angio equipment Flashcards
what is fluoroscopy
real time x-rays
what is angiography
imaging of blood vessels following a contrast media
equipment requirements
- specialised fluoroscopy unit
- generator
- tube stand
- floating top table
- contrast injector
- capable of high serial exposures
- DSA
what are the two types of image detectors
- image intensifier (II)
- flat panel detector (FPD)
what does angiography require
- high resolution for visualisation of small vessels
- FPD with highly specialised image post processing
mA generator requirement
100-1500 mA
kV generator requirement
50-125 kV
generator requirements
- short exposure time
- pulsed fluoroscopy
- high freq
angiography equipment specifics
- tube stand
- single plane
- biplane
- CCTV
- isocentre
- U arm / C arm
advantages of biplane
- less contrast agent used
- shorter procedure time
- help positioning of interventional devices
x-ray tube angiography equipment specifics
XR tube
- high heat storage capacity
- fast heat dissipation rate
dimensions FPD
40cm x 30cm
two types of angiography
- interventional radiology
- cardiology
what are images made up of
array of binary numbers
- large binary numbers shown in hexadecimal notation
interventional angiography systems
- c-arm that can be positioned around the patient
- FPD that offer high resolution images and low radiation dose
- DSA enhances visualisation of blood vessels using subtraction imaging
the principle of DSA
baseline image is taken before injection of contrast material and subsequent images are taken after injection
- these images are subtracted from baseline image
which system requires high frame rate and why
- cardiac angio
- capture rapid movement of heart and blood vessels
why does cardiac angio use a smaller detector size
- high spatial resolution for detailed view of coronary vessels
- focused FOV for small area
- reduced scatter
- faster frame rates
- lower dose
features of a contrast media injector
- warms contrast to reduce viscosity
- flashing light
- controlled flow rate
what happens if two images that are almost the same are subtracted from each other
the resulting image will only show what is different
what do you need to produce a DSA image
a sequence of pulsed fluoroscopic images of the relevant body part recorded
what happens in road mapping
one of the DSA images of blood vessels is superimposed over image while screening
- helps guide precise placement of devices
what does DSA require
- large field
- stable TV system
- XR tube with low noise
- XR tube with small focal spot size
- high voltage generator
what is remasking
used to reduce motion artefacts in subtracted images
what is pixel shifting
- shifting an image to create a higher effective resolution than the native resolution of imaging sensor
- improved registration features common to both images achieved
- reduces motion artefacts
