Mean Glandular Dose In Mammography Research Articles

Evaluating Factors Affecting Mean Glandular Dose in Mammography: Insights from a Retrospective Study in Dubai

Background/Objective: This study evaluates the mean glandular dose (MGD) in mammography screening for women aged 40–69 in Dubai, based on a retrospective analysis of a dose survey involving 2599 participants. Methods: MGD was calculated using the Dance formula. Results: The average MGD was 0.96 ± 0.39 mGy for mediolateral oblique (MLO) views and 0.81 ± 0.33 mGy for craniocaudal (CC) views. Weak inverse correlations were found between age and organ dose (OD) for both views, while a direct relationship was observed between breast thickness and entrance skin dose (ESD). In adjusted models, ESD was strongly associated with MGD (β = 1.04, 95% CI: 0.97, 1.09), while OD showed a moderate association (β = 0.44, 95% CI: 0.40, 0.49). Significant variations in ESD, OD, and MGD were noted across age groups and breast thicknesses. Conclusions: Lower MGD indicates reduced radiation exposure risk, while higher MGD in MLO views suggests improved imaging quality. Monitoring and optimizing MGD are essential for enhancing patient safety and screening efficacy.

A survey on mean glandular dose in mammography examination and the factors affecting it in Shahid Sadoughi Hospital, Yazd, Iran.

mammography is the gold standard in the early detection of breast cancer. Due to the increase in the rate of women suffering from this malignancy all over the world, this imaging modality has been widely used. Considering the side effects caused by ionizing radiation to measure the carcinogenic risk of mammography X-rays, mean glandular dose (MGD) is the best parameter to evaluate the dose received by patients undergoing mammography. The aims of this study were to measure MGD in mammography in mammographic craniocaudal (CC) and mediolateral oblique (MLO) projections and investigate the relationship of MGD with compressed breast thickness (CBT), body mass index, age of the patient, and device exposure conditions. this cross-sectional analytical study was conducted on women aged 30-70 referring to the mammography unit of Shahid Sadoughi Hospital in Yazd city from May to August 2022. The TLD-GR 200 (thermoluminescence dosimeter) was placed on the breast of the patients for CC and MLO projections, and then the MGD was obtained by multiplying the entrance surface dose and the normalized glandular dose. Analysis of data (such as demographic information of patients, CBT, kVp, and mAs) was done by SPSS 23 software. The normality of the data was checked using Shapiro-Wilk tests. It was found that except for age, other variables did not have a normal distribution; therefore, equivalent parametric and nonparametric tests were used. In this regard, Spearman's correlation was used to assess the correlation between variables. P-value < .05 was considered as level of significance. The mean±standard deviation (SD) age of patients was 47.3±7.1years. The median±IQR (the interquartile range (IQR) is a measure of statistical dispersion, which is the spread of the data. It is defined as the difference between the 75th and 25th percentiles of the data.) (mean±SD) value of MGD per woman was 1.2±0.4mGy (1.3±0.3mGy). The median±IQR MGD in the MLO and CC projections was 1.6±0.6mGy and 0.9±0.4mGy, respectively. Significant relationships (P-value ≤ .001) were observed between MGD with CBT (R=0.62) and age (R=-0.85). The results showed that the mammography unit at Shahid Sadoughi Hospital in Yazd is functioning properly. The calculated median±IQR MGD per woman referring to this unit (1.2±0.4mGy) was clearly below the dose limit recommended by American College of Radiology and International Commission on Radiological Protection (3mGy). Moreover, among the factors affecting MGD, the highest correlation was seen between MGD and age (R=-0.85).

Measurement of conversion factor into mean glandular dose in mammography using OSL dosimeters

Background: Currently, the DRL quantity in mammography are evaluated in terms of mean glandular dose (MGD). Since the MGD cannot be measured directly, it can be obtained by calculation using the equation (D=K*g*c*s). In previous studies, the conversion factor g was calculated by Monte Carlo simulation and is not reported from actual measurements. In this study, we focused on the g-factor, which is a conversion factor to the MGD at 50% glandularity, and attempted to measure it using a nanoDot dosimeter to see if it can be used in mammography. Methods: The nanoDot dosimeters were inserted in a PMMA phantom at depths ranging from 0 cm to 6 cm in 1 cm increments, and measurements were made in three HVLs of 0.3 mmAl, 0.35 mmAl, and 0.4 mmAl HVL. The g-factor was calculated from the nanoDot dosimeter values using a conversion equation. Results and Discussion: The measured g-factors for all the HVLs were in close agreement with those of Dance et al. The values of the previous studies did not include the backscatter factor, which may have underestimated the MGD. The difference was smaller for the 0.4 mm Al. Compared to the other HVLs, the 0.4 mm Al was measured without a compression plate, which may have been influenced by the presence or absence of a compression plate. Conclusion: The nanoDot dosimeters were used to calculate g-factors. The results agreed with those of previous studies within uncertainty. This indicates that nanoDot dosimeters can be used in the mammography field.

X-ray dosimetry in breast cancer screening: 2D and 3D mammography

According to the World Health Organization (WHO), at the end of 2020, 7.8 million women alive were diagnosed with breast cancer in the past 5 years, making it the world’s most prevalent cancer. It is largely recognized and demonstrated that early detection represents the first strategy to follow in the fight against cancer. The effectiveness of mammography screening for early breast cancer detection has been proven in several surveys and studies over the last three decades. The estimation of the Mean Glandular Dose (MGD) is important to understand the radiation-associated risk from breast x-ray imaging exams. It continues to be the subject of numerous studies and debates, since its accuracy is directly related to risk estimation and for optimizing breast cancer screening programs.This manuscript reviews the main dosimetry formalisms used to estimate the MGD in mammography and to understand the continuing efforts to reduce the absorbed dose over the last forty years. The dosimetry protocols were formulated initially for mammography. Digital breast tomosynthesis (DBT) either in conjunction with synthesized digital mammogram (SDM) or with digital mammography (DM), is routinely used in many breast cancer screening programs and consequently the dosimetry protocols were extended for these techniques.

Dosimetric evaluation of the mean glandular dose for mammography in Indian (North East) women.

Dosimetric evaluation of the mean glandular dose for mammography in Indian (North East) women.

Influence of the dosimeter calibration conditions on the mean glandular dose in mammography

Digital technology in mammography and breast tomosynthesis introduced the use of W and Rh target x-ray tubes with Al, Mo, Rh and Ag additional filters. In Brazil, due to the limited capability of metrology laboratories, x-ray dosimetry in mammography is done with different types of dosimeters that may not be calibrated for such specific clinical beams. The objective of this work was to study the influence of different calibration conditions on the determination of the mean glandular dose in dosimetry in mammography beams.

Feasibility of determining Entrance Surface Dose (ESD) and mean glandular dose (MGD) using OSL signal from BeO dosimeters in mammography

Mammography technique is based on imaging of human breast using low-x ray energies. The main purpose of mammography is to detect breast cancer and prevent deaths related to it. The breast is made up mainly of two types of tissue; one is fat and the second is glandular tissues which is the most sensitive tissue to radiation. The Mean Glandular Dose (MGD) is used to monitor the dose received by the breast during breast imaging procedures that use ionizing radiation, and could be associated to the risk of radiation induced cancer. The MGD cannot be measured directly but can be determined using measurements of the Entrance Surface Air Kerma (ESAK) at the breast surface and conversion factors calculated from Monte Carlo simulations. Beryllium oxide (BeO) dosimeters, which exhibit properties such as nearly tissue-equivalence, fast annealing protocol, easy to read in Optically Stimulated Luminescence (OSL) technique and low-cost commercially availability, has been attractive for radiation dosimetry. In this work, Entrance Surface Dose (ESD), Backscatter Factor (BSF) and MGD values were determined with BeO OSL, for polymethyl methacrylate (PMMA) phantoms of different thicknesses. This study is the first attempt in the literature to determine dosimetric quantities used in mammography, such as ESD and MGD using BeO dosimeters. Similar measurements were performed with TLD-100 dosimeters and ionization chamber and all results were compared with each other. The results for MGD are in good agreement both between each other and with EUREF protocol within error limits. BeO shows a linear response as a function of ESAK for values between 1.0 and 12.0 mGy. Good reproducibility, within 5%, of BeO OSL signal was observed when exposed to mammography X-ray beams. It is concluded that BeO dosimeters could be considered as an alternative dosimeter to determine MGD in mammography.

Homogeneous vs. patient specific breast models for Monte Carlo evaluation of mean glandular dose in mammography

PurposeTo compare, via Monte Carlo simulations, homogeneous and non-homogenous breast models adopted for mean glandular dose (MGD) estimates in mammography vs. patient specific digital breast phantoms. MethodsWe developed a GEANT4 Monte Carlo code simulating four homogenous cylindrical breast models featured as follows: (1) semi-cylindrical section enveloped in a 5-mm adipose layer; (2) semi-elliptical section with a 4-mm thick skin; (3) semi-cylindrical section with a 1.45-mm skin layer; (4) semi-cylindrical section in a 1.45-mm skin layer and 2-mm subcutaneous adipose layer. Twenty patient specific digital breast phantoms produced from a dedicated CT scanner were assumed as reference in the comparison. We simulated two spectra produced from two anode/filter combinations. An additional digital breast phantom was produced via BreastSimulator software. ResultsWith reference to the results for patient-specific breast phantoms and for W/Al spectra, models #1 and #3 showed higher MGD values by about 1% (ranges [–33%; +28%] and [−31%; +30%], respectively), while for model #4 it was 2% lower (range [−34%; +26%]) and for model #2 –11% (range [−39%; +14%]), on average. On the other hand, for W/Rh spectra, models #1 and #4 showed lower MGD values by 2% and 1%, while for model #2 and #3 it was 14% and 8% lower, respectively (ranges [−43%; +13%] and [−41%; +21%]). The simulation with the digital breast phantom produced with BreastSimulator showed a MGD overestimation of +33%. ConclusionsThe homogeneous breast models led to maximum MGD underestimation and overestimation of 43% and 28%, respectively, when compared to patient specific breast phantoms derived from clinical CT scans.

Skin models and their impact on mean glandular dose in mammography

PurposeTo quantify the influence of different skin models on mammographic breast dosimetry, based on dosimetric protocols and recent breast skin thickness findings. MethodsBy using an adapted PENELOPE (v. 2014) + PenEasy (v. 2015) Monte Carlo (MC) code, simulations were performed in order to obtain the mean glandular dose (MGD), the normalized MGD by incident air Kerma (DgN), and the glandular depth dose (GDD(z)). The geometry was based on a cranio-caudal mammographic examination. Monoenergetic and polyenergetic beams were implemented, for a breast thickness from 2 cm to 9 cm, with different compositions. Seven skin models were used: a 5 mm adipose layer; a skin layer ranging from 5 mm to 1.45 mm, a 1.45 mm skin thickness with a subcutaneous adipose layer of 2 mm and 3.55 mm. ResultsThe differences, for monoenergetic beams, are higher (up to 200%) for lower energies (8 keV), thicker and low glandular content breasts, decreasing to less than 5% at 40 keV. Without a skin layer, the differences reach a maximum of 1240%. The relative difference in DgN values for 1.45 mm skin and 5 mm adipose layers and polyenergetic beams varies from −14% to 12%. ConclusionsThe implemented MC code is suitable for mammography dosimetry calculations. The skin models have major impacts on MGD values, and the results complement previous literature findings. The current protocols should be updated to include a more realistic skin model, which provides a reliable breast dose estimation.

Air kerma calculation in Monte Carlo simulations for deriving normalized glandular dose coefficients in mammography

The estimation of the mean glandular dose in mammography using Monte Carlo simulations requires the calculation of the incident air kerma evaluated on the breast surface. In such a calculation, caution should be applied in considering explicitly the presence of the top compression paddle, since Compton scattering in this slab may produce a large spread of the incidence angles of x-ray photons on the scoring surface. Then, the calculation of the incident air kerma should contain the ‘effective’ area of the scoring surface, which takes into account the angle of incidence of photons on such a surface. Using Geant4 Monte Carlo simulations with a code previously validated according to the Task Group 195 of the American Association of Physicists in Medicine, we show that for typical x-ray spectra and energy range adopted in mammography, the resulting discrepancy in the calculation of the incident air kerma may lead to an overestimation from a minimum of 10% up to 12% of normalized dose coefficients and, hence, of the corresponding mean glandular dose if this contribution is not considered.

A Monte Carlo study of monoenergetic and polyenergetic normalized glandular dose (DgN) coefficients in mammography

We investigated the influence of model assumptions in GEANT4 Monte Carlo (MC) simulations for the calculation of monoenergetic and polyenergetic normalized glandular dose coefficients (DgN) in mammography, focussing on the effect of the skin thickness and composition, of the role of compression paddles and of the bremsstrahlung processes. We showed that selecting a skin thickness of 4 mm instead of 1.45 mm produced DgN values with deviations from 9% to 32% for x-ray spectra routinely adopted in mammography. Consideration of the bremsstrahlung radiation had a weak influence on monoenergetic DgN. Simulations (in the range 8–40 kVp) which included consideration of bremsstrahlung radiation, a skin thickness of 1.45 mm and a 2 mm thick compression paddles produced polyenergetic DgN coefficients up to 19% higher than corresponding literature data. Adding a 2 mm thick adipose layer between the skin layer and the radiosensitive portion of the breast produces polyenergetic DgN values up to 15% higher than those routinely adopted. These findings provide a quantitative estimate of the influence of model parameters on the calculation of the mean glandular dose in mammography.

Population dose from medical diagnostic exposure in Taiwan

Medical exposure showed a continuous increasing trend. This trend was due to the growth of diagnostic procedures such as computed tomography (CT) and interventional fluoroscopy (IVF). In the present work, results of a recent study on medical exposure in Taiwan are reported. This study analysed data from the National Health Insurance Research Database. Surveyed data on the dose indices, including the entrance surface dose in radiography, dose area product in fluoroscopy, CT dose index in CT and mean glandular dose in mammography, were applied. Using programmes and databases, dose indices were converted to the effective dose. For the year 2008, individual effective doses in Taiwan were estimated as 0.16, 0.37, 0.12 and 0.12 mSv for conventional radiography and fluoroscopy, CT, IVF and nuclear medicine, respectively. The total collective effective dose and the effective dose per individual for medical exposure were 17 788 person-Sv and 0.77 mSv, respectively.

Appendix E: Review of Monte Carlo Calculations for Assessment of Mean Glandular Dose in Mammography

Appendix E: Review of Monte Carlo Calculations for Assessment of Mean Glandular Dose in Mammography

Dosimetric Evaluation of the Mean Glandular Dose for Mammography in Korean Women: A Preliminary Report

The purpose of this study was to evaluate the thickness of the compressed breast in mediolateral oblique (MLO) and craniocaudal (CC) mammograms, to relate these thickness and breast patterns to mean glandular dose (MGD) in Korean women, and to evaluate the suitability of using the American College of Radiology's Recommendations for Korean women from a quality assurance standpoint. The study population consisted of 92 paired MLO and CC mammograms obtained on one mammographic unit. The digital readouts of compressed breast thickness, applied compression force and tube voltage were recorded. Entrance skin exposure was measured by dosimetry. MGD was calculated by multiplying entrance skin exposure by the exposure-to-absorbed dose conversion factor. The range of breast thickness was 1.3-6.2 cm in CC mammograms with a mean breast thickness of 3.6 cm, and 1.6-6.5 cm in MLO mammograms with a mean breast thickness of 3.9 cm. MGDs in CC and MLO mammograms were 1.77 mSv and 1.88 mSv per view, respectively. Breast composition patterns were divided into 4 groups according to ACR BI-RADS; P1 (n=20), P2 (n=16), P3 (n=48) and P4 (n=8). The MGDs for these groups were: 1.82, 1.84, 1.84, and 1.91 mSv, respectively. When subjects were subdivided by breast thickness into three groups, namely, below 3 cm, 3 cm to 4.2 cm, aaa and above 4.2 cm, the corresponding MGDs were 1.83, 1.86, and 1.91 mSv. According to our initial trial, the mean breast thickness and the MGDs of Korean women are lower than recommended by the American College of Radiology, which are commonly used for quality assurance purposes.

Estimation of mean glandular dose for mammography of augmentedbreasts

The standard quantity used to relate breast surface exposure to radiation riskis the mean dose received by the radiation sensitive tissue contained withinthe female breast, the mean glandular dose (MGD). At present, little is knownabout the MGD received by women with breast implants as there is no techniqueavailable to facilitate its calculation. The present work has involvedmodification of the conventional method for MGD estimation to make itapplicable to women with augmented breasts. The technique was used tocalculate MGDs for a cohort of 80 women with breast implants, which werecompared with similar data calculated for a total of 1258 non-augmented women.Little difference was found in median MGD at low compressed breast thickness.At high breast thickness, however, the MGDs received by women with augmentedbreasts were found to be considerably lower than those relating to theirnon-augmented counterparts.

Assessment of mean glandular dose in mammography.

The routine assessment of patient dose in the National Health Service Breast Screening Programme is performed as part of the quality assurance protocol recommended by the Institute of Physical Sciences in Medicine. The mean glandular dose to a standard breast is deduced from measurement of the air kerma at the entrance surface of a 4 cm Perspex phantom by applying a series of conversion factors. The exposure factors for this measurement are those used clinically. The measured mean glandular dose is then compared with nationally accepted action levels. In some centres the assessment of mean glandular dose using Perspex is supplemented by patient dose surveys. The mean glandular dose to a series of patients attending a breast screening unit may be estimated from a knowledge of the exposure factors and compressed breast thickness, using a knowledge of the X-ray tube output. Measurements made on units in the Northern Region of England and in Scotland using both methods are presented. The implication of these measurements with regard to patient dose surveys in mammography and quality assurance programmes are discussed. An analysis of the uncertainties associated with the measurement techniques is presented.

Technical note: perspex blocks for estimation of dose to a standard breast--effect of variation in block thickness.

Mean glandular dose in mammography may be deduced from measurements made using Perspex blocks. This method is almost universally used in the National Health Service Breast Screening Programme. The effect on the estimated mean glandular dose of variations in the measured thickness of Perspex from a nominal thickness of 40 mm was investigated. Results are presented from three UK Regions. Variations in measured Perspex thicknesses ranged from almost 8% below to about 2% above the 40 mm nominal, causing errors in dose estimation, if uncorrected, of about +20% to -6.5%. A means of correcting dose estimates for measured differences in block thickness is presented. An alternative method of ensuring consistent dosimetry would be to use accurately machined Perspex blocks.

An Investigation into Variations in the Estimation of Mean Glandular Dose in Mammography

An Investigation into Variations in the Estimation of Mean Glandular Dose in Mammography

An Investigation into Variations in the Estimation of Mean Glandular Dose in Mammography

The regular assessment of breast dose is an important part of a quality control programme in mammography. It is common practice in the United Kingdom to deduce the mean glandular dose from an estimate of air kerma at the entrance surface of a standard breast phantom manufactured from Perspex (ICI, Darwin) of nominal thickness 40 mm. Factors are used to deduce the mean glandular dose from the entrance air kerma. The objectives of this study were to assess the impact of variations in technique on the assessment of mean glandular dose and the implications for comparative surveys. It was deduced that it is possible to achieve consistent dosimetry measurements, provided standard Perspex blocks are used and tube output is measured at a specific position.