Imaging the Heart (PET and Echo) Flashcards
What is a PET scan? What does it involve?
- type of nuclear medicine
- involves injecting a radioactive tracer molecule that collects in the area of the body to be tested
True or False: is a PET scan a type of functional or physiological imaging?
true
What is a PET scan used to diagnose?
differences in biological activity in the body
What does a PET scan measure?
body functins such as blood flow, oxygen use, and metabolic rates
Can images from a PET scan be in colour or in blakc in white?
yes
PET scan in colour, what colour are the hot spots and what do hot spots indicate?
- red and orange
- indicate high chemical activity (large amounts of radioacive tracer have accumulated here)
In black and white, what do hot spots look like?
darker
Explain the 3 steps of a PET scan?
Step 1: inject a radioactive isotope
Step 2: a computer takes this data and converts it into an image
Step 3: The image is projected on the screen and read by physicians
The radioactive tracer that is injected into the body during a PET scan continually decayse what?
producing gamma radiation (an electromagnetic wave) that can be detected by a PET scanner
What are gamma rays?
a type of ionizing radiation
How long do you have to fast before a PET scan and how long do you have to refrain from tobacco, caffeine, adn alcohol?
4 hours and you must refrain from alcohol, tobacco, and caffeine for 24 hours before the test
Do you need to remove street clothes and jewlery for a PET scan?
yes
Can a PET scan be started with a full bladder?
no, it has to be empty
How long do you have to wait after they inject the radioactive tracer?
30-60 minutes
Do you need to lie still for a PET scan?
yes
What is a PET/CT fusion?
you overlay the results of both tests on top of each other so that you can directly see what area in the chest or abdomen is lighting up on PET
What is Single Positron Emission Computed Tomography (SPECT)?
isotopes with logner half lives are used, the way gamma radiation is produced is different, the resolution produced is lower, but the detector used is less expensive
What is a echocardiography?
a type of ultrasound
What happens during an echocardiography?
ultrasounds utilize ultrasonic sound waves that travel at a high grequency to produce and electronic image.
When sound waves hit something at an angle, a certain amount of the sound is transmitted through it and the rest bounces off. What is this reflected waves called?
echo
What is a M-Mode Echo?
simple line tracing image; used for size of chambers, thichness of walls or size of heart
What is Doppler Echo?
measures and assessed the flow of blood through the hearts valves and chambers (can be done in colour to designate the direction of flow)
What is 2D echo?
produces “real-time: motion of teh heart’s structures
What is 3D echo?
produces “real-time” motion of the heart in greater depth than 2D
What are the 3 steps of an Echo?
Step 1: transducer emits sound waves by converting electrical energy from the power course to sound waves
Step 2: sound waves travel into the body, creating echoes when tehy reach the boundaries between substances
Step 3: echoes are received by teh transducer where they are converted back into electrical energy which can be interpreted by a computer to create and image
Echo:
The higher the____, the greater the ____ but the less____of the wave.
- frequencies
- resolution
- penetration
What does white indicate of an echo?
dense substance like bone (reflects most of the sound waves; absorbs almost no waves)
What does greyscale indicate on an echo?
a medium dense substance like fat or muscle (reflects some of hte sound waves; but also absorbs some waves)
What does black indicate on an echo?
indicates fluid reflectors like blood (reflects none of the sound waves; absorbs most of the waves)
Do you need to remove street clothes from the waist up or waist down for an echo?
waist up
What may be attatched to the chest during an echo?
ECG electrodes
Do you need to lie down for an echo?
yes
Why does the technician apply clear gel to the ches of the patient during an echo?
becasue the sound waves need a material to travel fromt he transducer to the patient
How long will an echocardiograph take?
30-45 minutes
Waht are three risk of a PET scan?
1) might be uncomfortable
2) unsafe for pregnant or nursing women (radioactive tracer)
3) radiation even though levels are low
What are three benefits of a PET scan?
1) uses bright colours to detect chemical activity
2) in some cases it might prevent surgery
3) early detection; faster than other procedures
What are three risks of an Echo?
1) bad reaction to mediaction that may be used
2) stress test can bother heart
3) slight discomfort
What are three benefits of an Echo?
1) doesn’t use radiation, only sound waves
2) might prevent surgery
3) non-invasive
4) safe for all people
5) painless
