Object Localization, Extraoral Radiography, and Advanced Imaging Flashcards
What sides can you see and not see in 2D imaging?
Can see mesial-distal view, can’t see buccal-lingual
What are 3 techniques of object localization to help determine a spatial relationship? 3 answers.
- Examine 2 conventional 2D images at right angle soft each other
- Tube shift technique
- Image anatomy with 3D imaging modality
What does it mean to take 2 conventional 2D images at right angles to each other?
Take a PA and an occlusal view radiograph
What does the SLOB mnemonic stand for?
Same-side lingual, opposite-side buccal
When the tube head is moved mesially and the object of interest moves mesially, where is it located?
Lingual side
When the tube head is moved mesially and the object of interest moves distally, where is it located?
Buccal side
What causes superior/inferior positioning changes of objects of interest in a radiograph?
Tube shift/change in vertical angulation
What is an extra oral image?
The receptor is placed outside the patient’s mouth
What are a few purposes of extra oral radiographs?
- To evaluate large areas of skull/jaws
- To evaluate growth and development
- To evaluate impacted teeth
When can intraoral radiographs be challenging?
Swelling or discomfort
Where do you place the film inside of to protect it?
Cassette
What does the cassette have to reduce x-ray exposure?
Intensifying screen
What is the patient placement for a lateral cephalogram?
Receptor parallel to midsagittal plane
Where is the central beam for a lateral cephalogram?
Beam is perpendicular to the receptor
What is the patient placement for a posterior anterior cephalometric projection?
The cantho-meatal line at 10 degrees with the receptor
What is the central beam for a posterior anterior cephalometric projection?
Beam is perpendicular to receptor
What are the indications of a posterior anterior cephalometric projection? 3 answers.
- Asses jaw skeletal relationships
- Evaluate craniofacial asymmetry
- Orthognathic surgical treatment planning
What does lateral ceph and PA provide information on?
Skeletal relationship in all the three planes
What does Water’s projection evaluate?
Paranasal sinuses
What is the patient placement for Water’s projection?
Cantho-meatal line is 37 degree upward to the receptor
What is the central beam placement for Water’s projection?
Beam is perpendicular to receptor
What are the indications for Water’s projections?
Displays paranasal sinuses, predominantly the maxillary sinus and to a lesser extent the frontal and ethmoidal
What does CBCT utilize?
Cone shaped X-ray beam to capture the 3D image
What does CBCT stand for?
Cone beam computed tomography
What is the CBCT detector?
Records number of photon exiting the patient
What are the three principles of CBCT?
- Collimated x-ray source
- Detector
- Synchronously rotate around the patient
During each rotation of a CBCT, how may are captured?
600-700 images at several hundred rotation angles
What is the complete series of images called in a CBCT?
Raw data/projection data
What is image reconstruction and multiplayer reformation?
Stacks of images, projection data, and raw data is imported into viewing software to create 3D anatomical planes of the body
What is the axial anatomical plane?
Top to bottom
What is the coronal anatomical plane?
Front to back
What is the sagittal anatomical plane?
Left to right
How are CBCT images stored?
In a DICOM format, able to import images in any third party treatment planning software
What are four advantages of CBCT?
- Better visualization of structures
- Better spatial orientation
- Finer detail
- Less radiation dose
Does a conventional image dose or CBCT have more radiation exposure?
CBCT is more radiation
Does at CBCT or CT have more radiation exposure?
CT has more radiation
What are two disadvantages of CBCT?
- Patient motion during the scan creates artifacts
- Cost of equipment
