Browsing by Author "Johnson, K. Brandon"

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    Pediatric Phantom Dosimetry Evaluation of a New Rectangular Collimator
    (American Academy of Pediatric Dentistry, 2023) Martinez, Amanda; Yepes, Juan F.; Jones, James E.; Wong, Phillip; Johnson, K. Brandon; Canady, Sarah; Tang, Qing; Pediatric Dentistry, School of Dentistry
    Purpose: To compare the effective dose (E) of the Tru-Image® rectangular collimator and the universal round collimator of a Planmeca® wall-mounted radiograph unit for two bitewing radiographs (right and left) on a pediatric phantom. Methods: Absorbed doses utilizing the Tru-Image ®rectangular collimator and universal round collimator were acquired using an anthropomorphic 10-year-old child phantom. Each set of 24 dosimeters was exposed to two bitewing exposures with the manufacturer's child settings. Fifty clinical exposures were completed for each set and three sets were exposed for each collimator. The average E per exposure was calculated. Results: The overall E for the Tru-Image ®rectangular collimator and the universal round collimator were 6.3 microsieverts (μSv) and 25.3 μSv, respectively. This difference was statistically significant (P <0.001). The highest equivalent dose for both collimators was delivered to the oral mucosa. When compared to the universal round collimator, the Tru-Image ® rectangular collimator had significant dose reduction at all locations (P <0.05). When normalized and adjusted to the same source-to-end distance, there was an overall 65 percent dose reduction with the rectangular collimator. Conclusion: The average effective dose was significantly reduced with the use of the Tru-Image ®rectangular collimator. Clinical use of this rectangular collimator should be considered in the pediatric population.
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    Pediatric Phantom Dosimetry Evaluation of the Extraoral Bitewing
    (American Academy of Pediatric Dentistry, 2020-01) Wiley, Dillon; Yepes, Juan F.; Sanders, Brian J.; Jones, James E.; Johnson, K. Brandon; Tang, Qing; Pediatric Dentistry, School of Dentistry
    Purpose: This study’s purpose was to evaluate the effective dose (E) and equivalent dose (HT) of exposing a pediatric phantom to the extraoral bitewing programs of the Planmeca ProMax 2D S3 (ProMax) and Instrumentarium Orthopantomograph OP30 (OP30) and compare these results with dosimetry associated with the intraoral bitewing and panoramic radiograph. Methods: Dosimetry was acquired by placing 24 dosimeters in tissues of interest in a 10-year-old phantom. Manufacturer child settings were used for all scans. Repeat exposures of 20 scans were utilized. The average values of E and HT were calculated. Results: The E for the ProMax and OP30 units, respectively, were 16.84 μSv and 5.82 μSv. The highest E for both units was delivered to the thyroid, remainder tissues, and salivary glands. The highest HT for both units was delivered to the oral mucosa, salivary glands, extrathoracic airway, and thyroid. The mean differences between units were statistically significant (P<0.05). Conclusions: The average effective dose of the ProMax was higher than for the OP30. The effective dose of the pediatric extraoral bitewing is three to 11 times higher than that of the intraoral bitewing and comparable to the traditional panoramic radiograph of a pediatric phantom. Pediatric extraoral bitewing radiation protection guidelines are recommended.