A Monte Carlo (MC) simulation for calculating absorbed dose has been developed and applied for dental applications with an i-CAT cone beam CT (CBCT) system. To validate the method a comparison was made between calculated and measured dose values for two different clinical protocols. Measurements with a pencil CT chamber were performed free-in-air and in a CT dose head
phantom; measurements were also performed with a transmission ionization chamber. In addition for each protocol a total number of 58 thermoluminescence dosemeters (TLD) were packed in groups and placed at 16 representative anatomical locations of an
anthropomorphic phantom (Remab system) to assess absorbed doses. To simulate X-ray exposure, a software application based on the EGS4 package was applied. Dose quantities were calculated for different voxelized models representing the CT ionization and transmission chambers, the TLDs, and the
phantoms as well. The dose quantities evaluated in the comparison were the accumulated dose averaged along the rotation axis (), the volume average dose, for the dosimetric
phantom, the dose area product (DAP) and the absorbed dose for the TLDs. Absolute differences between measured and simulated outcomes were 鈮?.1%for free-in-air doses; 鈮?.2%in the 5 cavities of the CT dose head
phantom; 鈮?3%for TLDs inside the primary beam. Such differences were considered acceptable in all cases and confirmed the validity of the MC program for different geometries.
In conclusion, the devised MC simulation program can be a robust tool to optimize protocols and estimate patient doses for CBCT units in dental, oral and maxillofacial radiology.