Digital Radiography Notes

Digital Radiography

Digital Radiography Elements

• Capture element: X-ray capture.
• Coupling element: Transfers signal to collection element.
• Collection element: Photodiode, CCD, or TFT.

Scanned Projection Radiography

• X-ray tube-detector array fixed; patient translated.

Charge-Coupled Device (CCD)

• Light-sensing element for digital cameras.
  • Sensitivity: Detects low light levels.
  • Dynamic range: Responds to varied light intensity.
  • Size: Very small.
• High sensitivity to x-ray exposure and wide dynamic range.

Cesium Iodide/Charge-Coupled Device (CsI/CCD)

• Indirect DR: X-rays converted to light, then to electronic signal.

Cesium Iodide/Amorphous Silicon (CsI/a-Si)

• Indirect DR: X-rays converted to light, then to electronic signal.
• Spatial resolution in DR is pixel limited.

Amorphous Selenium (a-Se)

• Direct DR: X-rays converted directly into an electronic signal.