In some cases, the additional functionality includes a reconstructed panoramic image obtained from a CBCT dataset and reformatting within the software, which may remove some of the superposition of structures that are expected in the panoramic image. 1 Due to advances in dental cone beam computed tomography (CBCT), manufacturers are including additional functionality including panoramic-imaging capabilities to provide an all-in-one system for dental imaging. Panoramic radiography is a two-dimensional x-ray examination that produces an image of the dental arches. Significant dose savings may result by selecting age- and size- appropriate protocols for pediatric patients, but a wider range of protocols for children and adolescents may be beneficial. The panoramic-mode on the CBCT machines produce images suitable for clinical use with similar dose levels to the stand-alone panoramic device. When the same protocol was used for different-sized phantoms, the smaller phantom had a higher radiation dose due to less attenuation of x-rays by the smaller phantom and differences in the positioning of the ion chamber relative to the focal trough. For any individual phantom, using protocols with lower kVp, mA, or acquisition times resulted in statistically significant dose savings, as expected. For each machine, single-factor ANOVA was conducted to determine dose differences between protocols in each phantom, as well as determine the differences in absorbed dose when the same protocol was used for different-sized phantoms. Five repeat measurements were taken at each location. Point dose measurements were performed at the center, around the periphery and on the surface of each phantom using a thimble ionization chamber. Panoramic radiographs were performed using a Planmeca ProMax 2D and the panoramic mode on a Carestream 9300 CBCT and an i-CAT NG using the protocols used clinically. A SEDENTEXCT dose index adult phantom and custom-built adolescent and pediatric PMMA dosimetry phantoms were used. The aim of this study is to measure the radiographic dose in adult, adolescent, and child head-sized PMMA phantoms for three panoramic-imaging devices: the panoramic mode on two CBCT machines (Carestream 9300 and i-CAT NG) and the Planmeca ProMax 2D.
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