MDCB UPDATED FINAL EXAM QUESTIONS
AND ANSWERS SURE A+
✔✔For I-131 what is the:
-Physical half-life
-Biological half-life
-Energy - ✔✔-Physical half-life: 8 days
-Biological half-life: 12 hours
-Energy: 0.364 Mev
✔✔For Ru-106 what is the:
-Half-life
-Energy - ✔✔Half-life: 1 years
Energy: 3.54 Mev
✔✔What is the half-life of Ra-226? Energy? Exposure rate constant? - ✔✔Half-life:
1600 years
Energy: 0.830 Mev
ERC: 8.25 R-cm^2/hr-mCi
✔✔For Au-198 what is the:
-Half-life
-Energy
-Dose rate
-ERC - ✔✔Half-life: 2.7 days
Energy: 0.412 Mev
Dose rate: 64cGy/hr
-ERC: 2.38 R-cm^2/hr-mCi
✔✔What units are Cs-137 sources stated in? - ✔✔mg-Rad equivalency
✔✔What are the units of the exposure rate constant? - ✔✔R-cm^2/hr-mCi
,✔✔What exposure can the following personnel typically be exposed to:
-Radiation therapist
-Oncology floor nurse
-X-ray tech
-Nuc med tech
-PET tech
-Specials/cardiac cath tech - ✔✔ALL VALUES IN mR or mRem
-Radiation therapist=0
-Oncology floor nurse=100
-X-ray tech=300
-Nuc med tech=400
-PET tech=500
-Specials/cardiac cath tech=1500
✔✔What is the occupational exposure rate from the bedside of a Cs-137 or I-131
ablation patient? At 1 meter? - ✔✔Bedside: 100 mR/hour, 1 meter: 40mR/hr
✔✔What is the occupational exposure rate in front of a shield with a Cs-137 pt? Behind
the shield? Visitor line? - ✔✔In front=30 mR/hr
Behind=2 mR/hr
Visitor line=1 mR/hr
✔✔What is the exposure rate for a patient to be released after an inpatient I-131
procedure? - ✔✔5 mR/hr
✔✔According to 10 CFR part 20, what is the exposure rate guideline for unrestricted
areas? - ✔✔<2 mR/hr
✔✔What is the exposure rate from a prostate seed patient? - ✔✔100 uR/hr
✔✔What is the exposure rate from the back of an HDR unit when the source is in safe?
- ✔✔100 uR/hr
✔✔How much shielding is required for the following:
PET suite
Dental rooms, C-arms
Cs-137 portable shield - ✔✔PET suite= 1/8th-1" Pb
Dental rooms, C-arms: none
Cs-137 portable shield: 2cm Pb
✔✔With a PET/CT suite, what rooms are shielded? How much dose is absorbed by the
patient? - ✔✔-Shield the hot lab, injection room, bathroom, wait room, scanning room,
and console area
-Pt absorbs about 30% of the dose
,✔✔What is the magnitude of error if the following occurs:
-Missing physical wedge
-Normalize to field edge (50% line)
-Normalize 6x beam to 10cm vs 1.5cm
-Run hetero plan vs homo plan
-1cm SSD set-up error
-Failure to use Pb foil on TG-51 - ✔✔-Missing physical wedge=25-300%
-Normalize to field edge (50% line)=200%
-Normalize 6x beam to 10cm vs 1.5cm=50%
-Run hetero plan vs homo plan=5-30%
-1cm SSD set-up error=3-7%
-Failure to use Pb foil on TG-51=0.2%
✔✔What is the clinical dose for the following procedures:
Prostate seed implant with I-125
Prostate seed implant with Pd-103
Prostate EBRT + I-125 implant
Prostate EBRT + Pd-103 implant
Prostate IMRT only
Whole pelvis
LDR GYN brachy - ✔✔Prostate seed implant with I-125= 144 Gy
Prostate seed implant with Pd-103=110 Gy
Prostate EBRT + I-125 implant= 45Gy+120Gy
Prostate EBRT + Pd-103 implant= 45Gy + 90Gy
Prostate IMRT only=80 Gy
Whole pelivs=45 Gy
LDR GYN brachy=30Gy
✔✔What is the clinical dose for the following procedures:
SRS trigeminal neuraliga
Whole Brain
SRS Brain mets
1 fraction hip or spine mets - ✔✔SRS trigeminal neuraliga=90Gy
Whole Brain=30Gy
SRS brain mets=12-30Gy
1 fraction hip or spine mets=8Gy
✔✔What is the clinical dose for the following procedures:
H&N IMRT
Lung IMRT w/ boost
SBRT lung
Breast w/ boost
PBI breast - ✔✔H&N IMRT: 70Gy
Lung IMRT w/ boost: 66Gy
, SBRT lung: 48-60Gy
Breast w/ boost: 60-66Gy
PBI breast: 34Gy
✔✔Mass and energy are ___. - ✔✔interchangeable
✔✔What is mass defect? - ✔✔-The mass of protons and neutrons individually exceeds
the mass of C-12 as one element when put together.
-Energy is released with the formation of the nucleus
✔✔How do you find the max number of electrons in a shell? How many shells are
there? - ✔✔-2n^2 (n is the shell number)
-4 shells (k,l,m,n)
✔✔What are the 4 forces of nature? - ✔✔-Strong nuclear: force holding p-n together
-Electromagnetic: force attracting e(-) to nucleus(+)
-Weak Nuclear: force creating radioactive decay on nucleus
-Gravitational: gravity
✔✔Protons and neutrons have ___quarks. - ✔✔3
✔✔Atoms are made up of electrons and ___, which make up ___, which then makes
up___. - ✔✔Atoms=electrons & quarks
Quarks=protons & neutrons
P&N=nucleus
✔✔Particles can be broken down in ___,___, and ___. - ✔✔leptons, bosons, and
hadrons
✔✔Leptons contain what 4 things? - ✔✔-Electrons
-Positrons
-Muons
-Neutrinos
✔✔Bosons contain what thing? - ✔✔Photons
✔✔Hadrons contain what thing? - ✔✔Quarks (protons and neutrons)
✔✔How big are the following:
-Atom
-Nucleus
-Proton
-Quark/electron - ✔✔-Atom: 10^-10m
-Nucleus: 10^-14m
AND ANSWERS SURE A+
✔✔For I-131 what is the:
-Physical half-life
-Biological half-life
-Energy - ✔✔-Physical half-life: 8 days
-Biological half-life: 12 hours
-Energy: 0.364 Mev
✔✔For Ru-106 what is the:
-Half-life
-Energy - ✔✔Half-life: 1 years
Energy: 3.54 Mev
✔✔What is the half-life of Ra-226? Energy? Exposure rate constant? - ✔✔Half-life:
1600 years
Energy: 0.830 Mev
ERC: 8.25 R-cm^2/hr-mCi
✔✔For Au-198 what is the:
-Half-life
-Energy
-Dose rate
-ERC - ✔✔Half-life: 2.7 days
Energy: 0.412 Mev
Dose rate: 64cGy/hr
-ERC: 2.38 R-cm^2/hr-mCi
✔✔What units are Cs-137 sources stated in? - ✔✔mg-Rad equivalency
✔✔What are the units of the exposure rate constant? - ✔✔R-cm^2/hr-mCi
,✔✔What exposure can the following personnel typically be exposed to:
-Radiation therapist
-Oncology floor nurse
-X-ray tech
-Nuc med tech
-PET tech
-Specials/cardiac cath tech - ✔✔ALL VALUES IN mR or mRem
-Radiation therapist=0
-Oncology floor nurse=100
-X-ray tech=300
-Nuc med tech=400
-PET tech=500
-Specials/cardiac cath tech=1500
✔✔What is the occupational exposure rate from the bedside of a Cs-137 or I-131
ablation patient? At 1 meter? - ✔✔Bedside: 100 mR/hour, 1 meter: 40mR/hr
✔✔What is the occupational exposure rate in front of a shield with a Cs-137 pt? Behind
the shield? Visitor line? - ✔✔In front=30 mR/hr
Behind=2 mR/hr
Visitor line=1 mR/hr
✔✔What is the exposure rate for a patient to be released after an inpatient I-131
procedure? - ✔✔5 mR/hr
✔✔According to 10 CFR part 20, what is the exposure rate guideline for unrestricted
areas? - ✔✔<2 mR/hr
✔✔What is the exposure rate from a prostate seed patient? - ✔✔100 uR/hr
✔✔What is the exposure rate from the back of an HDR unit when the source is in safe?
- ✔✔100 uR/hr
✔✔How much shielding is required for the following:
PET suite
Dental rooms, C-arms
Cs-137 portable shield - ✔✔PET suite= 1/8th-1" Pb
Dental rooms, C-arms: none
Cs-137 portable shield: 2cm Pb
✔✔With a PET/CT suite, what rooms are shielded? How much dose is absorbed by the
patient? - ✔✔-Shield the hot lab, injection room, bathroom, wait room, scanning room,
and console area
-Pt absorbs about 30% of the dose
,✔✔What is the magnitude of error if the following occurs:
-Missing physical wedge
-Normalize to field edge (50% line)
-Normalize 6x beam to 10cm vs 1.5cm
-Run hetero plan vs homo plan
-1cm SSD set-up error
-Failure to use Pb foil on TG-51 - ✔✔-Missing physical wedge=25-300%
-Normalize to field edge (50% line)=200%
-Normalize 6x beam to 10cm vs 1.5cm=50%
-Run hetero plan vs homo plan=5-30%
-1cm SSD set-up error=3-7%
-Failure to use Pb foil on TG-51=0.2%
✔✔What is the clinical dose for the following procedures:
Prostate seed implant with I-125
Prostate seed implant with Pd-103
Prostate EBRT + I-125 implant
Prostate EBRT + Pd-103 implant
Prostate IMRT only
Whole pelvis
LDR GYN brachy - ✔✔Prostate seed implant with I-125= 144 Gy
Prostate seed implant with Pd-103=110 Gy
Prostate EBRT + I-125 implant= 45Gy+120Gy
Prostate EBRT + Pd-103 implant= 45Gy + 90Gy
Prostate IMRT only=80 Gy
Whole pelivs=45 Gy
LDR GYN brachy=30Gy
✔✔What is the clinical dose for the following procedures:
SRS trigeminal neuraliga
Whole Brain
SRS Brain mets
1 fraction hip or spine mets - ✔✔SRS trigeminal neuraliga=90Gy
Whole Brain=30Gy
SRS brain mets=12-30Gy
1 fraction hip or spine mets=8Gy
✔✔What is the clinical dose for the following procedures:
H&N IMRT
Lung IMRT w/ boost
SBRT lung
Breast w/ boost
PBI breast - ✔✔H&N IMRT: 70Gy
Lung IMRT w/ boost: 66Gy
, SBRT lung: 48-60Gy
Breast w/ boost: 60-66Gy
PBI breast: 34Gy
✔✔Mass and energy are ___. - ✔✔interchangeable
✔✔What is mass defect? - ✔✔-The mass of protons and neutrons individually exceeds
the mass of C-12 as one element when put together.
-Energy is released with the formation of the nucleus
✔✔How do you find the max number of electrons in a shell? How many shells are
there? - ✔✔-2n^2 (n is the shell number)
-4 shells (k,l,m,n)
✔✔What are the 4 forces of nature? - ✔✔-Strong nuclear: force holding p-n together
-Electromagnetic: force attracting e(-) to nucleus(+)
-Weak Nuclear: force creating radioactive decay on nucleus
-Gravitational: gravity
✔✔Protons and neutrons have ___quarks. - ✔✔3
✔✔Atoms are made up of electrons and ___, which make up ___, which then makes
up___. - ✔✔Atoms=electrons & quarks
Quarks=protons & neutrons
P&N=nucleus
✔✔Particles can be broken down in ___,___, and ___. - ✔✔leptons, bosons, and
hadrons
✔✔Leptons contain what 4 things? - ✔✔-Electrons
-Positrons
-Muons
-Neutrinos
✔✔Bosons contain what thing? - ✔✔Photons
✔✔Hadrons contain what thing? - ✔✔Quarks (protons and neutrons)
✔✔How big are the following:
-Atom
-Nucleus
-Proton
-Quark/electron - ✔✔-Atom: 10^-10m
-Nucleus: 10^-14m
