Investigation of mean glandular dose versus compressed breast thickness relationship for mammography

Abstract

The relationship between the mean glandular dose (MGD) and the compressed breast thickness (CBT) is commonly used for the presentation of mammographic dose survey results and could also be useful for the assessment of individual breast doses retrospectively in case of lack of necessary dosimetric instrumentation. The high data scattering from the best fit reduces the reliability of this technique. The aim of this study was to investigate the accuracy of this relationship using the data collected from a patient survey and phantom experiment. Patients were divided into three different groups according to their breast glandularities, which were predicted from the inspection of previous mammograms. X-ray beam qualities that will be used in patient examinations were determined according to breast thickness and predicted glandularities. The MGD versus CBT relationship for all the examined patients resulted in a poor correlation (R2 = 0.28). This relationship was separately obtained for each glandularity group and also for sub-groups of specific beam qualities. The best correlation (R(2) = 0.73) was obtained for the fatty breast group and Mo/Mo combination. A low correlation (R2 = 0.34) was observed in the mid-glandularity group due to inclusion of a wide range of glandularities in this group. In the case of the dense breast group, although the glandularity range was narrow, there were e still high data scattering (R2 = 0.25). This was probably due to the use of Mo/Rh and Mo/Mo combinations. This is validated by obtaining the MGD-CBT relationship specific to Mo/Mo combination (R2 = 0.61).

An Analysis of Application of Mean Glandular Dose and Factors on Which It Depends to Patients of Various Age Groups

“…A similar positive correlation between MGD and CBT was noted on a much smaller sample of Bosnian patients (Kunosic et al, 2010). An influence of CBT on patient doses during mammographic diagnostic examinations was confirmed by other authors in their researches (Wall & Roberts, 1992;Gentry & De Werd, 1996;Dance et al, 2000;Kruger et al, 2001;Oh et al, 2003;Bouzarjomehri et al, 2006;Sookpeng & Ketted, 2006;Bor et al, 2008;Robinson & Kotre, 2008) and some authors used this dependency to predict patient doses through training of artificial neural networks (Ceke et al, 2009). The number of previously conducted mammographic examinations for the complete group was 1,80 (SD: 0,66) while more than 75 % of patients underwent at least 2 mammographic examinations in their lives.…”

Risk Assessment From Ionizing Radiation in Mammography

“…Over 70% of all mammographic diagnostic examinations was done with doses less than 3.5 mGy. According to a correlation analysis there was a significant significance between MGD and CBT (r = 0.709, p < 0.01) [19,30]. MGD doses applied during the routine mammography ranged from 0.449 mGy for the thinnest compressed breast thickness to over 1 mGy for greater compressed breast thickness in the sample.…”

Relationship of the Mean Glandular Dose with Compressed Breast Thickness in Digital Mammography

“…Increase in MGD with CBT as in our study, has been documented in multiple other studies. 7,10,11 MGD is the exposure to a particular region of the body and depends upon kVp of the xray tube; target/filter combination, breast composition and breast thickness. In breast, the fibroglandular tissue is most radiosensitive and this itself may predispose to breast cancer.…”