Room: Exhibit Hall | Forum 8
Purpose: Collimators are widely used across modalities to lower radiation exposure to patients as well as improve image quality by reducing scatter. For intraoral dental x-ray procedures, several rectangular and circular collimators are commercially available; however, they are often specific to the model of x-ray unit and film/detector being used. The goal of this study was to use additive manufacturing (3D printing) to develop and assess the efficacy of customizable collimators and alignment devices for use with intraoral dental x-ray units.
Methods: 3D modeling software was used to design a collimator holder with alignment capabilities that snaps onto the end of intraoral dental x-ray cones with a diameter of approximately 75 mm. The holder was printed on a LulzBot Mini with acrylonitrile butadiene styrene (ABS) plastic and features channels that allow the user to attach collimator inserts. Collimator inserts were printed using a commercially-available filament comprised of a bismuth/ABS mixture with a stated density of 2.7 g/cmÂ³ and a lead equivalence of 1.9 mm at 75 kV when printed at a thickness of 1.0 cm. A collimator thickness of 1.5 mm was chosen to optimize weight and attenuation, and a cross-shaped active area (hole) was chosen to allow for both horizontal and vertical bitewing configurations. The collimators were then evaluated for uniformity, attenuating ability, and image quality using a Gendex GX-770 intraoral x-ray unit.
Results: Bismuth/ABS cross-collimator inserts were able to uniformly attenuate over 95% of the beam, reducing dose-area-product by between 64.3% and 80.2% for the largest and smallest available film sizes respectively. A measurable improvement in contrast and overall decrease in signal were also observed.
Conclusion: Customizable collimators printed with bismuth/ABS can provide an improvement in image quality and lower overall patient dose during intraoral dental radiography.