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[P048] Comparison of breast radiation dose for digital breast tomosynthesis estimated according compressed breast thickness by using breast phatom
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Abstracts / Physica Medica 52 (2018) 99–187
Based on the above values, TR and TE parameters were modified resulting in an optimized T1wSE sequence TR/TE = 1200 ms/10 ms and an optimized T2wTSE sequence TR/TE = 9500 ms/280 ms as estimated on a clinical MAGNETOM Sonata 1.5T system. Clinical MRI inter-equipment variability for T1 and T2 measurements remained <5% during a total sampling period of 2 months. TR and TE parameter variation in optimized T1w and T2w sequences remained less than 7% amongst the selected MRI systems included in this study. Conclusions. CNR optimization of T1w and T2w sequences for neonatal brain imaging at multiple 1.5T clinical MRI systems was accomplished with the aid of an in house developed tissuemimicking phantom. https://doi.org/10.1016/j.ejmp.2018.06.369
[P047] Ultrasound imaging: Towards smaller portable systems using signal and image processing tools Omri Soceanu a, Zvi Friedman b, Moshe Porat a,* a
Technion, Electrical Engineering, Haifa, Israel Technion, Biomedical Engineering, Haifa, Israel ⇑ Corresponding author. b
Introduction. Handheld pocket-sized ultrasound systems are becoming a useful diagnostic tool in recent years. The demand for higher resolution requires, however, an increasing number of elements in their transducer, thus driving up the associated data flow, which increases the size of the device, its battery consumption and cost. These considerations prevent the construction of smaller high-quality portable ultrasound devices. Purpose. The purpose of this research is to develop a suitable approach to the design of portable ultrasound devices with enhanced image quality that can be used outdoors and in emergency situations away from a clinic or hospital. Materials and methods. In this study we introduce a compact transducer in which the beamformed signals are multiplied and processed to form an image. Our analysis shows that the beam pattern of this transducer provides the same resolution as an array used in ordinary transducers with significantly more receiving elements. In order to compensate for the signal-to-noise (SNR) reduction, image processing techniques are used. Results. Our tests show that two sub-arrays amounting to 16 (i.e., 8 + 8) elements of a thinned array together with associated image processing techniques, produce better imaging results than the original imaging produced by a 64-element array. Conclusions. Due to the reduced number of elements and input channels, our proposed approach enables the implementation of computationally complex algorithms that were previously unrealistic for real-time ultrasound devices. As a result, our technique allows reduced costs and size, as well as lowering battery power consumption, while increasing image quality and resolution. Disclosure. Nothing to disclose. https://doi.org/10.1016/j.ejmp.2018.06.370
[P048] Comparison of breast radiation dose for digital breast tomosynthesis estimated according compressed breast thickness by using breast phatom Chia-Hui Chen a,*, Jih-Kuei Yeh b a Central Taiwan University of Science and Technology, Department of Medical Imaging and Radiological Science, Taichung, Taiwan
b Kaohsiung Municipal United Hospital, Division of Family Medicine, Kaohsiung, Taiwan ⇑ Corresponding author.
Purpose. To compare the surface radiation dose (ESD) and Average Glandular Dose (AGD) of digital breast tomosynthesis (DBT) examination according compressed breast thickness by using breast phantoms. Methods. Because of mammary glands have relatively high radiation sensitivity, that breast dose evaluation for mammography was using entrance surface dose (ESD) and average glandular dose (AGD). Many studies were proven that radiation dose from DBT was higher than that of Digital mammography. The DBT system determines target material, filtration and tube voltage by compressed breast thickness and adjusts to exposure output (mAs) using an automatic exposure control (AEC) system to obtain appropriate image density in clinical practice. An automatic exposure control (AEC) is proposed for ESD and AGD measurement s during DBT exposure. AGD and ESD were estimated using breast phantom thickness categories: 22 mm, 32 mm, 45 mm and 55 mm in clinical practice. Results. On DBT examination of 55 mm breast phantom, the mean ESD and AGD were 6.37 mGy and 1.95 mGy, respectively. The mean ESD and AGD values for DBT in 45 mm were 4.32 mGy and 1.43 mGy. The mean ESD and AGD values for DBT in 32 mm were 2.72 mGy and 1.08 mGy. The mean ESD and AGD values for DBT in 22 mm were 1.92 mGy and 0.91 mGy. The ESD was 2–3 times higher compared with the AGD. Conclusions. In DBT examination, The ESD and AGD were descending as breast phantom thickness decreases. This study suggests that it is useful for the quality control in DBT examination to mention values of ESD for each breast thickness as well as AGD. https://doi.org/10.1016/j.ejmp.2018.06.371
[P049] Moving forward to personalized pediatric dosimetry on computed tomography applications Theodora Kostou a,*, Panagiotis Papadimitroulas b, George Kagadis a a Department of Medical Physics, School of Medicine, University of Patras, Rion, Greece b Bet Solutions, R&d Department, Athens, Greece ⇑ Corresponding author.
Purpose. Personalized dosimetry is of high interest in pediatric applications where exposure to ionizing radiation is widely debated. This study intends to create an organ dose database for pediatric reference individuals undergoing computed tomography (CT) examinations. The data will permit quick estimates of organ effective doses for patients of different age, gender, and examination procedure. Methods. The GATE MC toolkit [1] was used for modeling a multislice helical CT system. The energy spectrum was calculated using Spektr software, and consequently imported in GATE as a gammaparticle point source with an almost continuous helical movement. To validate our results, simulations were performed with the standard CTDI head/body phantoms. A thin-walled ionization chamber was simulated according to the manufacturer specifications at 1 center, and 4 peripheral positions. Five pediatric computational models in the 5–15 y age-range [2,3], were used to simulate realistic helical chest protocols and compare the variations on absorbed dose/organ. Results. The CT scanner model was validated against experimental CTDI measurements with differences being lower than 18%. The simulated dose variations for the different pediatric phantoms are presented. Indicatively, normalized absorbed doses for selected organs inside the scan coverage varied between 25–35%, and 43– 51% for 5 vs. 8, and 8 vs. 11 years-old girls respectively.
Abstracts / Physica Medica 52 (2018) 99–187
Based on the above values, TR and TE parameters were modified resulting in an optimized T1wSE sequence TR/TE = 1200 ms/10 ms and an optimized T2wTSE sequence TR/TE = 9500 ms/280 ms as estimated on a clinical MAGNETOM Sonata 1.5T system. Clinical MRI inter-equipment variability for T1 and T2 measurements remained <5% during a total sampling period of 2 months. TR and TE parameter variation in optimized T1w and T2w sequences remained less than 7% amongst the selected MRI systems included in this study. Conclusions. CNR optimization of T1w and T2w sequences for neonatal brain imaging at multiple 1.5T clinical MRI systems was accomplished with the aid of an in house developed tissuemimicking phantom. https://doi.org/10.1016/j.ejmp.2018.06.369
[P047] Ultrasound imaging: Towards smaller portable systems using signal and image processing tools Omri Soceanu a, Zvi Friedman b, Moshe Porat a,* a
Technion, Electrical Engineering, Haifa, Israel Technion, Biomedical Engineering, Haifa, Israel ⇑ Corresponding author. b
Introduction. Handheld pocket-sized ultrasound systems are becoming a useful diagnostic tool in recent years. The demand for higher resolution requires, however, an increasing number of elements in their transducer, thus driving up the associated data flow, which increases the size of the device, its battery consumption and cost. These considerations prevent the construction of smaller high-quality portable ultrasound devices. Purpose. The purpose of this research is to develop a suitable approach to the design of portable ultrasound devices with enhanced image quality that can be used outdoors and in emergency situations away from a clinic or hospital. Materials and methods. In this study we introduce a compact transducer in which the beamformed signals are multiplied and processed to form an image. Our analysis shows that the beam pattern of this transducer provides the same resolution as an array used in ordinary transducers with significantly more receiving elements. In order to compensate for the signal-to-noise (SNR) reduction, image processing techniques are used. Results. Our tests show that two sub-arrays amounting to 16 (i.e., 8 + 8) elements of a thinned array together with associated image processing techniques, produce better imaging results than the original imaging produced by a 64-element array. Conclusions. Due to the reduced number of elements and input channels, our proposed approach enables the implementation of computationally complex algorithms that were previously unrealistic for real-time ultrasound devices. As a result, our technique allows reduced costs and size, as well as lowering battery power consumption, while increasing image quality and resolution. Disclosure. Nothing to disclose. https://doi.org/10.1016/j.ejmp.2018.06.370
[P048] Comparison of breast radiation dose for digital breast tomosynthesis estimated according compressed breast thickness by using breast phatom Chia-Hui Chen a,*, Jih-Kuei Yeh b a Central Taiwan University of Science and Technology, Department of Medical Imaging and Radiological Science, Taichung, Taiwan
b Kaohsiung Municipal United Hospital, Division of Family Medicine, Kaohsiung, Taiwan ⇑ Corresponding author.
Purpose. To compare the surface radiation dose (ESD) and Average Glandular Dose (AGD) of digital breast tomosynthesis (DBT) examination according compressed breast thickness by using breast phantoms. Methods. Because of mammary glands have relatively high radiation sensitivity, that breast dose evaluation for mammography was using entrance surface dose (ESD) and average glandular dose (AGD). Many studies were proven that radiation dose from DBT was higher than that of Digital mammography. The DBT system determines target material, filtration and tube voltage by compressed breast thickness and adjusts to exposure output (mAs) using an automatic exposure control (AEC) system to obtain appropriate image density in clinical practice. An automatic exposure control (AEC) is proposed for ESD and AGD measurement s during DBT exposure. AGD and ESD were estimated using breast phantom thickness categories: 22 mm, 32 mm, 45 mm and 55 mm in clinical practice. Results. On DBT examination of 55 mm breast phantom, the mean ESD and AGD were 6.37 mGy and 1.95 mGy, respectively. The mean ESD and AGD values for DBT in 45 mm were 4.32 mGy and 1.43 mGy. The mean ESD and AGD values for DBT in 32 mm were 2.72 mGy and 1.08 mGy. The mean ESD and AGD values for DBT in 22 mm were 1.92 mGy and 0.91 mGy. The ESD was 2–3 times higher compared with the AGD. Conclusions. In DBT examination, The ESD and AGD were descending as breast phantom thickness decreases. This study suggests that it is useful for the quality control in DBT examination to mention values of ESD for each breast thickness as well as AGD. https://doi.org/10.1016/j.ejmp.2018.06.371
[P049] Moving forward to personalized pediatric dosimetry on computed tomography applications Theodora Kostou a,*, Panagiotis Papadimitroulas b, George Kagadis a a Department of Medical Physics, School of Medicine, University of Patras, Rion, Greece b Bet Solutions, R&d Department, Athens, Greece ⇑ Corresponding author.
Purpose. Personalized dosimetry is of high interest in pediatric applications where exposure to ionizing radiation is widely debated. This study intends to create an organ dose database for pediatric reference individuals undergoing computed tomography (CT) examinations. The data will permit quick estimates of organ effective doses for patients of different age, gender, and examination procedure. Methods. The GATE MC toolkit [1] was used for modeling a multislice helical CT system. The energy spectrum was calculated using Spektr software, and consequently imported in GATE as a gammaparticle point source with an almost continuous helical movement. To validate our results, simulations were performed with the standard CTDI head/body phantoms. A thin-walled ionization chamber was simulated according to the manufacturer specifications at 1 center, and 4 peripheral positions. Five pediatric computational models in the 5–15 y age-range [2,3], were used to simulate realistic helical chest protocols and compare the variations on absorbed dose/organ. Results. The CT scanner model was validated against experimental CTDI measurements with differences being lower than 18%. The simulated dose variations for the different pediatric phantoms are presented. Indicatively, normalized absorbed doses for selected organs inside the scan coverage varied between 25–35%, and 43– 51% for 5 vs. 8, and 8 vs. 11 years-old girls respectively.