Dosimetric characterization of a dedicated breast computed tomography clinical prototype

Area of Science:

• Medical Imaging Physics
• Radiological Dosimetry
• Breast Imaging Technology

Background:

• Dedicated breast computed tomography (BCT) offers potential advancements in breast imaging.
• Accurate assessment of radiation dose is crucial for clinical adoption and patient safety.

Purpose of the Study:

• To quantify glandular dose magnitudes and characteristics of a dedicated breast computed tomography (BCT) clinical prototype.
• To compare BCT radiation doses with those from conventional mammography.

Main Methods:

• Empirical measurements and Monte Carlo simulations (GEANT4 toolkit) were used to characterize the BCT system's x-ray spectrum and output.
• Simulations were validated against experimental data and previous studies.
• Mean glandular dose was calculated for various breast sizes and compositions, and compared to mammography dose distributions.

Main Results:

• The BCT prototype's normalized mean glandular dose ranged from 0.278 to 0.582 mGy/mGy air kerma.
• Mean glandular dose for BCT acquisitions varied from 5.6 to 17.5 mGy, with a mean breast dose of 17.06 mGy.
• Mammography showed dose variations from 15% to 400% within the breast, while BCT dose varied by +/- 50%.

Conclusions:

• BCT mean glandular dose is equivalent to 3-5 two-view mammographic exams for a mean-sized breast.
• The glandular dose ratio between BCT and mammography ranged from 1.4 to 7.2 across studied breast types.
• BCT provides a more uniform dose distribution compared to mammography, where localized areas receive significantly higher doses.