CT

1
CT

• Seeram Chapter 2
• Introduction to Computers

2
Electronic Computer Technology

• Vacuum tubes
• Discrete Semiconductors
• Integrated Circuits

3
Early Computers

• 1951-1958
• Vacuum tube memory
• Input / Output
• Punch cards
• Magnetic Tape

4
Electronic Computer Technology
Vacuum Tubes

• Warm-up
• Ran hot
• tube filaments required constant heating
• computers required air conditioning
• Frequent failures

5
Computers after Vacuum Tubes

• 1959-1963
• Transistor magnetic core memory
• Smaller
• Less power needed

6
Discrete Semiconductor Components in Computers

• transistors
• magnetic memory cores
• Space requirements
• large but
• smaller than vacuum tubes
• Ran much cooler than vacuum tubes

7
Computers The Big JumpIntegrated Circuits

• millions of semiconductor components in tiny
  package
• lower production costs
• Extremely small
• Extremely fast
• Run very cool
• Very reliable

8
Categories of Computers

• Super computers
• Mainframes
• Minicomputers
• Microcomputers

9
5th Generation Supercomputers

• Large (even today)
• Expensive
• Found only in major research sites
• Applications
• weather
• scientific modeling
• oil exploration
• other research

10
Mainframe Computers

• Large
• Requires teams of experts
• Large of users
• Applications
• large corporations
• government
• hospitals

11
Microcomputer

• PC
• Rapidly changing technology
• Low cost
• Non-proprietary
• First common in 1980s

12
Minicomputers

• First seen in 1970s
• Much less expensive than mainframes
• Medium-sized
• Proprietary ()
• parts
• operating systems
• Computer used for CT
• Appropriate
• Size
• price
• Applications
• imaging, reconstruction
• archiving

13
Basics
Input
Processing
Output
14
Input

• Manual
• keyboard
• mouse
• Electronic
• CT detectors
• CR Plates

• Other
• Voice recognition

Input
Processing
Output
15
Analog to Digital Conversion(A to D)
Analog (continuously varying)
Digital (discretely varying)
16
Analog to Digital Conversion(A to D)

• Many real world inputs are analog voltages
• CT detector intensity
• Analog values must be converted to a to use in
  a computer

0.8
0.6
Input analog voltage
0.4
0.2
Digital conversion to computer
1
2
3
4
17
Processing

• Central Processing Unit (CPU)
• Arithmetic
• Logic
• Internal Memory
• Scratchpad

Input
Processing
Output
18
Output

• Hard copy
• printer
• Soft copy
• CRT

• Storage
• disk
• tape

Input
Processing
Output
19
Hardcopy Devices

• Printers
• impact (dot matrix)
• noisy
• multi-copy
• non-impact (quiet)
• ink jet
• laser
• Plotters
• Microfilm

20
Softcopy Devices

• CRT (Cathode ray tube or TV picture tube)
• Flat-panel monitors
• fairly new expensive
• prices rapidly decreasing
• LCD flat screens (liquid crystal displays)
• laptop computer screens

21
Digital to Analog Conversion(D to A)

• Computer reconstructs digital image
• set of numbers
• Computer displays analog image

22
Computer System Elements
Hardware
Software
People
23
Hardware
Hardware can be seen.
Hardware can be touched.

• Computer
• Peripherals
• keyboard
• printer

Hardware
Software
People
24
HardwareExamples

• Disk Drive
• Memory
• Random Access (RAM)
• Read only (ROM)
• Mouse
• Keyboard
• Cables

Hardware
Software
People
25
Software

• Instructions to computer
• Operating System
• Applications

Hardware
Software
People
26
Operating System

• Fundamental instructions to hardware
• What to do when computer first turned on
• How to interact with peripherals
• CRT
• Keyboard
• Mouse
• Modem

Hardware
Software
People
27
Operating System

• Computer face presented to users
• Windows
• DOS
• MAC OS
• Dictates how usersinteract withcomputer torun
  applicationsoftware

Hardware
Software
People
28
Application Software

• Computer instructions which perform some desired
  task
• Balance checkbook
• Play a game
• Calculate (reconstruct)a CT image

Hardware
Software
People
29
Application Software

• Usually a quasi-English language
• Basic
• Fortran
• COBOL
• C
• Languages provide tools to software developers
  to efficiently design application software

Forms!FDoSurvey!FExpsSub.Form!KVEff
Val(Mid(MyData, 2, 10)) Forms!FDoSurvey!FExpsS
ub.Form!KVAVG Val(Mid(MyData, 12,
10)) Forms!FDoSurvey!FExpsSub.Form!MRMEAS
Val(Mid(MyData, 22, 10)) Forms!FDoSurvey!FExps
Sub.Form!TIMEMEAS Val(Mid(MyData, 32,
10)) DumText Mid(MyData, 42, 3) 'MsgBox
(DumText) If Right(DumText, 1) "" Then
DumText Left(DumText, 2) Else DumText
Left(DumText, 1) End If 'MsgBox (DumText) MyData
Right(MyData, Len(MyData) - Len(DumText) -
41) 'MsgBox (MyData) NKvs Val(DumText) 'MsgBox
(NKvs) KVMAX 0 If NKvs gt 0 Then For DumNum
1 To NKvs 'MsgBox (Val(Mid(MyData, 10
(DumNum - 1) 1, 10))) If
(Val(Mid(MyData, 10 (DumNum - 1) 1, 10))) gt
KVMAX Then KVMAX (Val(Mid(MyData, 10
(DumNum - 1) 1, 10))) End If
Next Forms!FDoSurvey!FExpsSub.Form!KVMAX
KVMAX End If DoCmd.Close acForm, "FNeroExp" End
Sub
30
People

• Designers
• hardware
• software
• Users
• run applications
• provide input
• use output

These parties do not always communicate
31
Meaningless Slide
32
Storage HardwareRandom vs. Sequential

• Direct (random) access
• any data can be accessed at any time
• disks
• Sequential access
• data only accessed in serial fashion
• must pass through unwanted data to reach target
  data
• tapes
• information encoded magnetically

33
Data Storage Technologies(constantly changing)

• Disks
• Formats
• Hard
• removable
• non-removable
• Floppy
• CD
• CD-RW
• CD-R
• Tape
• lots of data
• serial access

• Technologies
• Magnetic (disks tape)
• re-writable
• optical (disks CDs)
• re-writable
• write once

Yellow items best for long-term archiving
34
Data Communication

• Data transmission between computers

• Features
• speed
• cost
• topology
• wiring scheme

35
Data Communication Technologies

• Telephone lines
• twisted pair wires
• Coaxial cable
• Fiber optic cable
• Microwaves
• Satellites
• Radio waves

36
Star Topology
Host Computer
37
Ring Topology
38
Bus Topology
39
Networks

• LAN (Local area network)
• computers connected in one area
• LANs can be connected together
• WAN (Wide area network)
• computers connected together over large distances
• Communications protocols
• Ethernet
• uses bus technology
• Internet

40
File Server

• Special computer which handles functions for
  connected computers
• disk access
• printing
• Incorporates security
• may limit user to selected files or directories
• may limit of connections per user
• may limit times when network available

41
Typical Lan
Network Gateway
Other Networks
42
Radiology Computer Systems
Hospital Admission/Discharge Billing Reports
Insurance Carrier
Voice to Text Dictation
PACS
Digital Spot Film
RIS
Web Server
Digital Dictation
Professional Billing
Angio / Digital Subtraction
CT
Mammography
MRI
CR
43
The Computerization of Radiology
Digital Fluoro
Digital Angio
Nuc Med
CT
CR
MRI
3D Workstation
Laser Printer
RIS
PACS
Dictation
Admin
Radiologist Workstation
Radiologist Workstation
Radiologist Workstation
44
The Internet

• Network connecting all computers
• Originally developed for security
• Single bomb cant destroy all U.S. computing
  facilities
• Can connect large number of computers in many
  locations
• Communicates in finite packets
• Each packet has specific destination (address)
• Packets can be
• E-mail
• Web site
• Allows linking of information