cone beam CT Flashcards
(16 cards)
what is CBCT suitable for assessing
radio dense structures
does cone beam ct use ionising radiation?
yes in the form of x-ray
benefits of CBCT over plain film 4
No superimposition
Can view subject from any angle
No magnification/distortion
3D reconstruction so can better visualise
downsides of CBCT over film 6
Increased radiation
Lower resolution
Susceptible to artefacts
Expensive
Images more complicated to interpret and manipulate
Requires additional training
what size field of view do u want for CBCT
smallest view possible because it results in the smallest radiation dose
what is a voxel
3D pixel
what does a smaller voxel size result in, in CBCT imaging 3
higher radiation dose and longer scan time and higher resolutio
what pt are more at risk from radiation
younger pts
what are artefacts
visualised structures on the scan that are not present in the object investigated
what are movement artefacts caused by?
pt moving
appearance of movement artefacts
Affects whole scan - blurriness or extra contours
what type of artefact is this?
movement artefact
what are streak artefacts caused by?
high attenuation objects - metals
what is the main problem with streak artefacts when diagnosing?
Can cause radiolucency in adjacent teeth - may think its caries but it isn’t
what type of artefact is this
streak artefact
contraindications for CBCT 5
Plain radiographs are sufficient
Pathology requiring soft tissue visualisation
High risk of debilitating artefacts e.g. lots of amalgam restorations
Pt unable to sit still - Parkinson’s, child
Pt unable to fit in machine - kyphosis, obese, bodybuilder
