Construction of Polyvinyl Alcohol (PVAL)-Based Breast Phantoms with Simulated Calcifications and Evaluation of the Effect of Breast Thickness on Radiation Dose in Full Field Digital Mammography

Abstract

The aim of the present study is to fabricate tissue equivalent breast phantoms with embedded calcification, to investigate their mean glandular dose (MGD) and entrance surface dose (ESD) at various thicknesses using Full Field Digital Mammography (FFDM). Four breast phantoms with embedded calcifications were fabricated using different 10% polyvinyl alcohol (PVAL)-based composites. The first three phantoms were composed of 10% PVAL + ethanol, 10% PVAL, and 10% PVAL + graphite powder, designed to simulate BI-RADS breast density categories 2, 3, and 4, respectively. The fourth phantom was a heterogeneous model constructed by combining the three composite materials in varying proportions. A total of 32 mammographic scans were carried out using AEC (automatic exposure control) mode at different compression force. All exposure parameters were recorded including the applied compression force, MGD and ESD. The study revealed that the compressed phantom thickness (CPT) of all the phantoms investigated ranged from 2.7 to 5.2 cm, MGD ranged from 1.58 – 3.29 mGy (mean = 2.36 ± 0.07) and ESD ranged from 3.7 – 12.33 mGy (mean = 7.10 ± 0.36). The MGD and ESD showed a positive correlation with CPT with r (30) = 0.72, P < 0.0000038 and r (30) = 0.91, P < 0.000001 respectively. The results of the present study are similar to published values, the MGD and ESD are also within the acceptable dose limit recommended by ACR protocol.