Chapter 31 Flashcards
Which of the following describes radiolucent lines observed across an image?
D) Streaking
Which of the following describes radiolucent distortion surrounding the dense radiopaque appearance of the metal object on an image?
B) Cupping
Which stabilizing aid is NOT utilized during a CBCT scan to avoid movement artifacts?
C) Lead apron
A smaller voxel size does all of the following except one. Which one is the exception?
D) Increases movement artifacts
A CBCT examination produces as many as ________ image slices available for interpretation (including all three anatomical planes).
C) 1,500
CBCT requires a higher dose of radiation compared to a medical CT scan.
FALSE
CBCT produces three-dimensional radiographic images.
TRUE
It is necessary to use a CBCT to determine the location of impacted third molars.
FALSE
CBCT machines today are only marketed and used in specialty oral health care practices such as endodontic and orthodontic offices.
FALSE
Most CBCT machines allow an operator to switch between 2-D and 3-D imaging options.
TRUE
The FOV setting can be reduced or enlarged as needed in CBCT.
TRUE
Voxel is short for ‘volume and element.’
TRUE
A pixel captures a third dimension.
FALSE
The coronal plane divides anatomy vertically into a right and left side.
FALSE
A medium FOV classification for CBCT is indicated for capturing both maxillary and mandibular arches.
TRUE
A CBCT examination requires multiple types of 2-D radiographs for orthodontic diagnoses and treatment planning.
FALSE
CBCT can help with diagnosing pathology for endodontic therapy that are not present on intraoral or 2-D extraoral radiographs.
TRUE
CBCT examinations are not meant to replace conventional 2-D oral and maxillofacial radiographic examinations for many conditions.
TRUE
CBCT examinations are used as a screening tool for occult disease.
FALSE
A lead/lead-equivalent barrier with a thyroid collar is not necessary if it will interfere with acquisition of the image.
TRUE
The presence of a large metallic restoration can cause streaking and cupping artifacts to appear on radiographic images.
TRUE
When an x-ray beam passes through two objects of equal high density that are close to one another, streaking may occur.
TRUE
A larger voxel size utilized during CBCT will increase image detail and may increase radiation exposure.
FALSE
A definitive interpretation of a CBCT image most commonly requires assistance from a trained oral and maxillofacial radiology specialist.
TRUE
An oral health care professional is only legally responsible for the detection and subsequent recommendation for treatment or referral of the specific dental need requiring the prescription of a CBCT examination.
FALSE
Please describe conditions classified under the Preferred category for the prescription of CBCT.
Conditions classified under the Preferred category require more careful consideration as a practitioner must assess whether the risk versus benefit warrants a CBCT examination; or could 2-D radiographs provide enough information. Examples include location of inferior alveolar nerve, endodontic therapy, evaluation of sinus cavities, evaluation of bony defects, evaluation of oral pathologic lesions, and TMJ evaluations.
How many times does the beam from a CBCT rotate around a patient’s head?
CBCT utilized a cone-shaped x-ray beam that rotates in one full or partial rotation around the head (194 to 360 degrees).
What do scatter correction algorithms do?
Scatter correction algorithms are built into CBCT computer software to reconstruct the digital signal into enhanced 2-D and 3-D images that are displayed on a monitor.
Why is a 3-D radiograph (CBCT) more useful than a 2-D radiograph in determining and monitoring orthodontic interventions?
CBCT is more reliable in determining location and position of unerupted, impacted, and supernumerary teeth, and other growth and developmental anomalies with a comparable radiation dose to a radiographic series of 2-D images.
What does ALARA stand for and what is it in regard to?
Keep radiation exposure ‘as low as reasonably achievable.’
Why should CBCT be considered prior to exposing a series of extra- and/or intraoral radiographs?
CBCT should be considered prior to exposing a series of extra- and/or intraoral radiographs to prevent duplication and overlap of exposures, negative the need for one or the other.
What are artifacts and how do they affect radiographic imaging?
Artifacts are images other than anatomy or pathology that do not contribute to a diagnosis and can be a significant problem affecting image quality.
Why do artifacts and electronic noise occur more often with CBCT technology than medical CT scans?
The cone-shape beam and use of lower radiation energy by CBCT scans can lead to production of scatter radiation that negatively affects an image and can also decrease the contrast of soft tissues making it harder to compare hard and soft tissue structures.
What causes the presence of artifacts that appear as a double or duplicate appearance of anatomical structures?
Patient movement during the scanning process causes duplication or movement artifacts.
Provide three examples of anatomy beyond the oral cavity that a comprehensive CBCT interpretation must include regarding potential diseases and abnormalities.
A comprehensive interpretation must include detection of conditions affecting anatomy beyond the oral cavity such as diseases and abnormalities noted in the nasal airways, paranasal sinuses, craniofacial structures, cervical vertebrae, and other tissues outside the dentition and supporting structures.
