Effective radiation dose of a MSCT, two CBCT and one conventional radiography device in the ankle region

BACKGROUND: The aim of this study was to assess and compare the effective doses (ICRP 103) in the ankle region of X-ray imaging resulting from a multi slice computed tomography (MSCT) device, two cone beam CT (CBCT) devices and one conventional x-ray device. METHODS: Organ dose measurements were performed using 20 metal oxide field effect transistor (MOSFET) dosimeters that were placed in a custom made anthropomorphic RANDO ankle phantom. The following scanners were assessed in this study: Siemens Sensation Open 24-slice MSCT-scanner (120 kVp, 54 mAs), NewTom 5G CBCT scanner (110 kVp, 2.3 - 59 mAs), Planmed Verity CBCT-scanner (90 kVp, 48 mAs), Shimadzu FH-21 HR direct radiography equipment (AP + LAT), (57 kVp, 16 mAs). RESULTS: Measurements of the MSCT device resulted in 21.4 μSv effective dose. The effective doses of CBCTs were between 1.9 μSv and 14.3 μSv for NewTom 5G and 6.0 μSv for Planmed Verity. Effective doses for the Shimadzu FH-21 HR conventional radiography were 1.0 μSv (LAT) and 0.5 μSv (AP), respectively. CONCLUSIONS: Compared with a conventional 2D radiographic device, this study showed a 14-fold effective dose for standard MSCT and 1.3 -10 fold effective dose for standard CBCT protocols. CBCT devices offers a 3D view of ankle imaging and exhibited lower effective doses compared with MSCT.