Breast dosimetry in alternative X-ray-based imaging modalities used in current clinical practices

Abstract

In X-ray breast imaging, Digital Mammography (DM) and Digital Breast Tomosynthesis (DBT), are the standard and largely used techniques, both for diagnostic and screening purposes. Other techniques, such as dedicated Breast Computed Tomography (BCT) and Contrast Enhanced Mammography (CEM) have been developed as an alternative or a complementary technique to the established ones. The performance of these imaging techniques is being continuously assessed to improve the image quality and to reduce the radiation dose. These imaging modalities are predominantly used in the diagnostic setting to resolve incomplete or indeterminate findings detected with conventional screening examinations and could potentially be used either as an adjunct or as a primary screening tool in select populations, such as for women with dense breasts. The aim of this review is to describe the radiation dosimetry for these imaging techniques, and to compare the mean glandular dose with standard breast imaging modalities, such as DM and DBT.

Keywords: Breast Computed Tomography; Breast dosimetry; Contrast Enhanced Mammography; Mean Glandular Dose.

Figure 1.

b: Koning breast CT: women lies prone with one breast suspended through a tabletop opening into the imaging field, the X-ray tube and the flat-panel detector rotate 360° around the breast for a single continuous acquisition. d: Advanced breast CT: women lies in a prone position on the tabletop, the examined breast is positioned in an aperture without compression, the gantry moves up and down independently allowing for spiral acquisition (Figure reprinted under permission of European Radiology journal [26]).

Figure 2.

Coronal and middle axial slices of the glandular dose distributions in DM, DBT and BCT for breast phantom. The dose distributions are embedded in the corresponding slices of the digital phantoms. Compressed breast thickness = 66 mm; equivalent diameter at the center of mass of the uncompressed phantom = 109 mm; glandular fraction by weight of the uncompressed phantom = 21%. It was assumed a MGD of 1 mGy (Figure reprinted under permission of Physica Medica journal [64]).

Figure 3.

MGD interval values for each imaging tool, as reported in literature [55] [29] [62]. For DM, DBT and CEM, the MGD values are for one-view acquisition. For CB-BCT and H-BCT, the MGD values are for a single scan. Blue line represents the MGD maximum value, as suggested by EUREF [52], permitted for one-view image acquisition in mammography in the case of an equivalent breast thickness of 5.3 cm.