Determination and analysis of absorbed doses resulting from various intraoral radiographic techniques

Abstract

A “Mix D” phantom was designed and constructed so that placement and removal of of thermoluminescent dosimeters at various anatomic locations throughout the head and neck were possible. The locations included the sella turcica, the orbits, the thyroid area, the parotid area, the submandibular gland area, the maxillary sinus, the base of the tongue, and a site within the body of the mandible. Measurements of the amount of radiation imparted to each area as well as entrance and exit exposures were made for fourty-five simulated complete-mouth intraoral radiographic surveys. The methods and procedures for accomplishing each twenty-one-exposure survey were standardized. Five radiographic techniques and three kilovoltages were utilized. The techniques included (1) a 12-inch open-end, lead-lined plastic cone; (2) a 12-inch open-end nonlined plastic cone; (3) a 4 1 2 - inch open-end lead-lined plastic cone; (4) a 4 1 2 - inch open-end nonlined plastic cone; and (5) a 4 1 2 - inch pointed plastic cone. The kilovoltages employed were 60, 70, and 90. The results were subjected to statistical analysis. Significant differences were found among the 5 techniques for measurements at the exit port, within the body of the mandible, in the submandibular areas, at the base of the tongue, at the sella turcica, and in the orbits. Significant differences among the three kilovoltages were noted for measurements in the submandibular areas and at the sella turcica.