Does "spreading" skin dose by rotating the C-arm during an intervention work?

Area of Science:

• Medical Physics
• Radiology
• Radiation Safety

Background:

• Patient radiation dose is a critical concern in interventional radiology (IR).
• Optimizing C-arm positioning is essential for minimizing radiation exposure.
• Peak skin dose (PSD) is a key metric for assessing potential skin injury.

Purpose of the Study:

• To evaluate the efficacy of C-arm rotation in reducing peak skin dose (PSD) during interventional radiology (IR) procedures.
• To identify specific conditions and techniques where C-arm rotation is beneficial for dose reduction.

Main Methods:

• Monte Carlo simulations and ray tracing were employed for detailed analysis.
• Simulations modeled various patient sizes, C-arm configurations, and procedure types.
• Measured automatic dose-rate control curves from modern fluoroscopic systems were incorporated.

Main Results:

• Rotating the C-arm from a standard posteroanterior projection typically increases PSD, sometimes by over 500%.
• Prophylactic C-arm rotation between opposed oblique angles significantly reduced PSD across all patient sizes.
• The combination of prophylactic rotation and tight x-ray beam collimation demonstrated substantial dose reduction benefits.

Conclusions:

• Routine C-arm rotation during IR procedures to "spread" dose is generally contraindicated and can increase PSD.
• Prophylactic C-arm rotation, when combined with tight beam collimation, is an effective strategy for reducing PSD.
• Tight collimation is crucial for maximizing the dose-reducing benefits of C-arm rotation.