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Fluoroscopy

• Fluoroscopy is a type of medical imaging that shows a real time X-ray image on a monitor, much like an X-ray movie.

• During a fluoroscopy procedure, an X-ray beam is passed through the body.

Image intensifier:

• The image-intensifier tube is a complex electronic device that receives the image-forming x-ray beam and converts it into a visible-light image of high intensity.

• Within an image intensifier, the input phosphor converts the

x-ray photons to light photons, which are then converted to photoelectrons within the photocathode

Image intensifier

• Through this process, several thousand light photons are produced for each x-ray photon reaching the input phosphor.

• Most modern image intensifiers use cesium iodide for the input phosphor because it has a high absorption efficiency and thus decreases patient dose.

IMAGE INTENSIFICAITON=

photons are amplified + multiplied

Image-intensifier tube• The image-intensifier tube is approximately 50 cm long. A

• potential difference of about 25,000 V is maintained across the tube between photocathode and anode so that electrons produced by photoemission will be accelerated to the anode

Photocathode

• The photocathode emits electrons when illuminated by the input phosphor.

ANODE:• The anode is a circular plate with a hole in the middle through which

electrons pass to the output phosphor, which is just the other side of the anode .

Advantage of Image intensifier

• The principal advantage of image-intensified fluoroscopy over earlier types of fluoroscopy is increased image brightness. this requires high levels of image brightness.

• The image intensifier was developed principally to replace the conventional fluorescent screen, which had to be viewed in a darkened room.

FLUOROSCOPIC DATA AQUSITION-IMAGE INTENSIFIED SYSTEM

1. X-RAY TUBE2. PATIENT3. IMAGE INTENSIFIER4. OUTPUT PHOSPHOR5. CAMERA6. MONITOR

IMAGE

The solid state charge-coupled device (CCD).

• Two methods are used to electronically convert the visible image on the output phosphor of the image intensifier into an electronic signal:

Thermionic television camera tube

Applications

Fluoroscopy is used in many types of examinations and procedures such as

• cardiac catheterization

• Arthrography (visualization of a joint or joints)

• lumbar puncture,

• placement of intravenous (IV) catheters (hollow tubes inserted into veins or arteries)

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