Digital Volume Tomography (DVT, Conebeam CT): An update

Many CBCT's are bought to perform Dentascan and 3D-Face/Skull studies. However sinus imaging today became the major application, but other applications as face/nose trauma, TMJ, swallow studies and pharyngography, temporal bone imaging (and cochlear implants), dacryocystography etc. are possible. Newer systems can even replace conventional CT for imaging of the wrist-hand, elbow, ankle-foot and knee.

Most CBCT systems are not able to perform all these different studies and therefore one has to look for a system that is able to provide the locally needed studies:

• All systems are able to perform dental and sinus studies

• High resolution systems are needed to perform temporal bone studies as well (with more power full X-ray tubes, resolution of 0.075mm), Fig.1

• Double rotation systems are needed to perform 3D-Face/Skull studies as well (2 overlapping slabs, stitched together to cover whole skull, Fig.2)

• Systems with a gantry are needed to perform studies of peripheral joints.

Immobilization is crucial and therefore the necessary time should be invested to position and immobilize the patients, as the slightest movements will destroy the high resolution ≤0.2mm quality. Moreover nurses must perform enough studies per day to become experienced enough especially when they have to perform the whole spectrum of possible studies.

However, CBCT can be considered the technique of choice in many areas when good quality images are produced. The easy access to the system, the very low irradiation dose and the spatial resolution have guaranteed CBCT a strong place between the other imaging systems. Therefore radiologists should be aware of the potential of CBCT and invest in systems, before colleagues of other specialities invest. In this presentation the different types of CBCT's will be discussed and the applications which are possible today will be illustrated.

Lernziele:

• CBCT uses less irradiation than conventional CT

• CBCT has a much better spatial resolution (0.075mm) than conventional CT and produces less metal artefacts

• CBCT should not be used for “soft tissue“ imaging

• The most frequent application is no longer dental, sinus imaging is now the most frequent CBCT study and will in the near future probably be challenged by musculoskeletal studies.

• Other growing applications: trauma, TMJ, temporal bone.

• Ethically radiologist can now longer justify a conventional sinus or dental CT study when this can be donne better at 10–20% of the irradiation on CBCT. Hence they should invest in CBCT

Korrespondierender Autor: Casselman J

AZ Sint-Jan te Brugge, Department of Radiology & Maxillo-Facial Surgery, Ruddershove 10, 8000, Brügge

E-Mail: [e-mail]