3D CBCT – Cone Beam Computer Tomograph 

Whenever you are having a 3D – CBCT taken in the DentaVis Centers, you will benefit from the latest technology in the field of maxillofacial radiology, with the lowest level of radiation.

How can we obtain highly accurate volumes at such low level of radiation?

In order to understand this, we must first understand the difference between the classic 3D – Computer Tomograph and the 3D – CBCT (Cone Beam Computer Tomograph) used in the DentaVis Centers.

The advanced CBCT technology uses a cone beam fascicle transmitted on a static sensor, producing the entire volume in one scan (one rotation around the patient’s head). The CBCT captures a series of images of a certain thickness which it then combines, following a certain algorithm.

The 3D – CBCT uses the voxel (the volumetric pixel). The voxel is a tridimensional unit, which comprises a higher quantity of information in one scan.

The classic Computer Tomograph uses a fascicle in the shape of a fan for image acquisition. The reconstruction of any point found on the path of the X-ray is presented as an image made out of pixels. The pixel is a bidimensional unit, expressed using terms of relative radiodensity. The high power anode tube spreads the X-rays towards the detectors which are positioned as a semi-circle around the the patient, obtaining one image per scan, thus making multiple rotations and multiple scans necessary. Each image obtained with each scan requires a small overlap area with the previous image, for the volume reconstruction to be correct. This means the same information, using a higher radiation dose, for a longer time.

The single rotation image capturing method as the Cone Beam Computer Tomograph is much faster than the traditional spiral method used by the classic computer tomograph.

The radiation dose is much lower in 3D – CBCT as there is no need to overlap the images in order to reconstruct the volume.

How noticeable are the radiation dose differences between the two?

A conclusive example:

Abdomen CT = 8.000 microsievert
Complete CBCT (the whole head) = 32 microsievert
The daily environmental dose = 10 microsievert