Radiation dose and shielding considerations for digital dynamic radiography (DDR) compared to mobile C-arms

Area of Science:

• Medical Physics
• Radiological Sciences
• Imaging Technology

Background:

• Digital dynamic radiography (DDR) offers dynamic imaging for various applications but raises radiation exposure concerns due to its pulsed x-ray use.
• Unlike fluoroscopy, DDR lacks a primary beam stop, increasing potential radiation risks with high output capabilities.

Purpose of the Study:

• To quantify the radiation output and scatter of a DDR system.
• To compare DDR radiation characteristics with mobile C-arm fluoroscopy units.
• To assess shielding requirements and occupational exposure risks associated with DDR.

Main Methods:

• Measured primary air kerma, scatter fraction, and normalized scatter for a Konica Minolta mKDR system and three mobile C-arms.
• Utilized a PMMA phantom and ion chamber for scatter measurements at various angles and distances.
• Estimated shielding requirements based on NCRP 147 methodology.

Main Results:

• DDR dose rates were 2-3 times higher than C-arms at medium/high settings; scatter doses were 1.5-3 times higher.
• Scatter fraction increased with lower beam energy and peaked at 165°.
• Shielding requirements for DDR could reach 145 mm concrete due to high primary beam output.

Conclusions:

• DDR systems produce significantly higher radiation output and scatter compared to mobile C-arms.
• Elevated radiation doses necessitate careful safety protocols, scatter management, and shielding planning.
• Evolving DDR technology may require updated regulatory and design guidance for safe clinical integration.