- radiologist - nm technologist - physicist - radiochemist

nuclear medecine Flashcards by Melanie B

what is nuclear medecine

an imaging modality focusing on the use of radiopharmaceuticals

How well did you know this?

Not at all

Perfectly

is nuc med for diagnosis or treatment?

noth!

How well did you know this?

Not at all

Perfectly

what is the functional info obtained from nuc med

the info from imaging the distribution of radiopharmaceuticals

How well did you know this?

Not at all

Perfectly

nuc med function scan properties (3)

limited anatomic info
less spatial resolution
high sensitivity and specificity of molecular processes

How well did you know this?

Not at all

Perfectly

nuc med anatomy scan properties (3)

excellent soft tissue contrast
high spatial resolution
poor sensitivity for molecular processes

How well did you know this?

Not at all

Perfectly

radiopharmaceuticals used innuc med are referred to as:

radio tracer or tracer

How well did you know this?

Not at all

Perfectly

how are tracers introduced to the body

injection or inhalation

How well did you know this?

Not at all

Perfectly

what is intrathecal

into the fluid filled space between tissue layers of spinal cord or brain

How well did you know this?

Not at all

Perfectly

what type of detectors detect gamma emissions

scintillation detectors

How well did you know this?

Not at all

Perfectly

how much tracer is used in nm

lowest amount possible without compromising image quality

How well did you know this?

Not at all

Perfectly

4 nm proffessionals

radiologist
nm technologist
physicist
radiochemist

How well did you know this?

Not at all

Perfectly

how are radionuclides produced

in particle accelerators (cyclotrons)
and nuclear generators

How well did you know this?

Not at all

Perfectly

why don’t we use naturally occurring radionuclides

very long half lives
tfr high absorbed pt dose
limited availability

How well did you know this?

Not at all

Perfectly

what is the radionuclide portion of radiopharmeceutical

radioactive material used to tag the pharmaceutical

How well did you know this?

Not at all

Perfectly

what is the pharmaceutical component of radiopharmaceutical

biologically active with preferential localization in or function of an organ

How well did you know this?

Not at all

Perfectly

what are the 4 commonly used radionuclides

11C
13N
15O
18F

How well did you know this?

Not at all

Perfectly

why are 11C, 13N, and 15O used for radionuclides

they can replace their stable isotopes in substrates, metabolites, and drugs

How well did you know this?

Not at all

Perfectly

what can 18F replace

the hydroxyl group in many molecules

How well did you know this?

Not at all

Perfectly

what does 18F emit

positrons

How well did you know this?

Not at all

Perfectly

what is step 1 of a nm tx

isotope production
(has to be done same day)

How well did you know this?

Not at all

Perfectly

what are the half lives of the main 4

11C - 20.4 mins
18F - 109.8
13N - 9.97
15O - 2.03

How well did you know this?

Not at all

Perfectly

how long does isotope production in a cyclotron generally take

around 40 mins

How well did you know this?

Not at all

Perfectly

what is step 2 of nm tx

attach the radioisotope to a biomolecule

How well did you know this?

Not at all

Perfectly

(more/less) stable radionuclides have shorter half lives

less stable

How well did you know this?

Not at all

Perfectly

what are the 2 most common radionuclides used

18F 11C

what are the 2 distinct imaging modes in nm

positrons emission tomography single photon emission imaging

PET uses what scanner

PET scanner

single photon emission imaging uses what scanner

gamma camera

what is step 3 in nm tx

imaging and analysis

how long does step 2 take

60 mins

how long does step 3 take

imaging and analysis

what reaction happens in PET

annihlation

what creates the gamma rays in PET

the annihlation reaction

what is the annihlation reaction formula

e- + e+ -> y + y

what type of detection happens in PET

coincidence detection of pairs

gamma rays have shorter/longer wavelength and higher/lower freq than xrays

shorter wavelength higher frequency

what is formed when 18F replaces the OH group

creates FDG fluorodeoxyglucose

what can FDG be used for

to identify sites of malignancy

what has been created here

18F-fluorodeoxyglucose

what does FDG measure

glucose metabolism

what percent of PET scans use FDG

about 95%

what is the gold standard for oncological imaging

FDG

what compound is used for Brian mapping

FDG

define PET sensitiivty

fraction of annihlation pairs that are detected

the image farthest left has which of the following: high/low sensitivity short/long scan high/low dose

high sensitivity long scan high dose

the image farthest right has which of the following: high/low sensitivity short/long scan high/low dose

low sensitivity short scan low dose

PET sensitivity is also affected by:

the number and type of detector

what is LoR

line of response

describe true coincidences

both annihlation photons escape without interaction and strike detectors

what type of coincidence is this

true

what type of coincidence is this

random

what type of coincidence is this

scatter

describe random coincidence

two annphotons from SEPARATE emissions strike detectors at the same time falsely attributed to same event

describe scatter coincidence

one or both annphotons get scattered in tissue

what is the basic component of a PET scanner

PET scanner blocks

what is a PET scanner block

scintillation crystal with 4 PMTs

how many detectors are there per ring on average, in PET

800-1000

how do PET scanncer blocks detect and process signal (3)

- scintillation crystals detect gamma rays - converts gamma rays into low E visible photons - photosensor (PMT) used to convert light to an electrical signal

what is the chem formula of the PET scintillation crystal

Lu2 Si O5 (Ce) aka LSO:Ce

properties of LSO;Ce

high mass density high atomic number

why is LSO;Ce used for PET

effcetive at stopping photons high efficiency of light output

where are PET collimators located

at the face of the detector (where photons enter)

what are the 4 PET collimator types

parallel diverging converging pinhole

type of collimators?

parallel diverging

type of collimators?

converging pinhole

PET detector module measure what 3 aspects of the signal

- time it takes gamma ray to hit detector - position - energy

what does coincidence processing do

recognized the true events generated by the same annihlation event along a specific LoR

what 2 methods of image reconstruction does PET use

filtered back projection iterative reconstruction

what are the majority of PET scans done for

diagnose, stage, or restage cancers

what radiopharmaceutical is used for cancer dg/staging

18F-FDG

what has changed from a to b?

profound and widely disseminated hypermetabolic metastases

what is SPECT

single photon emission computed tomography

what is the difference from PET to SPECT

a single photon is emitted, as opposed to positrons

what 6 radionuclides are used in SPECT

99mTc 123I 131I 111In (indium) 201Tl (thallium) 67Ga (gallium)

what is the most used radionuclides in SPECT

99mTc (technetium)

what is used to produce 99mTc

nuclear generators

what is the parent of 99mTc

99Mo

compare the half lives of 99Mo to 99mTc

99Mo - 66.7 hours 99mTc - 6 hours

how is the gamma ray emitted from 99mTc

isometric transition releases 140keV

what is the equation for the isometric transition of 99mTc

99Mo (B-) 99mTc (y) 99Tc

to what is 99mTc tagged for a lung scan

macroaggregated albumin (MAA)

to what is 99mTc tagged for a bone scan for a fracture

methyl-diphosphonate (MDP)

99mTc tagged to macroaggregated albumin for what

lung scan

99mTc tagged to methyl-diphosphonate for what

bone scan for #

99mTc shows what

shows cold spot in lungs

SPECT is most commonly used for what pathologies? (5)

cardiac perfusion Brian liver tumour bone studies

gamma camera, aka...

scintillation camera anger camera

what process doe she gamma camera use

scintigraphy

what is the most common number of detectors in SPECT

dual head systems

what are these

anger cameras

what are SPECT static or spot views

snapshots in various orientations, low activity levels

what must be set for SPECT static/spot views

pre-set time minimum n of counts/emissions

what are sweep SPECT images used for (3)

metastatic tumours bones infection imaging

what type of imaging is this

SPECT imaging

what type of imaging is this

SPECT whole body imaging

what is SPECT dynamic imaging

multiple sequential imgs "flow" study

what type of imaging is this

SPECT dynamic imaging

what hybrid imaging systems exist?

PET/CT SPECT/CT

wy are hybrid imaging systems used

provides increased diagnostic accuracy can identify both metabolic AND anatomic evaluation simultaneously

what type of imaging is this

hybrid imaging system

type?

PET/CT fusion

type?

PET/CT fusion

what is radioimmunotherapy

antibodies designed for the surface of a cancer type if success, use beta-emittin

what 2 radioisotopes are being developed for radioimmunotherapy of non-Hodgkin lymphoma

90Y-ibritumomab tiuxetan (aka zevalin) 131I-tositumobab (aka bexxar)

90Y-ibritumomab tiuxetan aka

zevalin

131I-tositumobab aka

bexxar

what 3 major radiation protection measures are used in nucmed

TLD badges hot labs isolated vents, protective equipment

what are hot labs

designated prep areas for nucmed, due to high acitivty

what must be removes from pts before nucmed tx

all metal objects bc they attenuate