Chapter 28

For a digital imaging system, the values of intensities must be rounded out to the nearest allowable discrete unit so that the computer can manage them.

(the function of the analog- to digital converter)

Real Time Processing

-an array of processors work in parallel to perform a complex computation on a large amount of data at high speed. --this creates an illusion of instantaneous feedback or image display

Computer

-any machine that can perform mathematical computations, manipulate information, make decisions, and interact accurately and quickly -based on the fundamental ability of the machine to follow preprogrammed instructions (known as algorithms)

Analog Data

-data presented in continuous form, such that its presentation is precisely proportional to its actual magnitude (this means that its units are infinitely divisible) -broad data -think of the steel rails on a railroad track, these rails are continuous and can be infinitely subdivided

Operating System

-determines the general format of operation for a computer, based on the broadest sense in which it is intended to be used (home, business, etc.) and presents an appropriate interactive interface (desktop) at the display screen for the user in connection with the most appropriate input devices (keyboard, mouse, etc.) -often written by the computer manufacturer and stored in ROM in the CPU

Control Unit

-directs the flow of data between the primary memory and the arithmetic/logic unit, as well as between input devices, the CPU, and output devices -operates on information and data retrieved from a primary memory storage system -tells input devices when to start and stop transferring data to the primary memory -is programmed to select these instructions in proper order, interpret them, and relay commands between primary memory and the arithmetic/logic unit

Wide Area Network (WAN)

-extends to other businesses or locations that may be at great distances -usually publicly or commercially owned and uses transmission services provided by common carriers such as phone or cable companies -Example: corporation hospitals

Local Area Network (LAN)

-is a computerized communications network generally contained within a single building or business -share one server and typically the system is privately owned -example: small isolated hospital

4 General Approaches to Processing Data on a Computer

-online processing -batch processing -real time processing -time sharing

Arithmetic/logic unit (ALU)

-performs all the arithmetic calculations and logic functions required to solve a problem -operates on information and data retrieved from a primary memory storage system

Digital Data

-presented on a discrete scale, a scale made up of separated, distinct parts (how small these parts are limits the degree to which measurements can be subdivided) -new improved data -has to be rounded -ex: binary code -think of the wooden ties on a railroad track, they cannot be divided into fractions as one steps across them

Modem

-receives digital information from the computer in the form of electronic signals of differing voltages -it converts these into analog audio signals, or distinct tones, for transmission over phone lines -a similar process can be used with optical fiber bundles to transmit different wavelengths of light along a cable from one computer to another

Time Sharing

-refers to the use of a large central computer that creates the illusion of serving several terminals simultaneously ****common in medical imaging (particularly in PACS which allows centralized patient files to be brought up at a number of different terminals****

Central Processing Unit (CPU)

-the part of a computer that interprets and executes instructions -"The brain" -performs data manipulation in the computer -tells the computer how to carry out software instructions -divided into two basic components: the control unit & the arithmetic/logic unit

Byte

-the unit for measuring storage capacity -consists of 8 bits (binary digits) of information

10. By using base __ notation rather than a base 10 numbering system, binary code allows all data to be reduced to two values or bits, 1 and zero.

2

5) Each address in primary memory consists of how many bit storage units?

8

8. Mathematically, the __ essentially rounds out numbers to discrete values, thus reducing the volume of data to a dynamic range which the computer can manage.

ADC

12) What code was the first standardization of intermediate computer languages which provided compatibility between different manufacturers?

ASCII (American Standard Code for Info Interchange)

8) Data which can have any values, without limitation on its number of decimal places is __ data.

Analog

7. __ information is on a continuous spectrum, whereas __ information is discrete.

Analog Digital

9. Although __ information is inherently less accurate than __ information, as long as the discrete units are smaller than a human can detect, read-out accuracy is improved.

Digitized Analog

13. __ memory access speeds up the display process through bypassing the CPU>

Direct

12. __ provide that ability to transmit images and other data over phone lines or fiber optic lines.

Modems

14. In medical imaging the __ is a local area network which facilitates access to and management of images for all the nodes in the RIS and HIS system.

PACS

__ is used within a medical imaging department to make radiographs, CT and MRI scans, ultrasound and nuclear medicine images for a particular patient available at any node within the network.

PACS

13) The specific type of LAN used for managing images within a radiology department is called?

PACS (Picture Archiving and Communication System)

There are 3 types of LANS with which radiographers should be familiar:

PACS (Picture Archiving and Communication System) RIS (Radiology Information System) HIS (Hospital Information System)

The greatest efficiency of communication is achieved when these systems, ___, __, and __ are compatible and fully integrated

PACS, RIS, and HIS

6. The __ system, widely used in medical imaging, prevents the accidental loss of information by multiple, independent back-up storage. (off campus way to back up computers)

RAID

7) What does RAID stand for?

Redundant Array of Independent Discs

2) What does USB stand for?

Universal Serial Bus

Microprocessor

a CPU that is contained on a single integrated circuit chip

Computer Program

a collection of many hundreds or even thousands of interrelated algorithms which allow the user to perform a general application Example: calculating taxes, word processing, organizing a data base

The various intensities of x-rays that strike the image receptor can have any value and therefore constitute __ information

analog

Much more complex computer languages are used for operating systems software and for various applications, but these languages are all based upon the basic __ __ b/c the hardware of the computer requires this format

binary code

9) The term bit is an acronym for:

binary digit

4. A __ consists of 8 bits and is sufficient to create a single character.

byte

Both hardware and software components must be __, that is, they must operate on the same physical principles and use the same basic languages and codes.

compatible

Hardware of the Computer

consists of all the physical components, including input devices, the processing system, memory and storage devices, output devices and systems for communication

11. __ processing can be executed online, in batches, in real-time or in a time-sharing format.

data

Interface

describes the connection between a computer or imaging machine and any of its peripherals, other computers or devices

All image data must be converted into __ form by the ADC before being passed along to any computerized portion of the equipment

digital

ADC

effectively rounds out x-ray exposure measurements into discrete values that the digital computer can cope with

Computer Languages

higher-level codes

As long as the discrete units for a digital computer are smaller than a human can detect, digitizing the information __ read-out accuracy

improves

10) The ability of a single computer's peripherals and components to all work together is termed its __ compatibility.

internal

Compatibility may be divided into 2 broad categories

internal compatibility and external compatibility

Every computer within a network has a unique __ __ or IP address.

internet protocol

1) Artificial Intelligence is defined as the ability to perform _ functions such as "if then" and "if else".

logic

Both LANs and WANs are widely used in...

medical imaging

2. Most x-ray machine consoles are __

microcomputers

1. The power of a computer is measured by how many millions of instructions per second (MIPS) it can process, largely determined by the speed of the __ which is measured in gigahertz or terahertz.

microprocessors

3. MRI and CT scanners use __

minicomputers

11) Any single access point within a WAN or LAN is called a...

node

5. Each address in computer memory stores __ byte of data.

one

For radiographers, it is important to understand __ __ __ __, b/c not only is image storage capacity expressed in powers of 2, but so are the dynamic range (grayscale) and the matrix sizes of the images themselves.

power of 2 notation

Analog

precisely proportional

Algorithms

preprogrammed instructions

4) List the four main sectors of primary memory

program storage, working or scratch pad storage, temporary input storage, temperature output storage

Computer Software

refers to all the instructions given to the hardware of the computer in order to carry out tasks, which is written in higher level codes

Teleradiology

refers to any system which allows the remote transmission and viewing of radiographic images via modems over phone or cable lines

Batch Processing

refers to the method used when large amounts of data must be processed and only a few operations need to be executed on it

6) What type of transformer must be used for regular electrical power coming into a computer?

step down transformer

Artificial Intelligence (AI)

the ability of a machine to make decisions based on logic functions Example: "do" "if then" "if else"

Internal Compatibility

the ability of computer's own components and software to work together, including graphics and sound cards, modems, printers, and software programs

External Compatibility

the ability of different computer systems to communicate with each other

3) Which portion of the CPU directs the flow of data between the ALU, primary memory, and input and output devices?

the control unit

Microcomputer

the operating console of a standard diagnostic x-ray machine with the same overall processing power as a PC, but with the power dedicated to the selection of proper radiographic technique while compensating for electronic and other variables

Bit

the unit for the binary number system

Online Processing

transactions are processed immediately upon entering a command, and the user must be present at the terminal to execute the command