1. Dawn Guzman Charman, M.Ed., R.T. RAD TECH A
COMPUTED RADIOGRAPHY
Dawn Guzman Charman, M.Ed., R.T.
RAD TECH A
Good Morning
My Presentation to you today is the process , procedure and the reason that I undertook the task to develop a CURRICULUM GUIDE TO TEACH COMPUTED RADIOGRAPHY My

2. filmless’ radiology departments
Diagnostic radiographers
have traded their film and chemistry
for a computer mouse
and monitor
advance for Rad Sci Prof, 8/9/99

3. What Is Digital Imaging?
Digital imaging is the acquisition of images to a computer rather than directly to film.
FOR MANY YEARS WE HAVE BEEN PUTTING IMAGINES ONFILM RATHER THAN INTO A FILM

5. New Technology Has impacted practicing radiologic technologist
educators
Administrators
students in the radiologic sciences.
READ NOTE
The phenomenal growth of new knowledge is especially difficult because of the complexity of much of the new information. In addition, new approaches to this new knowledge demand new methods
There is general agreement among educators and professional leaders that graduates of programs in the radiologic sciences should be both competent and involved professionals. They should be committed to improving their skills and defining their values through lifelong learning

6. Many local area hospitals
and medical centers
have this equipment NOW

7. Computed Radiography
Fundamentals of
Computerized
Radiography

8. CR SYSTEM COMPONENTS CASSETTES (phosphor plates) ID STATION
IMAGE PREVIEW (QC) STATION
DIGITIZER
VIEWING STATION

9. Medical Imaging is changing
COMPUTED RADIOGRAPHY
Medical Imaging is changing
“FILMLESS” Radiology is the future
And the Future is here!
El Camino College
First educational institution in California or across the country to offer this new technology on a college campus
COMPUTED RADIOGRAPHY IS HERE
READ SLIDE
Now RT’s must further refine who they are and what they will contribute in the
context of
rapidly changing health care needs

10. Equipment Costs
Don Visintainer successfully wrote grants, and received funding from VTEA, P4E, and private sources
The Carl D. Perkins Vocational and Technical Education Act (VTEA) of 1991 was instrumental in helping to provide funds needed to purchase this equipment for an on-campus laboratory
State of California, Performance for Excellence (P4E), and private funding were also key
Total $410,
HIDDEN COSTS *

11. History of CR
INDUSTRY
Theory of “filmless radiography” first introduced in 1970
1981 Fugi introduced special cassettes with PSP plates (replaces film)
Technology could not support system
First clinical use in Japan

12. Predictions
1980 – Bell Labs believed that Unix would be the worlds dominant operating system
1982 – Bill Gates thought 640K of main memory would suffice for workplace operating systems ( This presentation is 80,000 kb)
1984 – IBM predicted that personal computers would not amount to anything

13. History of CR By 1998 – over 5000 CR systems in use nationwide
1998 – Local area hospitals begin to incorporate CR systems in their departments
(Riverside Co. Hosp builds new hospital in Moreno Valley) – completely CR system – 1st generation equipment

14. TERMINOLOGY F/S - Film/Screen (currently used method)
CR Computed Radiography
DR Digital Radiography
DDR - Direct to Digital Radiography

15. IMAGE CREATION SAME RADIOGRAPHY EQUIPMENT USED
THE DIFFERENCE IS HOW IT IS CAPTURED
STORED
VIEWED
And POST -PROCESSED

16. CONVENTIAL vs DIGITAL IMAGING
Currently, most x-ray imaging systems produce an analog image (radiographs, & fluoroscopy).
Using x-ray tube – films in cassettes

17. CONVENTIAL vs DIGITAL IMAGING
Digital radiography systems require that the electronic signal be converted to a digital signal –
Using x-ray tube – cassettes with phosphor plate OR
DR systems - transistors

18. COMPUTED RADIOGRAPHY & DIRECT RADIOGRAPHY & FILM SCREEN IMAGE CAPTURE
FS - Film inside of cassette
CR - PHOTOSTIMULABLE PHOSPHOR PLATE
DR(DDR) - TFT (THIN FILM TRANSISTOR)

19. Cassette w/ film CR w psp plate

21. Directed Digital Radiography (DDR)
Directed digital radiography, a
term used to describe total
electronic imaging capturing.
Eliminates the need for an image plate altogether.

22. Amorphous Selenium detector technology for
DR Direct Radiography

24. IMAGE CAPTURE CR DR – NO CASSETTE – PHOTONS
PSP – photostimulable phosphor plate
REPLACES FILM IN THE CASSETTE
DR – NO CASSETTE – PHOTONS
CAPTURED DIRECTLY
ONTO A TRANSISTOR
SENT DIRECTLY TO A MONITOR

25. CR vs FS CR FILM PSP in cassette Film in cassette Digital image
Scanned & read- CR reader
COMPUTER
Image stored on computer
Viewed on a Monitor
Hard copy (film) can be made with laser printer
FILM
Film in cassette
loaded in a darkroom
Processed in a processor
Hard copy image – stores the image
Viewboxes – view the images

26. CASSETTES with Intensifying Screens
The CASSETTE holds the film in a light tight container
It consist of front and back intensifying screens

27. CR BASICS
Eliminates the need for film as a recording, storage & viewing medium.
PSP Plate – receiver
Archive Manager – storage
Monitor - Viewing

28. PSP cassette exposed by conventional X-ray equipment.
General Overview CR
PSP cassette exposed by
conventional X-ray equipment.
Latent image generated as a matrix of trapped electrons in the plate.

29. CR – PSP plate photostimulable phosphor (PSP) plate Captures photons
Stored in traps on plate (latent image)
PLATE scanned in CR READER

30. CR Phosphor Plates ABSORPTION EMISSION X-RAY LIGHT LASER STIMULATION
ELECTRON
TRAP
ELECTRON
TRAP
X-RAY
LIGHT

31. CR – PSP plate Stimulated by a RED LIGHT
Energy is RELEASED in a form of BLUE light
LIGHT captured by PMT –
changed to a digiial signal

32. How CR works
Released light is captured by a PMT (photo multiplier tube)
This light is sent as a digital signal to the computer
The intensity (brightness) of the light – correlates to the density on the image

33. Densities of the IMAGE
The light is proportional to amount of light received
digital values are then equivalent (not exactly the same) to a value of optical density (OD) from a film, at that location of the image

35. ERASING PLATE After image is recorded
Plate is erased with high intensity white light
and re-used

36. CR VS DR
CR -Indirect capture where the image is first captured on plate and stored = then converted to digital signal
DDR -Direct capture where the image is acquired immediately as a matrix of pixels – sent to a monitor

37. DIRECT RADIOGRAPHY uses a transistor receiver (like bucky)
that captures and converts x-ray energy
directly into digital signal
seen immediately on monitor
then sent to PACS/ printer/ other workstations FOR VIEWING

38. CR vs DR CR imaging plate processed in a Digital Reader
Signal sent to computer
Viewed on a monitor DR
transistor receiver (like bucky)
directly into digital signal
seen immediately on monitor –

40. Image Resolution – (how sharply is the image seen)CR
4000 x 4000
image only as good a monitor*
525 vs 1000 line
more pixels = more memory needed to store
CR 2 -5 lp/mm
RAD 3-6 lp/mm
DR ?
IMAGE APPEARS SHARPER BECAUSE CONTRAST CAN BE ADJUSTED BY THE COMPUTER –
(DIFFERENCES IN DENSITY)

41. ADVANTAGE OF CR/DR Can optimize image quality
by manipulating digital data
to improve visualization of anatomy and pathology
AFTER EXPOSURE TO PATIENT

42. ADVANTAGE OF CR/DR AFTER THE EXPOSURE
CHANGES MADE TO IMAGE
AFTER THE EXPOSURE
CAN ELIMINATE THE NEED TO REPEAT THE EXPOSURE

43. ADVANTAGE OF CR/DR vs FS
Rapid storage
retrieval of images NO LOST FILMS!
PAC (storage management)
Teleradiology - long distance transmission of image information
Economic advantage - at least in the long run?

44. CR/DR VS FILM/SCREEN
FILM these can not be modified once processed
If copied – lose quality
DR/CR – print from file – no loss of quality

45. “no fault” TECHNIQUES F/S: RT must choose technical factors
(mAs & kvp) to optimally visualize anatomic detail
CR: the selection of processing algorithms and anatomical regions controls how the acquired latent image is presented for display
HOW THE IMAGE LOOKS CAN BE ALTERED BY THE COMPUTER – EVEN WHEN “BAD” TECHNIQUES ARE SET

46. DR Initial expense high very low dose to pt –
image quality of 100s using a 400s technique
Therfore ¼ the dose needed to make the image

47. Storage /Archiving FILM/SCREEN films: bulky deteriorates over time
requires large storage & expense
environmental concerns
CR & DR
8000 images stored on CD-R
Jukebox CD storage
no deterioration of images
easy access

48. Transmission of Images
PACS - Picture Archiving & Communications
System
DICOM - Digital Images & Communication
in Medicine
TELERADIOGRAPHY -Remote Transmission of Images

49. Benefits of Computer (web)-based Viewing Systems
Hardcopy studies are no longer misplaced or lost- eliminates films
Multiple physicians may access same patient films
Patients do not have to wait in Radiology for films once study is completed

50. “Film-less” components
CR or DR
CD-ROM or similar output
capability
Digitizing capability or service
This slide describes some of the components necessary to make radiology departments filmless.
CR and DR are machines that will replace the standard X-rays we take, and will produce digital images of the pictures taken. (MRI, CT and Ultra Sound pictures are taken as a routine course in digital mode – but are generally converted to film for viewing because there are no digital viewing stations and software).
CD-ROM’s allow radiologists currently to disperse images to attending or referring physicians, via US mail or delivery services
Ideally, these images could be transferred electronically over the internet or via .
To take existing film to digital mode, it will require hospitals to have the film “digitized”.

51. Histogram Analysis A histogram is a plot of gray scale value
vs. the frequency of occurrence
(# pixels) of the gray value in the image

53. HISTOGRAM – a bar graph depicting the density distribution (in numerical values) of the imaging plate
ALGORITHM – a set of mathematical values used to solve a problem or find an average

54. Adapted from AAPM TG10

55. Statistical plots of the frequency of occurrence of each pixel's value

56. Basics of Digital Images
digital images are a (matrix) of pixel (picture element) values

58. The algorithm attempts to distinguish among the parts of the histogram which represent the range of densities from bone to soft tissue

59. Histograms set for specific exams (body parts)
should produce digital images that are consistant (regardless of kVp or mAs used
Correct Algorithm (body part) must be selected prior to processing imaging plate

61. Methods to Digitize an Image
1. Film Digitizer - Teleradiography system (PACS, DICOM)
2. Video Camera (vidicon or plumbicon)
3. Computed Radiography
4. Direct Radiography

62. FILM DIGITIZER

63. Analog vs Digital Analog - one value blends into another
(like a thermometer)
Digital - distinct separation
98.6
exact

64. ANALOG TO DIGITAL IMAGE
Conversion of conventional analog films
to digital format for PACs and teleradiology applications
with scanning laser digitizers

65. CONTRAST & DENSITY
Most digital systems are capable of 1024 shades of gray - but the human eye can see only about 30 shades of gray
The Optical Density and Contrast can be adjusted after the exposure by the Radiographer.
This is POST - PROCESSING

66. High displayed contrast – narrow window width

67. Low displayed contrast (stretched) – wide window width

68. Basics of Digital Images
Pixel values can be any bit depth (values from 0 to 1023)
Image contrast can be manipulated to stretched or contracted to alter the displayed contrast.
Typically use “window width” and “window level” to alter displayed contrast

69. 80 KVP 5 30 5 15
100
200
500

70. Then the COMPUTER corrects any exposure errors
Therefore almost ANY technique can be used on the patient –
The computer will fix it

71. DOSE IMPLICATIONS MORE EXPSOURE TO PATIENT TECHNIQUES ESTABLISHED
HIGHER KVP = LESS MAS
LESS PATIENT DOSE

72. 80 kvp 200mas
10 mas 80 kvp
Note
Quantum Mottle

73. Dose Implications
Images nearly always look better at higher exposures.
Huge dynamic range means nearly impossible to overexpose.

74. POST PROCESSING

75. TECHNIQUE CONISDERATIONS
KVP Dependant
Now COMPUTER controls CONTRAST
Higher kVp to stimulate electron traps

76. standard image
edge sharpening

79. DEVELOPER
FIXER
WASH
DRY
WATER - SOLVENT

80. PROCESSOR PROBLEM – FIXER RETENTION

81. scratch

82. Crimping /cresent mark

83. REPEAT IMAGES

85. EMERGING PROBLEMS “BETTER” –NOT NECESSARILY FASTER
“LEARNING CURVE” FOR TECHNOLOGIST & PHYSICIANS
STUDENT APPLICATIONS & “ISSUES”
“PITFALLS OF CR”

86. POSITIONING & PROPER COLLIMATION ARE CRITICAL TO GOOD IMAGING OUTCOMES
Just like Phototiming, it can magnify your mistakes

87. COLLIMATION CRITICAL
AS THE COMPUTER READS THE DENSITY VALUE OF EACH PIXEL – IT IS AVERAGED INTO THE TOTAL
CLOSE COLLIMATION = BETTER CONTRAST
BAD COLLIMATION = MORE GRAYS AND LESS DETAIL

89. Digital imaging is not the end all, cure all for imaging problems.
It is still technologist dependent.
You must continue to think and apply everything learned in Imaging 101.
A computer is not an intelligent machine.
It can only perform as good as the information it was given.

90. To Produce Quality Images
For Conventional Projection
or CR Radiography:
The same rules, theories, and laws still apply and can not be overlooked FFD/OFD (SID/SOD) Inverse Square Law Beam Alignment Tube-Part-Film Alignment Collimation Grids
Exposure Factors: KVP, MaS
Patient Positioning
PATIENT POSITIONING
Accounts for 85% of the total number of repeat exposures.
Has a direct affect on exposure technique.

91. NEW IMAGE
towel that was used to help in positioning a child
CR is MORE sensitive to
ARTIFACTS

92. CR image – NEW IMAGE
Line caused from dirt collected in a CR Reader

93. Double exposure Child

94. ?
Hands over upper abdomen

95. High resolution with digital imaging