Glandularity and mean glandular dose determined for individual women at four regional breast cancer screening units in The Netherlands

Abstract

The nationwide breast cancer screening programme using mammography has been in full operation in The Netherlands since 1997. There is concern that the mean glandular doses due to mammography might be differing between different regions of the country due to differences in glandularity and compressed breast thickness. To investigate regional differences, glandularity, compressed breast thickness and mean glandular dose were determined for individual breasts during screening at mammography units at four locations in The Netherlands. Differences in glandularity were observed, which could be related qualitatively to differences in age of the participants at the different locations. Mean glandular dose depends on compressed breast thickness, glandularity and technical conditions of screening. The lowest average value of the mean glandular dose was found for the unit in Amsterdam. This is most likely due to the use of the Mo/Rh anode/filter combination at this unit, in addition to the Mo/Mo combination. At the other three units, almost exclusively the Mo/Mo anode/filter combination was used. Differences in mean glandular dose averaged per unit could be related mainly to differences in tube-current exposure-time product values. Consequently, it is concluded that differences in mean glandular dose at different units are marginal.

Glandularity Estimation in Japanese Women by Using a Breast Model Made from Mammographic Findings of European Women

“…Additionally, estimation of mean glandularity is essential for calculating the numerical value of AGD for the DRL, because a typical breast exhibits different local values of glandularity and compressed breast thickness (CBT), similar to the variations in typical height and weight among different regions and countries. Although typical glandularities estimated by the conventional method using breast models derived from the data of European women have been reported in several regions and countries, 4,5,[13][14][15] the typical glandularity of Japanese women has yet to be fully characteri ed.…”

“…This study aimed to estimate the breast glandularity of Japanese women using a previously published method 5,[13][14][15] based on the evaluation of patient exposure conditions and a model breast composed of tissue-equivalent materials. Breast glandularities were estimated from the digital mammographic data of 600 Japanese women examined at two different institutions.…”

“…In the present study, we evaluated the right craniocaudal images because the craniocaudal view corresponds to the model breast used in the Monte Carlo simulation 4) and includes less muscle, which simpli es the process of analysis of glandularity based on exposure conditions using AEC. 5,[13][14][15] Data regarding patient age, CBT, tube voltage (kV), target-lter combination, and tube loading were recorded for each subject from the digital imaging and communications in medicine (DICOM) headers. As part of the quality control procedure, 3) uncertainties in the displayed CBT were clari ed by performing CBT measurement every 6 months.…”

“…Glandularity estimation was performed using the methods employed in previous studies as references. 5,[13][14][15] In clinical mammographic examination, AEC serves to maintain the signal produced for the X-ray detector. 16) Different tissue-equivalent materials were evaluated using the two mammography units with different AECs in order to determine the relationships among thickness, beam quality (target/ lter and tube voltage), tube loading, and glandularity.…”

“…Following this, the value of "g" was determined from the tube-loading values of each patient. In previous studies, 5,[13][14][15] equation (2) had been constructed based on the most common target/ lter and tube voltage combination alone. However, in the present study, we constructed equation (2) from each target/ lter and tube voltage combination under all exposure conditions.…”