Evaluation of a Mobile C-Arm Fluoroscopic Device with Cone Beam Tomosynthesis Capabilities for Pediatric Orthopedic Spinal Procedures
Presentations
TU-D1000-IePD-F9-2 (Tuesday, 7/12/2022) 10:00 AM - 10:30 AM [Eastern Time (GMT-4)]
Exhibit Hall | Forum 9
Purpose: To evaluate the patient dose and safety, image quality, staff safety, as well as to summarize the clinical implementation of a cone beam tomosynthesis device, nView.
Methods: The nView is a c-arm fluoroscopy imaging system capable of tomosynthesis imaging via a continuously rotating x-ray tube and fixed detector. The unique geometry poses challenges for routine performance evaluation in terms of both radiation output and image quality. Patient safety was evaluated in terms of the maximum entrance skin exposure using a 0.6 cc thimble ion chamber and the kerma area product (KAP) using a 180 cc pancake ion chamber. Staff safety was evaluated by measuring the scattered radiation from the system’s highest output settings (4 s acquisition) at the +/- 30-degree tilts. An ACR CT phantom was used for initial evaluation of high and low contrast resolution for the four different dose levels. A single view acquisition was also compared to a 2-view acquisition. Clinical implementation was evaluated in terms of the frequency of use and the number of tomosynthesis acquisitions per procedure.
Results: A maximum dose rate of 51 mGy/min was measured at the "cone of tomosynthesis" (23 cm from detector face) with a nonlinear, nonlogarithmic decrease both towards the detector face and the center of tube rotation. The KAP at the detector face was measured 2.3 Gy·cm². Cumulative staff exposures ranged from 0.44 to 0.73 mR; with a peak exposure rate of 600 mR/hr. Image quality was evaluated qualitatively given the high slice sensitivity profile and the heterogeneity of the phantom. Clinical usage averages 2 procedures/month. Originally, 2 tomosynthesis acquisitions were used per procedure, more recently 5 to 7 acquisitions were performed.
Conclusion: This work offers guidance for routine evaluation of the mobile tomosynthesis c-arm as well as some initial clinical experiences.
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