Comparação da dose absorvida em radiografias intraorais entre objetos simuladores virtuais antropomórficos geométricos e baseados em voxel

Abstract

Intraoral radiographs are widely used in dentistry for the diagnosis and monitoring of oral diseases, allowing for detailed visualization of various regions of the oral cavity through interproximal, periapical, and occlusal techniques. Due to the high frequency of these examinations in clinical practice, there is concern regarding the accumulated exposure to radiosensitive tissues in the head and neck region, such as the lens of the eyes, the thyroid gland, and the major salivary glands, as certain X-ray beam angles can directly irradiate these organs. This study aims to quantify the dose absorbed by these tissues using numerical simulations based on the Monte Carlo Method (MCM) and an experimental component involving the RTI RED PIRANHA detector. The simulations involve different angles of intraoral radiographs performed at the Dental Hospital of the Federal University of Uberlândia and utilize both geometric and voxel phantoms to identify which phantom is more suitable for these analyses. Additionally, comparisons of variations in absorbed doses with and without the presence of orthodontic appliances were conducted. The results indicate that the absorbed dose in radiosensitive tissues varies according to their proximity to the X-ray beam and the simulation model used. Salivary glands, especially the parotid and sublingual glands, recorded the highest doses in most of the angles analyzed. In simulations with the voxel phantom, these glands showed higher absorption compared to the geometric phantom, which underestimated the doses due to its less detailed structure. This behavior confirms that the voxel model is more accurate for representing anatomy and dose distribution, highlighting the importance of accurate anatomical modeling in dental radiodiagnostic simulations. The presence of orthodontic appliances influenced the absorbed doses, particularly in tissues outside the oral cavity, due to X-ray scattering. The stainless-steel appliance, for instance, increased the dose at the vertex angle, affecting the lens of the eye, while in tissues within the oral cavity, the appliance reduced the absorbed dose at certain angles, acting as a barrier. These findings reinforce the need for optimization of positioning and technical settings to minimize exposure to sensitive tissues, with the aim of reducing the absorbed dose to these tissues, considering the stochastic effect.