Narrow beam breast CT: proof-of-concept

Area of Science:

• Medical Imaging
• Radiological Physics
• Biomedical Engineering

Background:

• Scattered photons in breast CT degrade image quality by affecting the entire frequency response.
• Prior research indicated a Narrow Beam Breast CT (NB-bCT) acquisition design could prevent scatter.
• This study focuses on the practical implementation of such a system.

Purpose of the Study:

• To report the design and implementation of the first Narrow Beam Breast CT (NB-bCT) prototype.
• To perform initial characterization of the NB-bCT system's performance.
• To evaluate the system's ability to minimize scatter acquisition.

Main Methods:

• Developed a prototype system with a dynamic Fluence Modulator (collimator) and photon-counting line detector.
• The narrow beam system swept across the fan angle during acquisition.
• Imaged three breast phantoms (small, average, large) to analyze scatter as a function of size and measured spatial resolution.

Main Results:

• NB-bCT demonstrated minimal scatter acquisition, with scatter-to-primary ratios of 0.05, 0.07, and 0.9 for small, average, and large phantoms, respectively.
• Achieved high spatial resolution: 5.2 lp/mm (10% MTF) and 2.9 lp/mm (50% MTF) at the field of view center.
• Resolution remained high at the periphery: 5.0 lp/mm (10% MTF) and 2.5 lp/mm (50% MTF).

Conclusions:

• The NB-bCT prototype successfully minimizes scatter contamination in acquired projections.
• The system achieves high spatial resolution, crucial for detailed breast imaging.
• This methodology offers a promising approach for CT applications requiring reduced scatter.