notebook exam 1

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notebook exam 1
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  1. Thomas Edison
    discovered fluoroscope. real time. the difference between x-ray and fluoroscope is the dynamic
  2. x-ray tube has two side they are
    positive and negative.
  3. negative
    cathode-filament
  4. positive
    anode-target
  5. the difference between positive and negative is
    the kilo-voltage (kVP)= high potential difference
  6. the % of x-ray
    • 1% x-ray
    • 99% heat
  7. common inches and cm of x-ray cassettes
    8 x 10 inches multiply by 2.5 = 20x25cm

    10 x 12 inches multiply by 2.5=25x30cm

    14 x 17 inches multiply by 2.5=35x43
  8. for x-rays to be produced you need 4 things
    vacuum=pyrix glass

    source of electron=filament

    target for electron=anode: the focal spot

    high potential difference between the source and the target=negative and positive=kVp
  9. photon
    the smallest possible unit of electromagnetic energy. x-ray is a photon
  10. voltage between source and target
    the negative will go to the positive. the energy is converted into 99%heat and 1% x-ray
  11. negative and positive is
    the potential difference. thermoeotic emission = heat related and form a space charge
  12. the target is the
    anode
  13. wavelength
    distance from one crest to the next
  14. frequency is the
    number of times per second that a crest passes a given point
  15. a increase in frequency will
    decrease wavelength and equal more energy
  16. kVp controls
    wavelength and frequency
  17. radiation=x-rays they
    travel in a straight line

    cannot be refracted by a lens

    diverges into space from its source

    cannot be detected
  18. 3 types of x-ray
    primary-what leaves the x-ray tube to the patient

    • scatter (secondary)Once
    • primary beam hits solid matter, what is not absorbed will scatter in many
    • directions

    • remnant-what passes through the body what's left over Remainder of the primary been after its been attenuated Pattern
    • of intensity is what creates the radiographic image
  19. The beam that passes through the patient and exposes the film is called “Exit
    Radiation

    ”This“Exit” radiation is what creates the image.
    • White image on
    • film is what was absorbed

    Black is what was exposed

    Shades of gray are what was attenuated
  20. LATENT IMAGE
    THE INVISIBLE IMAGE ON AN EXPOSED FILM OR PSP PRIOR TO PROCESSING
  21. MANIFEST IMAGE
    A VISIBLE IMAGE AFTER PROCESSING
  22. Radiographic Factors
    Time (s)

    Milliamperes (mA)

    Millamperes per second (mAs)

    Kilovoltage Peak (kVp)

    Distance
  23. time
    • Duration of the exposure of
    • radiation

    measured in seconds
  24. Effect on Film
    • Longer exposure Time will increase
    • Density of Film & Patient Exposure

    Shorter exposure Time will decrease Density of Film & Patient Exposure
  25. Milliamperage (mA)
    the quantity current going to the filament
  26. Milliamperers per second (mAs)
    the total amount of radiation expoure
  27. kilovoltage peak (kVp)
    controls the energy of the radiation beam. also known as high potential difference. more energy more kVp
  28. distance
    is the SID how far away from the source x-ray tube

    SID inverse square law

    the closer more exposure

    farther away less exposure
  29. SID
    Source to Image Receptor Distance the x-ray tube to the cassette itself
  30. SOD
    Source to Object Distance
  31. OID
    Object to Image Receptor Distance
  32. Focal Spot
    controls detail

    • the smaller the focal spot the better the detail
    • the larger the focal spot the less detail
  33. Four Principles in Image Quality
    Density

    Contrast

    Detail

    Distortion
  34. Density
    The amount of blackness of an image

    Also known as optical density

    Controlled by mAs

    Increase mAs = increase blackness

    Decrease mAs = decrease blackness
  35. Contrast controlled by kVp
    • The degree of difference between
    • the light and dark areas of an x-ray

    High contrast =  more black and white

    Low contrast = overall gray appearance
  36. Detail
    The degree of sharpness of a structural line on an x-ray  Focal spot size
  37. Distortion
    • Refers to a variation in the size and/or
    • shape of the image in comparison to the object it represents

    misreprensentation of size and shape

    size- in x-ray magnification looks bigger than it is

    shape - shorting or elongation
  38. Radiation Units/Measurements
    Roentgen (R)

    Radiation absorbed dose (RAD)

    Roentgen equivalent in man (REM)
  39. Roentgen (R)
    Amount of radiation in air (not pt. dose)
  40. Radiation absorbed dose (RAD)
    radiation dose what goes into the patient
  41. Roentgen equivalent in man (REM)
    the biological effect the damage to the body
  42. not all x-rays are equal
    x-rays 1 R=1RAD=1REM

    at least 6 feet from the beam
  43. 3 CARDINAL RULES FOR RADIATION
    SAFETY
    • time
    • distance
    • shielding
  44. Inverse Square Law
    In regards to radiography

    • The intensity of the radiation is INVERSELY proportional to the SQUARE of the
    • Distance
  45. ALARA
    As low as reasonably achievable

    For X-ray Techs, the maximum radiation dose per year is 5 rem or 50mSv

    • Applies to workers age 18 and over and
    • not pregnant.
  46. Device for monitoring radiation exposure.
    OSL-optically stimulated luminescence (read by laser)
  47. Imaging Systems
    • Analog
    • Film Screen

    • Digital
    • CR
    • DR
  48. Fluoroscopy
    Dynamic or real time imaging

    (X-ray are static/still images)

    Alarm sounds after 5 minutes of total exposure

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