Dosimetric analysis of the use of CBCT in diagnostic radiology: sinus and middle ear

Abstract

The use of cone beam computed tomography (CBCT) in diagnostic radiology departments is increasing. Several discussions arise whether with the CBCT application, some multi-slice CT (MSCT) examinations can be replaced by it. High hopes are set regarding the dosimetric aspects of CBCT: are patient doses in between those of conventional X-rays and MSCT? In this study, effective dose and organ doses were evaluated for two non-dental CBCT examinations: sinus and middle ear. A comparison with the dose obtained with a MSCT protocol was performed. Moreover, the sinus examination was also compared with the dose obtained by projection radiography (RX). Effective doses were estimated from thermoluminescent detector dose measurements in an anthropomorphic phantom and were compared against Monte Carlo simulations. Results show that the effective dose for the sinus examination is more than three times higher with MSCT than with CBCT and about five times lower with RX compared with CBCT, whereas for the middle ear examination, the effective dose obtained with MSCT is almost six times higher than that of CBCT. Finally, a sensitivity study on the size and position of the CBCT field of view showed the influence of these two factors on the dose received by the patient.

Radiation dose in non-dental cone beam CT applications: a systematic review

“…The main reasons for exclusion were that the studies did not focus on the field of dosimetry or did not report the effective dose. Among the 15 papers selected (14 original papers [27][28][29][30][31][32][33][34][35][36][37][38][39][40] and 1 conference proceeding [41]), two of them analysed two anatomical areas; all the others analysed only one anatomical area ( Table 2). The following anatomical areas were analysed: ear [27][28][29][30][31][32], paranasal sinuses [27,33,34,41], ankle [35][36][37], wrist [38,39], knee [40], and cervical spine [32].…”

“…In the 15 studies examined, 16 CBCT-units (seven different models) were used, of which five were from the USA [29,33,34,36,41], Finland [31,35,37,38,40], and Italy [27,28,32,35,39], and the remaining one from Japan [30]. One study [31] used a modified specific acquisition system that involved a pause during each exposure of the multiple frames to reduce potential motion artefacts generated by the rotating "C" arm.…”

“…No physical/technical parameter was referred to in the three studies [34,37,41]. The tube voltage was mentioned in all the other studies, whereas some of them did not report field of view (FOV) [28,29], mAs [30,38,39], and voxel size [27,28,40].…”

“…• Scanner outputs Computed tomography dose index (CTDI) [39] and dose area product (DAP) [37,38], each of which was multiplied by a conversion factor. • Monte Carlo simulations [27,34].…”

Dosimetric study of the use of CBCT in diagnostic radiology: Sinus and middle ear

“…Image quality is typically is assessed using images acquired with the Contrast Detail mammography (CDMAM) phantom (1, 2). Detector performance was then re-evaluated using ideal observer analysis, on the basis of previous work, generalising the definition of Hotelling observer to include the effects of focal spot unsharpness, magnification and scattering (5)(6)(7)(8)(9). Recent work tried to link automated readings with humanobserver performance, but results can be dependent on structural differences between CDMAM phantoms (3)(4).…”