Comparison of average glandular dose in mammography for patients with breast implants when using automatic or manual exposure technique.

Background. Mammography aims to obtain mammograms of best possible image quality with least possible radiation dose.1 Theoretically, an increase in breast compression gives a reduction in thickness, without changing the density, resulting in improved image quality and reduced radiation dose. 
 Aim. This study aims to investigate the relationship between compression force, phantom thickness, image quality and radiation dose. The existence of a compression point beyond which increased compression gives a change in density rather than thickness is also considered.
 Method. Image quality is assessed with a contrast-detail phantom within Superflab phantom on a computed radiography (CR) mammography unit using automatic exposure control (AEC). Image quality is determined by visual inspection and image quality figure (IQF) scoring. The effect of compression and lesion depth on image quality is determined. Entrance and exit doses are calculated. The relationship between entrance dose, compression and thickness is investigated, as is the existence of a compression point beyond which a change in phantom density occurs. The average glandular dose (AGD) is calculated from the scanning average level (SAL) and logarithmic mean (LgM) according to Koen et al,2 and compared to the allowable limit. 
 Results. The geometry effect was not observed. An improvement in image quality with increased compression was found. Entrance dose did decrease with increased compression. This trend was not observed with exit dose as AEC was used and exit dose was calculated from SAL values. The “change-in-density” point of compression was determined. Both LgM and SAL could be used successfully for AGD calculation.

P048] Comparison of breast radiation dose for digital breast tomosynthesis estimated according compressed breast thickness by using breast phatom

First results of the integration of a dose monitoring system in the National Breast Screening Program

above the age of 40, women are advised to begin breast examinations and screenings for early detection of breast cancer. The average glandular dose (AGD) provides dosimetric information about the quantity of radiation received by the mammary glands during mammographic exposures. There is, therefore, the need to analyse the radiation dose received by patients presenting for mammography examinations. a retrospective cross-sectional design was carried out on the data of 663 participants, conveniently sampled between the months of July 2021 and June 2022. Paired T-test was used to compare imaging parameters for cranio-caudal (CC), medio-lateral (ML), automatic exposure control (AEC), manual exposure control (MEC), and left and right breast. Pearson´s correlation was used to test for relationship between imaging parameters and AGD. the mean AGD per exposure was 1.9 ± 0.7 mGy for CC projections and 2.3 ± 1.2 mGy for ML projections. The mean AGD per examination for the study was 4.1 ± 1.4 mGy. A positive correlation was found between AGD per examination and exposure factors (tube loading and tube voltage), compressed breast thickness, and compression force. Patient age had no statistically significant relationship with the AGD per examination. average glandular dose (AGD) was consistent with other findings in literature studies. It was also observed that MEC yielded lower AGD per exposure values than AEC. There was no significant difference in the mean AGD per exposure for left and right breasts.

Mammography image is expected to have high image resolution quality so that the image is able to show microcalcifications as a sign of a malignant breast tumor with a size ranging from 0.1 mm . Automatic Exposure Control (AEC) is an image acquisition mode in mammography that is designed to strike a balance between patient dose and image quality by accommodating differences in breast size. This study aims to obtain the results of measuring mammographic image quality using Normalized Anisotropic Quality Index (NAQI), assessing the performance of AEC against variations in Compressed Breast Thicknes ( CBT), density and Average Glandular Dose (AGD). This study using 20 mammographic images in AEC mode, Cranio Caudal (CC) projections. The data in the forms of CBT, breast density and AGD were also taken. In this study, the CBT range was 45-81 mm, the density range was 14-18%, the AGD range was 1.25-2.26 mGy with the patient's age ranged from 39-67 years and the compression pressure ranged from 20.0169- 157.9111 N. Then the images are grouped based on CBT, density and AGD, to get the NAQI values. The results of NAQI values are e ues sults o (0.111-2) . The highest NAQI value obtained on CBT images of 61 mm, density 14.64% and AGD 1.41 mGy .

Average glandular dose and phantom image quality in mammography

For the evaluation of the average glandular dose (AGD) in digital mammography (DM) and digital breast tomosynthesis (DBT) phantoms simulating standard model breasts are used. These phantoms consist of slabs of polymethyl methacrylate (PMMA) or a combination of PMMA and polyethylene (PE). In the last decades the automatic exposure control (AEC) increased in complexity and became more sensitive to (local) differences in breast composition. The question is how well the AGD estimated using these simple dosimetry phantoms agrees with the average patient AGD. In this study the AGDs for both dosimetry phantoms and for patients have been evaluated for 5 different x-ray systems in DM and DBT modes. It was found that the ratios between patient and phantom AGD did not differ considerably using both dosimetry phantoms. These ratios averaged over all breast thicknesses were 1.14 and 1.15 for the PMMA and PMMA-PE dosimetry phantoms respectively in DM mode and 1.00 and 1.02 in the DBT mode. These ratios were deemed to be sufficiently close to unity to be suitable for dosimetry evaluation in quality control procedures. However care should be taken when comparing systems for DM and DBT since depending on the AEC operation, ratios for particular breast thicknesses may differ substantially (0.83–1.96). Although the predictions of both phantoms are similar we advise the use of PMMA + PE slabs for both DM and DBT to harmonize dosimetry protocols and avoid any potential issues with the use of spacers with the PMMA phantoms.

Technologic advances have reduced medical radiation exposure while maintaining image quality. The purpose of this study was to determine the effects of the presence of total hip arthroplasty implants, compared with native hips, on radiation exposure of the most radiosensitive organs when manual and automatic exposure control settings are used. Detection probes were placed at six locations (stomach, sigmoid colon, right pelvic wall, left pelvic wall, pubic symphysis, and anterior pubic skin) in a cadaver. Radiographs were obtained with the use of manual and automatic exposure control protocols, with exposures recorded. A total hip arthroplasty implant was placed in the cadaver, probe positioning was confirmed, and the radiographs were repeated, with exposure values recorded. The control probe placed at the stomach had values ranging from 0.00 mSv to 0.01 mSv in protocols with and without implants. With the manual protocol, exposures in the pelvis ranged from 0.36 mSv to 2.74 mSv in the native hip and from 0.33 mSv to 2.24 mSv after implant placement. The increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 0.818; left pelvic wall, 1.381; sigmoid colon, 1.550; right pelvic wall, 0.917; and anterior pubic skin, 1.015. With automatic exposure control, exposures in the pelvis ranged from 0.07 mSv to 0.89 mSv in the native hip and from 0.21 mSv to 1.15 mSv after implant placement. With automatic exposure control, the increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 1.292; left pelvic wall, 1.476; sigmoid colon, 2.182; right pelvic wall, 3.000; and anterior pubic skin, 1.378. The amount of radiation to which patients are exposed as a result of medical procedures or imaging, and whether exposure is associated with an increased risk of malignant transformation, are the subject of ongoing debate. We found that after insertion of a total hip arthroplasty implant, exposure values increased threefold at some anatomic locations and surpassed 1 mSv, the generally accepted threshold for concern. Radiation exposure to radiosensitive organs increased up to threefold after total hip implantation with automatic exposure control and up to approximately 1.5 times with the manual protocol. Doses were greater with manual exposures than with automatic exposure control (except at the control probe on the stomach, where exposure was negligible, as expected). However, after implant placement, doses increased more with automatic exposure control than with manual exposure. This difference can be attributed to increased scatter and the difficulty of dose modification because of the density of the implant. Current radiographic protocols should be reassessed to determine if the benefits of frequent radiographs outweigh the newly demonstrated risks.

Purpose: In Japan, mammography units are shifting from screen‐film (S/F) mammography to digital (DR) mammography. However, no studies have investigated the actual radiation dose received by patients undergoing mammography using DR units. In order to assess the present situation, we conducted a survey of the actual radiation dose at 92 participating mammography facilities in 2010. Methods: The units used were F/S (5%), computed radiography (CR) (47%), and flat panel display (FPD) (48%).The incident air kerma was obtained from the irradiation conditions of each facility, and the average glandular dose (AGD) was calculated. Specifically, the AGD was calculated using a quality control phantom (model 156 phantom) and a polymethyl methacrylate (PMMA) phantom (10, 20, 30, 40, 50 and 60 mm thicknesses) equipped with automatic exposure control (AEC) systems. An ionization chamber dosimeter （Radcal Model 9015） with a parallel plate ionization chamber calibrated based on national standards was used. Aluminum plates (99.997 % purity) were used for half value layer assessment. Results: The AGD was not greater than 3 mGy in all cases and was taken to be the patient dose. Mean dose was 1.8 mGy, and coefficient of variation (CV) was not greater than 0.3. Approximately 75% of facilities used a dose of not greater than 2 mGy. The range of doses was approximately three‐fold. Mean AGD was the lowest for F/S and highest for CR. Conclusions: There are about 10,000 radiologic technologists for mammography in Japan, and radiographic imaging at most facilities is performed by these technologists. As a result, there is little variation among facilities, and a minimum radiation dose is used.

For the establishment of reference doses in mammography it is important to apply a dosimetric model relevant for risk assessment. Differences in dosimetric methods applied in mammography are related to the dosemeters used, e.g. thermoluminescent detectors and ionisation chambers, and the dosimetric quantities determined, i.e. entrance surface air kerma, entrance surface dose or average glandular dose. The exposure parameters influencing absorbed dose due to mammography include the X ray tube assembly, i.e. anode material, filtration and tube voltage; the exposure conditions, e.g. antiscatter grid, automatic exposure control and magnification; and characteristics of the film-screen combination including film processing and film density. The female breasts examined can be represented, on average, by a phantom or by a representative sample of patients. Reference values established in various protocols for entrance surface air kerma, entrance surface dose and average glandular dose are presented and discussed.

This paper presents the optimized image quality and average glandular dose in digital mammography, and provides recommendations concerning anode-filter combinations in digital mammography, which is based on amorphous selenium ( a -Se) detector technology. The full field digital mammography (FFDM) system based on a -Se technology, which is also a platform of tomosynthesis prototype, was used in this study. X-ray tube anode-filter combinations, which we studied, were tungsten (W) - rhodium (Rh) and tungsten (W) - silver (Ag). Anatomically adaptable fully automatic exposure control (AAEC) was used. The average glandular doses (AGD) were calculated using a specific program developed by Planmed, which automates the method described by Dance et al. Image quality was evaluated in two different ways: a subjective image quality evaluation, and contrast and noise analysis. By using W-Rh and W-Ag anode-filter combinations can be achieved a significantly lower average glandular dose compared with molybdenum (Mo) - molybdenum (Mo) or Mo-Rh. The average glandular dose reduction was achieved from 25 % to 60 %. In the future, the evaluation will concentrate to study more filter combinations and the effect of higher kV (>35 kV) values, which seems be useful while optimizing the dose in digital mammography.

Contrast-enhanced mammography (CEM) is a highly accurate, patient-friendly imaging technique. This study aimed to compare the radiation dose of CEM with other mammographic modalities and examine factors influencing radiation exposure to minimize doses.This retrospective study was conducted at a tertiary care teaching institute.We analyzed 184 craniocaudal (CC) and 184 mediolateral oblique (MLO) views from 93 participants who underwent both Combo mode (digital mammography [DM] with digital breast tomosynthesis [DBT]) and CEM. Data on automatic exposure control, average glandular dose (AGD), compressed breast thickness (CBT), compression force (CF), breast density, and the anode/filter used were collected.Scheffe's post hoc analysis compared AGD across different modalities and factors.The mean AGD for CEM (including low-energy [LE] and high-energy [HE] components) was 1.35 times that of DM, 1.3 times that of DBT alone or with synthetic mammography (SM), and 0.66 times that of the Combo mode. AGD in CEM_LE and DBT with SM was comparable to DM across views. Higher AGDs were observed in the MLO view, dense breasts, and when using a tungsten–copper anode/filter. AGD positively correlated with CBT and CF.CEM_LE and DBT with SM, showing similar AGD to DM in this study and comparable diagnostic value in the literature, may reduce the need for additional DM. CC views may be preferred over MLO for delayed imaging of contrast kinetics. With high diagnostic accuracy and acceptable radiation dose, CEM may be preferred over the Combo mode (DM + DBT).

INTRODUCTION: Digital mammography units usually record the entrance surface exposure (ESE) and the average glandular dose (AGD) received by the patient for each exposure. This information is usually available in the DICOM headers and can be used to perform dose surveys. The main objective of this paper was to develop a software tool to automatically analyze digital mammography image headers in order to assess the dose received by each patient. MATERIALS AND METHODS: Images were acquired on a Senographe Essential (GE Healthcare) digital mammography system, using automatic exposure control. Patients with breast implants were excluded. Images were queried and downloaded from the institution's PACS using the DCM4CHE 3.0 open source toolkit. MATLAB code was developed to extract the breast thickness and the AGD from the DICOM headers. This data was exported to a spreadsheet for further analysis. RESULTS: Demographic data, breast thickness and dose per view for 59 patients were analyzed. A AGD of 1.56 mGy and 1.53 mGy was obtained for the craniocaudal (CC) and mediolateral oblique (MLO) views respectively. CONCLUSIONS: the developed tool proved to be useful for the dosimetric survey of digital mammographic techniques, allowing us to implement a dose management program.

A comparative analysis of the mean glandular doses was conducted in 100 female patients who underwent screening mammography in 2011 and 2013. Siemens Mammomat Novation with the application of the W/Rh anode/filter combination was used in 2011, whereas in 2013 anode/filter combination was Mo/Mo or Mo/Rh. The functioning of mammography was checked and the effectiveness of the automatic exposure control (AEC) system was verified by measuring compensation of changes in the phantom thickness and measuring tube voltage. On the base of exposure parameters, an average glandular dose for each of 100 female patients was estimated. The images obtained by using AEC system had the acceptable threshold contrast visibility irrespective of the applied anode/filter combination. Mean glandular doses in the females, examined with the application of the W/Rh anode/filter combination, were on average 23.6% lower than that of the Mo/Mo or Mo/Rh anode/filter combinations. It is recommended to use a combination of the W/Rh anode /filter which exhibited lower mean glandular doses.

The average glandular tissue dose in mammography is generally determined from published tables with knowledge of the breast entrance skin exposure, x-ray tube target material, beam quality (half-value layer [HVL]), breast thickness, and breast composition. Using a carefully designed and experimentally validated Monte Carlo simulation, the authors found that average glandular dose also depends on x-ray tube voltage and, to a lesser extent, on x-ray tube voltage waveform. For currently employed molybdenum target-molybdenum filter source assemblies, a difference in dose of 10% or more is possible in estimating the average glandular dose obtained with different x-ray tube voltages but with the same HVL. Presented are normalized average glandular tissue doses in units of radiation absorbed dose per unit entrance skin exposure for different tube voltages and tube voltage waveforms as well as for different breast thicknesses and compositions and beam filtrations.