hrvatski

Utjecaj parametara snimanja dentalnim CBCT uređajem na doze organa i efektivnu dozu pacijenta

Cone beam computed tomography (CBCT) used in dental medicine results in complex dose distributions owing to different performance of devices and examination procedures. The aim of this study is to examine the influence of scanning parameters on organ doses and effective dose of the patient undergoing dental CBCT examinations. Investigation was performed by the use of Monte Carlo simulation. CBCT dental unit was simulated using Monte Carlo N-Particle transport code (MCNP® 6.1.1beta). For calculation of organ doses and for the assessment of effective doses computational anthropomorphic phantom was used („Zubal“). Most often clinical protocols involving different exposure geometries including sizes and positions of FOVs, 180o and 360o X-ray tube rotation angles and different tube current- exposure time products (mAs) were simulated. Organ doses in all simulated CBCT protocols ranged from 55 μGy (brain) to 4119 μGy (bone surface) and effective doses from 31 μSv to 214 μSv, depending on scanning parameters. In average, thyroid gland has the highest contribution to the effective dose (31 %) followed by salivary glands (25 %) and extra thoracic region (21 %). Results of this study indicate importance of careful choice of FOV's size and its position in optimisation of CBCT procedures considering clinical question and anthropometric features of the patient since size and position of FOV have great impact on organ doses and effective dose, especially on thyroid gland and salivary glands. Choosing 180o for the X-ray tube rotation angle instead of 360o would not decrease image quality but may significantly decrease doses of the organs contributing the most to the effective dose. Due to linear dependence of organ doses and effective dose on mAs, whenever possible lowest mAs should be used, considering level of the image quality required.

CBCT, efektivna doza, očna leća, doza organa

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