Optimising Radiation Exposure in Synchrotron Phase Contrast CT for Breast Imaging: A Patient-Specific Study

<p dir="ltr">Breast cancer remains the second leading cause of cancer-related deaths among women, and mammography contributes to a reduction of 30% in mortality rates. Recent advances in synchrotron-based phase contrast CT (PBCT) have shown significant improvements in image quality, and clinical trials at the Australian Synchrotron are set to begin in early 2025. This thesis evaluates the potential of synchrotron-based PBCT in the context of patient-specific dosimetry, comparing it with conventional imaging modalities. The study integrates both experimental and simulation-based approaches to assess how breast size, glandularity, and composition influence the radiation dose delivered during imaging.</p><p dir="ltr">A custom breast phantom was developed that replicates the average breast size of the patient for dosimetric analysis. This allowed for a detailed examination of radiation exposure during both planar and 3D breast imaging procedures. The study also focused on determining the dose delivered to the breast using various monoenergetic X-ray energies commonly employed in PBCT. Radiation transport simulations, performed with the GEANT4 Monte Carlo toolkit, were used to model the mean glandular dose (MGD) for different breast anatomies. Experimental dosimetric measurements were conducted using ion chambers and the MOSkin™ dosimeter to provide a reliable basis for comparison.</p>