Radiation dose reduction in newborns without anti-scatter grids in fluoroscopy: A whole-body phantom study

To determine whether removing the anti-scatter grid (ASG) in fluoroscopy can reduce entrance surface dose (ESD) at anatomical locations corresponding to eyes, thyroid, lungs, heart, abdomen, and genitals inside and outside the fluoroscopic shutter, while maintaining the visibility of peripherally inserted central catheters (PI catheters), nasogastric tubes, and diluted contrast agents in the digestive tract.

Dosimetric, visual, contrast-to-noise ratio (CNR), and dose efficiency (CNR²/dose) assessments were performed using a newborn whole-body phantom under radiography and fluoroscopy. ESD was measured at the specified locations. Two observers independently assessed the PI catheters, nasogastric tubes, and a simulated contrast-enhanced rectum (1/2 to 1/10 dilutions). The Wilcoxon signed-rank test compared median values between with and without ASG. Inter- and intra-observer agreements were calculated using weighted kappa statistics.

ASG removal reduced the median radiographic ESD (p = 0.03; 25.9 %-65.4 % reduction), and median fluoroscopic ESD (p = 0.03; 22.7 %-41.0 % reduction), except for the two furthest locations (p = 0.09-0.22). Fluoroscopic CNR increased (up to + 10.5 %, p = 0.03), while radiographic CNR decreased. ASG removal increased dose efficiency across contrast dilutions in both fluoroscopy (+51.8 % to + 87.2 %; p = 0.03) and radiography (+37.8 % to + 48.7 %; p = 0.03). Visual scores were similar with and without ASG (p = 0.25 to > 0.99). Inter- and intra-observer agreements were almost perfect (range: 0.81 to > 0.99).

ASG removal significantly reduces ESD and improves dose efficiency in a newborn phantom setting, while maintaining acceptable visibility of the tested targets.