Design of a digital beam attenuation system for computed tomography: part I. System design and simulation framework

Area of Science:

• Medical Imaging
• Radiological Physics

Background:

• Current CT imaging methods often deliver a uniform radiation dose, which may not be optimal for all patient anatomies.
• Personalized medicine approaches aim to tailor treatments and diagnostics to individual patient needs, including radiation dose optimization.

Purpose of the Study:

• To introduce a novel device, the digital beam attenuator (DBA), for patient-specific imaging dose modulation in conventional and cone-beam CT.
• To present a simulation framework for studying the DBA's performance under various configurations.
• To conduct a material selection study for the DBA filters.

Main Methods:

• The DBA utilizes an overlapping wedge design to modulate X-ray beam attenuation across the fan angle.
• A simulation environment was developed to model different system geometries, source spectra, and phantom types.
• Various elements were evaluated as potential filter materials, calculating dynamic range and tube loading.

Main Results:

• The DBA design and a simulation framework for DBA-implemented fluence field modulated CT (DBA-FFMCT) were successfully developed.
• Simulations allowed for comparisons between DBA-FFMCT, bowtie filter CT, and unmodulated CT acquisitions.
• Filter material analysis indicated optimal atomic numbers between 21-34; iron was selected for experimental validation, showing negligible increases in tube power demands.

Conclusions:

• The DBA concept, simulation framework, and filter selection study provide a foundation for advanced CT dose delivery.
• The DBA facilitates patient-specific CT dose modulation, enabling unique dose delivery based on view and fan angle.
• This technology represents a significant advancement towards personalized radiation dosimetry in CT imaging.