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Mammography has played an essential role in the screening and treatment of breast cancer. However, the application of X-rays will also increase the risks of breast cancer while improving its detection rate. Moreover, the risks will increase with an increase in the radiation dose. Since the glandular tissue in breasts is sensitive to radiation, the evaluation of the average glandular dose (AGD) in mammography has attracted considerable international attention. Compared to relatively mature dosimetric studies on traditional two-dimension mammography and digital breast tomosynthesis, the method for the dose evaluation of the new cone beam CT for breasts are still subjected to research. This paper reviews and explores the current status of studies on the assessment method and relevant influencing factors of AGD under different types of mammography equipment.
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Objective:To compare radiation dose between digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM), and explore the correlation of average glandular dose(AGD) with breast density and compression thickness.Methods:The mammographic data of patients with breast diseases who underwent digital breast tomosynthesis (DBT) and the population who underwent full-field digital mammography (FFDM) screening in the First Affiliated Hospital of Kunming Medical University from October 2020 to May 2022 were retrospectively collected. The compression thickness, compression force and AGD were recorded. According to the 2013 ACR BI-RADS MAMMOGRAPHY, the breast gland density was classified into 4 types: a(glandular tissue<25%), b(glandular tissue 25%~50%), c(glandular tissue 50%~75%) and d(glandular tissue >75%), by two senior doctors engaged in breast imaging diagnosis. The relationships between different gland densities, different compression thicknesses and AGD under FFDM and DBT mode were analyzed.Results:In both FFDM and DBT modes, the AGD increased significantly with the increase of breast density( F=861.63, 617.83, 330.33, 451.45, 290.47, P<0.001), and AGD a<AGD b<AGD c<AGD d. For type c and d breasts undergoing FFDM, AGD was lowest when the compression thickness was 31~40 mm. Under the same compression thickness, The AGD DBT was significantly higher than the AGD FFDMin all types (Type a: t=-17.88, -42.19, -29.90, -28.14, -24.95, P<0.001; Type b: t=-49.18, -35.94, -27.25, -28.37, -24.10, P<0.001; Type c: t=-11.78, -32.90, -23.13, -20.51, -18.24, P<0.001; Type d: t=-7.94, -26.24, -17.24, -15.44, -13.81, P<0.001). The difference between two AGDs of Type d with compression thickness of 61~70 mm was the largest, which was 1.07 mGy (95% CI: 0.92~1.22). The AGD was positively correlated with breast density and compression thickness, and the relationship of FFDM was stronger than that of DBT. Conclusions:The AGD is positively correlated with breast density and compression thickness in mammography. Compared with FFDM, DBT can increase AGD, The AGD would increase in DBT than FFDM but be safe. DBT would be beneficial to patients with breast diseases in clinical practice.
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Objective To investigate the average glandular dose of digital mammography in Zigong, China, and to explore the methods of reducing average glandular dose. Methods A total of 260 patients who underwent digital mammography at six hospitals located in Zigong during the year 2022 were included in this study. Their personal information, photography position, breast compression thickness, exposure parameters, and average glandular dose were collected. Analysis of variance and correlation analysis were performed for data analysis. Results Among the 260 patients who underwent digital mammography, the average breast compression thickness was 46.3 mm and the average glandular dose was 1.70 mGy. There was a significant difference in average glandular dose between patients with different breast compression thickness(P <0.05), and average glandular dose was positively correlated with breast compression thickness. There were no significant differences in average glandular dose between patients with different photography positions and patients with different ages (P>0.05). Conclusion The average glandular dose of patients undergoing digital mammography is at an acceptable level in Zigong. The average glandular dose is impacted by the breast compression thickness, target/filter, and exposure parameters. These factors should be optimized to reduce glandular dose during digital mammography.
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Objective:To compare and analyze the relationship between average glandular dose (AGD) and breast density and compression thickness in digital breast tomosynthesis(DBT)/full-field digital mammography(FFDM), and to explore the optimal selection and application of imaging parameters for different types of breast (thickness and density) in specific situations.Methods:The clinical data of 229 cases of breast Combo (DBT+ FFDM) were retrospectively analyzed. The compression thickness, AGD, kVp and type of quantified breast density (Q_abd) of CC and MLO view were collected respectively. The relationship between the AGD and the breast compression thickness and Q_abd density classification was analyzed.Results:There was a positive correlation between AGD and compression thickness (CC: r =0.55, 0.53, P< 0.001; MLO: r =0.62, 0.48, P< 0.001) and breast density(CC: r =0.36, 0.39, P< 0.001; MLO: r =0.16, 0.30, P < 0.001) in DBT/FFDM. The difference between groups for AGD was little in CC of DBT, but significant in CC of FFDM(groups by thickness, CC: F =35.29, 31.32, P<0.005; MLO: F =44.83, 27.02, P<0.005; groups by Q_abd, CC: F =18.68, 19.76, P<0.005, MLO: F=4.58, 10.52, P<0.005); the breast Q_abd was inversely proportion to the mean compression thickness (CC: F =16.28, P<0.005; MLO: F =17.81, P<0.005). At the same time, the interaction effect on AGD between the breast density and thickness was considered, and only for the MLO in FFDM mode they had an interaction on AGD ( F =3.16, P =0.005). Conclusions:The cumulative dose of DBT and FFDM may increase the radiation risk. Single-view CC/MLO-DBT or CC/MLO-(DBT+ FFDM)+ single-view MLO/CC-FFDM mode is preferred for mammography, which plays a positive role in radiation risk reduction.
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Objective: The average glandular dose (AGD) is used to evaluate the radiation dosage in mammography. Dance et al. (2000) presented a computation formula to estimate the AGD based on several coefficient factors, such as compressed breast thickness, breast tissue composition, and half-value layers (HVLs). The objective of this study was to improve the preciseness of AGD estimation.Materials and Methods: We interpolated the coefficients developed by Dance et al. to generate an approximation formulae and reference datasets with higher granularity and breast thickness (2–6 cm) relevant to a Japanese population.Results: The results from this study indicate that the incorporation of HVLs and breast thickness required in mammography densitometry leads to an advancement in the current method for estimating the average glandular dose.Conclusions: We expect that these interpolated values will serve as a reference for other researchers and allow for a more accurate, detailed, and individualized AGD estimation.
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OBJECTIVE@#To understand the distribution of the average glandular dose (AGD) in mammography by investigating 1,828 exposure parameters of 8 mammography machines in three cities, by using random sampling.@*METHODS@#A survey of 8 mammography machines in three different cities, sampled using stratified random sampling methods, was performed, and 1,828 mammography exposure parameters were recorded. Incident air kerma (k) was measured by Quality-Assurance (QA) dosimeters, and AGD was calculated by series conversion coefficients based on a 3D detailed Monte Carlo breast model, published by Wang et al. RESULTS: The distribution of compressed breast thickness (CBT) fitted a normal distribution, while that of AGD fitted a skewed distribution. The mean value of CBT in a medio-lateral oblique (MLO) view was about 5.6% higher than that in the craniocaudal (CC) view, with significant statistical difference; mean value of AGD and CBT in the sample was 1.3 mGy and 4.6 cm, respectively. The AGD trended upward with increasing CBT, similar to the results of other researches.@*CONCLUSION@#The mean AGD and CBT levels in our study for mammography practice in China were 1.3 mGy and 4.6 cm, respectively. AGD is influenced by manufacturer-specific variation as machine response to CBT changes and target/filter combination. The present study can provide evidence for establishing a diagnostic reference level in China.
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Adult , Female , Humans , Middle Aged , China , Mammography , Radiation DosageABSTRACT
Objective To test the spatial resolution and average glandular dose (AGD) of full field digital mammography system to obtain high-resolution and contrast breast X-ray images with the lowest dose.Methods The M12 breast X-ray performance test phantom was placed on the breast support center position,then line-pair card was put on the M12 phantom and fixed groove,and exposure was carried out with auto exposure control,28 kV tube voltage and common anode filtration combination so as to detect the spatial resolution.Half-value layer (HVL) was measured by Fluke TNT12000 ray detection tools,2 mm-thickness plate and aluminum sheets with different thicknesses,and then AGD was calculated accordingly.Results The spatial resolutions were all higher than 7 lp/mm and proved to meet the quality standard,which had the vertical spatial resolution being 8 lp/mm,the maximum value of the lateral spatial resolution being 10 lp/mm and the minimum value being 8 lp/mm.AGD was lower than 2 mGy and then proved qualified which was limited within 0.60 and 0.61 mGy.Conclusion The test of spatial resolution and AGD of full digital mammography system can assess the performance and radiation dose,reflect the performance of equipment,ensure image quality and lower radiation dose.
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Objective To test the spatial resolution and average glandular dose (AGD) of full field digital mammography system to obtain high-resolution and contrast breast X-ray images with the lowest dose.Methods The M12 breast X-ray performance test phantom was placed on the breast support center position,then line-pair card was put on the M12 phantom and fixed groove,and exposure was carried out with auto exposure control,28 kV tube voltage and common anode filtration combination so as to detect the spatial resolution.Half-value layer (HVL) was measured by Fluke TNT12000 ray detection tools,2 mm-thickness plate and aluminum sheets with different thicknesses,and then AGD was calculated accordingly.Results The spatial resolutions were all higher than 7 lp/mm and proved to meet the quality standard,which had the vertical spatial resolution being 8 lp/mm,the maximum value of the lateral spatial resolution being 10 lp/mm and the minimum value being 8 lp/mm.AGD was lower than 2 mGy and then proved qualified which was limited within 0.60 and 0.61 mGy.Conclusion The test of spatial resolution and AGD of full digital mammography system can assess the performance and radiation dose,reflect the performance of equipment,ensure image quality and lower radiation dose.
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Objective To study the angular dependence of four different mammographic dosimeters to monoenergetic X-ray beams and observe the variation tendency in angular dependence to different energy X-rays and to discuss the evaluation of average glandular dose(AGD)in digital breast tomosynthesis(DBT)system.Methods One ionization chamber and three semiconductor dosimeters were exposed by four kinds of beam quality.The signal of each dosimeter was tested over an angular range of 0° to 90°.The dosimeters were exposed for three times at each selected angular position.The measurement at each angle was normalized to the appropriate measurement at perpendicular incidence.Results The responses from all the dosimeters had a maximum at 0° and decreased with increasing angles.When the radiation incidence angle was 10°,the angular dependence were 0.99,0.99,0.96 and 0.96 for dosimeters A,B,C and D,respectively.And the angular dependence decreased to 0.96,1.00,0.78 and 0.52 when the incidence angle was up to 25°.For semiconductor dosimeters,no signal was recorded when incidence angle was beyond 45°.For ionization chamber,the magnitude of the angular dependence generally decreased with increasing energy.Conclusions All of the dosimeters will underestimate the dose if used in DBT.In order to minimize the error due to the rotation angle of X-ray tube,correction factor of mammography dosimeter should be used for the measurement of AGD in DBT systems.
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Mammography is the most effective way to detect breast abnormality among women. However, mammography is believed to be able to cause radiation induced carcinogenesis. Therefore dose measurement is important to estimate the risk and to control the quality of the image. This study was conducted to compare the average glandular dose (AGD) acquired by the breast phantom with two different anode/filter combination which are tungsten/rhodium (W/Rh) and tungsten/argentum (W/Ag). CIRS 012A breast phantom was exposed in craniocaudal (CC) projection using Hologic Selenia digital mammography system. Entrance surface air kerma (ESAK) was measured using thermoluminescent dosimeter (TLD). AGD was obtained from basic calculation of ESAK with conversion factors according to Euref protocol. Independent t-test showed significant difference in the mean AGD. The AGD for W/Rh is higher as compared to the AGD for W/Ag (p = 0.002, 95% CI: 0.22, 0.53). In conclusion, the use of W/Ag contributes to dose reduction during mammography examination.
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OBJETIVO: Para comparar o benefício da mamografia e o risco de câncer induzido por raios X, devese investigar as doses absorvidas. Nesse sentido, determinaram-se espectros dos raios X de um mamógrafo clínico, para combinação alvo/filtro Mo/Mo, utilizando espectrometria Compton, e avaliou-se a dose glandular média (DGM) em um simulador de mamas de BR-12. MATERIAL E MÉTODO:Um detector de CdTe foi usado para espectrometria dos raios X espalhados a ~ 100° por um cilindrode PMMA, para diferentes profundidades de BR-12 e tensões entre 28 e 35 kV. Após a reconstrução do espectro dos feixes primários, a partir dos medidos, determinou-se a DGM. RESULTADOS:Obtiveram-se camadas semirredutoras de 0,39 a 0,45 mmAl (espectrometricamente) e de 0,38 a0,42 mmAl (com câmara de ionização) para os feixes incidentes na superfície do simulador. A DGMNnormalizada por unidade de kerma no ar incidente, na superfície de BR-12, variou de 0,156 a 0,226.CONCLUSÃO: Os valores de DGMN variaram de 1% a 3%, em relação aos obtidos com câmara. O método empregado é uma boa alternativa para a determinação de DGMN e da distribuição de dose em profundidade em simuladores mamários.
OBJECTIVE: To compare mammography benefit and X-ray induced cancer risk, one should investigate absorbed doses. For this purpose, spectra of primary X-ray beams from a clinical mammographyequipment were determined for Mo/Mo target/filter combination,using Compton spectrometry and average glandular dose (AGD) in a BR-12 breast phantom was evaluated. MATERIAL AND METHOD: A CdTe detector was used for spectrometry of X-ray beams Compton scattered around 100°, by a PMMA cylinder, for different depths inside the BR-12 phantom and voltages between 28 and 35 kV. The reconstruction of the primary beam spectra from the measured ones was followed by the determination of AGD. RESULTS: Half-value layer values determined by spectra resulted 0.39 to 0.45 mmAl, and by ionization chamber, 0.38 to 0.42 mmAl, respectively, for beams incident on the phantom surface. The AGDN normalized per unitary incident air kerma, on the BR-12 surface, ranged from 0.156 to 0.226. CONCLUSION: The percentage deviation of AGDN, relative to the chamber measurements, ranged from 1% to 3%. The utilized method is a good alternative to determineAGDN and depth-dose distributions in breast phantoms.
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Early Detection of Cancer , Spectrometry, X-Ray Emission/methods , Mammography , Breast Neoplasms/diagnosis , Breast Neoplasms/prevention & control , Radiometry/adverse effects , Radiometry/methodsABSTRACT
Objective To carry out the quality control testing and evaluation for three digital mammography systems.Methods The performance of three digital mammography systems was assessed by applying methods recommended in the European guidelines for quality assurance in breast cancer screening and diagnosis and Chinese specification for testing of quality control in X-ray mammography.The performance of X-ray generator of three digital mammography systems were tested and evaluated.CDMAM 3.4 phantom with four different thickness(30,40,50,60 mm) were exposured in DR,PCM,and CR system,respectively.The average glandular dose (AGD) value was measured and image quality figure (IQF) analysis was performed in each thickness.Results The X-ray machine performance of DR and CR was in accordance with existing standard,however the standard was inappropriate to evaluate part of X-ray machine performance of PCM system.The AGDs for system DR were 1.20,1.42,1.75 and 2.20 mGy for 30,40,50 and 60 mm PMMA thickness,respectively.The respective AGDs for system PCM and CR were 0.82,1.19,1.33,1.70 mGy and 0.59,0.88,1.47,2.19 mGy.For the same phantom thickness sequence,the IQFs were 21.36,21.57,27.25 and 30.58 for system DR,28.02,29.10,35.90,and 41.24 for system PCM,whereas they were 39.78,39.30,43.85 and 48.08 for system CR.Conclusions The AGDs of all three systems were in accordance with the values recommended in European guideline.The AGD and IQF could provide an effective way for performance assessment and constancy checks for digital mammography systems.