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Flashcards in Physics - Nucs Deck (83):
1

Mass number: A means what?

sum of protons (Z) and neutrons (N) within nucleus

2

If A is the same what's that called?

Isobars

3

If Z is the same what is that called?

Z = Protons , Isotope

4

Transmutation is what?

Decay involving the change in the number of protons

5

What state is the most stable?

Ground State

6

Isomeric states are

Higher / excited states which are unstable

7

Excited states transform back to lower-energy states by what?

Gamma-radiation

8

Gamma rays are what?

Electromagnetic radiation from a nuclear process

9

What is the change between in the parent and daughter of A and Z after an isomeric transition

They are the same Mass number (A) and Atomic number (Z) is unchanged between parent and daughter

10

Isomeric states with long lifetimes are called?

Metastable

11

What happens to A/Z/N from a parent to daughter for the following transition?

Isomeric

No change to A (Mass number) Z (Atomic Number) N (Neutron number)

12

What happens to A/Z/N from a parent to daughter for the following transition?

Beta Minus

A (Mass number) Z (Atomic Number) N (Neutron number)

A = no change

Z + 1

N - 1

Nucleus emits electrons

13

What happens to A/Z/N from a parent to daughter for the following transition?

Beta plus

A (Mass number) Z (Atomic Number) N (Neutron number)

A = no change

Z - 1

N + 1

Nucleus emits positrons

14

What happens to A/Z/N from a parent to daughter for the following transition?

Electron Capture

A (Mass number) Z (Atomic Number) N (Neutron number)

A = no change

Z - 1

N + 1

Atoms emit characteristic x-rays

15

What happens to A/Z/N from a parent to daughter for the following transition?

Alpha decay

A (Mass number) Z (Atomic Number) N (Neutron number)

A - 4

Z - 2

N - 2

heavy nuclei (Z>82)

16

What nucs isotopes decay via electron capture?

67-Ga

111 - In

123 - I

17

What is activity?

transformations per unit time

18

What is the SI unit of activity

Becquerel = 1 nuclear transformation / second

19

Non-SI unit of activity

Millicuries 9MCi) 1 mCi = 37 MBq

20

How is activity related to the decay constant?

Directly proportional

21

What is the relationship between the decay constant (lambda) and the halflife?

T(1/2) = 0.69/(lambda)

22

What is effective half-life as related too Physical and biologic half-life

1/effective = 1/phsical decay + 1/biologic

23

What are the isotopes created by cyclotron?

Ga-67, I-123, F-18, In-111

24

What isotopes can be made from fission products?

I-131, Xe-133, Sr-90 Mo-99

25

How do fission products decay

beta minus

26

Ga-67

Half life

Photons

Production

Decay

78 hours

90,190,290,390

Cyclotron

EC

27

Tc-99m

Photons

Production

Decay

Half Life

140

Generator

IT - Isomeric transition

6 hours

28

IN - 111

Photons

Production

Decay

Half life

173, 247

Cyclotron

EC

68 hours

29

123 I

Photons

Projection

Decay

Half life

159

Cyclotron

EC

13 hours

30

131 I 

Photons

Production

Decay

Half - Life

364

Fission product

Beta

8 days

31

What is specific activity?

Activity per unit mass (Bq/g)

32

How is Tc-99m obtained

Moly Mo99 generator

33

How is Rb82 obtained? Half life?

Sr-82 generator. 1.25 minutes

34

Starting with a fresh generator how long before equlibrium is reached between parent and daughter?

About 4 half-lives of the daughter

35

Half life of Mo99. How long is the generator useful?

66 hours (HL), and about 5 working days.

36

What is transient equilibrium?

What is secular equilibrium? 

How long until they are reached?

When the parent is short lived

When the parent is long lived

~ 4 (HL)

37

In nucs what is an example of: Active transport?

Thyroid Update I 123

38

In nucs what is an example of: Capillary blockade

MAA for lung perfusion

39

In nucs what is an example of: Compartmental localization?

Tc99m red cells for blood pool scanning

40

In nucs what is an example of: Compartmental leakage

Tc99 RBC GI bleed study

41

In nucs what is an example of: Diffusion

DTPA renal scan

42

In nucs what is an example of: Phagocytosis

Tc99m sulfur colloid for liver/spleen function

43

In nucs what is an example of: Physiochemical adsoprtion

Tc99 pyrophosphates for bone scan

44

In nucs what is an example of: Cell sequestration

111In leukocytes for spleen scan

45

In nucs what is an example of:  Metabolism?

FDG pet

46

In nucs what is an example of:  Neuroreceptor imaing?

F18-florbetaben 

47

In nucs what is an example of: Antibiody reactions

TC-99m monoclonal antibiodies

48

What is the regulatory limit for moly breakthrough?

5.5 kBq moly per 37 MBq of Tc99m

49

How do you test for alumina breakthrough?

color paper

50

How do you check for radionuclide purity 

Photopeak in spectroscopy (Mo in Tc)

51

How do you test for radiochemical purity?

Thin-layer chromatography (Free pertechnetate in 99mTc-DTPA)

52

What is chemical purity?

Amount of unwated chemical contaminants in the agent

53

What testing should be performed on radionuclides prior to administration to patients?

Sterility and pyrogen testing

54

What is the rate of adverse reactions in radiopharmaceuticals?

2 per 100,000

55

What is the photopeak for 123 - I?

160

56

What is the photopeak for Tc99m?

140

57

What is decetion efficiency as it relates to NaI?

% of incident gamma rays totally absorbed in the scintillator via photoelectric effect

58

How does increasing photon energy effect detection effiency?

decreases it.

59

How is photoelectric effect and energy related?

PE = 1/E^3

60

FWHM of Tc99M in a 10 mm NaI crystal is 14 KeV what is the energy resolution?

10% (140 KeV energy for Tc)

61

The PHA window is likely set to what?

Twice energy resolution

62

What is a well counter? What is is good for?

Sample is inserted into a well within the crystal. 

Identify radionuclides from photopeak energy

Can also measure activity

63

What is an uptake probe used for?

Quantify radioiodine in patients

64

Iodine update is measured at once distance and what time after administration?

30 cm and 24 hours after administration.

65

What is a dose calibrator?

An ionization chamber, meausing dose in MBq or mCi

66

Administered dose must be within what of the perscrived dose?

20%

67

Dose calibrator response is checked how often and with what?

Daily, 137 Cs. Measurements should be within 5%

68

Accuracy of dose calibrators is checked when?

Installation and annually

69

Linearity of dose calibrators is checked when? How?

Quaterly.

Decay of Tc99m over 72 hours or with lead cylinders to attenuate the signal.

70

How is location of interaction determined in a PMT system?

Pulse arithemitc circuit board

71

How do parallel hole collimators change the image size? How does it change with distence? What about resolution as a function of distance?

They don't. FOV stays the same with distance.

Resolution drops dramaticlly with distance.

72

How do converging columnators affect image size?

They magnifiy it

73

How do diverging columnators affect image size?

They minify it

74

How do pin-hole collimators affect image size?

magnified and inverted

75

What are useful to use with a low-energy collimator? (Isotope wise)

99m-Tc and 123 I

76

What isotopes are good to use with a medium-energy collimator?

67 Ga and 111 In

77

In plannar imaging what is system reolution dominated by?

Collimator resolution

78

How is collimator sensitivity related to distance?

independent of distance.

79

How many counts are in a typical scintillation images?

500,000

80

What is the usual matrix size for nuclear medicine scintillation images?

64^2 or 128 ^2

81

What is the count/pixel roughtly in NM images?

100

82

Number of 140 Kev photons absorbed by a 10mm NaI crystal? (percent)

90%

83

Gamma camera energy resolution is changed how often?

Annually. Measured by FWHM