Treatment Planning for Board Study

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Treatment Planning for Board Study
2014-04-12 14:04:15
Candice Treatment Planning Board Study

Treatment Planning for Board Study
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  1. What is the correction factor for air/lung___, bone____, and normal tissue____
    • .3
    • 1.3
    • 1.
  2. How many HVLs dose a photon block need to be?
  3. As electron energy increases, skin dose
  4. True or False
    Setting up to bolus will help you NOT to have to worry about correction factor
  5. As you increase field size but keep your monitor units the same, what happens to the dose being measured and why
    dose will increase because even tho the MU stay the same, the fs increased which means more scatter which means the dose increased
  6. In order for a block to have as little penumbra as possible, the block edge must be
  7. Most common used contrast for MRIs
  8. When field size increases, monitor units
    decrease because we have more scatter and do not need more monitor units since the dose will increase via scatter
  9. As field size decreases, the monitor units need to
    increase because there is less scatter
  10. Iodine contrast media is toxic to what organ?
    • kidneys
    • This is why docs will sometimes order a BUN or Creatine test to test the strength of the kidneys 1st
  11. As slice thickness decreases, noise will
    • increase
    • Image will be grainer. You can increase the MAs to correct it, but then the patient will receive more dose.
  12. Rotational arc tx time/monitor units are calculated using which method?
  13. Why will tissue inhomogeneities like air cavities, lung, fat, and bone alter the dose distribution?
    because any tissues without the same density as water may alter the dose
  14. Back scatter factor depends on the ____and _____but is independent of
    • Field size and energy
    • SSD
  15. 1st objective in tx planning is to determine ____ ____ and ____ ____
    • tumor boundaries and
    • critical structures
  16. What is administered to the peritoneal cavity in the tx of gyno malignancies?
    Phosphorus 32
  17. NTTD (normal tissue tolerance dose) is affected by 2 factors
    Volume and fraction size
  18. What is GTV and 1. cm of margin
  19. reticule is also called the
    fiducial plate
  20.  The ____ is a source of electrons and the ____ stops the electrons
    • Cathode
    • anode
  21. Positive or negative
    • Cathode is negative
    • Anode is positive
  22. The # of electrons which pass from the cathode to the anode represents the ____ ____ and is measure in _____ and the potential difference between the cathode and the anode is measured in ____
    • tube current
    • mA (milliampere)
    • kV kilivolts
  23. What is barium sulfate commonly used for
    • used to outline the GI tract (orally or rectally) and most often used for
    • Esophagus
    • stomach
    • small bowel
    • colon
    • oral cavity
  24. Iodine contrast is typically used for
    • kidney
    • bladder
    • prostate
  25. list the symptoms of anaphylactic shock
    • difficulty breathing
    • wheezing
    • abnormal (high pitched) breathing sounds
    • Treat with epinephrine which will open up the airways and raise the blood pressure by constricting blood vessels
  26. by subtracting the SSD from the SAD you can solve for
    • isocenter location
    • SSD-SAD= ioscenter depth
  27. How would the wedge be positioned for an AP/PA Larynx treatment?
    The heal would be anteriorly positioned to make the open area between the patient's chin and chest a virtual box, to help even the dose distributions.
  28. x jaws =
    y jaws=
    • width
    • length
  29. When calculating Moving Rotational (SAD) fields, ____ is the calculation of choice
  30. BSF is the ____ at dmax
  31. T or F
    Increase in beam energy will decrease the BSF, due to the forward motion of the beam.
  32. What is defined as the ratio of dose on the CAX at dmax to the dose at the same point in air?
    What is defined as the ratio of absorbed dose at a given depth in phantom to the absorbed dose at the same point in free space?
    • BSF
    • TAR
  33. As TAR increases, depth will
  34. Would you use TMR or TAR for irregular field calculations?
    TMR because you are measuring the ratio of dose anywhere and comparing it to dmax.

    You wouldn't use TAR because that only compares the ratio of absorbed dose to the dose at the same point in free space.
  35. ____ is the calculation of choice for isocentric field calcs and ____ is the calculation of choice for SSD (non isocentric) calcs
    • TMR
    • PDD
  36. SDD and SCD are the same thing and is defined as
    the distance along the beams axis
  37. an Increase in SCD/SDD will____ Penumbra
  38. Why do we use the Mayneord's factor
    to calculate the change in PDD for small fields
  39. The wedge transmission factor: the filter ____ the machine output
  40. The ___ ____ is the angle, in which an isodose curve is tilted at the cax  of the beam at a specified depth
    The ___ ___ is the ratio of dose with and without the wedge at a point in phantom along the beams CAX
    • wedge angle
    • wedge factor
  41. What does a larger focal spot do to the penumbra?
    increases the penumbra
  42. The width of the penumbra depends on what 3 things
    • SSD
    • field size
    • collimator size
  43. Where on the beam is the highest portion of dose?
    • on the CAX
    • the dose is greatest at the cax and it decreases towards the edges of the penumbra.
  44. smaller focal size will produce ___ and a larger focal spot size will produce ____
    • a sharper beam edge
    • decrease the sharpness of the beam's edge
  45. The best way to make sure that the portal borders are accurate is to take a ____ ____. The best way to verify the isocenter is correct is to take _____ _____
    • port films
    • orthogonal films
  46. _____ has a low melting point of 158- 163f  and a high Z. blocks are used to attenuate primary radiation to _____ of the unblocked beam intensity
    • cerrobend
    • less than 5 %
  47. what does cerrobend contain and how much
    • Bismuth-50%
    • Lead- 26.7%
    • Tin- 13.3%
    • cadmium- 10%
  48. The effective energy of the beam increases as it passes through the filter due to
    beam hardening
  49. Increase the collimator setting and it will ___ scatter
  50. isodose shift method is used to correct for ____ _____
    contour irregularities
  51. photoelectric effect will be accompanied by a ____ ____ emission
    characteristic xray
  52. what defines the beam
  53. The creation of a positron results from
    pair production
  54. TLD releases stored energy as ____ when heated