A tissue-equivalent phantom series for mammography dosimetry

A breast tissue-equivalent series (BRTES) of phantoms is manufactured to mimic both the attenuation and the density of the range of glandular and adipose tissue compositions encountered in mammography. The BRTES simulates breast tissues across the range of 20% to 70% glandularity and can be assembled in a variety of thicknesses to represent a compressed breast thickness corresponding to glandularity to simulate various patient demographics. The fabrication techniques are presented, and the physical properties of the completed series of phantoms are described. The BRTES phantoms provide a dosimetry comparison with commonly used phantoms, including the American College of Radiology accreditation phantom and BR12, a 50% glandularity tissue-equivalent material. The comparison shows that the average glandular dose is a strong function of compressed breast thickness and tissue composition. Patient doses measured using photo-timed exposures with the BRTES phantoms can be up to a factor of 3 greater than or less than the doses predicted using conventional phantoms.