RAD 100 ch 8 att. 2

• Diagnostic yield


  The likelihood that a test or procedure will provide enough information to establish a diagnosis
• What does x-ray equipment consist of?

  X-ray tube, support system, collimator, x-ray table, x-ray generator, control console and upright image receptor holder device
• What component produces x-rays?

  X-ray tube
• What is the x-ray tube made of?

  Pyrex glass encased in a lead housing
• What are the x-ray tubes main components?

  Anode and cathode
• What supports the x-ray tube?

  Overhead tubercane (OTC)
• What is needed in order for the cathode to produce x-rays?

  Electrical energy
• What causes the rapid acceleration of electrons to pass through the tube from cathode to anode?

  The potential difference expressed in kVp
• What does the tube convert the elecrical energy into?

  1% X-rays and 99% heat.
• Cathode filament


  A tightly wound tungston wire helix
• Thermionic emission


  The boiling off electrons as electrical current passes through the cathode filament wire
• What happens when the electrons accelerate from the cathode and collide with the positively charged anode?

  The kinectic energy from the steam is is converted into heat and x-radiation
• What is the anode assembly made of?

  Rotating disk of tungston
• What controls the number and energy of the x-rays produced by adjusting the amount of electrical energy going into the tube?

  The radiographer
• Where is the adjustment of the amount of electrical energy going into the x-ray tube located?

  At the radiohraphers system's control console.
• Collimator


  Beam limiting device
• What does the collimator contol?

  Controls the size and shape of the x-ray field coming out of the x-ray tube
• What determines the size of the collimator field?

  The radiographer by adjusting 2 controls on the front sides of the collimator box
• Does coning down increase or decrease the collimation field?

  Increase collimation
• Tubehead angulation scale?


  Goniometer
• Positive beam limitation


  X-ray unit detects the size of the image receptor and automatically collimates to a size not larger than the IR
• What does a radiographic table have?

  Tilting mechanism, free-floating or stationary tabletop and a height adjuster
• What is the workhorse for the control console?

  X-ray generator
• What 2 components does the control console consist of?

  Electronics cabinet and operator console
• What does the control console allow the radiographer to do?

  Turn system on and off, select the x-ray exposure factors, initiate and terminate the exposure and provide an audible and visual indication of x-ray exposure.
• What 5 generic controls does a console have?

  Main power, kVp and mAs selection, timer and rotor switch
• What is the device that begins the exposure called?

  Rotor-exposure switch
• What causes the anode to rotate and prepares the x-ray tube for exposure?

  The prep switch on the rotor switch
• What can damage the x-ray tube?

  Repeatedly prepping the tube unnecessarily
• What is the purpose of the IR?

  To absorb the energies of the x-ray beam.
• What do underexposed images produce?

  Noisy or grainy images
• What do overexposed images produce?

  Low contrast images
• What do cassette based systems have?

  A PSP (computed radiography)
• What are cassette-less systems?


  DR
• What is taking the place of film-screen radiography?

  CR/DR systems
• What is all radiation detected by the IR called?

  Remnant radiation
• What does remnant radiation consist of?

  Primary beam, Scatter and secondary radiation
• Is the image displayed on a monitor screen hard copy or soft copy?

  Soft copy
• Where do PSP detectors store the energy of the remnant beam in CR?

  In electron traps
• What IR uses a sophisticated reader device that opens the cassette removes the PSP plate and scans the plate with precise a low-energy laser beam?

  Computed radiography