Digital Fluoroscopy

1
Digital Fluoroscopy

• Chapter 28

2
High Voltage Generator

• Digital Fluoro operates in the radiographic mode
  instead of fluoro mode.
• This makes patient exposure higher
• Because exposure is higher, fluoro is usually
  pulsed to reduce patient dose.

3
Pulsed fluoro mode

• Interrogation time
• The time that the x-ray tube is switched on
• Extinction time
• The time required for the tube to be switched off.

4
Charged Couple Devices

• Composed of crystalline silicon
• When illuminated, electrical charge is generated,
  pixel by pixel to create an image.

5
Video System

• Digital fluoro reads the fluoro monitor in the
  progressive mode instead of the interlaced mode.
• The TV camera tube sweeps the target assembly
  continuously from top to bottom.

6
Computer

• Analog-to-digital converter (ADC)
• Accepts the TV camera output signal in an analog
  mode and digitizes it to be used in image
  manipulation

7
Types of Image Subtraction

• Temporal subtraction
• A mask image is created (mask mode)
• Contrast is introduced
• The mask is subtracted from the image desired
  leaving only the contrast material

8
Types of Image Subtraction

• Energy subtraction
• Uses the principles of characteristic x-ray
  production to subtract the k-edge of the lower
  and higher energy ranges leaving only the
  contrast material

9
Types of Subtraction

• Time-interval-difference mode (TID)
• Creates a new mask for each frame of viewing
• Subtracts the new mask from the new image

10
Picture Archiving and Communication System (PACS)

• Allows for acquisition, interpretation and
  storage of each medical image in digital form
  without having a hard copy film on hand.

11
Components of PACS

• Display system
• CRT monitor in which tech and docs may use to
  look at and manipulate images
• Network
• The cable or phone wire that connects the storage
  area with each display system
• Storage system
• Uses a magnetic or optical memory device.

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THE END