HomeStretch CRACK Physics NUCS

Question 1

Isobaric transition means?

Answer 1

No change in mass (like a barbell)

Question 2

beta minus decay

Answer 2

neutron excess (proton deficient)

changes neutron to proton and emits a beta particle - isobaric transition

e- emission can damage DNA - basis of radionucleotide therapy

Question 3

alpha decay

Answer 3

heavy unstable atoms

lots of tissue damage

Question 4

Beta Positive decay

Answer 4

Proton excess (neutron deficient) [rival of e- capture]

has at least 1.02MeV

positron emission, leading to two 511 keV photons which fly 180 degrees apart

Question 5

e- capture

Answer 5

proton excess (neutron deficient) [rival of beta + decay]

Does not require 1.02 MeV

Leads to gamma emission and characteristic radiation

GIT! Gallium, indium and thalliam decay this way. . .

Question 6

Cyclotron produce radioisotopes

Answer 6

Moly-99

F-18

Ga-67

Tl-201

Question 7

Reactor produced radioisotopes

Answer 7

Moly-98 (which can then be placed in a cyclotron to make moly-99)

I-131

Xenon-133

Tl-201

Question 8

Generator produced radionuclides

Answer 8

Tech-99m (from cyclotron produced Moly-99, which was made from reactor produced moly-98)

Krypton-81m (from cyclotron rubidium-81)

Question 9

The NRC allows what moly99 to tech99m ratio in the ______ purity test

Answer 9

0.15 micro Ci of Mo to 1 milli Ci of Tech-99m in the radionuclide chemical test at the time of administration

Question 10

Chemical purity test

Limit/number?

What do you see in a liver/spleen scan if this is not correct?

How about in other scans?

Answer 10

the chemical = aluminum!

performed with a pH paper

the allowed amount is < 10 microgram of Al / 1 mL

Liver/spleen scan + LUNG = Al contamination

Tc scan + LIVER activtiy = Al contamination

Question 11

Radiochemical purity test

Limits

Answer 11

radiochemical = free tech99m!

thin-layer chromatography is used to test for this

95% Na99mTcO4

92% for 99mTc Sulfor colloid MAA

91% for all other Tc radiopharmaceuticals

Question 12

What radioisotopes use collimator:

Low energy

Medium Energy

High energy

Answer 12

Low (1-200keV) = Tech99m, I123, Xe133, TI 201

Medium (200-400keV) = Ga67, In111

High (>400) = I131

Question 13

Field uniformity recommended counts for both extrinsic and intrinsic range?

Answer 13

5-10 million

Question 14

QA intervals for:

Field uniformity (external and internal) (and limit)

Energy window

Image linearity and spatial resolution

Center of rotation

Answer 14

• Field uniformity (external and internal)
  
  • external (with collimator) = daily
  • internal (without collimator) = weekly
    
    • 2-5% non-uniformity is allowed (1% if SPECT!)
• Energy window = DAILY
• Image linearity and spatial resolution = WEEKLY
• Center of rotation = MONTHLY

Question 15

Maximum dose a GM counter can handle before goes into dead time?

Answer 15

100 mR/h

Question 16

Ion chambers can be used to detect exposure rates from ___ to ___

Answer 16

0.1 to 100 R/h

Question 17

Dose calibrator QA

Dose should be with __% of computed activity?

Consistency

Linearity

Accuracy

Geometry

Answer 17

• 5%
• Consistency = DAILY
• Linearity = Quarterly
• Accuracy = at instillation and annually
• Geometry = at installation and when you move the device

Question 18

NRC Trivia

10 CFR Part 19

10 CFR Part 20

10 CFR Part 35

Answer 18

• 10 CFR Part 19 = notices, instructions, and reports to workers
• 10 CFR Part 20 = standards for protection against radiation
• 10 CFR Part 35 = medical use of by-product material

Question 19

Regulations affecting the general public

Annual dose limit

No greater than what limit in an “unrestricted area”

“restricted area” = ?

Answer 19

• Annual dose limit = 100 mrem (1mSv)
• No greater than what limit in an “unrestricted area” = 2 millirem/hour
• “restricted area” = any place that receives a dose greater than 2mrem/h

Question 20

Signs must be placed with the following slogans with what radiation levels:

Radiation area

High radiation area

Very high radiation area

Answer 20

• Radiation area = 0.005 rem (0.05mSv) in 1 hour at 30cm
• High radiation area = 0.1 rem (1mSv) in 1 hour at 30cm
• Very high radiation area = 500 rads (5gray) in 1 hour at 1 meter

Question 21

1mSv = __ rem = ___ rad = ___ Gy

Answer 21

1mSv = 0.1 rem = 0.1 rad = 0.001 Gy

Question 22

NRC occupational exposure dose limits

Total body dose per year

Dose to ocular lens per year

Total equivalent organ dose (including skin) per year

Total equivalent extremity dose per year

Total dose to embryo/fetus over entire 9 months

If fetus already got that dose, how much more for the remainder of the pregnancy?

Answer 22

• Total body dose per year = 50 mSv
• Dose to ocular lens per year = 150 mSv
• Total equivalent organ dose (including skin) per year = 500 mSv
• Total equivalent extremity dose per year = 500 mSv
• Total dose to embryo/fetus over entire 9 months = 5 mSv
• If fetus already got that dose, how much more for the remainder of the pregnancy? = 0.5 mSv

Question 23

Reportable medical event doses

Whole body dose

Single organ dose

Answer 23

Whole-body dose of > 50 mSv

single organ dose of > 500 mSv

anything less than this is a recordable event (need to hold for 5 years)

Question 24

Package labels and their allowable limits and transport index:

White 1

Yellow 1

Yellow 3

Answer 24

• White 1 = @ 1 meter = 0 mRem/hr; surface dose < 0.5mRem/hr; TI = none
• Yellow 2 = @ 1 meter = 1 mRem/hr; surface dose < 50mRem/hr; TI < 1.0mRem/hr
• Yellow 3 = @ 1 meter = 10 mRem/hr; surface dose < 200 mRem/hr; TI >1mRem/hr

Question 25

Common carrier transportation index should not exceed what limit? what about surface rate? How about limit of dose for multiple packages?

Answer 25

TI = 10 mRem/hr

Surface = 200 mRem

multiple packages = 50 mRem

Question 26

PET QA intervals

blank and uniformity scan

normalization scan

Answer 26

daily

monthly