Author: Gary Y. Ge, Azmul Siddique, Jie Zhang 👨🔬
Affiliation: Department of Radiology, University of Kentucky, University of Kentucky 🌍
Purpose: Virtual grid technology addresses scattered radiation without a physical grid, offering the potential to reduce patient radiation dose while maintaining image quality. However, this potential may not be fully realized in clinical practice. This retrospective study compares the deviation index (DI) between virtual and physical grid systems to evaluate the dose-reduction potential of virtual grids and barriers to achieving it in practice.
Methods: Portable radiographic systems—FUJIFILM (virtual grid) and GE AMX-4 (physical grid)—were analyzed using data from 100 randomly selected adult patients imaged on each system between 2021 and 2025. All cases involved abdominal anteroposterior (AP) exams. Parameters included DI, patient demographics (age, gender), anatomical data (weight, height, BMI), and technique factors (tube potential and current). Statistical analyses were conducted using Welch’s T-test for DI and Mann-Whitney U test for BMI.
Results: For the physical grid group, the mean age was 43.83 years, BMI 28.69 kg/m², and tube parameters were 79.83 ± 2.10 kV and 24.89 ± 11.40 mAs. For the virtual grid group, the corresponding values were 44.07 years, 27.74 kg/m², 80.22 ± 2.03 kV, and 21.09 ± 8.50 mAs. T-test indicated a significant difference in DI between the two systems (P = 1.05E-15), while the U-test found no significant difference in BMI (P = 0.63). The average DI was -0.67 and 1.82 for physical and virtual grid, respectively. Overexposure (DI > 0) was observed in 39% of physical grid cases and 85% for virtual grids.
Conclusion: The findings suggest that virtual grid technology has significant potential to reduce patient dose. However, this potential is often unrealized clinically due to similar techniques being applied to both virtual and physical grid systems. The higher incidence of overexposure using virtual grid systems suggests a need for additional training and updated protocols to optimize their use and leverage their dose-reduction capabilities.