Scotts test Chapter 14

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Scotts test Chapter 14
2013-02-26 21:48:16
Review notes

taken from class review
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  1. What is the maximum number of electrons in the outer shell?
  2. An incident photon hits the electron in the outer  shell and knocks it out ( e-)
    Compton Scattering
  3. What is the most common interaction ?
    Compton or incoherent Scattering
  4. What are the 5 types of interactions?
    • 1.Coherent scattering
    • 2.Photoelectric scattering
    • 3.Compton Scattering (incoherent)
    • 4.Pair Production
    • 5.Photodisintegration
  5. Who are the scientists responsible for the work performed relating to interactions of photons/
    Thomson, Einstein, Compton,Rutherford
  6. Which interaction is not energetic enough to ionize the atom?
    Coherent scattering
  7. In which interaction is the incident photon of low energy, coming into region close to atom and absorbed, reemitting a second photon of same energy as incident but headed in new direction ( no ionizrion takes place because energy is too low)
    coherent scattering
  8. What energy does the incident photon have to have
  9. During pair production, what happens to incident electron?
    it gets absorbed by nucleus
  10. What happens in pair production after the incident photon is absorbed by nucleus?
    • releases a positron (β+) and neutron(β-) each with the energy of 
    • .511 each
  11. Which interaction collides with the nucleus
  12. An incident photon comes in and gets turned around and sent another way
  13. What are the electrons on the outer shell called?
    free electrons or valance electrons
  14. Which interaction hits an inner shell (K or L) and leaves a hole and knocks out the e-
  15. What are the 5 types of Photon interactions?
    • 1.Coherent scattering
    • 2.Photoelectric scattering
    • 3.Compton (coherent) scattering
    • 4.Pair Production
    • 5.Photodisintegration
  16. What is the inverse square law?
    I2=I1(d1 / d2 )2
  17. What does the half value layer due to the intensity?
    each layer halves the intensity

    X isotope has an intensity of 100 cGY.
    It's hvl is 12mm lead
    how many mm of lead will it take to get to 3%?
    • 1 layer   drops to 50% (12mm)
    • 2 layers drops  to 25% 
    • 3 layers drops to 12.5
    • 4 layers drops to 6.25
    • 5 layers drops to 3.12 %

    5 layers x 12 mm = 60 mm lead to reach 3%
  19. Attentuation coefficient
    .693/whatever coefficient you are using (see table page 291 table 14-4 will equal the half value layer
  20. What is HVL and what is it used for?
    HVL is the amount of material used to reduce the radiation to half its initial value

    Initially used to express the beam quality.. Hard or soft.
  21. What is the difference between a hard beam and a soft beam?
    a hard beam will have a higher HVL and higher penetrating ability
  22. Which beam is unable to penetrate through patient to film but instead leaves a large amount of dose inside patient without contributing to the film
    Soft Beam
  23. Which beam increases the skin dose to a patient?
    soft beam
  24. What happen as a beam passes through lead?
    the softer beams are absorbed by lead
  25. Name the effect of passing a beam through a lead attenuator to increase the the overall HVL of beam, and decreased the intensity of the beam
    beam hardening
  26. μ
    linear coefficient
  27. What are the 3 physical characteristics of the EM wave?
    • Frequency (nu)
    • wavelength (lambda)
    • velocity (v)
  28. What is point to point?
    Wavelength λ  lambda
  29. How many times something comes through
    ( nu )  frequency
  30. NOTE
    label a EM energy field page 283
    • velocity
    • wavelength
    • frequency
  31. what is braking radiation?
  32. What is the most important method of producing xray beams in therapy units?
  33. Which ELECTRON interaction has a high energy electron passing close to nucleus of target atom, strongly attracted by the charges in nucleus, it slows down, losing kinetic energy (emitted as as photon with energy equal to incident electron when it slowed)
  34. Energy that is caused by motion in space
  35. If NO kinetic energy is lost in the collsion, the collision is ___________
  36. If kinetic energy IS lost from the system , the collision is__________
  37. Name the 3 electron interactions
    • Electron- Electron interaction
    • Elastic Electron-Nuclei Collisions
    • Inelastic Electron-Nuclei Collision
  38. Name the interactions which emit a gamma ray
    (more than one)
  39. These interactions cannot ionize the atoms
    (more than one)
    Pair Production and Photodisintegration
  40. How many seconds are in 4.44 hours?
    • 4hr x 60min=240min x60sec= 14400 sec
    • .44%x60min=26.4 min x 60 sec=1584 sec

  41. Cobalt 60 decays by _____________
    β- decay to an excited state of nickel
  42. What does Lambda represent (λ)  ?
    • exponential decay constant
    • wavelength
  43. Excess energy , no longer needed to maintain stability, given off in the form of this type of xray
    characteristic xray
  44. Compton (incoherent) scattering
  45. Compton (incoherent) scattering
  46. Pair Production
  47. photoelectric scattering
  48. Photodisintegration
  49. Coherent Scattering