PACS Chp. 8
twisted pair wire
Is similar to telephone wire, but whereas a telephone has only 4 wires, this one usually consist of 4 twisted pairs of copper wires that are insulated and bundled with an RJ-45 termination the minimum recommendation standard is Cat 5 (category 5) cable. it is the most commonly used connection medium in LANs
local area network
LAN is a small area networked with a series of cables or *wireless access points* that allow computers to share information and devices on the same network. They are the least expensive to install and much faster than WANs because of their smaller size. a LAN has the fastest communication technology because less equipment and fewer resources are needed to complete the network. Larger networks are composed of several LANs interconnected to create the WAN. the picture archiving and communication system (PACS) workstations in a radiology reading room would be considered a LAN. the computers are interconnected and communicate by sharing images and reports.
network switch
Similar to a hub, but it sends data only to those devices to which the data are directed. it will read the destination address from the data and select a direct path to the intended target. this reduces the network traffic, speeds up the overall network connection, and makes the network more efficient. switches are not commonly used in small office or home applications because there is not enough traffic to warrant the equipment
computers
3 types of computers found on a network: -server -thin client -thick client
network hub
The simplest device that can be used to connect several pieces of equipment together for network communication purposes. it has several wiring ports to receive and transmit data to the various connected pieces of equipment. the hub receives data and generally sends data to all devices connected to it. commonly used in small office and home applications
Bus Topology
A network in which all devices are physically attached to and listen for communication on a single wire. there is a single point of failure - the wire. if at some point on the wire there is a break, the entire network is down. this topology does not need any switches or hubs because the computers simply broadcast all the information down the single wire, and all computers connected to that single wire receive the information
Star Topology
A network that has the devices connected to a central hub or switch. can be thought of as a bus topology with the bus collapsed into a central box: the hub or switch the data are sent through the hub out to the destination device. this transmission of data may be through another hub or switch to an adjacent network or directly to the device. star topology is the most commonly used network topology
DICOM
Digital Imaging and Communications in Medicine is layered on top of TCP/IP the most common network communication standard used, and it has multiple layers, as does TCP/IP developed by the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) the first version was completed in 1985, addressing only point to point connection between devices the DICOM standard is made up of 20 different parts, ranging from image display to media storage. a device will conform to the parts that are necessary to perform the tasks it is assigned according to what is desired by the user. a device performs either as a service class user (SCU) for a given service and object or as a service class provider (SCP), or as both common service classes: image storage, query/retrieval, print, modality worklist, modality performed procedure, storage commitment, and interchange media storage. DICOM uses unique identifiers (UIDs) to globally identify each image set, so that if the images are sent to multiple systems, the identifying number will remain unique and not be confused with those images on other systems. the technologist either has to manually put in the patient demographics or pull the information from the radiology information system (RIS)
Health Level Seven (HL7)
HL-7 is an American National Standards Institute (ANSI) accredited Standards Developing Organization (SDO) used in most health care applications such as medical devices, imaging, insurance, and pharmacy. HL-7 standards oversee most clinical and administrative data such as demographics, reports, claims, and orders. communication between the *hospital information system (HIS)* and the *radiology information system (RIS) the HIS holds the patients full medical information, from hospital billing to the inpatient ordering system. the RIS holds all radiology-specific patient data, from the patient scheduling information to the radiologists dictated and transcribed report. the electronic medical record (EMR) has come to the forefront of information technology contains all of the patients record, including lab results, radiology reports, pathology results, and nurses and doctors notes PACS have also begun interfacing with EMRs to present images to referring physicians through the same common system.
network interface card
NIC provides the interface between the computer and the network medium; it provides the physical connection between the network and computer. NIC works with the networking software to establish and manage the data, to chop up the data into packets, and to handle addressing issues. most NICs plug directly into the motherboard as an expansion card, they can also come as small adapter cards that insert into a slot on the side of the portable computer
network bridge
Sometimes created so that larger networks can be segmented or broken up into smaller networks to reduce traffic within that network. These segments can then be connected with a bridge. the bridge is a physical (wired) connection from one network segment to another. it can recognize in which segment a particular destination address resides and send data to it. the bridge can also bring two or more networks together that speak the same language
wide area network
WAN is a network that spans a large area: city, state, nation, continent, or the world it is used to connect computers that are not physically attached through conventional network cables but are rather connected through other means, such as telephone lines, satellite links, or other types of communication cable. because of the distance covered, the cost of having the highest speed equipment is expensive.
network
a computer network is 1) two or more objects sharing resources and information 2) computers, terminals, and servers that are interconnected by communication channels sharing data and program resources. devices other than computers can be found on a network, such as printers, scanners, and barcode readers. these can be shared amount a group of computers to save money and space for the users
thick client
a computer that can work independently of the network and process and manage its own files the thick client is networked so that it can share resources such as printing and take advantage of the additional security available on networks through dedicated servers is generally a high-end computer that does high level processing for specific purposes. most often found in sectional imaging modalities for with 3D imaging is used to aid diagnosis
server
a computer that manages resources for other computers, servers, and networked devices it may also house applications, provide storage for files, or manage various other networked tasks there may be one server that provides storage for files, one that manages the print functions, and another that provides internet access for the network
geographic classification
a network can be classified into two major geographic categories: 1) local area network (LAN) 2) wide area network (WAN) others such as metropolitan area network (MAN), tiny area network (TAN), and controller area network (CAN) also exist but have little to do with radiology. LAN is close by, whereas WAN expands over a distance
server-based network
centralized computer (the server) that controls the operations, files, and sometimes the programs of the computers (the clients) attached to the network. the server provides a location for centralized storage and retrieval on the network. this allows the users to move from computer to computer and access their files from a central location. the server sends the entire changed file back to the server for storage. the server must be high quality and high capacity, although the client computers can be less expensive. there can be multiple servers but there must be one dedicated server that controls the network. Ex. PACS to read and distribute images throughout the hospital
communication medium
determined what files and resources are to be shared and the pieces of equipment are in pieces of equipment are in place. components are connected via some sort of communication medium the connection between the devices is one of four types: -coaxial cable -twisted-pair wire -fiber optic cable -electromagnetic waves
thin client
device that is found on a network that requests services and resources from a server. it may be another computer, printer, or any other networkable device that needs a server to complete its tasks. almost any personal computer (PC) can be a client, as long as it can be attached to the network
network communication
each computer on the network is assigned a unique address. the address is a combination of a physical address from the computers hardware and a node address given by the network. Ex. IP addressing, which is made up of 4 octets (groups of 8 bits) of numbers. the first set of numbers indicates the network class, and the rest of the numbers tell other devices the networks exact location. when a message is sent, the computers NIC will read the destination address and check to see whether it matches the computers network address. if it matches, it will receive the message. the data travels along the network using an agreed on set of rules known as a *network protocol* most network protocols send data in packets from one device to another. a packet is a piece of data with added information, such s the destination address, the source address, the sequence of the packets, and whether there were any errors in transmission. the protocol is delivered in layers of communication known as protocol stacks. each layer of the communication represents a particular aspect of network functionality. a network communication model is used the seven layers (OSI model) Layer 4: transport layer makes sure data packets are sequenced correctly and that they do not contain errors Layer 3: network layer breaks up the data into frames and decides which network path the frame will take to its destination Layer 2: data link layer packages the data so that they can be transmitted over the physical layer, ex. ethernet Layer 1: physical layer consists of the networking media and the components required to pass on a signal from one end of the network to the other. this layer moves bits from one place to another. as long as the machines share the same low-level protocols or known how to convert from one into another, the packets can be received and reconstructed
peer to peer network
each computer on the network is considered equal; no computer has ultimate control over another. each computer controls its own information and operation and can function either as a client or as a server depending on the needs of the other computers on the network. it is the most popular small office or home network configuration and least expensive and most simple to set up. it has a limited scope because the maximum number of peers that should be connected is 10. more than 10 peers causes bottlenecks and collisions on the network.
Mesh Topology
is a network that has multiple pathways interconnecting devices and networks. it has the redundancy built in with the multiple connections. the internet is based on mesh topology, and this topology is used most often to connect networks to other networks
wireless
is more of a commonplace as technology continues to improve. made by using either infrared or radio frequencies as its means of communication. there is no physical wireless transmitter/receiver it has mobility and convenience but a limited range. thickness and composition of the wall and the distance from the source must be taken into account
network router
it can read portions of messages and direct them to their intended target, even if the device is on a separate network and uses a different network protocol. it also helps with segmenting the network to allow access only for approved devices within that segment
Ring Topology
network in which the devices are connected in a circle each device passes its received messages to the next node on the ring and the data transmissions move around the circle until they reach the correct receiver. if there is a break at some point in the ring the entire network comes to a halt. one type of ring topology is called a "token ring" computers are connected in a circle, and a token is transmitted around the ring. when a computer is ready to send a token as it passes by and fills it with the message. the token passes the other computers, the destination address is read by each passing computer and is ignored if the address does not belong to that computer when the addressed computer is found, the data are deposited, and the token is now free again
component role classification
networks are typically classified as either peer to peer or server/client based, depending on what role their various components play. the network is classified according to what role the computers play in the networks operation and which computer controls the network operation
client-based network
similar to a server-based network, in that there is a centralized computer that controls the operations of the network, but rather than sending the entire original resource to the client for processing, the server processes the resource as requested by the client and returns only the results back to the client it lessens the load on the network and allows more room for other requests
coaxial cable
similar to the wiring used for the cable television that is run into a house. consists of a center conducting wire surrounded by insulation and then a grounded shield of braided wire. the shield minimizes electrical and radio frequency interference this is the sturdiest of wire used and is often found in the network infrastructure throughout a building.
network topology
topology is the physical (geometric) layout of the connected devices on a network. there are 4 common topology configurations: -bus -ring -star -mesh the type of communication media, the network speed, the connecting equipment design, and the number of devices to be connected.
fiber optic cable
uses glass threads to transmit data on the network. it consists of fiber optic core that is surrounded by a plastic protective covering. this cable is much faster than its metal counterparts, but more expensive and much more fragile. it can be easily be damaged by kinking and twisting the cable. it is most often used in the infrastructure of the network, in network closets, and in large archive/computer rooms
