Cone Beam CT Flashcards
benefits of cone beam over plain radiography?
- No superimposition
- Ability to view subject from any angle
- No magnification/distortion
- Allows for volumetric (3D) reconstruction
Downsides over plain radiography?
- Increased radiation dose to patient
- Lower spatial resolution (i.e. not as “sharp”)
- Susceptible to artefacts
- Equipment more expensive
- Images more complicated to manipulate & interpret
- Requires additional training
CBCT vs conventional CT?
CBCT main benefits
* Lower radiation dose
* Potential for “sharper” images (higher resolution)
* Cheaper
* Initial, running & maintenance costs
* Smaller footprint
CT main benefits
* Able to differentiate soft tissues better
* “Cleaner” images (better signal to noise ratio)
* Larger field of view possible
common uses of CBCT in dentistry?
- Clarifying relationship between impacted mandibular third
molar & inferior alveolar canal prior to intervention
> After plain radiograph has suggested a possible close relationship - Measuring alveolar bone dimensions to help plan implant placement
- Visualising complex root canal morphology to aid endodontic treatment
- Investigating external root resorption next to impacted teeth
> If not clear on plain radiographs - Assessing large cystic jaw lesions & their involvement of important anatomical structures
what are uses and drawbacks of 3D volume reconstruction/
Uses
* May help clinician to picture the extent/shape
of disease
* Can be an informative teaching aid for the
patient
Drawbacks
* It is a modified reconstruction of the data &
so can create misleading images
> Particularly poor at showing thin bone
contra indications for cbct?
- If plain radiographs are sufficient
- Pathology requiring soft tissue visualisation
- Malignancy
- Infection spreading in soft tissue
- If high risk of debilitating artefacts
- Patient factors
- Patient unable to stay still
- Patient unable to fit in machine
