CR, DR for WHO.pdf FOR RADIOGRAPHERS DIGITAL X RAY

DEFERINT BEWEEN DR ANCR DIGITAL X RAY

1. Analogue, CR &DR Systems
By:
Dr. Najeebullah Hatam MD, MSc ( Imaging )
Consultant Radiologist
Director Hatam Ultrasound Training Institute -Kabul
DR HATAM

3. ANALOGUE , CR , DR
How an X ray Image is produced ?
We need a detector for imaging !
What is a detector ? Or what can be a detector
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4. ANALOGUE , CR , DR
We need a detector for imaging !
1.Film
2.Plate
3.Electronic detector (fixed, charged coupled device CCD)
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5. ANALOGUE , CR , DR
How an X ray Image is produced ?
Difference in X ray Absorption
As x-rays pass through the human body they are attenuated by
interaction with body tissues (absorption and scatter) and
produce an image pattern on detector that is recognizable as
human anatomy.
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6. ANALOGUE , CR , DR
Can we make changes in the image ?
Prepressing
Post processing
Which detector is used ?
Can we store/ communicate the image ?
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7. CONVENTIONAL RADIOGRAPY
Analogue
•It dates back to the genesis of diagnostic radiology in 1895
when Wilhelm Roentgen produced the first x-ray film image
of his wife’s hand.
•Remains fundamental to the practice of diagnostic imaging.
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8. Analogue
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9. Analogue
Uses film and its processing technique. Film and cassette
•Cassette
•Film
•Dipped into fixer solutions
•Chemical developer solution
•Rinsed
•Dried.
•takes 5-6 minutes.
•Dark Room
•Advantage :generally costs a lot less.
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10. Analogue
•Patient information
Name
Age
Sex
•General information
Date
Type
Centre
Technician
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11. Analogue
•Can you make any changes ? Post processing :No
Contrast
Brightness
Filtration
Zoom
Size
Any correction
No information can be added /subtracted
No copy
No archive
Cannot be communicated
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12. CONVENTIONAL FILM RADIOGRAPHY
ANALOGUE
Film Radiography utilizes a screen-film system within a film cassette
as the x-ray detector.
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13. CONVENTIONAL RADIOGRAPHY
Image Generation X-rays are a form of radiant energy similar in
many ways to visible light. X-rays differ from visible light in
that they have a very short wavelength and are able to penetrate
many substances that are opaque to light.
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14. CONVENTIONAL FILM RADIOGRAPHY
•X-rays transmitted through the patient bombard a fluorescent particle–
coated screen within the film cassette causing a photochemical
interaction that emits light rays, which expose photographic film within
the cassette .
•The film is removed from the cassette and developed by an automated
chemical film processor.
•The final product is an x-ray image of the patient’s anatomy on a film
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15. DR HATAM

16. COMPUTED RADIOGRAPHY (CR)
Is a filmless system that eliminates chemical processingand provides
digital radiographic images.
CR substitutes a phosphor imaging plate (IP) for the film-screen
cassette. CR cassette sizes match those available for traditional film-
screen cassettes. The same gantry, x-ray tube, and exposure control
systems, and cassette holders used in conventional radiography are
utilized for CR.
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17. COMPUTED RADIOGRAPHY (CR)
•The phosphor-coated imaging plate interacts with x-rays transmitted
through the patient to capture a latent image.
•The phosphor plate is placed within a reading device that scans the
plate with a helium-neon laser, emitting light, which is captured by
a photomultiplier tube and processed into a digital image.
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18. COMPUTED RADIOGRAPHY (CR)
CR comprises of
1.Photostimulable storage phosphor (IP), Phosphor plate
2.CR reader to extract the electronic latent image
3.Digital electronics to convert signals to digital form.
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19. DR HATAM

20. COMPUTED RADIOGRAPHY (CR)
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CR networking
DICOM
•Digital imaging communications in medicine
•Provide open architecture solutions for modality, interfaces,
storage retrieval and print functions
•Technologist workstation
•Modality work list input
•Processed image output

21. COMPUTED RADIOGRAPHY (CR)
•The CR receptor is erased with white light and is used repeatedly.
•The digital image is transferred to a computerized picture
archiving and communication system (PACS).
•The PACS stores and transmits digital images via computer
networks to give physicians and healthcare providers in many
locations simultaneous instant access to the diagnostic images.
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22. DR HATAM

23. DIGITAL RADIOGRAPHY (DR)
Provides a filmless and cassette less system for capturing x-ray images in
digital format.
•DR substitutes a fixed electronic detector or charge-coupled device (CCD)
for the film-screen cassette or phosphor imaging plat.
•Direct read-out detectors produce an immediate digital radiographic image.
•Most DR detectors are installed in a fixed gantry limiting the ability of the
system to obtain images portably at the patient’s bedside.
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24. DIGITAL RADIOGRAPHY (DR)
CR is generally used for that purpose in a digital imaging department.
Direct digital image capture is particularly useful for
•Angiography providing rapid digital image subtraction
•Fluoroscopy
•Image guided interventional procedures capturing video images with
low, continuous radiation.
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25. DR HATAM

26. IMAGING PRINCIPLE OF CCD
After the flashing screen is exposed by XRay, the X-ray photon is
converted to visible light, visible light is reflected mirror reflection,
and then the visible light is projected onto the CCD chip by lens
focusing, and the CCD chip converts visible light into electrical
signal, and finally obtains the digital image. The DR the CCD
detector belongs to indirect energy Conversion Mode.
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27. DR HATAM

28. Thank You
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