Table 1.

CBCT (standard-regular protocol) and multislice spiral CT (MSCT) exposure parameters about the head, cervical spine, ear and dental arches

Device	Anatomical area	Tube voltage (kV)	CTDIvola (mGy)	DLP (mGy cm)	DAP (mGy cm2)	Air kerma (mGy)	Current × exposure time (mAs)	Rotation timeb (s)	Scan diameter (cm)	Scan length (cm)	Reconstruction FOV (AP, LL × CC) (cm cm)	Reconstruction kernel	Voxel side (mm)	Pixel sizec (mm)	Slice thickness (mm)	Pitch (mm)
CBCT	Head	110	2.49	39.87	794.87	3.75	10.23	18	18	16	18 × 16	—	0.30	—	—	—
	Cervical spine	110	2.84	45.39	904.85	4.27	13.08	18	18	16	18 × 16	—	0.30	—	—	—
	Ear	110	20.57	128.57	1835.18	29.10	141.92	36	15	5	15 × 5	—	0.15	—	—	—
	Dental arches	110	10.53	94.80	1502.40	17.41	77.60	36	12	8	12 × 8	—	0.15	—	—	—
	Dental arches	110	7.44	66.98	1006.42	14.85	63.80	36	8	8	8 × 8	—	0.15	—	—	—
MSCT	Head	120	23.24	553.00	—	—	150	—	—	22	24 × 22	H40s medium	—	0.34	4.80	—
	Cervical spine	120	13.49	314.33	—	—	200	1	—	18	12 × 18	B40s medium	—	0.39	2.00	0.90
	Ear	120	36.94	317.69	—	—	120	1	—	6	15 × 6	U90u ultra sharp	—	0.41	2.00	0.85
	Dental arches	120	12.53	173.53	—	—	80	1	—	10	15 × 10	H60s sharp	—	0.39	0.60	0.90

AP, anteroposterior diameters; CC, craniocaudal diameters; CTDI, CT dose index; DAP, dose–area product; DLP, dose–length product; FOV, field of view; LL, laterolateral diameters.

Size of AP and LL was equal.

The protocols were optimized in such a way as to simulate the routine clinical practice. Since the acquisition was performed in a sequential manner, no rotation time and pitch value have been indicated for the MSCT head scan.

^aCTDI_vol values are referenced to a 16-cm-diameter CTDI phantom.

^bThe rotation time was the time for each 360° rotation. In CBCT, the rotation time corresponds to the full scan time.

^cThe pixel size was measured in the axial plane.