Tungsten-bismuth shielding sheets for radiation safety in fluoroscopy-guided bronchoscopy: a phantom study

Radiation safety is a critical concern in fluoroscopy-guided bronchoscopy. While standard personal protective equipment (PPE) such as lead aprons, thyroid collars, and eyewear protects vulnerable regions, other areas remain exposed. Supplemental shielding (e.g., glass screens, table skirts) can improve safety, but ceiling-mounted lead-acrylic barriers, though effective, are limited by cost and space. This study evaluated tungsten-bismuth (W-Bi) shielding sheets as a low-cost, deployable alternative.

Using a C-arm fluoroscope (65 kVp, 4.2 mA) on an anthropomorphic phantom, we compared the attenuation performance, weight, and cost of PPE and structural shielding devices. Scatter radiation was measured at four vertical heights (50-170 cm) to simulate body-level exposures, with additional hand-level assessments for the bronchoscopist and assistant. Over-couch protection was tested across five conditions: no shielding, lead-acrylic barrier (0.50 mmPb), and single to triple layers of W-Bi sheets (0.15 mmPb each).

Lead-acrylic and ≥ double-layer W-Bi achieved >96% dose reduction across most body regions, excluding the thigh. Triple-layer W-Bi sheets provided up to 98.8% attenuation at the upper thorax and >99% reduction at hand level, surpassing lead-acrylic in some measurements. The assistant's hand received the highest unshielded dose (2,439.47±11.19 µGy/h), over threefold greater than the bronchoscopist's. Combined PPE and structural shielding yielded markedly enhanced protection, particularly in regions not covered by PPE.

Triple-layer W-Bi shielding offers radiation protection comparable to or exceeding lead-acrylic barriers. Its affordability and ease of deployment support its use as a practical strategy for improving radiation safety in bronchoscopy, especially in resource-limited settings.