Digital ImagingDigital ImagingDigital ImagingDigital Imaging

acronyms1. PSP2. CRT3. ADC4. IP5. CR6. DR7. PACS8. SNR9. CNR

10. CCD11. FOV12. LUT13. DICOM14. RIS15. HIS16. TFT17. DQE18. DAP19. DEL20. Voxel

1. Photostimulable phosphor-europian activated barium fluorohalide (=200 speed)

2. Cathode-ray tube or computer monitor3. Analog to digital converter4. Imaging plate5. computed6. /digital radiography7. Picture archiving communication systems

8. SIGNAL TO NOISE RATIO PG 410 –BUSHONG The higher the signal the less the noise.

9. CONTRAST TO NOISE RATIO can be manipulated until noise

becomes too apparent-limited by the SNR 10. Charge coupled device- crystal silicon- small, replaces

vidicon in fluoro, device used in DR

11. Field of View –how much of the patient is imaged in the matrix

12. Look up Table – plotting grays on a scale

13. Digital imaging and communications in medicine -blending PACS and other imaging modalities

14. Radiology Information system15. Hospital Information system

16.Thin Film Transmitters- indirect conversion detector in DR. Stores electronic charge (from converted light) before computer processes it.

17.Detective Quantum Efficiency converting x-ray intensities into a radiographic image

18.DAP-Dose Area Product-multiplication of the dose and the area exposed

19, DEL- Detector Element. -size of the TFT..smaller-better resolution

20. Voxel-tissue volume 16. NYQUIST-Sampling frequency of digital data

20. Voxel-tissue volume

X,y and z lines

NYQUIST-Sampling frequency of digital data

Z lineX line

y line

• Computers connected together in a hospital by LAN

• Outside computers connected to hospital server by VPN

INDIRECT LAYERING• FLUORESCENT (ONLY IN INDIRECT-

WHY?)• PHOTODETECTOR LAYER• TFT

• AMORPHOUS SILICON-RELEASES ELECTRONS WHEN STRUCK BY LITE (INDIRECT)

• AMORPHOUS SELENIUM-RELEASES ELECTRONS WHEN STRUCK BY X-RAY PHOTONS (DIRECT)

FOV/MATRIX/PIXEL• FOV can increase without change

to Matrix or Matrix can change w/o change to FOV –

• What about the pixel?

Question?• Does the pixel size change if the

FOV changes and the matrix stays the same? Or what if the matrix changes but the FOV stays the same?

• If the FOV increases and the matrix stays the same, the pixel size increases