Cone Beam Computed Tomography (CBCT)
CONE BEAM COMPUTED TOMOGRAPHY (CBCT)
What is a 3D cone beam CT scan?
Dental x-rays and 2D panographs cannot clearly see the inside of the bone, and cannot see the tongue-side of the bone at all. Only a cone beam CT (CBCT image) can create a 3D view and cross sections of the area of interest. The information provided in a CBCT scan is extremely important when placing dental implants, performing a complex root canal or extraction, or looking for the source of pain or infection. We want to have as much information as possible about your condition and anatomy before operating or planning.
How does your dental CBCT scan differ from a CT or CAT scan in a hospital?
Dental cone beam CT emits less radiation and provides a more complete picture. Hospital CTs take a series of parallel x-ray images of the head, from top to bottom. There’s a gap between each image, and a computer uses educated guesses to fill in the gaps. This type of CT imaging is adequate (albeit with excessive radiation) for large pathology, like a skull fracture or sinus infection.
A cone beam CT circles the head, so each image or slice overlaps. There is no gap. In addition, the radiation is much weaker. Only in areas of overlap (the area of interest) is there enough radiation and data to construct a 3D model. This is why CBCT images provide a more complete image with less radiation, compared to hospital CT machines.
How much radiation is used? Should I be concerned?
An extremely small amount of radiation is emitted—but any radiation should concern you.
The majority of CT scans have a radiation effective dose equivalent to four or five hours of high-altitude air flight, or 11 to 15 days of normal background radiation in the United States. This risk from radiation exposure is much less than the risk of inaccurate diagnosis or treatment from proceeding with the knowledge provided by a CBCT scan.
Effective radiation dose in adults
Following are comparisons of effective radiation dose in adults with background radiation exposure for several radiological procedures.
For this procedure:
* An adult’s approximate effective radiation dose is:
Comparable to natural background radiation for:
Computed Tomography (CT)-Abdomen and Pelvis
Computed Tomography (CT)-Abdomen and Pelvis, repeated with and without contrast material
Computed Tomography (CT)-Colonography
Intravenous Pyelogram (IVP)
Radiography (X-ray)-Lower GI Tract
Radiography (X-ray)-Upper GI Tract
CENTRAL NERVOUS SYSTEM:
Computed Tomography (CT)-Head
Computed Tomography (CT)-Head, repeated with and without contrast material
Computed Tomography (CT)-Spine
Computed Tomography (CT)-Chest
Computed Tomography (CT)-Lung Cancer Screening
Coronary Computed Tomography Angiography (CTA)
Cardiac CT for Calcium Scoring
Bone Densitometry (DEXA)
Positron Emission Tomography – Computed Tomography (PET/CT)
Bone Densitometry (DEXA)
Note for pediatric patients: Pediatric patients vary in size. Doses given to pediatric patients will vary significantly from those given to adults.
* The effective doses are typical values for an average-sized adult. The actual dose can vary substantially, depending on a person’s size as well as on differences in imaging practices.
Please note that the above chart attempts to simplify a highly complex topic for patients’ informational use. Patients with radiation dose questions should consult with their radiation physicists and/or radiologists as part of a larger discussion on the benefits and risks of radiologic care.
The International Commission on Radiological Protection (ICRP) Report 103 states: “The use of effective dose for assessing the exposure of patients has severe limitations that must be considered when quantifying medical exposure”, and “The assessment and interpretation of effective dose from medical exposure of patients is very problematic when organs and tissues receive only partial exposure or a very heterogeneous exposure which is the case especially with x-ray diagnostics.”
Will my insurance cover this?
Some dental insurance plans will occasionally reimburse for some 3D imaging procedures, and some medical insurance carriers will reimburse you if you were referred by a medical doctor.
For more information on CBCT imaging, click here.