History and Importance in Dentistry
- Dr Yoshinori Arai and Dr Piero Mozzo independently developed Cone Beam Computed Technology for oral and maxillofacial radiology.
- The first commercial system, the NewTom 9000, was introduced in the European market in 1996 and the US market in 2001.
- CBCT is considered the gold standard for imaging the oral and maxillofacial area.
- CBCT can show critical root canal anatomical features that conventional intraoral or panoramic images cannot.
- 3D images produced by CBCT enhance diagnosis and influence treatment in endodontics.
- CBCT is used for presurgical assessment of dental implant sites.
- CBCT provides an undistorted view of the dentition, allowing accurate visualization of erupted and non-erupted teeth, tooth root orientation, and anomalous structures.
Applications in Interventional Radiology
- CBCT became practical for clinical use in interventional radiology procedures with the adoption of flat-panel X-ray detectors.
- Many C-arm fluoroscopy systems are capable of CBCT acquisitions.
- CBCT aids image guidance during interventional radiology procedures for various medical conditions.
- CBCT is used in the treatment of knee osteoarthritis, benign prostatic hyperplasia, and hepatocellular carcinoma.
- CBCT potentially reduces patient radiation exposure when used before fluoroscopy.
Industrial Applications
- CBCT is used for material analysis, metrology, and nondestructive testing in the manufacturing sector.
- CBCT can inspect and detect defects of tiny sizes, such as internal pitting corrosion or cracks, in quality control.
- Cone beam reconstruction algorithms, such as filtered backprojection or iterative reconstruction, are used in CBCT for material analysis.
- CBCT is used to improve quality control and ensure the integrity of manufactured objects.
- CBCT is effective in detecting and analyzing defects in industrial applications.
Risks and Disadvantages
- CBCT involves ionizing radiation, which carries potential risks.
- Total radiation doses from CBCT exams are lower than conventional CT exams but higher than standard dental 2D x-ray.
- The recommended standard of care is to use the smallest possible field of view, voxel size, mA setting, and exposure time.
- International organizations and legislation emphasize the importance of weighing risks and benefits before performing CBCT procedures.
- CBCT technology may be susceptible to movement artifacts and lacks appropriate bone density determination.
- The Hounsfield scale, used to measure radiodensity, may be inaccurate in CBCT scans due to varying greyscale values.
- CBCT HU values are unreliable for determining site-specific bone density for dental implant placement.
- CBCT systems do not employ a standardised system for scaling grey levels, making assessment of bone quality difficult.
Integration and Advancements
- Image quality and time are significant factors affecting the integration of CBCT in interventional radiology.
- Wider collimation in CBCT leads to increased scatter radiation and decreased image quality.
- The temporal resolution of CBCT detectors slows data acquisition time and increases motion artifacts.
- CBCT image reconstruction takes longer compared to MDCT due to computationally demanding algorithms.
- Ongoing advancements in CBCT technology aim to improve image quality and reduce acquisition and reconstruction time.
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.
| Cone beam computed tomography | |
|---|---|
 Cone Beam CT scanner | |
| MeSH | D054894 |
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).
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 visualised with specialised software. 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.
