Author: Awens Alphonse, Nebi Demez, Brian P. Laffey, Shyam Pokharel, Suresh Rana, Nishan Shrestha 👨🔬
Affiliation: Lynn Cancer Institute, Boca Raton Regional Hospital, Baptist Health South Florida 🌍
Purpose: The Imaging Ring is a mobile digital X-ray system capable of producing 2D planar X-rays, fluoroscopy, and 3D Cone-Beam Computed Tomography (CBCT) images. This study aimed to evaluate the long-term stability of the Imaging Ring over one year using monthly quality assurance (QA) data.
Methods: Monthly QA assessments included evaluations of system mechanical alignment (arm positions, source-detector alignment, and laser accuracy), pixels evaluation, image uniformity, and transmission deviation, CBCT imaging performance, and geometric stability (Flexmap calibration).
Results: The system demonstrated consistent performance across all parameters. Mechanical alignment adhered to manufacturer recommendations throughout the year. Spatial resolution averaged 20.83 lp/cm (baseline: 21 lp/cm), with minimal variation (SD = 0.39). Low contrast resolution remained stable at 1 mm, with no observed variation. HU accuracy showed an average difference of 2.74 HU (relative to 0 HU), ranging from -5.16 HU to 16.79 HU, well within the tolerance of ±20 HU. Transaxial noise averaged 17.63 HU, with a mean difference of -2.37 HU (relative to the 20 HU requirement), ranging from 10.04 HU to 20 HU, indicating performance close to the threshold. Flexmap calibration exhibited excellent geometric stability, with Euclidean distances averaging 0.022 cm (range: 0.021–0.025 cm), well within the ≤0.05 cm requirement.
Conclusion: One year of monthly QA data confirms the Imaging Ring's stability across mechanical alignment, CBCT imaging performance, and geometric accuracy. These findings validate the system’s reliability for clinical applications based on established QA standards.