The feasibility of utilizing the mid-energy in-line phase-contrast imaging system in the breast x-ray imaging

Mammographic studies have always been a challenge in women with large or dense breasts. A contrast-detail (CD) phantom and an American College of Radiology (ACR) accredited phantom are used in this study to compare the detectability of the mid-energy phase-contrast x-ray imaging system and conventional x-ray imaging mode among women with hyper-glandular breast tissue. Insert wax from ACR phantom and the contrast-detail test pattern are both inserted between two 70/30 glandular-adipose tissue equivalent plates, to simulate a 5 cm thick compressed dense breast. Both phantoms are imaged by the two modalities: (a): the x-ray bench-top imaging system in contact mode, similar to conventional mammography, operated at 35kV with 0.5 mm aluminum filter, and (b): the mid-energy in-line phase-sensitive prototype, which is operated at 59kV, 1.3 mm aluminum filter and the magnification factor of 2.5. Both imaging systems applied an average glandular radiation dose of 1.6 mGy. The results show that the image of ACR phantom which is acquired by mid-energy phase-contrast imaging system reveals more embedded objects within the phantom compare to conventional imaging system under the similar average glandular dose. The contrast-detail curves for CD phantom, obtained from two imaging prototypes, confirm the superior detectability of phase contrast imaging system. Therefore, this preliminary experiment demonstrates that mid-energy phase-contrast x-ray imaging system exceeds the performance of conventional mammography in hyper-glandular breast tissue at the equal level of radiation dose to the patients.