MDCB STUDY EXAM GUIDE LATEST
QUESTIONS AND ANSWERS SURE A+
✔✔According to TG-142, what is the tolerance for the following monthly checks:
-gantry/collimator
-field size
-profile constancy
-electron beam energy constancy
-compensator placement
-symmetry/flatness (TG-40) - ✔✔-gantry/collimator: 1 degree
-field size: 2mm for symmetric, 1mm for asymmetric
-profile constancy: 1% from baseline
-electron beam energy constancy: 2%/2mm
-compensator placement: 1mm
-symmetry/flatness: 3%
✔✔According to TG-142, what is the tolerance for the following annual checks:
-flatness/symmetry
-calibration from TG-51
-output factors for small fields
-PDD/TMR - ✔✔-flatness/symmetry: 1% from baseline
-calibration from TG-51: 1%
-output factors for small fields: <2%
-PDD/TMR: 1%
✔✔According to TG-142, what is the tolerance for the following annual checks:
-TBI PDD x-ray
-TSET PDD electron
-TBI/TSET output - ✔✔-TBI PDD x-ray: 1%
-TSET PDD electron: 1mm
-TBI/TSET output: 2%
✔✔According to TG-142, when are the following linac wedge checks done:
-Check to see if they are functional
,-Check output
-Check profile - ✔✔-Check to see if they are functional: daily
-Check output: monthly
-Check profile: annually
✔✔According to TG-142, when are the following MLC checks done and what are the
tolerances:
-Leaf position accuracy
-travel speed
-leaf setting vs. radiation field
-transmission
-leaf position repeatability
-MLC spoke shot
-Rad-light coincidence
-Step & shoot/sliding window - ✔✔-Leaf position accuracy: monthly, 1mm at 4 cardinal
anlgles
-travel speed: monthly
-leaf setting vs. radiation field: monthly, 2mm
-transmission: annual, 0.5% from baseline
-leaf position repeatability: annual, 1mm
-MLC spoke shot: annual, 1mm
-Rad-light coincidence: annual, 2mm
-Step & shoot/sliding window: annual
✔✔According to TG-142, what is the frequency and tolerance for the following checks
with IGRT:
-iso check with KVCT and MVCT - ✔✔-iso check with KVCT and MVCT: daily, 2mm or
1mm for SRS
✔✔What things are checked for daily QA of imaging (EPID, KVCT, MVCT)? - ✔✔-
functional
-safety
-mechanical
✔✔What are 5 things that are checked for monthly QA of imaging (EPID, KVCT,
MVCT)? - ✔✔-Uniformity
-Registration
-Magnification/scaling (1mm for SRS)
-Contrast
-Resolution
✔✔What things are checked annual for QA of imaging (EPID, KVCT, MVCT)? -
✔✔dose
✔✔According to TG-51,
,-What is the frequency of calibration?
-What is the tolerance?
-What should it be measured in?
-What equipment should be used for photons vs electrons? - ✔✔-annually
-1%
-measured in water
-use ion chamber for photons
-use point detector/parallel plate ion chamber for low energy electrons
✔✔According to TG-51,
-What calibration factor is used?
-Photons should be measured at ___, but calibrated at ___
-Electrons should be measured at __, but calibrated at ___
-Why is Pb foil used when calibrating photons? - ✔✔-NDw
-photons: measure at 10cm, cal at dmax
-electrons: measure at dref, cal at dmax
-to remove electron contamination
✔✔TG-40 for TPS was replaced by ___, which was replaced by____. - ✔✔TG-40>>
TG-53 >> MPPG 5a
✔✔According to TG-40, what are the tolerances for the following monthly QA checks of
the TPS:
-Input/output device
-Checksum
-QA test set - ✔✔-Input/output device: 1mm
-Checksum: no change
-QA test set: 2% or 2mm
✔✔When using calibration equipment for linac QA, how often should the leakage of the
equipment be checked? When should a potential check be done? When should a
calibration by the ADCL be done? - ✔✔-Leakage: every use
-Potential check: every use, with voltage of +/-300
-ADCL cal: 2 years
✔✔When calibrating the linac, what type of phantom is ideal? - ✔✔-adequate size:
>5cm on side, >10cm depth extra
-same electron and physical density
-does not store charge
✔✔According to 10CFR part 20, what is the exposure rate limit if
T=1
T=0.50
T=0.025 - ✔✔T=1, survey limit is 2 mR/hr
T=0.50, survey limit is 4 mR/hr
, T=0.025, survey limit is 80 mR/hr
✔✔What is the exposure rate at 1 meter for a Cs-137 or I-131 patient? - ✔✔40 mR/hour
✔✔TARtotal=___ - ✔✔TARo + SAR
✔✔Pencil beam algorithm should not be used for ___. - ✔✔SBRT
✔✔Dose kernal is derived from what algorithm? - ✔✔Monte carlo
✔✔What algorithms are used with electrons? - ✔✔-2D and 3D pencil beam
-Phase space
-Monte Carlo
✔✔What 4 algorithms are used with brachytherapy? - ✔✔-Boltzman equation
-Superposition convolution
-Collapsed cone convolution
-Monte Carlo
✔✔With dose algorithms, where does the dose come from? - ✔✔dose is the convolution
of TERMA x kernel
✔✔Which one is spatially invariant vs variant: convolution or superposition -
✔✔convolution: spatially invariant
superposition: variant
✔✔What is the difference between secular equilibrium, transient equilibrium, and no
equilibrium? - ✔✔-secular: parent half life is much much greater than daughter
-transient: parent half life is more than daughter
-no equilibrium: when daughter half life is more than parent
✔✔What are two examples of isotopes that follow secular equilibrium? - ✔✔-Ra-
226(parent) to Ra-223(daughter)
-Sr-90 to Y-90
✔✔What are two examples of isotopes that follow transient equilibrium? - ✔✔Mo-
99(parent) and Tc-99m(daughter)
✔✔What is the equation for transient equilibrium? - ✔✔Ad= [(Ap)(Tp)] / [Tp-Td]
✔✔What are the predominate energy ranges for the following interactions:
-photoelectric
QUESTIONS AND ANSWERS SURE A+
✔✔According to TG-142, what is the tolerance for the following monthly checks:
-gantry/collimator
-field size
-profile constancy
-electron beam energy constancy
-compensator placement
-symmetry/flatness (TG-40) - ✔✔-gantry/collimator: 1 degree
-field size: 2mm for symmetric, 1mm for asymmetric
-profile constancy: 1% from baseline
-electron beam energy constancy: 2%/2mm
-compensator placement: 1mm
-symmetry/flatness: 3%
✔✔According to TG-142, what is the tolerance for the following annual checks:
-flatness/symmetry
-calibration from TG-51
-output factors for small fields
-PDD/TMR - ✔✔-flatness/symmetry: 1% from baseline
-calibration from TG-51: 1%
-output factors for small fields: <2%
-PDD/TMR: 1%
✔✔According to TG-142, what is the tolerance for the following annual checks:
-TBI PDD x-ray
-TSET PDD electron
-TBI/TSET output - ✔✔-TBI PDD x-ray: 1%
-TSET PDD electron: 1mm
-TBI/TSET output: 2%
✔✔According to TG-142, when are the following linac wedge checks done:
-Check to see if they are functional
,-Check output
-Check profile - ✔✔-Check to see if they are functional: daily
-Check output: monthly
-Check profile: annually
✔✔According to TG-142, when are the following MLC checks done and what are the
tolerances:
-Leaf position accuracy
-travel speed
-leaf setting vs. radiation field
-transmission
-leaf position repeatability
-MLC spoke shot
-Rad-light coincidence
-Step & shoot/sliding window - ✔✔-Leaf position accuracy: monthly, 1mm at 4 cardinal
anlgles
-travel speed: monthly
-leaf setting vs. radiation field: monthly, 2mm
-transmission: annual, 0.5% from baseline
-leaf position repeatability: annual, 1mm
-MLC spoke shot: annual, 1mm
-Rad-light coincidence: annual, 2mm
-Step & shoot/sliding window: annual
✔✔According to TG-142, what is the frequency and tolerance for the following checks
with IGRT:
-iso check with KVCT and MVCT - ✔✔-iso check with KVCT and MVCT: daily, 2mm or
1mm for SRS
✔✔What things are checked for daily QA of imaging (EPID, KVCT, MVCT)? - ✔✔-
functional
-safety
-mechanical
✔✔What are 5 things that are checked for monthly QA of imaging (EPID, KVCT,
MVCT)? - ✔✔-Uniformity
-Registration
-Magnification/scaling (1mm for SRS)
-Contrast
-Resolution
✔✔What things are checked annual for QA of imaging (EPID, KVCT, MVCT)? -
✔✔dose
✔✔According to TG-51,
,-What is the frequency of calibration?
-What is the tolerance?
-What should it be measured in?
-What equipment should be used for photons vs electrons? - ✔✔-annually
-1%
-measured in water
-use ion chamber for photons
-use point detector/parallel plate ion chamber for low energy electrons
✔✔According to TG-51,
-What calibration factor is used?
-Photons should be measured at ___, but calibrated at ___
-Electrons should be measured at __, but calibrated at ___
-Why is Pb foil used when calibrating photons? - ✔✔-NDw
-photons: measure at 10cm, cal at dmax
-electrons: measure at dref, cal at dmax
-to remove electron contamination
✔✔TG-40 for TPS was replaced by ___, which was replaced by____. - ✔✔TG-40>>
TG-53 >> MPPG 5a
✔✔According to TG-40, what are the tolerances for the following monthly QA checks of
the TPS:
-Input/output device
-Checksum
-QA test set - ✔✔-Input/output device: 1mm
-Checksum: no change
-QA test set: 2% or 2mm
✔✔When using calibration equipment for linac QA, how often should the leakage of the
equipment be checked? When should a potential check be done? When should a
calibration by the ADCL be done? - ✔✔-Leakage: every use
-Potential check: every use, with voltage of +/-300
-ADCL cal: 2 years
✔✔When calibrating the linac, what type of phantom is ideal? - ✔✔-adequate size:
>5cm on side, >10cm depth extra
-same electron and physical density
-does not store charge
✔✔According to 10CFR part 20, what is the exposure rate limit if
T=1
T=0.50
T=0.025 - ✔✔T=1, survey limit is 2 mR/hr
T=0.50, survey limit is 4 mR/hr
, T=0.025, survey limit is 80 mR/hr
✔✔What is the exposure rate at 1 meter for a Cs-137 or I-131 patient? - ✔✔40 mR/hour
✔✔TARtotal=___ - ✔✔TARo + SAR
✔✔Pencil beam algorithm should not be used for ___. - ✔✔SBRT
✔✔Dose kernal is derived from what algorithm? - ✔✔Monte carlo
✔✔What algorithms are used with electrons? - ✔✔-2D and 3D pencil beam
-Phase space
-Monte Carlo
✔✔What 4 algorithms are used with brachytherapy? - ✔✔-Boltzman equation
-Superposition convolution
-Collapsed cone convolution
-Monte Carlo
✔✔With dose algorithms, where does the dose come from? - ✔✔dose is the convolution
of TERMA x kernel
✔✔Which one is spatially invariant vs variant: convolution or superposition -
✔✔convolution: spatially invariant
superposition: variant
✔✔What is the difference between secular equilibrium, transient equilibrium, and no
equilibrium? - ✔✔-secular: parent half life is much much greater than daughter
-transient: parent half life is more than daughter
-no equilibrium: when daughter half life is more than parent
✔✔What are two examples of isotopes that follow secular equilibrium? - ✔✔-Ra-
226(parent) to Ra-223(daughter)
-Sr-90 to Y-90
✔✔What are two examples of isotopes that follow transient equilibrium? - ✔✔Mo-
99(parent) and Tc-99m(daughter)
✔✔What is the equation for transient equilibrium? - ✔✔Ad= [(Ap)(Tp)] / [Tp-Td]
✔✔What are the predominate energy ranges for the following interactions:
-photoelectric
