MDCB Studying Exam Questions and
Answers Graded A+
CTP = - Correct answer-273+C/295 x 760/P
"Electrons, formula to find 50% dd" - Correct answer-E/2.33
Clinical range Electrons - Correct answer-E/3 - E/4
max energy of scattered photon at 90deg - Correct answer-511 keV
rest energy proton - Correct answer-938 MeV
Daily check, QA, gamma knife - Correct answer-timer, safety checks
List the KiloV units - Correct answer-Grenz, contact, superficial, ortho
QA, how often check output for gamma knife? - Correct answer-monthly
1 AMU - Correct answer-?? MeV
1 AMU - Correct answer-931 MeV
How far do b+ travel in tissue? - Correct answer-0.5 cm/MeV
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,How to calculate change in dose due to pt seperation parallel opposed 6xsw -
Correct answer-remember 3% per cm
Conv QA for photons is... - Correct answer-2% or 2mm
Conv QA for electrons is... - Correct answer-"3%, 3 mm"
Dose under %HVT kidney block - Correct answer-"10 - 20% depending energy,
FS"
HVT superficial units - Correct answer-1 - 8 mm Al
Range energy ortho - Correct answer-150 - 500 KvP
SSD ortho - Correct answer-50 - 70 cm
Dose monitoring system in beam path... - Correct answer-dose rate, integral dose,
beam symmetry
tx distance superficial units SSD - Correct answer-15 - 20 cm
What determines beam penumbra? - Correct answer-source size secondary
collimator
Conv E [MeV] to wavelength l [meters] - Correct answer-1.24/l
Activity per unit mass (G/m) = - Correct answer-specific activity
increase eff xray unit - Correct answer-Voltage Z
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, "Supervoltage therapy, energy" - Correct answer-500 - 1000 kV
energy xrays van der Graff - Correct answer-2 - 10 MV
What magnifies microwaves in linac? - Correct answer-klystron
Describe grazing hit Compton effect - Correct answer-photon goes forward
electron at 90° w/T=0
Describe direct hit Compton - Correct answer-Max energy electron, which travels
fwd photon @ 180°
Max energy Compton photon scattered @ 180° - Correct answer-me/2 = 0.255
MeV
Max energy Compton photon scattered @ 90° - Correct answer-me =0.511 MeV
max Energy compton photon scattered @ 0° - Correct answer-energy initial photon
total KE available for e+e- pair for pair production - Correct answer-hf - 2*me = hf
- 1.02 MeV
"Annihilation radiation, energy each annihilation photon" - Correct answer-0.511
MeV
Describe the photons created in annihilation radiation - Correct answer-Two 0.511
MeV particles scattered in opposite directions
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Answers Graded A+
CTP = - Correct answer-273+C/295 x 760/P
"Electrons, formula to find 50% dd" - Correct answer-E/2.33
Clinical range Electrons - Correct answer-E/3 - E/4
max energy of scattered photon at 90deg - Correct answer-511 keV
rest energy proton - Correct answer-938 MeV
Daily check, QA, gamma knife - Correct answer-timer, safety checks
List the KiloV units - Correct answer-Grenz, contact, superficial, ortho
QA, how often check output for gamma knife? - Correct answer-monthly
1 AMU - Correct answer-?? MeV
1 AMU - Correct answer-931 MeV
How far do b+ travel in tissue? - Correct answer-0.5 cm/MeV
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,How to calculate change in dose due to pt seperation parallel opposed 6xsw -
Correct answer-remember 3% per cm
Conv QA for photons is... - Correct answer-2% or 2mm
Conv QA for electrons is... - Correct answer-"3%, 3 mm"
Dose under %HVT kidney block - Correct answer-"10 - 20% depending energy,
FS"
HVT superficial units - Correct answer-1 - 8 mm Al
Range energy ortho - Correct answer-150 - 500 KvP
SSD ortho - Correct answer-50 - 70 cm
Dose monitoring system in beam path... - Correct answer-dose rate, integral dose,
beam symmetry
tx distance superficial units SSD - Correct answer-15 - 20 cm
What determines beam penumbra? - Correct answer-source size secondary
collimator
Conv E [MeV] to wavelength l [meters] - Correct answer-1.24/l
Activity per unit mass (G/m) = - Correct answer-specific activity
increase eff xray unit - Correct answer-Voltage Z
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
, "Supervoltage therapy, energy" - Correct answer-500 - 1000 kV
energy xrays van der Graff - Correct answer-2 - 10 MV
What magnifies microwaves in linac? - Correct answer-klystron
Describe grazing hit Compton effect - Correct answer-photon goes forward
electron at 90° w/T=0
Describe direct hit Compton - Correct answer-Max energy electron, which travels
fwd photon @ 180°
Max energy Compton photon scattered @ 180° - Correct answer-me/2 = 0.255
MeV
Max energy Compton photon scattered @ 90° - Correct answer-me =0.511 MeV
max Energy compton photon scattered @ 0° - Correct answer-energy initial photon
total KE available for e+e- pair for pair production - Correct answer-hf - 2*me = hf
- 1.02 MeV
"Annihilation radiation, energy each annihilation photon" - Correct answer-0.511
MeV
Describe the photons created in annihilation radiation - Correct answer-Two 0.511
MeV particles scattered in opposite directions
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