good for imaging? - beta minus decay - beta plus decay - electron capture

- beta minus decay: no - beta plus decay: Y --> positron - electron capture: Y --> gamma

Physics Ch 9 Nuc Med Flashcards by Michelle Cho

neutrons > protons –> what kind of decay?

beta minus

How well did you know this?

Not at all

Perfectly

protons > neutrons –> what kind of decay?

beta plus

How well did you know this?

Not at all

Perfectly

what happen in beta minus decay?

beta particle eject
anti-neutrino eject
neutron change to proton

How well did you know this?

Not at all

Perfectly

beta minus decay –> involve kind of transition? –> isobar/isotope/isotone?

isobaric –> same mass

How well did you know this?

Not at all

Perfectly

beta minus decay –> should use what kind of shield –> lead/plastic?

plastic

How well did you know this?

Not at all

Perfectly

what happen in beta plus decay?

positron eject
neutrino eject
proton change to neutron

How well did you know this?

Not at all

Perfectly

what happen after positron emission?

travel very short distance
annihilate w electron
two 511 keV photons –> 180 deg apart

How well did you know this?

Not at all

Perfectly

what happen in electron capture?

K shell electron –> into nucleus
proton change to neutron
release gamma photon

How well did you know this?

Not at all

Perfectly

electron capture –> involve kind of transition? –> isobar/isotope/isotone/isomer?

1) isobaric –> same mass

2) isomeric –> release gamma photon

How well did you know this?

Not at all

Perfectly

good for imaging?

beta minus decay
beta plus decay
electron capture

beta minus decay: no
beta plus decay: Y –> positron
electron capture: Y –> gamma

How well did you know this?

Not at all

Perfectly

Tc-99m –> release what kind of photon? keV?

gamma –> 140 keV

How well did you know this?

Not at all

Perfectly

cyclotron –> radioisotopes? (4)

molybdenum-99
fluorine-18
gallium-67
thallium-201

How well did you know this?

Not at all

Perfectly

nuclear reactor –> radioisotopes? (4)

molybdenum-98
iodine-131
xenon-133
thallium-201

How well did you know this?

Not at all

Perfectly

nuclear reactor –> radioisotope production –> cons? (2)

low yield of desired radioisotope

- produce undesired things

How well did you know this?

Not at all

Perfectly

radionuclide generator –> radioisotopes? (2)

Tc-99m

- krypton-81m

How well did you know this?

Not at all

Perfectly

radionuclide generator –> molybdenum-99 –> Tc-99 –> what must be done before can use Tc?

Tc in + state –> stannous ions –> reduce Tc to useable state

How well did you know this?

Not at all

Perfectly

Tc-99 –> radionuclide purity test –> what is break-thru?

Mo that is in sample

How well did you know this?

Not at all

Perfectly

NRC: Tc-99 –> how much breakthru is allowed?

time of admin –> 0.15 microCi Mo per 1 milliCi Tc

How well did you know this?

Not at all

Perfectly

Tc-99 –> chemical purity test –> test for what?

Aluminum contamination

How well did you know this?

Not at all

Perfectly

Tc-99 –> Aluminum contamination –> allowable amt?

<10 microgram Al per 1 mL

How well did you know this?

Not at all

Perfectly

Tc-99 –> Aluminum contamination –> how test for it?

pH paper

How well did you know this?

Not at all

Perfectly

Tc-99 –> Aluminum contamination –> manifestation on imaging? (2)

Tc scan –> liver activity

- sulfur colloid scan –> lung activity

How well did you know this?

Not at all

Perfectly

Tc-99 –> radionuclide purity test –> which assay 1st? –> Mo vs Tc

How well did you know this?

Not at all

Perfectly

presence of free Tc –> MOA? (2)

lack of stannous ions

- accidental air inject into syringe/vial

How well did you know this?

Not at all

Perfectly

presence of free Tc --> imaging finding?

uptake in: - gastric - salivary gland - thyroid

Tc-99 --> radiochemical purity test --> test for what?

free Tc

Tc-99 --> radiochemical purity test --> how test for it?

thin layer chromatography

Tc-99 --> radionuclide purity test --> how test for it?

dose calibrator w lead shield

what is equilibrium?

concentration of parent isotope = conc daughter isotope [Mo-99] = [Tc-99]

what is transient equilibrium? how many half lives to reach equilibrium? example?

parent isotope half life > daughter half life 4 half lives --> equilibrium for short time Mo-99 --> Tc-99

what is secular equilibrium?

parent isotope half life >>> daughter half life parent & daugther reach equilibrium --> in equilibrium for long time

what is half life? - physical - biological - effective

- physical: activity --> dec by 1/2 - biological: eliminate (pee/poo) 1/2 substance - effective: considering both physical + biological half life

effective half life --> formula?

1/effective = 1/physical + 1/biologic

radioactive activity --> unit?

- curie (Ci) | - SI unit --> Becquerel (Bq) = 1 disintegration per sec

nuc med --> what is specific activity?

activity per unit mass (Bq/g)

how specific activity relate to half life?

longer half life --> lower specific activity

how does collimator sensitivity affect resolution?

inc collimator sensitivity --> inc counts to be imaged --> dec resolution

how does distance affect collimator sensitivity?

no effect

collimator --> how does septal length (collimator depth) affect sensitivity? spatial resolution?

- shorter septa: inc sens --> dec resolution | - longer septa: dec sens --> inc resolution

collimator --> how does hole diameter affect sensitivity? spatial resolution?

- small hole: dec sens --> inc resolution | - bigger hole: inc sens --> dec resolution

collimator: low vs high energy tracer --> should use short/long septa length? small/big hole?

low energy: - short septa - small hole high energy: - long septa - big hole

collimator --> 4 types?

- parallel - pinhole - converging - diverging

pinhole collimator --> used to image what organ?

- thyroid | - other small parts

pinhole collimator --> image charact: - not/magnify? - not/invert?

- mag | - invert

converging collimator (cone beam) --> image charact: - not/magnify? - not/invert?

- mag | - not invert

scintillation crystal --> thin vs thick --> how affect.. - sens - spatial resolution

thin xl: - worse sens - better resolution thick: - better sens - worse resolution

V/Q scan --> which image first? --> Xe vs Tc? why?

lower energy photon 1st: Xe --> Tc if Tc first --> downscatter --> Xe --> can't accurately pick up Xe peak

what is star artifact? MC seen in what situation?

collimator holes --> hexagonal pattern --> focal intense energy --> penetrate collimator septa --> star artifact? high therapeutic dose --> thyroid scan --> use med energy collimator instead of high

gamma camera --> quality control --> tested parameters? (4)

- field uniformity - window setting - image linearity & spatial resolution - center of rotation

gamma camera --> quality control --> what is field uniformity --> what test?

flood --> camera produce uniform image across entire xl surface?

gamma camera --> quality control --> field uniformity --> how often?

- extrinsic (w collimator) --> daily | - intrinsinc (no collimator) --> wkly

gamma camera --> quality control --> field uniformity --> recommended count for extrinsic & intrinsic flood test?

5-10million counts

gamma camera --> quality control --> energy window setting --> how often?

daily

gamma camera --> quality control --> image linearity & spatial resolution --> how often?

wkly

gamma camera --> quality control --> center of rotation --> how often?

monthly

gamma camera --> quality control --> center of rotation --> how test?

done w Tc-99 point sources along axis of rotation --> axis should be straight

ring badge --> how to properly wear?

dominant hand --> index finger --> label towards source (usu towards palm) --> glove over

no lead apron in nuc med --> why? (2)

- thin lead not stop gamma rays | - lead --> slow down gamma ray --> transform into Bremmstrahlung XR --> worsen dose exposure

sodium iodine well counter --> like a small gamma camera --> good for what kind of samples? (3)

- "wipe test" samples - blood - urine

Geiger-Muller counter --> click once then stop --> what happened?

lrg radiation --> overload device --> "dead time" before device can respond again

Geiger-Muller counter --> max dose before dead time?

100 mR/h

when use ion chamber over Geiger-Muller counter? (2)

- measure dose rate | - expect higher doses

ion chamber --> exposure rate --> detectable range?

0.1-100 R/h

dose calibrator (ionizing chamber) --> quality assurance --> what parameters need to be tested? (4)

- consistency - linearity - accuracy - geometry

dose calibrator (ionizing chamber) --> quality assurance --> what is tested? (4) how often?

CLAG: - constancy: daily - linearity: qtrly - accuracy: annual - geometry: when mv

what is major spill? - Tc-99m - Tl-201 - In-111 - I-123 - Ga-67 - I-131

- Tc-99m: >100 mCi - Tl-201: 100 - In-111: 10 - I-123: 10 - Ga-67: 10 - I-131: 1

major spill occurs --> what do you do?

- do NOT clean it up | - call radiation safety officer

minor spill occur --> what do you do? 5 steps?

1) protect pt 2) confine spill/limit spread 3) clean spill 4) survey cleanup items 5) survey cleanup ppl

minor spill occur --> contaminated items --> how many half lives to decay to safe level?

wipe test --> does NOT work for what kind of radioistope contamination?

Xenon

general public --> annual dose limit?

100 mrem

Sv to rem --> conversion?

1 mSv = 100 mrem

NRC occupation exposure dose limit? - total body dose per yr - ocular lens - organ (incl skin)

- total body dose per yr: 5 rem (50mSv) - ocular lens: 15 rem (150 mSv) - organ (incl skin): 50 rem (500 mSv)

NRC occupation exposure dose limit --> fetus over entire 9 mo?

0.5 rem (5 mSv)

difference: recordable event vs reportable medical event? (2)

recordable event: - whole body dose <5 rem - organ dose <50 rem reportable medical event - whole body dose >5 rem - organ dose >50 rem

recordable event --> keep document --> how long?

5yr

reportable medical event occurs --> next step?

notify: - NRC - ordering physician - pt

exposure rate? - radiation area - high radiation area

- radiation area: 5 mRem/hr (0.05mSv) | - high radiation area: 100 mRem/hr

what is target organ?

organ of interest --> want tracer to accumulate in

what is critical organ?

organ --> inc susceptibility for cancer --> limit dose of radiopharmaceutical

HIDA --> critical organ?

GB wall

DMSA --> critical organ?

kidney

pertechnetate --> critical organ?

stomach

sulfur colloid --> critical organ? - IV - PO

- IV: liver | - PO: prox colon

sestamibi --> critical organ?

prox colon

MAG3 --> critical organ?

bladder

I-123 MIBG --> critical organ?

bladder

I-131 MIBG --> critical organ?

liver

gallium --> critical organ?

distal colon

thallium --> critical organ?

kidney

octreotide --> critical organ?

spleen

In-WBC --> critical organ?

spleen

damage RBC --> critical organ?

spleen

#1 advantage of SPECT over planar?

improved contrast from overlapping struct

SPECT is depth-dependent --> T/F?

PET is depth-dependent --> T/F?

brain SPECT --> use what kind of collimator?

fan beam

cardiac SPECT --> what is tuning fork artifact?

error w center of rotation (misregistration error) --> point source look like tuning fork

SPECT vs PET --> match: - few cameras rotate around pt - set of complete rings/detectors around pt

- SPECT --> few cameras rotate around pt | - PET --> set of complete rings/detectors around pt

PET --> uses thicker crystal than SPECT --> T/F?

PET: inc dose --> inc random coincidence --> T/F?

PET: what is noise equivalent counts (NEC)?

ratio: true coincidences/total coincidences (true/true+false) same as signal to noise ratio (SNR)

PET: scintillator crystal --> which has best density/resolution/decay time? worst?

- best --> lutetium oxyorthosilicate (LSO) | - worst --> bismuth germanate (BGO)

PET: spatial resolution --> #1 limiting factor?

xl thickness

PET: obese pt --> what can use to improve spatial resolution & image contrast?

time of flight

time of flight PET vs standard PET --> is there a difference in SUV values?

time of flight --> higher SUV than standard PET

contraindications for vasodilator pharmacologic stress? (2)

- 2nd- or 3rd-degree atrioventricular (AV) block without a pacemaker - sick sinus syndrome

antidote for adenosine?

Aminophylline

F-18 FDG --> cardiac --> eval for?

cardiac viability

Dipyridamole --> MOA?

indirect coronary artery vasodilator

Exercise stress test --> need to reach heart rate of?

85% of age-predicted maximal heart rate

what is transient ischemic dilation (TID)?

paradoxical phenomenon seen in myocardial perfusion SPECT imaging --> severe balanced coronary artery disease, myocardial ischemia may result in apparent enlargement of the left ventricular cavity during stress

cardiac study --> Tc-99m tetrofosmin --> mech of uptake?

passive diffusion

what is Roentgen?

measure of exposure to x-ray or gamma ray radiation. One roentgen is that amount of x-ray or gamma radiation that will deposit enough energy to liberate 1 electrostatic unit in 1 cubic centimeter of dry air.

what is absorbed dose? unit?

amount of energy that ionizing radiation imparts to a given mass of matter - Gy - rad

what is equivalent dose? unit?

dose equivalent relates the absorbed dose to the biological effect of that dose. The absorbed dose of specific types of radiation is multiplied by a "quality factor" to arrive at the dose equivalent - Sv - rem

Tl-201 thallous chloride --> CNS lymphoma vs toxo?

- lymphoma: pos | - toxo: neg

Gastric emptying study - what is normal study?

4 hours --> 10% or less of initial activity should remain in the stomach

Physics Ch 9 Nuc Med Flashcards

(118 cards)