Development and construction of an image quality mannequin for CBCT dental tomographs

The Cone Beam Computed Tomography (CBCT-Dental) technology is a new modality in the field of medical physics. These equipment's involve a series of processes that involve not only the generation of X-rays, the formation of the image to be seen on a digital monitor, but also reconstruction algorithms that allow to obtain an image, in addition to other parameters that influence the quality of the same, which can negatively affect the properties in the image, minimizing the diagnostic efficiency and increasing possible explorations by the staff to the patient. A mannequin was developed in the study for image quality, which also contains dental materials that are used for prosthesis and dental tights, these materials were assigned for the first time Computed Tomography (CT) numbers. In clinical conditions the operation of the mannequin was demonstrated and its usefulness in terms of image quality is concerned. With this prototype Modulation Transfer Function (MTF), Contrast Noise Ratio (CNR), Uniformity, Noise, Artifacts, and CT numbers were evaluated. Three dental clinics were evaluated, two of which are private centers and one belongs to the Facultad de Odontologia de la Universidad de Costa Rica. For each clinic a calibration curve corresponding to the CT numbers of each material studied was assigned, these values, are independent of each equipment, therefore they will vary between clinics depending on the Field of View (FOV), clinical protocol used, effective energy, reconstruction system of image. There is a need for quality control of dental Cone Beam Tomography (CBT) equipment, in addition to ratifying the importance of having a record of the parameters that influence the quality of the image for a more effective diagnosis. (author)