New method to organ dose assessment in cone-beam computed tomography using Im PACT software

Background: This study sought to assess the organ absorbed dose using Im PACT software and evaluate the effect of small and large fields of view (FOVs) for three cone-beam computed tomography (CBCT) devices on the organ absorbed dose. Materials and Methods: The weighted computed tomography dose index (CTDIw) is measured using a pencil ionization chamber which was incorporated in a polymethyl methacrylate (PMMA) phantom for three CBCT devices with small and large FOVs. The calculated CTDIw was entered into the ImPACT software. Then the organ absorbed dose of the thyroid gland, salivary glands, oral mucosa, skin, brain, and red bone marrow and the whole-body effective dose were calculated by the software. Results: Irrespective of the type of CBCT device, the organ absorbed dose was obtained higher value in use of a larger FOV (P<0.01). The mean organ absorbed dose in use of large and small FOVs was 0.13 and 0.08 for New Tom GiANO, 0.49 and 0.13 for Vista Vox S and 0.69 and 0.38 for XMIND Trium, respectively. Salivary glands had the highest organ absorbed dose among all of the organs within the field. Larger FOVs yielded higher whole-body effective and organ absorbed doses compared with smaller FOVs. Conclusion: The results showed that using the ImPACT software to estimate the organ absorbed dose can serve as a suitable alternative to other costly and time-consuming methods available for this dose assessment in CBCT.