The SCANORA® 3Dx CBCT system
The SCANORA® 3Dx is a new member of the SCANORA® CBCT product family. Compared to its predecessors, the SCANORA® 3Dx has a larger flat panel detector that enables now a wider range of imaging fields-of-view (FOV) to be used. The same smooth workflow with clear control screen and motorized patient positioning movements characterize this new accuracy instrument. The optional dental panoramic sensor is available as before.
In the unit there are now eight user selectable FOVs available. All the FOVs have their typical applications. The smallest cylindrical FOV 50 x 50 mm with the highest resolution of 0.1 mm voxel (volume element) size is intended for localized problems, such as detailed imaging of single tooth endodontic structures or the ossicular chain of the inner ear. Several medium size FOVs are available for imaging, for instance, both temporal bones in one volume. The most suitable FOV for sinus and ENT imaging is the 140 x 165 mm (HxD) with 0.2 mm voxel size. The largest FOV 240 x 165 mm (HxD) with 0.5 mm voxel size is intended for whole skull examinations, for instance follow-up of facial surgery operations. The voxel volume is isotropic, which ensures that measurements in any direction are accurate.
The SCANORA® 3Dx takes the advantage of the latest imaging technology. The 3D detector is a large amorphous Silicon flat panel for acquiring high-resolution projection images. The reconstruction method SARA (SOREDEX Advanced Reconstruction Algorithm) produces 3D volumes out of these projection images.
More accurate patient positioning is achieved with more developed laser lights and scout programs. The overall radiation dose for specific diagnostic tasks can therefore be optimized by selecting the smallest FOV for each task and adjusting the mA and resolution accordingly.
Head & neck imaging
CBCT in recent years has had a remarkable effect on the diagnosis of head and neck diseases. The advantages of CBCT over MDCT are the low radiation dosage, patient comfort, minimal patient interaction and lower expenses.
SCANORA® 3Dx was installed in December 2011 in the University Hospital of Tampere, Finland. By September 2012 over 800 patients had been examined. The patient group varies from children to the elderly. SCANORA® 3Dx has been used for dentomaxillofacial, dental, trauma, cervical spine, temporal bone and sinonasal imaging. The use of various FOVs, resolutions and mA settings has been systematically developed to optimize the image quality and the radiation dose in various indications.
Sinonasal imaging is an excellent example of the benefits of the CBCT compared to native X-ray and MDCT. The radiation dose of lower resolution and low mA setting is near to the dose of native X-ray. CBCT gives much superior information regarding the detailed anatomy and pathology in the area. In sinonasal infections (acute and chronic sinusitis), polyposis and odontogenic sinusitis the dose can be minimized for pediatric patients or follow up studies, and for FESS (Functional Endoscopic Sinus Surgery) operation planning higher resolution is optimal. Critical areas such as osteomeatal complex, the frontal ostium/recess and sphenoethmoidal recess/ostium are well defined on CBCT.
In addition, fractures of the mandible, orbit and facial skeleton, trauma of the base of skull and skeletal destruction of the head and neck area due to malignancies are indications for CBCT. Also, calculi of the parotid and submandibular glands can be well detected.
Due to a wide FOV, one can also image the cervical spine to a level of C7 – Th1, in fractures and skeletal degeneration.
Use of the CBCT in the dentomaxillofacial area and for dental indications are well recognized and documented before. SCANORA® 3Dx has been used for every possible indication, starting from the single misplaced tooth to a large field of view scans for orthognathic surgery planning and postoperative follow up studies. The datasets have also been used for computer-assisted planning and navigation.
In the University Hospital of Tampere, CBCT is used instead of MDCT in previously mentioned areas, when a contrast agent is not needed. Also, preoperative complicated traumas are often scanned with MDCT, because of better soft tissue contrast. In those cases most postoperative scans are made
When malignancy is suspected, MRI is the first imaging method, but bony destruction is scanned with CBCT.
Jorma Järnstedt DDS, Dentomaxillofacial
Radiologist, and Prasun Dastidar, MD, PhD,
Medical Imaging Centre, Tampere University Hospital, Tampere, Finland
Matti Linnosaari, Product Manager,