Results of a 2011 national questionnaire for investigation of mean glandular dose from mammography in Japan

Establishment of regional diagnostic reference levels for digital mammography in Western Province of Sri Lanka

The radiation dose to the breasts should be kept to a minimum as breast tissues are highly sensitive to radiation. In mammography, the mean glandular dose (MGD) is used to specify the patient dose. In this study, data on the MGD during diagnostic mammographic examinations was collected using the database from six digital mammography facilities available in the Western Province in Sri Lanka. Examinations involving breast pathology, breast implants, or compressed breast thicknesses (CBT) outside the range of 20-110 mm were excluded in this study. The mean MGD per breast was 3.50 mGy, with a mean CBT of 57 mm. The mean MGD per facility varies from 1.58 to 2.27 mGy, with overall 75th and 95th percentiles of 2.15 and 2.82 mGy, respectively. The 75th and 95th percentile MGD per image, for the average CBT of 57 ± 12 mm, were 2.00 and 2.65 mGy respectively. The 75th percentile value of the MGD is suggested for the Western Province and it depends on the specific CBT.

AVERAGE GLANDULAR DOSES AND NATIONAL DIAGNOSTIC REFERENCE LEVELS IN MAMMOGRAPHY EXAMINATIONS IN TURKEY

In order to establish national diagnostic reference levels for mammography examinations, entrance skin air kerma, entrance skin dose and average glandular doses (AGDs) were calculated for a total of 25 624 cranio-caudal (CC) and mediolateral oblique (MLO) projections of 6309 patients for 40-49 and 50-64 age groups. The average entrance skin air kerma and entrance skin dose values for both age groups were found to be higher in MLO projections compared with CC projections. The minimum and maximum values of AGDs were determined as 0.4 and 7.9 mGy for both projections. The maximum numbers of AGDs for CC and MLO projections were calculated in the range of 1.1-1.5 and 1.6-2.0 mGy, respectively. The third quartile values of AGDs were calculated for each compressed breast thickness between 20 and 99 mm. The first national diagnostic reference levels of the country were established for each 10-mm compressed breast thickness in mammography examinations.

INSTITUTIONAL BREAST DOSES IN DIGITAL MAMMOGRAPHY

The objective of this study was to survey breast dose in screening mammography, establish institutional doses and compare them with the corresponding dose values. Three hundred women between the ages of 40 and 80 years old participated in the study. All mammographic examinations were performed with a digital mammography system. The women characteristics (age, weight, height, BMI), technical and exposure parameters (anode/filter material, projection, compressed breast thickness (CBT), compression force, tube voltage, tube load), the entrance surface dose (ESD) and the average glandular dose (AGD) were recorded. The mean, median, 75th and 95th percentiles of the AGD and ESD distributions were estimated for all examinations, for right and left breast, as well as for CBT within 55-65 mm, for Cranio-Caudal (CC) and Medio-Lateral Oblique (MLO) projections. A statistical analysis was also performed, to investigate the impact of the recorded parameters on the ESD and AGD. The mean/median values of the ESD and AGD for all examinations, for CC and MLO projections were 4.60/4.29 and 5.42/5.25 mGy and 1.18/1.13 and 1.32/1.30 mGy, respectively. The mean/median values of the ESD and AGD for CC and MLO projections at CBT range 55-65 mm were 5.29/5.08 and 5.56/5.42 mGy and 1.30/1.24 and 1.36/1.32 mGy, respectively. The 75th percentile for CC and MLO projections were estimated 5.79 and 6.17 mGy, as well as 1.41 and 1.48 mGy in terms of ESD and AGD values, respectively. The 95th percentile of the ESD and AGD for CC and MLO projections were also 7.40 and 7.53 mGy and 1.76 and 1.78 mGy, respectively. The tube voltage, tube load, age and CBT had a significant influence on the dose values. The estimated values were found to be comparable, or in most cases lower, than the corresponding 75th and 95th percentile values from previous studies.

Survey of patient exposure from general radiography and mammography in Japan in 2014

With the objective of reducing patient exposure to radiation, we conducted a questionnaire survey regarding radiographic conditions in 2014. Here we report estimates of dose exposure in general radiography and mammography through an investigation and comparison of present patient exposure conditions. Questionnaires were sent to 3000 facilities nationwide in Japan. Surveys asked questions on a total of 16 items related to general radiography, including the chest, abdomen, and breast. Output data from x-ray tubes measured in the Chubu area of Japan were used as the mean in these estimates. The index of patient exposure was adopted as the entrance skin dose (ESD) for general radiography and as the mean glandular dose (MGD) for mammography. The response rate for this survey was 21.9%. Our results showed that doses received through the use of flat-panel detector (FPD) devices were lower than those received through computed radiography devices, except for the ankle joint (e.g. in chest examination, the dose from FPD and CR was 0.24 mGy, 0.31 mGy on the average, respectively). These results suggest that more widespread use of FPD devices could lead to decreases in the ESD and MGD, thereby reducing patient exposure.

Diagnostic reference levels in digital mammography: a systematic review

This study aims to review the literature on existing diagnostic reference levels (DRLs) in digital mammography and methodologies for establishing them. To this end, a systematic search through Medline, Cinahl, Web of Science, Scopus and Google scholar was conducted using search terms extracted from three terms: DRLs, digital mammography and breast screen. The search resulted in 1539 articles of which 22 were included after a screening process. Relevant data from the included studies were summarised and analysed. Differences were found in the methods utilised to establish DRLs including test subjects types, protocols followed, conversion factors employed, breast compressed thicknesses and percentile values adopted. These differences complicate comparison of DRLs among countries; hence, an internationally accepted protocol would be valuable so that international comparisons can be made.