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NUKS Flashcards

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1
Q

Beta minus

too many?

what’s emitted?

What kind of transition

A

Too many neutrons

N > P

electron (beta particle) emitted from nucleus

Neutrino also emitted to balance energy

ISOBARIC - neutron and proton have same mass

ATOMIC NUMBER GOES UP

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2
Q

Beta emitter shielding?

A

PLASTIC

low Z

High Z would produce Brems

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3
Q

\

\

\

A

Beta Minus

Energy down, Z up

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4
Q

I

I

/

/

/

A

Energy lost and Z goes down

Proton to neutron

Beta positive decay

requires 1.02 MeV

Positron and a neutrino

511 keV x2 when positron hits electron

ISOBARIC

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5
Q

/

/

/

/

A

No steep initial drop

loss of proton and energy

ELECTRON CAPTURE

ISOBARIC

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6
Q

isobaric transitions

A

Beta emission

positron emission

electron capture

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7
Q

“Isometric transitions”

when do they occur?

A

after an isobaric (A the same) transition

leftover energy released

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8
Q

Gamma emission

what type of transition

A

isomeric transition

nucleus emits extra energy

I

I

V

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9
Q

Between Isobaric transition and subsequent isomeric (GAMMA EMITTING) transitions

A

These usually happen bam bam, but some hang out for a minute before gamma emission, these are METASTABLE

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10
Q

Tc 99m example of isobaric metastable isomeric

A

Mo99 —> Tc99m (ISOBARIC Beta MINUS, electron emitted)

Tc99m ——> Tc99 (ISOMERIC, gamma photon (140keV))

Tc99m hangs out as metastable for a couple hours

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11
Q

Enemy of gamma photon emission

A

Internal conversion

instead of gamma emission

energy given to an electron —–> characteristic Xray or Auger

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12
Q

Alpha decay

use?

A

helium nuclei

2 protons, 2 neutrons

Slow and fat

rare treatmentn situations

bone pain cancer mets via rAdium 223 (Alpha2protons2 neutrons)

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13
Q

Production

Bombardment

A

Striking targets with

Neutrons - in a reactor

Charged particles (alpha, protons, deuterons) - in a cyclotron

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14
Q

Bombardment

downside to using a reactor

(bombarding with neutrons)

A

Leftover parent to clean up

NOT “carrier free”

Cyclotron produces via transmutation, no parents to clean up, “carrier free”

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15
Q

Production

Fission

A

Neutrons fired into large elements

split into pieces, random crap made

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16
Q

effective half life formula

A

1/effective = 1/physical + 1/biologic

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17
Q

What does ‘activity’ measure

units

Specific activity

A

disintegrations per second

Curie = Ci = 3.7x10^10 disintegrations per second

SI unit = becquerel Bq = one disintegration per second

Specific activity = activity per unit mass (Bq/g)

(longer half life = lower specific activity)

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18
Q

Gamma camera general set up

A

Photons

Collimator

Crystal

PMT’s

computer

gamma photons –> light pulse –>voltage –> picture

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19
Q

MC collimator “work horse”

A

parallel hole

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20
Q

Parallel hole energies and examples

low

medium

high

A

LOW 1 - 200 keV (Tc99, I123, Xe133, TI201)

MEDIUM 200-400 keV (Ga67, In111) (medium needs to GaIn)

High > 400 keV (I131)

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21
Q

Sensitivity and Resolution

when are high sensitivity collimators good

A

Inversely related

High sensitivity collimator allows twice as many counts to be imaged with shitty resolution

High sensitivity good for dynamic imaging (flow phase)

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22
Q

Distance effect on sensitivity and resolution

A

NO EFFECT on sensitivity (net counts the same, bigger FoV)

Resolution WORSENS with distance

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23
Q

Pinhole collimator

what does?

what for?

?mag

A

magnifies and inverts

thyroids and small parts

pinhole to detector = f

patient to pinhole = b

F>B = mag

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24
Q

Pinhole cons

A

distorts large objects

Shitty sensitivity

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25
Q

Converging collimator

what look like?

what does?

A

fan out towards detector

mags without inverting

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26
Q

Diverging collimator

what is

what does

A

Opposite of converging

fan towards patient

MINIMIZES

Able to image a large body part on a small crystal

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27
Q

After collimator, photons hit?

A

Scintillation crystal

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28
Q

scintillation crystal made of?

what does

A

NaI doped with Thallium

when hit with a gamma photon, produces a pulse of light

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29
Q

Thick vs thin scintillator crystal?

A

Thick = super sensitive, fewer pass through. PMT’s are further away = WORSE resolution

Thin = less sensitive, better resoltution

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30
Q

After scintillator crystal?

A

PMT’s

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31
Q

PMT’s

do what?

more means what

what do they record

A

detect light and convert to an electric signal

More = more light picked up, greater resolution

PMT’s record X,Y location- read by computer and..

Z location/intensity goes to pulse height analyzer

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32
Q

Pulse height analyzer

job?

A

distinguishing, discarding background crap

Compton scatter from patient is very close in energy to what you want, but can really fuck it up

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33
Q

Downscatter

A

high energy photons spill into the window of a low energy emitter, mostly via Compton scatter

Ex

V/Q with Tc (140) and Xe (81)

Tc scatter will range down from 135 -90

So if you give Tc first, subsequent Xe image will be covered in Tc scatter

USE LOWER ENERGY FIRST

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34
Q

SPECT and matrix

A

SPECT overall improves spatial resolution

image longer, looks better

Bigger matrix better but takes longer (motion problem)

and fewer counts per pixel = worse image contrast

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35
Q

Startifact

A

“septal penetration”

using medium energy collimator instead of high

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36
Q

Gamma camera QC

Uniformity

% allowed

what is test?

extrinsic vs intrinsic

A

2-5% non-uniformity

1% for SPECT

Test = Flood

Extrinsic = with collimator

Intrinsic = without

test with Co57 or NaPertech

EXTRINSIC DAILY, INTRINSIC WEEKLY

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37
Q

Gamma camera QC

Window setting

when?

how?

A

DAILY

Use a symmetric window set at peak energy used for desired test

source = syringe or vial

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38
Q

Gamma camera QC

Linearity and Spatial resolution

When?

How?

A

WEEKLY

lead line phantoms placed between collimator and a Co57 sheet. Want straight not wavy lines

linearity = lines

spatial res = they’re separate

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39
Q

Gamma camera QC

Center of rotation

A

WEEKLY

SPECT

monitor for alignment offset at COR

Tc99 point sources along axis of rotation, axis should be straight with minimal deviation

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40
Q

Instruments

NaI well counter

what is

con

A

basically a small gamma camera with a single PMT

EASILY OVERWHELMED

used for in vitro blood or urine samples, “wipe test” samples

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41
Q

Instruments

Thyroid probe

what is

A

Modified NaI counter

shielding with a small opening pointed at patient, at a precise distance, compared to a calibrated capsule of same radionuclide

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42
Q

Instruments

Geiger-Muller

dead time?

A

gas ionization chamber

sensitive to large dose, must wait for ionization to dissipate before it can respond again.

max dose = 100mR/h

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43
Q

Instruments

Ion chamber

A

no dead time problem

0.1 - 100R/h (big unit)

higher doses

less sensitive than GM counter

excellent for accurate estimates (or exposure)

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44
Q

Personal dosimeters

Pocket ionization detector

A

uses a mini-chamber

real time estimated dose

must be charged and zero’d

NOT used anymore

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45
Q

Solid state dosimeter

A

accumulated dose or rate can be read real time with LCD display

solid state think LCD

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46
Q

Personal dosimeters

Film badge

A

thin metallic radiosensitive film

degree of darkening (relative optic density) corresponds to dose

sensitive to damage by temp, humidity

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47
Q

Personal dosimeters

optically stimulated

A

Replaced film badge

chips/strips placed under a filter

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48
Q

Personal dosimeters

ring badge

A

dominant index, label in

Thermo-luminescent

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49
Q

Dose calibrator QA

Consistency

A

DAILY

should be within 5%

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50
Q

Dose calibrator QA

A

accurate readout over whole range of potentially encountered activities

check either with a large (200mCi) amount of Tc and decaying it down

or easier

use a kit with sheets of varied thickness of lead

QUARTERLY

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51
Q

Camera linearity and spatial res

vs

Dose calibrator linearity

A

Camera linearity and spatial res - WEEKLY

vs

Dose calibrator linearity - QUARTERLY

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52
Q

Calibrator QA

Accuracy

A

Standard measurements measured and compared to what they shoud be

INSTALLATION AND ANNUALLY

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53
Q

Dose calibrator QA

Geometry

A

Correction for different positioning and size (different volumes of samples with same activity)

INSTALLATION AND ANY TIME YOU MOVE DEVICE

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54
Q

calibrator QA mnemonic

A

GALCulations (decreasing frequency)

Geometry - install/move

Accuracy- annual

Linearity- quarterly

Consistency - DAILY

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55
Q

Major spills

Tc99

A

> 100 mCi

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56
Q

Major spills

Tl - 201

A

>100 mCi

57
Q

Major spills

In-111

A

> 10 mCi

58
Q

Major spills

Ga-67

A

> 10mCi

59
Q

Major spills

I 131

A

> 1mCi

60
Q

Major vs minor spill who ya gonna call

A

minor - clean it yourself

major call RSO

61
Q

Minor spill to do list

A

1) address a sick patient first
2) Confine/limit - secure area
3) Clean up (gloves)
4) survey cleanup items
5) survey cleanup people

62
Q

General public regs

annual dose limit

A

100 mrem

63
Q

“unrestricted area” max dose

A

2 mrem per hour

64
Q

Restricted area =

A

any area getting over 2mrem per hour

65
Q

“radiation area”

A

.005 rem (.05 mSv) in 1 hour at 30 cm

66
Q

“high radiation area”

A

0.1 rem (1mSv) in 1 hour at 30 cm

67
Q

“Very High radiation area”

A

500 rads (5Gy) in 1 hour at 1 meter

68
Q

Occupational dose limits

Total body dose per year

A

5 rem (50mSv)

69
Q

Lens

A

2 rem per year (20 mSv)

70
Q

Total equivalent organ dose

A

50 rem (500 mSV)

71
Q

Extremity dose per year

A

50 rem (500mSv)

72
Q

fetus dose for 9 months

A

0.5 rem (5mSv)

73
Q

Unit fuckery

rad rem

rad Gy

mSv mrem rem

A

1 rad = 1 rem

1 rad = 0.01 Gy

1mSv = 100 mrem = 0.1 rem

74
Q

NRC

part 19

A

Notices, instructions, reports to workers

75
Q

NRC

part 20

A

Standards for protection

76
Q

NRC

part 35

A

Medical use of by-product material

77
Q

Medical event vs recordable event

A

medical event = wrong drug, patient, or dose

or dose to unintended body part other than intended treatment site 50% or more over dose expected

AND

Have to harm the patient

-whole body dose > 5 rem or single organ dose > 50 rem

78
Q

Recordable

A

Whole body <5rem

Single organ < 50rem

79
Q

For medical events what u do

A

call the doctor, patient, NRC

Recordable… record it (document) and keep for 5 years

80
Q

Receiving and storage

A

survey package within 3 hours

GM at surface and 1 meter away

surface wipes

81
Q

Package labels

White 1

A

NO special handling

<0.5 mrem/hr at surface

0 mrem/hr at 1 meter

82
Q

Labels

Yellow 2

A

Special handling required

surface <50 mrem/hr

1 meter <1 mrem/hr

83
Q

Labels

Yellow 3

A

Special handling required

surface <200mrem/hr

1 meter <10mrem/hr

84
Q

Transport index

A

measured max dose at 1 meter

Radioactive 1, white 1, no TI, too low

Radioactive II, yellow 2, < 1.0 mR per hour

Radioactive III, yellow 3, TI > 1.0mR per hour

85
Q

how Tc is made

Mo and Tc

A

Mo - 67 hours

Tc - 6 hours

Mo-99 lined aluminum canister, as it decays can be washed off with saline

Tc comes out stuck to Na (Na99Tc04)

+7 valence state, must be reduced to be used

Reduced with Stannous ions

86
Q

How Tc is made

moly breakthrough

A

If Mo comes out in the wash

“break through”

assayed behind a lead shield

Mo (740 keV) will penetrate

87
Q

Mo breakthrough, what kind of purity?

allowed?

A

RADIONUCLIDE PURITY

0.15 microCi of Mo per 1 mCi of Tc

15 micro per milli Mo to Tc

ratio must be known at time of ADMINISTRATION

88
Q

Chemical purity

A

Al oxide can wash off, clump with Tc and show up in liver or cause sulfur colloid aggregation and show up in the lungs

Test?

pH paper

<10 micrograms Al per 1ml

Testing for chemical purity NOT REQUIRED in NRC states

89
Q

Radiochemical purity

A

Tc comes out of generator as Na99TcO4, needs to be reduced with SnCl2

Assessed with thin layer chromotography

limits for free Tc

95% for Na99TcO4

92% for Tc sulfur colloid (MAA)

91% for the rest

90
Q

Equilibria

Equilibrium

A

[] of parent and daughter are equal

91
Q

Transient equilibrium

A

half life of daughter is shorter than parent (not by a ton)

moly and Tc after 4 half lives

92
Q

Secular equilibrium

A

half life of daughter is way way way shorter than parent

93
Q

Critical Organ

Indium

A

Liver

94
Q

Critical Organ

I 131 MIBG

A

Liver

95
Q

Critical Organ

Sulfur Colloid (IV)

A

Liver

96
Q

Critical Organ

Octreotide

A

Spleen

97
Q

Critical Organ

Damaged RBC

A

Spleen

98
Q

Critical Organ

pertechnetate

A

Stomach

99
Q

Critical Organ

Gallium

A

Distal colon

100
Q

Critical Organ

Mag3

A

bladder

101
Q

Critical Organ

DTPA

A

bladder

102
Q

Critical Organ

I 123 MIBG

A

bladder

103
Q

Critical Organ

MDP

A

bladder

104
Q

Critical Organ

Sestamibi

A

Proximal colon

105
Q

Critical Organ

sulfur colloid (oral)

A

proximal colon

106
Q

Critical Organ

DMSA

A

Renal CORTEX

107
Q

Critical Organ

Thallium

A

Renal cortex

108
Q

Critical Organ

HIDA

A

GB wall

109
Q

SPECT vs PET

?depth dependent

A

SPECT is depth dependent

PET IS NOT

110
Q

Main advantage to SPECT?

A

Improved contrast from overlapping structures

111
Q

SPECT center of rotation artifact

A

TUNING FORK appearance

misregistration

112
Q

Crystals in PET

(vs SPECT)

A

PET tends to use thicker crystals (BGO, LSO, LYSO)

(SPECT uses planar crystals, NaI)

113
Q

PET

limiting factor for spatial res?

A

BIG thick crystals (bigger means fewer)

114
Q

Positron range

A

actually detecting location of anihilation event

positron can travel 1-2mm prior to event

115
Q

PET

angulation

A

sometimes 180 is a generalization

180.5, will be off a little bit in localization

116
Q

PET coincidence events detected

3 types

A

True

Scatter coincidence - one of pair is scatterd, hits within time window but not in right location)

Random coincidence - Different anihilation events, land within same coincident window creating false calculation

117
Q

PET

2d vs 3d

A

2D has lead septa - also decreasing sensitivity for unscattered photons

3D no septa - MORE sensitive, allows for decreased tracer dose.

3D usually done with small parts - CNS and PEDS

118
Q

PET

3d disadvantages

A

Dead time

more random events - no septa

More scatter - no septa

119
Q

SUV’s

equation

A

Tissue radioactivity concentration at time point 1 x patient weight

Injected dose activity

120
Q

SUV’s and fat people

LBM vs weight

A

SUV’s are overestimated in fat people

More accurate to use LBM

121
Q

PET and glucose

PET and small stuff

A

High glucose lowers SUV

Smaller than 1cm, lower SUV

122
Q

Truncation PET FOV vs CT FOV

A

CT FOV is SMALLER

Lesion in the outlying blubber gets cut off by CT, seen by PET

Lesion appears ARTIFICIALLY HOT at the margin, ARTIFICIALLY COLD outside the CT FOV

123
Q

PET prep

?fasting

Causes of muscle uptake?

Brown fat drugs

A

4 hours minimum fasting

exercise, eating or insulin

Propranolol and valium

124
Q

PET QA

Blank scan

A

DAILY

equivalent of uniformity

keeps attenuation correction data accurate

‘start each day with a blank slate’

125
Q

PET QA

Normalization scan

A

MONTHLY

disrepancies in the detector elements

scan a calibrated position source

NM Normal month

HORIZONTAL LINEAR STREAKS if normalization is off

126
Q

PET QA

bucket setup

A

dark block rotating on a sinogram

power surge or sudden power loss

127
Q

TRACER TRIVIA- Tc99

Analog

Energy

Physical half life

A

140 keV - LOW

6 hours

128
Q

TRACER TRIVIA- I 123

Analog

Energy

Physical half life

A

Iodine

159 keV - LOW

13 hours

129
Q

TRACER TRIVIA- Xenon 133

Analog

Energy

Physical half life

A

81 keV - LOW

PHYSICAL 125 hours

BIOLOGIC 30 seconds

130
Q

TRACER TRIVIA- Thallium 201

Analog

Energy

Physical half life

A

Potassium

LOW 135, 167 keV

USE daughter Hg xrays

131
Q

TRACER TRIVIA- Indium 111

Analog

Energy

Physical half life

A

MEDIUM 173 keV, 247 keV

67 hours

132
Q

TRACER TRIVIA- Ga 67

Analog

Energy

Physical half life

A

IRON

93, 184, 300, 393 (100, 200, 300, 400)

78 hours

133
Q

TRACER TRIVIA- I 131

Analog

Energy

Physical half life

A

Iodine

365 keV HIGH

8 days

134
Q

TRACER TRIVIA- F 18

Analog

Energy

Physical half life

A

GLUCOSE

511 keV HIGH

110 minutes

135
Q

Treatment radionuclides 1/2 life

Strontium 89

A

50.5 days (14 days in bone)

136
Q

Treatment radionuclides 1/2 life

Samarium 153

A

46 hours

137
Q

Treatment radionuclides 1/2 life

Y 90

A

64 hours

138
Q

Treatment radionuclides 1/2 life

Radium 223

A

11.4 days

139
Q
A

physics factoids (8 decks)

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