X-ray Principles

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X-ray Principles Physics Laboratory

• Russell L. Wilson , CRT, RT(R)

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Properties of X-ray

• X-rays travel in a straight line and diverge from
  their point of origin.
• X-ray photons have many different energies.
• X-rays are highly penetrating.
• X-rays are invisible.
• X-rays travel at the speed of light.

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Properties of X-ray

• X-rays produce scatter radiation when they
  enter-act with matter.
• X-rays affect radiographic and photographic film.
• X-rays cause fluorescence of some materials.
• X-rays cause biologic damage.

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Properties of X-ray

• X-rays respond according to the inverse square
  law.

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X-ray Protection

• Because x-rays cause biologic damage, the
  operator of the machine and the patient must be
  protected from the radiation.
• Lead is used to absorb radiation.

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X-ray Hazards

• In the early days of radiography, the patient
  often was burned by the radiation.
• With proper operation of equipment, x-rays are
  relatively safe today.

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X-ray Injuries Still Occur

• These are serial photographs on a patient that
  had multiple long fluoroscopic examination.
• Last image is after skin graphs.

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Patient Radiation Protection

• Later in the quarter, we will covers methods
  used to keep the exposure to the patient as low
  as possible.
• Keeping the exposure low is the responsibility of
  the operator of the x-ray machine.

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X-ray Hazards

• With early x-ray machine, there was a real
  possibility of electrocution.
• Today with proper safety precautions, radiography
  is very safe for the operator.

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X-ray Hazards

• X-ray was also very hazardous for the operator in
  those early years.
• X-ray operators would use their hands to make
  sure the machine was working .

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X-ray Hazards

• It was not uncommon for both the operator and
  patient to receive burns.
• Today, with proper precautions, x-ray is safe for
  the operator.

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The X-ray Room

• The radiographic equipment consists of
• The Tube Stand, Tube Collimator
• Grid Holder or Bucky
• Controls in the Control Booth.

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The X-ray Room

• The wall of the x-ray room and door are shielded
  with lead to protect the operator and staff.

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Operator X-ray Protection

• The Door to the X-ray Room contains lead.
• It must be closed during exposures.

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Operator X-ray Protection

• The wall of the control booth is leaded. Stand
  completely behind the wall during exposures.

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Operator X-ray Protection

• Observe the patient or experiment through the
  lead glass window. No peeking around the wall!

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X-ray Tube

• X-rays are produced inside the x-ray tube.
• Many properties of light and x-ray are the same.

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Modern X-ray Tube

• This is a modern rotating anode general
• radiographic x-ray tube.
• The leaded glass holds the vacuum in the tube.
• Anode rotated to cool tube.

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X-ray Collimator

• Using light in the collimator, lead shutters are
  moved to restrict the area of exposure.

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X-ray Collimator

• Collimation is our best tool for reducing
  radiation exposure to the patient.

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Observations

• 1. Did the light field match the x-ray beam? Yes
• 2. What principle did this demonstrate? X-ray
  s travel in a straight line line and diverge from
  the point of origin. X-rays have similar
  properties to light.

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Observations

• 3. Did the intensity of the fluorescence of the
  screen change when the kVp was increased? Yes
• 4. Would this indicate that the intensity of the
  beam changed? Yes
• 5. During the exposure could you see inside the
  phantom? Yes

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Observations

• 6. What property of x-ray did this demonstrate?
  X-rays are highly penetrating.
• 7.After the tone from the control terminated, did
  the screen continue to fluoresce? No
• 8.If the screen did not fluoresce, was there any
  radiation coming from the tube after the tone
  stopped? No

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Observations

• 9. Did you hear any noise coming from the tube
  after the tone stopped? Yes the rotor continued
  to rotate.
• 10. What did you see on the film that was sitting
  near the phantom? A blurry image.
• 11. What principle did this demonstrate? X-rays
  produce scatter radiation. Scatter radiation is
  not divergent.

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The End

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