.
CCD (charge-coupled device) - A charge-coupled device (CCD) is an analog shift register that enables the transportation of analog signals (electric charges) through successive stages (capacitors), controlled by a clock signal. Charge-coupled devices can be used as a form of memory or for delaying samples of analog signals. Today, they are most widely used in arrays of photoelectric light sensors.
Clock rate - The clock rate is the fundamental rate in cycles per second (measured in hertz) for the frequency of the clock in any synchronous circuit. For example, a crystal oscillator frequency reference typically is synonymous with a fixed sinusoidal waveform, a clock rate is that frequency reference translated by electronic circuitry into a corresponding square wave pulse [typically] for digital electronics applications, such as CPUs.
Computer networking - Computer networking is the engineering discipline concerned with communication between computer systems or devices. Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs.[1] Computer networking is sometimes considered a sub-discipline oftelecommunications, computer science, information technology and/or computer engineering.
Consultation system - a teleradiology system used to determine the completeness of examinations, to discuss findings with other physicians, or for other applications with the knowledge that the original images will serve as the basis for the final official interpretation rendered at some later time by the physician responsible for that report.
CPU (Central Processing Unit) - A central processing unit (CPU) or processor is an electronic circuit that can execute computer programs.
CR (Computed Radiography) - Computed Radiography (CR) uses very similar equipment to conventional radiography except that in place of a film to create the image, an imaging plate (IP) made of photostimulable phosphor is used. The imaging plate housed in a special cassette and placed under the body part or object to be examined and the x-ray exposure is made. Hence, instead of taking an exposed film into a darkroom for developing in chemical tanks or an automatic film processor, the imaging plate is run through a special laser scanner, or CR reader, that reads and digitizes the image. The digital image can then be viewed and enhanced using software that has functions very similar to other conventional digital image-processing software, such as contrast, brightness, filtration and zoom.
CT (Computed Tomography) - Computed Tomography (CT) is a medical imaging method employing tomography. Digital geometry processing is used to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. The word "tomography" is derived from the Greek tomos (slice) and graphein (to write). Computed Tomography was originally known as the "EMI scan" as it was developed at a research branch of EMI, a company best known today for its music and recording business. It was later known as Computed Axial Tomography (CAT or CT scan) and body section röntgenography.
Data compression - In computer science and information theory, data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an unencoded representation would use through use of specific encoding schemes.
Dedicated line - In computer networks and telecommunications, a dedicated line is a communications cable or other facility dedicated to a specific application, in contrast with a shared resource such as the telephone network or the Internet. In practice, such services may not be provided by a single, discrete, end-to-end cable, but they do provide guarantees of constant bandwidth availability and near-constant latency, properties that cannot be absolutely guaranteed for more public systems.
DICOM - Digital Imaging and Communications in Medicine (DICOM) is a standard for handling, storing, printing, and transmitting information in medical imaging. It includes a file format definition and a network communications protocol. The communication protocol is an application protocol that uses TCP/IP to communicate between systems. DICOM files can be exchanged between two entities that are capable of receiving image and patient data in DICOM format. The National Electrical Manufacturers Association (NEMA) holds the copyright to this standard.[1] It was developed by the DICOM Standards Committee, whose members[2] are also partly members of NEMA.[3]
Digital signal - The term digital signal is used to refer to more than one concept. It can refer to discrete-time signals that have a discrete number of levels, for example a sampled and quantified analog signal, or to the continuous-time waveform signals in a digital system, representing a bit-stream. In the first case, a signal that is generated by means of a digital modulation method is considered as converted to an analog signal, while it is considered as a digital signal in the second case.
Digitize - Digitizing or digitization[1] is representing an object, image, sound, document or a signal (usually an analog signal) by a discrete set of its points or samples. The result is called "digital representation" or, more specifically, a "digital image", for the object, and "digital form", for the signal. Strictly speaking, digitizing means simply capturing an analog signal in digital form.
DPI (Dots per inch) - While in conventional radiography resolution this is commonly expressed in line pairs per millimeter (lp/mm), dots per inch (DPI) is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed within the span of one linear inch (2.54 cm.) The DPI value tends to correlate with image resolution, but is related only indirectly.
Direct Radiography (DR) - Digital Radiography (DR) is essentially filmless X-ray image capture. In place of X-ray film, a digital image capture device is used to record the X-ray image and make it available as a digital file that can be presented for interpretation and saved as part of the patient's medical record. The advantages of DR over film include immediate image preview and availability, a wider dynamic range which makes it more forgiving for over- and under-exposure as well as the ability to apply special image processing techniques that enhance overall display of the image. The largest motivator for healthcare facilities to adopt DR is its potential to reduce costs associated with processing, managing and storing films. Typically there are two variants of digital image capture devices. These devices include Flat Panel detectors (FPDs), and High Density Line Scan Solid State detectors.
Dynamic range - The dynamic range of a system or device is a term used frequently in numerous fields to describe the ratio between the smallest and largest possible values of a changeable quantity, such as in sound and light. It is measured as a ratio, or as a base-10 (decibel) or base-2 (doublings, bits or stops) logarithmic value.
EMR (Electronic Medical Record) - In health informatics and most contexts, EMR and EHR (Electronic Health Record) are used synonymously, but many people define an EMR as just the physician interface and EHR including both a physician and patient interface. The term has sometimes included other systems which keep track of medical information, such as the practice management system which supports the electronic medical record.
File - A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. A file is durable in the sense that it remains available for programs to use after the current program has finished. Computer files can be considered as the modern counterpart of paper documents which traditionally are kept in offices' and libraries' files, and this is the source of the term. A file type is normally identified by a dot followed by a series of letters, with the name of the file appearing before the dot, e.g. name.doc or pic.jpg.
GB (Ggigabyte) - on computers, stands for the number 230 = 1,073,741,824. It is used primarily when referring to computer storage capacities; for example, 1 GB = 230 bytes. 1 GB = 220 kilobytes. 1 GB = 210 megabytes.
Gray scale - In photography and computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information. Images of this sort, also known as black-and-white, are composed exclusively of shades of gray, varying from black at the weakest intensity to white at the strongest.
Hard disk drive - A hard disk drive[1] (often shortened as "hard disk"[2], "hard drive"[3], or "HDD"), is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces.
Hardware - a collective term used to describe the physical components that form a computer. The monitor, CPU, disk drives, memory, modem, and other components are all considered hardware.
HIS (hospital information system) - A hospital information system (HIS), variously also called clinical information system (CIS) is a comprehensive, integrated information system designed to manage the administrative, financial and clinical aspects of a hospital.
IHE (Integrating the Healthcare Enterprise) - IHE is an initiative by healthcare professionals and industry to improve the way computer systems
in healthcare share information. IHE promotes the coordinated use of established standards such as DICOM and HL7 to address specific clinical needs in support of optimal patient care.
Image - A digital image is a representation of a two-dimensional image using ones and zeros (binary). Depending on whether or not the image resolution is fixed, it may be of vector or raster type. Without qualifications, the term "digital image" usually refers to raster images also called bitmap images.
Image compression - reduction of the amount of data required to represent an image. This is accomplished by encoding the spatial and contrast information more efficiently or discarding some non-essential information or both.
Interface - An interface generally refers to an abstraction that an entity provides of itself to the outside. This separates the methods of external communication from internal operation, and allows it to be internally modified without affecting the way outside entities interact with it, as well as provide multiple abstractions of itself. It may also provide a means of translation between entities which do not speak the same language, such as between a human and a computer.
IP address - an Internet Protocol (IP) address is a numerical label that is assigned to devices participating in a computer network, that uses the Internet Protocol for communication between its nodes. An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."
HL7 (Health Level 7) - The name Health Level 7 (HL7) is a reference to the seventh application layer of the ISO OSI Reference model. The name indicates that HL7 focuses on application layer protocols for the health care domain, independent of lower layers. HL7 effectively considers all lower layers merely as tools. It is used to transmit data such as scheduling information and patient demographics between different computer systems.
KB (kilobyte) - stands for the number 210 = 1024. It is used primarily when referring to computer storage and memory capacities: for example, 1 KB = 210 bytes.
LAN (Local Area Network) - A local area network (LAN) is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport. The defining characteristics of LANs, in contrast to wide-area networks (WANs), include their usually higher data-transfer rates, smaller geographic place, and lack of a need for leased telecommunication lines.
Laser film scanner - a device that uses a laser beam to convert an image on X-ray into digital image data.
Leased line - same as a dedicated line.
Login (sign in) - In computer security, login (logging or signing in, also log on) is the process by which individual access to a computer system is controlled by identification of the user using credentials provided by the user.
Lossless compression - Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange for better compression rates.
Lossy compression - A lossy compression method is one where compressing data and then decompressing it retrieves data that is different from the original, but is close enough to be useful in some way.
MB (megabyte) - on computers, stands for the number 220 = 1,048,576. It is used primarily when referring to computer storage and memory capacities: for example, 1 MB = 220 bytes. 1 MB = 210 kilobytes.
Memory - Computer memory refers to devices that are used to store data or programs (sequences of instructions) on a temporary or permanent basis for use in an electronic digital computer. Computers represent information in binary code, written as sequences of 0s and 1s. Each binary digit (or "bit") may be stored by any physical system that can be in either of two stable states, to represent 0 and 1.
Modem (modulator-demodulator) - A device, such as a cable modem, that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data.
Mouse - In computing, a mouse (plural mouses, mice, or mouse devices) is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations.
MRI (Magnetic Resonance Imaging or MR) - A medical imaging technique most commonly used in radiology to visualize the internal structure and function of the body. MRI provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular, and oncological (cancer) imaging. Unlike CT, it uses no ionizing radiation, but uses a powerful magnetic field to align the nuclear magnetization of (usually) hydrogen atoms in water in the body. Radio frequency (RF) fields are used to systematically alter the alignment of this magnetization, causing the hydrogen nuclei to produce a rotating magnetic field detectable by the scanner. This signal can be manipulated by additional magnetic fields to build up enough information to construct an image of the body.
NIC (Network Interface Card) - A network card, network adapter, network interface card (NIC), network interface card, or LAN adapter is a computer hardware component designed to allow computers to communicate over a computer network.
Nuclear Medicine (NM) - Nuclear medicine is a branch of medicine and medical imaging that uses radioactive isotopes (radionuclides) in the diagnosis and treatment of disease. Nuclear medicine thus relies on the process of radioactive decay. Molecular imaging may employ nuclear medical techniques when it uses radioisotopes to produce images that reflect biological processes that take place at the cellular and sub cellular level.
Operating system - An operating system (commonly abbreviated to OS) is an interface between hardware and user; an OS is responsible for the management and coordination of activities and the sharing of the resources of the computer. The operating system acts as a host for computing applications that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware. UNIX, DOS, Mac OS, and Windows are examples of operating systems.
PACS (Picture Archiving and Communication Systems) - In medical imaging, picture archiving and communication systems (PACS) are computers, commonly servers, dedicated to the storage, retrieval, distribution and presentation of images. The medical images are stored in an independent format. The most common format for image storage is DICOM (Digital Imaging and Communications in Medicine). Electronic images and reports are transmitted digitally via PACS; this eliminates the need to manually file, retrieve or transport film jackets. A PACS consists of four major components: the imaging modalities such as CT and MRI, a secured network for the transmission of patient information, workstations for interpreting and reviewing images, and long and short term archives for the storage and retrieval of images and reports. Combined with available and emerging Web technology, PACS has the ability to deliver timely and efficient access to images, interpretations and related data. PACS breaks down the physical and time barriers associated with traditional film-based image retrieval, distribution and display.
Pixel (picture element) - In digital imaging, a pixel (or picture element) is the smallest item of information in an image. Pixels are normally arranged in a 2-dimensional grid, and are often represented using dots or squares. Each pixel is a sample of an original image, where more samples typically provide more-accurate representations of the original. The intensity of each pixel is variable; in color systems, each pixel has typically three or four components such as red, green, and blue, or cyan, magenta, yellow, and black.
Port - A software port (usually just called a 'port') is a virtual/logical data connection that can be used by programs to exchange data directly, instead of going through a file or other temporary storage location. The most common of these are TCP and UDP ports, which are used to exchange data between computers on the Internet.
Practice Management Software (PMS) - Practice Management Software is a category of software that deals with the day-to-day operations of a medical practice. Such software frequently allows users to capture patient demographics, schedule appointments, maintain lists of insurance payers, perform billing tasks, and generate reports. Practice Management Software is often connected to Electronic Medical Records (EMR) systems. While some information in a PMS and an EMR overlaps, for example, patient and provider data in general the EMR system is used for the assisting the practice with clinical matters, while PMS is used for administrative and financial matters.
Protocol - In computing, a protocol is a set of rules which is used by computers to communicate with each other across a network. A protocol is a convention or standard that controls or enables the connection, communication, and data transfer between computing endpoints. In its simplest form, a protocol can be defined as the rules governing the syntax, semantics, and synchronization of communication.
RAM (Random Access Memory) - Random-access memory (usually known by its acronym, RAM) is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order (i.e., at random). The word random thus refers to the fact that any piece of data can be returned in a constant time, regardless of its physical location and whether or not it is related to the previous piece of data.
Resolution - The display resolution of a digital television or display typically refers to the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube (CRT) and flat panel or projection displays using fixed picture-element (pixel) arrays.
RIS (Radiology Information System) - A Radiology Information System (RIS) is a computerized database used by radiology departments to store, manipulate and distribute patient radiological data and imagery. The system generally consists of patient tracking and scheduling, result reporting and image tracking capabilities.
Secondary image capture - the capture in digital format of image data that originally existed in another primary format (e.g., a digital image data file on a CT scanner, or a screen-film radiographic film) through the process of video capture or film digitization.
Software - Computer software, or just software is a general term used to describe the computer programs and procedures in a computer system. Computer software is sometimes regarded as anything but hardware, meaning that the "hard" are the parts that are tangible while the "soft" part is the intangible objects inside the computer. Software encompasses an extremely wide array of products and technologies developed using different techniques like programming languages, scripting languages or even microcode.
Terabyte (TB) - on computers, stands for the number 240 = 1,099,511,627,776. It is used primarily when referring to computer storage and memory capacities: for example, 1 TB = 240 bytes. 1 TB = 230 kB. 1 TB = 220 MB. 1TB = 210 GB.
Thin client - A thin client (sometimes also called a lean or slim client) is a client computer or client software in client-server architecture networks which depends primarily on the central server for processing activities, and mainly focuses on conveying input and output between the user and the remote server.
TLS - Transport Layer Security (TLS) and its predecessor, Secure Socket Layer (SSL), are cryptographic protocols that provide security for communications over networks such as the Internet. TLS and SSL encrypt the segments of network connections at the Transport Layer end-to-end. Several versions of the protocols are in widespread use in applications like web browsing, electronic mail, Internet faxing, instant messaging, and voice-over-IP (VoIP). TLS is an IETF standards track protocol, last updated in RFC 5246.
Fat client - A fat client or rich client is a computer (client) in client-server architecture networks which typically provides rich functionality independently of the central server. Originally known as just a 'client' or 'thick client', the name is contrasted to thin client, which describes a computer heavily dependent on a server's applications.
Throughput - In communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel. These data may be delivered over a physical or logical link, or pass through a certain network node. The throughput is usually measured in bits per second (bit/s or bps), and sometimes in data packets per second or data packets per time slot.
Ultrasound (US) - Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Although this limit varies from person to person, it is approximately 20 kilohertz (20,000 hertz) in healthy, young adults and thus, 20 kHz serves as a useful lower limit in describing ultrasound. The production of ultrasound is used in many different fields, typically to penetrate a medium and measure the reflection signature or supply focused energy. The reflection signature can reveal details about the inner structure of the medium. The most well known application of this technique is its use in sonography to produce pictures of fetuses in the human womb.
Video capture - the process by which images are digitized directly from the video display console of a modality, such as CT, MRI, or ultrasound. The video signal is converted to a digital signal. This process is more efficient and produces better quality images than scanning films that are produced by the same equipment.
Voxel (volume element, derived from pixel) - A voxel (a portmanteau of the words volumetric and pixel) is a volume element, representing a value on a regular grid in three dimensional space. This is analogous to a pixel, which represents 2D image data. Voxels are frequently used in the visualization and analysis of medical and scientific data.
WAN (Wide Area Network) - A Wide Area Network (WAN) is a computer network that covers a broad area (i.e., any network whose communications links cross metropolitan, regional, or national boundaries [1]). This is in contrast with personal area networks (PANs), local area networks (LANs), campus area networks (CANs), or metropolitan area networks (MANs) which are usually limited to a room, building, campus or specific metropolitan area (e.g., a city) respectively. The largest and most well-known example of a WAN is the Internet.
X-ray (XR) - Radiography started in 1895 with the discovery of X-rays, also referred to as Röntgen rays after Wilhelm Conrad Röntgen who first described their properties in rigorous detail. These previously unknown rays (hence the X) were found to be a type of electromagnetic radiation. It wasn't long before X-rays were used in various applications, from helping to fit shoes, to the medical uses that have persisted. X-rays were put to diagnostic use very early, before the dangers of ionizing radiation were discovered. Indeed, Marie Curie pushed for radiography to be used to treat wounded soldiers in World War I. Initially, many kinds of staff conducted radiography in hospitals, including physicists, photographers, doctors, nurses, and engineers. The medical specialty of radiology grew up over many years around the new technology. When new diagnostic tests were developed, it was natural for the radiographers to be trained in and to adopt this new technology.