What is fluoroscopy?
- Fluoroscopy is an imaging technique commonly used by physicians to obtain real-time moving images of the internal structures of a patient through the use of a fluoroscope. In its simplest form, a fluoroscope consists of an x-ray source and fluorescent screen between which a patient is placed. Fluoroscopy is used for examination of moving internal structures and fluids.
FLUOROSCOPY AND ASSOCIATED PARTS
SPECIAL DEMANDS OF FLUOROSCOPY
- Fluoroscopy is a dynamic process; thus, the radiologist must adapt to moving images that are sometimes dim.
- Illumination- levels are measured in units of lumen per square meter or lux.
- Radiographs are visualized under illumination levels of 100 to 100 lux
Image-Intensifier Tube
Image Intensification
- Input phosphor
•Made of cesium iodide (CsI)
•Receives radiation exiting patient
•Emits light photons - Photo cathode
•Responds to light exiting input phosphor
•Emits electrons - Electrostatic lenses
- •Focus electrons
- Output phosphor
•Receives electrons from photocathode
•Emits 50-75× more light than received by photocathode
Flux Gain
Flux Gain=Number of output light photons/Number of input x-ray photons
Brightness Gain
Brightness gain = Minification gain × Flux gain
Magnification Modes
- Better spatial resolution
- Better contrast resolution
- Higher patient dose
Vidicon Television Camera Tube
Fiber Optics vs Lens System Coupling
A Television Picture Tube (CRT)
