Cone beam computed tomography (or CBCT, also referred to as C-arm CT, cone beam volume CT, flat panel CT or Digital Volume Tomography (DVT)) is a medical imaging technique consisting of X-ray computed tomography where the X-rays are divergent, forming a cone.
CBCT has become increasingly important in treatment planning and diagnosis in implant dentistry, ENT, orthopedics, and interventional radiology (IR), among other things. Perhaps because of the increased access to such technology, CBCT scanners are now finding many uses in dentistry, such as in the fields of oral surgery, endodontics and orthodontics. Integrated CBCT is also an important tool for patient positioning and verification in image-guided radiation therapy (IGRT).
Dental cone beam computed tomography (CT) is a special type of x-ray equipment used when regular dental or facial x-rays are not sufficient. Your doctor may use this technology to produce three dimensional (3-D) images of your teeth, soft tissues, nerve pathways and bone in a single scan.
During dental/orthodontic imaging, the CBCT scanner rotates around the patient's head, obtaining up to nearly 600 distinct images. For interventional radiology, the patient is positioned offset to the table so that the region of interest is centered in the field of view for the cone beam. A single 200 degree rotation over the region of interest acquires a volumetric data set. The scanning software collects the data and reconstructs it, producing what is termed a digital volume composed of three-dimensional voxels of anatomical data that can then be manipulated and visualized with specialized software.[2][3] CBCT shares many similarities with traditional (fan beam) CT however there are important differences, particularly for reconstruction. CBCT has been described as the gold standard for imaging the oral and maxillofacial area.
Dental cone beam computed tomography (CT) is a special type of x-ray machine used in situations where regular dental or facial x-rays are not sufficient. It is not used routinely because the radiation exposure from this scanner is significantly more than regular dental x-rays. See the Safety page for more information about x-rays. This type of CT scanner uses a special type of technology to generate three dimensional (3-D) images of dental structures, soft tissues, nerve paths and bone in the craniofacial region in a single scan. Images obtained with cone beam CT allow for more precise treatment planning.
Cone beam CT is not the same as conventional CT. However, dental cone beam CT can be used to produce images that are similar to those produced by conventional CT imaging.
With cone beam CT, an x-ray beam in the shape of a cone is moved around the patient to produce a large number of images, also called views. CT scans and cone beam CT both produce high-quality images.
5. CT-Scan
X-Ray Source and detector rotate 360 degree
Patient table move continuously
X-ray beam passes through patient
Each structure attenuate the beam differently
According to density
Produce a Helix of image information
Reconstructed by computer into
a cross sectional image
6. CT-Scan
vs.
Radiography
Limitations of Radiography
Collapses the 3D into 2D
Loss of information
CT Advantages:
3D Imaging
Improves Contrast
Overlaying structures
do not decrees contrast
Produce little Scatter
Ability to image bone, soft tissue,
and blood vessels
Provides very detailed images
7. Fan Beam
VS.
Cone Beam
Fan Beam
Fan type X-ray beam
Linear detector array
Greater soft tissue definition
Greater bone resolution
Multiple rotation
Used in CT-Scan
Cone beam
Cone type X-ray
Panel Sensor
Lower radiation dosage
Lower cost
single rotation
8. Cone Beam
Computed
Tomography
(CBCT)
Uses a Cone Beam x-ray source
X-ray source and Panel detector
rotate 360 degree
Only One Rotation
The Hole volume is acquired
Image Processing
3D Image
2D cross sectional images
9. CBCT
VS.
CTSCAN
CT Scan:
slices are acquired then reconstructed to create the volume
CBCT:
The volume is acquired then slices are reconstructed from the
volume.
10. Advantages
OF
CBCT
Rapid scan
Reduce patient radiation dose
1o times less than CT
3D volume rendering
Accurate images
Good spatial resolution.
Economically comfortable and safe