Organ and Size-Specific effective doses from dental cone beam CT based on Body Mass Indexes (BMIs): Monte-Carlo simulation study

The role and benefits of Cone-Beam CT(CBCT) in dental imaging, diagnosis and treatment planning are well known, but using the x-rays, it is not risk-free. This study aimed to provide an accurate and comprehensive data base of organs and size-specific effective doses based on body mass indexes (BMI) of patients in dental-CBCT units. In this regard, the Monte-Carlo (MC) method used to simulate the exposure geometry for three different imaging protocols with GIANO CBCT which is one of the commonly used unit in Iran. The population of the Extended-Cardiac Torso(XCAT) adult male and female computational phantoms with various BMIs were used as MC simulation input files. The measured doses using Rando phantom and thermoluminescence dosimeters were compared with simulated doses using CT images of Rando phantom to validate the simulations. The results showed the organs doses for the different Fields-of-View(FOVs) was varied usually in the adult females was higher. The maximum size-specific effective doses for temporomandibular-joint(TMJ), single and both arch protocols were 94±5μSv, 63±4μSv, and 62±2μSv for adult males with BMIs 25.82, 21.70, and 21.71kg m -2, respectively, and 98±3μSv, 69±1 μSv and 66±1μSv for adult females with BMIs 21.69, 21.71 and 21.72kg m-2, respectively. Also, the difference between the minimum and maximum value of effective dose in TMJ, single and both-arch protocols were 24%, 37% and 32%for AM. These values for AF were 24%, 32% and 35%, respectively. Eventually, this study provides comprehensive data set of patient doses for wide ranges of BMIs without the need for experimental measurement.