Acquisition terms
kVp: tube voltage in kilovolts peak. Higher kVp gives more penetration, lower contrast. Typical CBCT: 80–120 kVp. mA·s: tube current × exposure time, total photon output. Higher mA·s reduces noise but increases dose.
FOV (field of view): the cylindrical region the scanner captures. See the dedicated page for protocols. Pulsed vs continuous: pulsed acquisition fires the X-ray only during detector windows, cutting dose by half or more without losing image quality.
Reconstruction and display terms
Voxel: 3D pixel. Voxel size sets spatial resolution. Isotropic: voxel with equal X, Y, Z dimensions — what makes MPR work without resolution loss. MPR: multiplanar reconstruction, generating arbitrary planes from the volume. MAR: metal artifact reduction, post-processing to dampen streaks from dense restorations.
Window/level: brightness/contrast settings that map raw 16-bit data to a displayable 8-bit screen range. Hounsfield units: a calibrated CT density scale (water = 0, air = -1000, dense bone ~+1500). CBCT voxels are not true Hounsfield units; they vary by manufacturer and scan.
Safety and protocol terms
ALARA: As Low As Reasonably Achievable — the principle of using the smallest dose that answers the clinical question. SafeBeam: trade name for pulsed acquisition. Effective dose: a measure in microsieverts (μSv) that estimates whole-body biological risk from a localized exposure. RDSR: Radiation Dose Structured Report, a DICOM object that records exposure parameters per study.