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.
Prior to the introduction of CBCT, multiplanar views were obtained primarily with multi-detector CTs (MDCT) and magnetic resonance imaging (MRI). Physical dimensions and cost of MDCT and MRI equipment are prohibitive for installation in a typical OMS office.
Smaller physical dimension, lower cost and easier operation have led to rapid acceptance of CBCT units. There are many instances where an oral and maxillofacial surgeon may reliably use a CBCT scan where an MDCT may otherwise have been chosen to provide diagnostic information. However, the need of MDCT and MRI examinations in oral surgery is not obsolete, even though the quality of CBCT images may be better than MDCT scans.A study that evaluated the image quality of bone structures acquired by five different CBCT machines and one MDCT machine showed that the image quality of one CBCT machine was superior to that from the tested MDCT machine while images from other CBCT units were comparable to the test MDCT
However, soft tissues are better displayed on MRI and soft-tissue window CTs. Currently, neither MDCT nor CBCT can replace the MRI where soft tissue diagnosis is the primary aim. These situations include analysis of soft tissue tumours, extension of intraosseous tumours into surrounding soft tissue and position of the disc in temporomandibular joints.
Cone beam computed tomography (CBCT) is a type of X-ray imaging that uses a cone-shaped beam to create 3D images of the body
How it works
A CBCT machine rotates around the patient's head, emitting X-rays in a cone shape. The machine then uses a 2D sensor to capture the X-rays and reconstruct them into 3D images.
Medical imaging is an indispensable tool in radiotherapy for dose planning, image guidance and treatment monitoring. Cone beam CT (CBCT) is a low dose imaging technique with high spatial resolution capability as a direct by-product of using flat-panel detectors.
In CBCT systems, the x-ray beam forms a conical geometry between the source (apex) and the detector (base) (Fig 2). This is in contrast to conventional fan-beam geometry (Fig 2), in which the collimator restricts the x-ray beam to approximately 2D geometry.
Uses
CBCT can be used in a variety of clinical settings, including dentistry, breast imaging, and other procedures
Major uses of CBCT examination in oral surgery practice include surgical extraction of third molars and impacted teeth, tracing of the inferior alveolar canals, implant planning, evaluation of cysts and tumours, fracture diagnosis, orthognathic surgical planning and follow-up, inflammatory conditions of the jaws and the sinuses, evaluation of the temporomandibular joints, and as an aid in diagnosing unexplained symptoms of pain. The following subsections provide utility of CBCT in different surgical situations.
Dentistry: CBCTs are used to evaluate the teeth, jaws, and face, and can help determine bone structure and tooth orientation.
Breast imaging: CBCTs can help reduce the overlap of breast lesions and provide high contrast between normal and pathological breast tissues.
Other procedures: CBCTs can be used to guide needle placement during biopsies, confirm the location of stents, and more.
Benefits
CBCTs have several advantages over traditional CT scans, including:
Lower radiation exposure: CBCTs use a low-power X-ray tube and rotate less often than traditional CT scanners.
Faster: CBCT scans are quicker than traditional CT scans.
Better image quality: CBCTs can produce high-quality images with better accuracy.
Here are some advantages of CBCT scans:
Reduced radiation: CBCT scans use a lower dose of radiation than traditional CT scans.
Less expensive: CBCT scans are less expensive than other imaging techniques.
Shorter scanning time: CBCT scans have a shorter scanning time than other imaging techniques.
3D images: CBCT scans provide 3D images of the head and neck, including the teeth, jaw, and face.
Precise treatment planning: CBCT scans provide information that helps with more precise treatment planning.
Comentários