OBJECTIVES: The aim of this study was to determine the effect of shielding and scanning parameters on radiation dose reduction to the organs in the head and neck region in cone beam computed tomography (CBCT). STUDY DESIGN: An anthropomorphic phantom and optically stimulated luminescent dosimeters were used to calculate the changes in effective or equivalent doses to 9 anatomic structures through the addition of a thyroid collar, radiation safety glasses, and a radiation safety cap and by using different scanning protocols on a CS 9300 CBCT unit. RESULTS: The thyroid collar alone yielded dose reductions of 46% to the thyroid gland and at least 38% to the esophagus, but no more than 12% to the salivary glands. The radiation safety cap significantly reduced doses to the brain and the pituitary gland. Full shielding resulted in dose reductions of at least 50% to the thyroid gland, at least 47% to the esophagus, and approximately 35% to the brain and the pituitary gland. Significant dose reductions were recorded for all tissues with the "low dose" setting compared with the standard setting. CONCLUSIONS: Increased protection of the organs in the head and neck regions can be achieved by using various forms of shielding in CBCT imaging, with selection of the most appropriate scanning parameters based on the purpose of the examination.
OBJECTIVES: The aim of this study was to determine the effect of shielding and scanning parameters on radiation dose reduction to the organs in the head and neck region in cone beam computed tomography (CBCT). STUDY DESIGN: An anthropomorphic phantom and optically stimulated luminescent dosimeters were used to calculate the changes in effective or equivalent doses to 9 anatomic structures through the addition of a thyroid collar, radiation safety glasses, and a radiation safety cap and by using different scanning protocols on a CS 9300 CBCT unit. RESULTS: The thyroid collar alone yielded dose reductions of 46% to the thyroid gland and at least 38% to the esophagus, but no more than 12% to the salivary glands. The radiation safety cap significantly reduced doses to the brain and the pituitary gland. Full shielding resulted in dose reductions of at least 50% to the thyroid gland, at least 47% to the esophagus, and approximately 35% to the brain and the pituitary gland. Significant dose reductions were recorded for all tissues with the "low dose" setting compared with the standard setting. CONCLUSIONS: Increased protection of the organs in the head and neck regions can be achieved by using various forms of shielding in CBCT imaging, with selection of the most appropriate scanning parameters based on the purpose of the examination.