DDS 6234DH 3234 About 10 years in dentistry Replaced film based tomography in dentistry Development possible as: Availability of sensors (flat panel sensors and intensifying tubes) Better computing power X-ray tube that can continuously expose (some are pulsed) 180+ degree scan Continuous or pulsed exposure  Field of view: collimation to reduce area of x-ray exposure. Also improves image quality Speed of image acquisition is frame rate ( frame per second) Higher frame rate: better image Higher frame rate: longer exposure Higher frame rate : higher radiation Flat panels consisting of multiple 2-D digital arrays Cesium iodide crystals on amorphous silicon layer Records large area of the tissue volume with a beam similar to a cone or a pyramid Scan time is shorter compared to CT Intensifying tube used by one manufacturer 10- 30 second scan time 500+ frames Reconstruction of the raw image data into a continuous visible image Early machines needed 30 minutes to several hours for reconstruction Newer machines: 5 minutes or less to reconstruct Viewed on a computer screen Can be viewed from multiple angles: multiplanar reformat Selection of similar image density: segmentation Viewing of highest density points: maximum intensity projection 3D surface rendering 3D volume rendering Viewed on a computer screen Can be viewed from multiple angles: multiplanar reformat Selection of similar image density: segmentation Viewing of highest density points: maximum intensity projection 3D surface rendering 3D volume rendering Smaller size, lighter weight Large volume exposed at a time: faster scanning Sensor has array of detectors: resolution can be less 0.2 mm Fast reconstruction with ‘regular’ computer Lower radiation dose  Software for dentistry Detector surface is large, collects scatter radiation Soft tissue resolution is low Presence of metal restorations degrade the images Low dose (effective) FMX: 76 μSv Bitewing: 12 μSv Pan : 6-11 μSv Ceph: 17 μSv CBCT: 46-477 μSv CT head: 1800