Patrizio Barca - Academia.edu (original) (raw)
Papers by Patrizio Barca
In this work a proposal for a new heterogeneous breast phantom to be adopted in Monte Carlo calcu... more In this work a proposal for a new heterogeneous breast phantom to be adopted in Monte Carlo calculations for dosimetry in digital mammography is presented. The heterogeneous phantom is designed to avoid the current assumption of the homogeneous compound of the breast tissue adopted in the current international dosimetry protocols. With the aim to improve Monte Carlo accuracy, the phantom is chosen between two models developed using different approaches: a voxelized phantom and a ducts-and-lobules phantom using mathematical solids. For both models, dose estimates are calculated and compared with the reference homogeneous phantom, and the most reliable digital phantom is chosen and proposed for dosimetry purpose
PLOS ONE
Nowadays, given the technological advance in CT imaging and increasing heterogeneity in character... more Nowadays, given the technological advance in CT imaging and increasing heterogeneity in characteristics of CT scanners, a number of CT scanners with different manufacturers/technologies are often installed in a hospital centre and used by various departments. In this phantom study, a comprehensive assessment of image quality of 5 scanners (from 3 manufacturers and with different models) for head CT imaging, as clinically used at a single hospital centre, was hence carried out. Helical and/or sequential acquisitions of the Catphan-504 phantom were performed, using the scanning protocols (CTDIvol range: 54.7–57.5 mGy) employed by the staff of various Radiology/Neuroradiology departments of our institution for routine head examinations. CT image quality for each scanner/acquisition protocol was assessed through noise level, noise power spectrum (NPS), contrast-to-noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD) and non-uniformity index analyses. N...
Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies, 2019
The rationale of this study is to perform a personalized dosimetry in digital mammography, using ... more The rationale of this study is to perform a personalized dosimetry in digital mammography, using Monte Carlo simulations. We developed a GEANT4-based application that reproduces mammographic investigations editable in different setups and conditions. Mean Glandular Dose (MGD) is estimated for different compressed breast sizes and compositions. Breast compositions are obtained with homogeneous mixture of glandular and adipose tissues. The simulated setup reproduces the Hologic Selenia® Dimensions® Mammography System and the TASMIPM tool for deriving the photon fluence from the X-ray source has been employed. The influence of different skin models is also investigated, deriving the mean glandular dose in the breast using adipose tissue for different skin thicknesses, from 2 mm to 5 mm, and a dedicated composition found in literature with the specific thickness of 1.45 mm. We denoted different photon shielding properties on the MGD values.
Archives of Breast Cancer, 2021
Background: In this work a new method for the Mean Glandular Dose evaluation in digital breast to... more Background: In this work a new method for the Mean Glandular Dose evaluation in digital breast tomosynthesis (DBT) is presented. Methods: Starting from the experimental-based dosimetric index, 2ABD, which represents the average absorbed breast dose, the mean glandular dose MGD2ABD was calculated using a conversion function of glandularity f(G), obtained through the use of Monte Carlo simulations.Results: f(G) was computed for a 4.5 cm thick breast: from its value MGD2ABD for different compressed breast thicknesses and glandularities was obtained. The comparison between MGD2ABD estimates and the dosimetric index provided in the current dosimetry protocols, following the Dance's approach, MGDDance, showed a good agreement (<10%) for all the analyzed breast thicknesses and glandularities. Conclusion: The strength of the proposed method can be considered an accurate mean glandular dose assessment starting from few and accessible parameters, reported in the header DICOM of each DB...
Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies, 2018
Lung cancer is one of the leading cause of cancer death worldwide. Computed Tomography (CT) is th... more Lung cancer is one of the leading cause of cancer death worldwide. Computed Tomography (CT) is the best imaging modality for the detection of small pulmonary nodules and for this reason its employment as a screening tool has been widely studied. However, radiation dose delivered in a chest CT examination must be considered, especially when potentially healthy people are examined in screening programs. In this context, iterative reconstruction (IR) algorithms have shown the potential to reduce image noise and radiation dose and computer aided detection (CAD) systems can be employed for supporting radiologists. Thus, the combined use of IR algorithms and CAD systems can be of practical interest. In this preliminary work we studied the potential improvements in the quality of phantom and clinical chest images reconstructed trough the Adaptive Statistical Iterative Reconstruction (ASIR, GE Healthcare, Waukesha, WI, USA) algorithm, in order to evaluate a possible employment of this algorithm in low dose chest CT imaging with CAD analysis. We analysed both clinical and phantom CT images. Noise, noise power spectrum (NPS) and modulation transfer function (MTF) were estimated for different inserts in the phantom images. Image contrast and contrast-to-noise ratio (CNR) of different nodules contained in clinical chest images were evaluated. Noise decreases non-linearly when increasing the ASIR blending level of reconstruction. ASIR modified the NPS. The MTF for ASIR-reconstructed images depended on tube load, contrast and blending level. Both image contrast and CNR increased with the ASIR blending level.
BioMed Research International, 2022
The purpose of this study was to investigate the effect of image preprocessing on radiomic featur... more The purpose of this study was to investigate the effect of image preprocessing on radiomic features estimation from computed tomography (CT) imaging of locally advanced rectal cancer (LARC). CT images of 20 patients with LARC were used to estimate 105 radiomic features of 7 classes (shape, first-order, GLCM, GLDM, GLRLM, GLSZM, and NGTDM). Radiomic features were estimated for 6 different isotropic resampling voxel sizes, using 10 interpolation algorithms (at fixed bin width) and 6 different bin widths (at fixed interpolation algorithm). The intraclass correlation coefficient (ICC) and the coefficient of variation (CV) were calculated to assess the variability in radiomic features estimation due to preprocessing. A repeated measures correlation analysis was performed to assess any linear correlation between radiomic feature estimate and resampling voxel size or bin width. Reproducibility of radiomic feature estimate, when assessed through ICC analysis, was nominally excellent ( ICC &...
CT images of the Catphan 504 phantom.
Poster: "EuroSafe Imaging 2018 / ESI-0036 / RADIOMA Project (IOnizing RADiation in MAmmograp... more Poster: "EuroSafe Imaging 2018 / ESI-0036 / RADIOMA Project (IOnizing RADiation in MAmmography): an Italian proposal for the development of an innovative dose index in mammography" by: "D. Caramella1, G. Aringhieri1, C. Sottocornola2, M. E. Fantacci2, P. Barca2, F. Paolicchi3, A. C. Traino3; 1Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Universita di Pisa Pisa/IT, 2Dipartimento Di Fisica E. Fermi Universita di Pisa Pisa/IT, 3Azienda Ospedaliero Universitaria Pisana Pisa/IT"
Applied Sciences, 2021
Given the inherent characteristics of nonlinearity and nonstationarity of iterative reconstructio... more Given the inherent characteristics of nonlinearity and nonstationarity of iterative reconstruction algorithms in computed tomography (CT) imaging, this study aimed to perform, for the first time, a voxel-based characterization of noise properties in CT imaging with the ASiR-V and ASiR algorithms as compared with conventional filtered back projection (FBP). Multiple repeated scans of the Catphan-504 phantom were carried out. CT images were reconstructed using FBP and ASiR/ASiR-V with different blending levels of reconstruction (20%, 40%, 60%, 80%, 100%). Noise maps and their nonuniformity index (NUI) were obtained according to the approach proposed by the report of AAPM TG-233. For the homogeneous CTP486 module, ASiR-V/ASiR allowed a noise reduction of up to 63.7%/52.9% relative to FBP. While the noise reduction values of ASiR-V-/ASiR-reconstructed images ranged up to 33.8%/39.9% and 31.2%/35.5% for air and Teflon contrast objects, respectively, these values were approximately 60%/50...
2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA), 2018
Digital mammography represents the most sensitive technique to detect and diagnose breast cancer ... more Digital mammography represents the most sensitive technique to detect and diagnose breast cancer and is hence the preferred method for clinical and screening diagnostic tests. Nevertheless, the absorbed dose in a mammographic procedure can not be neglected even due to the highly radiosensitivity of the breast. In this work we developed a practical method to assess the average absorbed dose both in digital mammography and digital breast tomosynthesis. A new dose index is here proposed as an easily evaluable dosimetric quantity according to the requests of the European Directive 2013/59 EURATOM.
Proceedings of the 14th International Joint Conference on Biomedical Engineering Systems and Technologies, 2021
X-ray breast imaging techniques are an essential part of breast cancer screening programs and the... more X-ray breast imaging techniques are an essential part of breast cancer screening programs and their improvements lead to gain in performance and accuracy. Radiation dose estimate and control play an important role in digital mammography and digital breast tomosynthesis investigations, since the risk of radioinduced cancer to the gland must be contained and dose delivered to the gland must be declared in the medical report. The actual dosimetric protocols suggest the assessment of radiation dose by means of Monte Carlo calculation on digital breast phantoms, providing the assumption of the homogeneous mixture of glandular and adipose tissues within the breast organ, leading to a drastic approximation. In line with the trend of other research groups, with the aim of improving the Monte Carlo model, in the current work a new heterogeneous digital breast model is proposed, involving a voxelized approach and disengaging from the concept of homogeneous phantom. The proposed model is based on new findings in the literature and after a validation process, the model is adopted to evaluate mean glandular dose discrepancies with the traditional model which is adopted in clinic for decades.
Proceedings of the 13th International Joint Conference on Biomedical Engineering Systems and Technologies, 2020
The aim of this work is to characterize 3D-printing materials to be used for breast physical phan... more The aim of this work is to characterize 3D-printing materials to be used for breast physical phantoms in mammography and digital breast tomosynthesis QA procedures or research. Our approach involves both Monte Carlo (MC) calculations and experimental measurements. Using a GEANT4-based application, MC simulations are involved in order to compare transmission properties of the digital "standard breast", which is composed by the external skin layer and the breast tissue inside, with those of typical printable materials. Substitute materials for skin layer and breast tissue have been identified and a 3D-printed physical breast phantom has been derived. Finally, a comparison between MC results and experimental measurements has been performed with the Hologic Selenia® Dimensions® mammography unit using XR-QA2 radiochromic films.
Physical and Engineering Sciences in Medicine, 2020
Digital breast tomosynthesis (DBT) has recently gained interest both for breast cancer screening ... more Digital breast tomosynthesis (DBT) has recently gained interest both for breast cancer screening and diagnosis. Its employment has increased also in conjunction with digital mammography (DM), to improve cancer detection and reduce false positive recall rate. Synthetic mammograms (SMs) reconstructed from DBT data have been introduced to replace DM in the DBT + DM approach, for preserving the benefits of the dual-acquisition modality whilst reducing radiation dose and compression time. Therefore, different DBT models have been commercialized and the effective potential of each system has been investigated. In particular, wide-angle DBT was shown to provide better depth resolution than narrow-angle DBT, while narrow-angle DBT allows better identification of microcalcifications compared to wide-angle DBT. Given the increasing employment of SMs as supplement to DBT, a comparison of image quality between SMs obtained in narrow-angle and wide-angle DBT is of practical interest. Therefore, the aim of this phantom study was to evaluate and compare the image quality of SMs reconstructed from 15° (SM 15) and 40° (SM 40) DBT in a commercial system. Spatial resolution, noise and contrast properties were evaluated through the modulation transfer function (MTF), noise power spectrum, maps of signalto-noise ratio (SNR), image contrast, contrast-to-noise ratio (CNR) and contrast-detail (CD) thresholds. SM 40 expressed higher MTF than SM 15 , but also lower SNR and CNR levels. SM 15 and SM 40 were characterized by slight different texture, and a different behavior in terms of contrast was found. SM 15 provided better CD performances than SM 40. These results suggest that the employment of wide/narrow-angle DBT + SM images should be optimized based on the specific image task.
Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies, 2018
According to the World Health Organization (WHO), breast cancer is the most common cancer in wome... more According to the World Health Organization (WHO), breast cancer is the most common cancer in women, constituting 29% of all cancers related to the female population. In this context, Full Field Digital Mammography (FFDM) is the reference imaging technique for breast cancer early detection and diagnosis and it is widely employed in screening programs. Therefore, the absorbed radiation dose for each examination shall be evaluated in order to ensure proper radiation exposures for the patient. In addition, the new European Directive 59/2013/EURATOM requires that dosimetric data referred to the radiation exposure should be inserted in the radiological report. For these reasons, we designed a multidisciplinary research project with the intention of realizing and validating a new method for calculating the Average Absorbed Breast Dose (2ABD) by the patient during a mammography procedure. The innovative aspect regards the availability of a quantitative and personalized dosimetric parameter, providing an index that is patient-specific rather than related to the X-ray machine output, directly related to the risk of radiation. Specifically, in this work we present our scientific approach as well as the initial results.
Copyright © 2021 Di Martino, Barca, Barone, Bortoli, Borgheresi, De Stefano, Di Francesco, Failla... more Copyright © 2021 Di Martino, Barca, Barone, Bortoli, Borgheresi, De Stefano, Di Francesco, Faillace, Giuliano, Grasso, Linsalata, Marfisi, Migliorati, Pacitti, Palumbo, and Felici. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Approved by: Frontiers Editorial Office, Frontiers Media SA, Switzerland
Applied Sciences, 2021
Quantitative analyses in nuclear medicine are increasingly used, both for diagnostic and therapeu... more Quantitative analyses in nuclear medicine are increasingly used, both for diagnostic and therapeutic purposes. The Partial Volume Effect (PVE) is the most important factor of loss of quantification in Nuclear Medicine, especially for evaluation in Region of Interest (ROI) smaller than the Full Width at Half Maximum (FWHM) of the PSF. The aim of this work is to present a new approach for the correction of PVE, using a post-reconstruction process starting from a mathematical expression, which only requires the knowledge of the FWHM of the final PSF of the imaging system used. After the presentation of the theoretical derivation, the experimental evaluation of this method is performed using a PET/CT hybrid system and acquiring the IEC NEMA phantom with six spherical “hot” ROIs (with diameters of 10, 13, 17, 22, 28, and 37 mm) and a homogeneous “colder” background. In order to evaluate the recovery of quantitative data, the effect of statistical noise (different acquisition times), tomo...
Frontiers in Physics, 2020
Various in vivo experimental works carried out on different animals and organs have shown that it... more Various in vivo experimental works carried out on different animals and organs have shown that it is possible to reduce the damage caused to healthy tissue still preserving the therapeutic efficacy on the tumor tissue, by drastically reducing the total time of dose delivery (<200 ms). This effect, called the FLASH effect, immediately attracted considerable attention within the radiotherapy community, due to the possibility of widening the therapeutic window and treating effectively tumors which appear radioresistant to conventional techniques. Despite the experimental evidence, the radiobiological mechanisms underlying the FLASH effect and the beam parameters contributing to its optimization are not yet known in details. In order to fully understand the FLASH effect, it might be worthy to investigate some alternatives which can further improve the tools adopted so far, in terms of both linac technology and dosimetric systems. This work investigates the problems and solutions conc...
Frontiers in Physics, 2020
European Radiology Experimental, 2020
Background: To propose a practical and simple method to individually evaluate the average absorbe... more Background: To propose a practical and simple method to individually evaluate the average absorbed dose for digital breast tomosynthesis. Methods: The method is based on the estimate of incident air kerma (k a,i) on the breast surface. An analytical model was developed to calculate the k a,i from the tube voltage, tube load, breast thickness, x-ray tube yield, and anode-filter combination. A homogeneous phantom was employed to simulate the breast in experimental measurements and to assess the dose-depth relationship. The k a,i values were employed to calculate the "average absorbed breast dose" (2ABD) index. Four mammographic units were used to develop and test our method under many conditions close to clinical settings. The average glandular dose (AGD) calculated following the method described by Dance et al., and the 2ABD computed through our method (i.e., from the exposure parameters) were compared in a number of conditions. Results: A good agreement was obtained between the k a,i computed through our model and that measured under different clinical conditions: discrepancies < 6% were found in all conditions. 2ABD matches with a good accuracy the AGD for a 100% glandular-breast: the minimum, maximum, and mean differences were < 0.1%, 7%, and 2.4%, respectively; the discrepancies increase with decreasing breast glandularity. Conclusions: The proposed model, based on only few exposure parameters, represents a simple way to individually calculate an index, 2ABD, which can be interpreted as the average absorbed dose in a homogeneous phantom, approximating a 100% glandular breast. The method could be easily implemented in any mammographic device performing DBT.
In this work a proposal for a new heterogeneous breast phantom to be adopted in Monte Carlo calcu... more In this work a proposal for a new heterogeneous breast phantom to be adopted in Monte Carlo calculations for dosimetry in digital mammography is presented. The heterogeneous phantom is designed to avoid the current assumption of the homogeneous compound of the breast tissue adopted in the current international dosimetry protocols. With the aim to improve Monte Carlo accuracy, the phantom is chosen between two models developed using different approaches: a voxelized phantom and a ducts-and-lobules phantom using mathematical solids. For both models, dose estimates are calculated and compared with the reference homogeneous phantom, and the most reliable digital phantom is chosen and proposed for dosimetry purpose
PLOS ONE
Nowadays, given the technological advance in CT imaging and increasing heterogeneity in character... more Nowadays, given the technological advance in CT imaging and increasing heterogeneity in characteristics of CT scanners, a number of CT scanners with different manufacturers/technologies are often installed in a hospital centre and used by various departments. In this phantom study, a comprehensive assessment of image quality of 5 scanners (from 3 manufacturers and with different models) for head CT imaging, as clinically used at a single hospital centre, was hence carried out. Helical and/or sequential acquisitions of the Catphan-504 phantom were performed, using the scanning protocols (CTDIvol range: 54.7–57.5 mGy) employed by the staff of various Radiology/Neuroradiology departments of our institution for routine head examinations. CT image quality for each scanner/acquisition protocol was assessed through noise level, noise power spectrum (NPS), contrast-to-noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD) and non-uniformity index analyses. N...
Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies, 2019
The rationale of this study is to perform a personalized dosimetry in digital mammography, using ... more The rationale of this study is to perform a personalized dosimetry in digital mammography, using Monte Carlo simulations. We developed a GEANT4-based application that reproduces mammographic investigations editable in different setups and conditions. Mean Glandular Dose (MGD) is estimated for different compressed breast sizes and compositions. Breast compositions are obtained with homogeneous mixture of glandular and adipose tissues. The simulated setup reproduces the Hologic Selenia® Dimensions® Mammography System and the TASMIPM tool for deriving the photon fluence from the X-ray source has been employed. The influence of different skin models is also investigated, deriving the mean glandular dose in the breast using adipose tissue for different skin thicknesses, from 2 mm to 5 mm, and a dedicated composition found in literature with the specific thickness of 1.45 mm. We denoted different photon shielding properties on the MGD values.
Archives of Breast Cancer, 2021
Background: In this work a new method for the Mean Glandular Dose evaluation in digital breast to... more Background: In this work a new method for the Mean Glandular Dose evaluation in digital breast tomosynthesis (DBT) is presented. Methods: Starting from the experimental-based dosimetric index, 2ABD, which represents the average absorbed breast dose, the mean glandular dose MGD2ABD was calculated using a conversion function of glandularity f(G), obtained through the use of Monte Carlo simulations.Results: f(G) was computed for a 4.5 cm thick breast: from its value MGD2ABD for different compressed breast thicknesses and glandularities was obtained. The comparison between MGD2ABD estimates and the dosimetric index provided in the current dosimetry protocols, following the Dance's approach, MGDDance, showed a good agreement (<10%) for all the analyzed breast thicknesses and glandularities. Conclusion: The strength of the proposed method can be considered an accurate mean glandular dose assessment starting from few and accessible parameters, reported in the header DICOM of each DB...
Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies, 2018
Lung cancer is one of the leading cause of cancer death worldwide. Computed Tomography (CT) is th... more Lung cancer is one of the leading cause of cancer death worldwide. Computed Tomography (CT) is the best imaging modality for the detection of small pulmonary nodules and for this reason its employment as a screening tool has been widely studied. However, radiation dose delivered in a chest CT examination must be considered, especially when potentially healthy people are examined in screening programs. In this context, iterative reconstruction (IR) algorithms have shown the potential to reduce image noise and radiation dose and computer aided detection (CAD) systems can be employed for supporting radiologists. Thus, the combined use of IR algorithms and CAD systems can be of practical interest. In this preliminary work we studied the potential improvements in the quality of phantom and clinical chest images reconstructed trough the Adaptive Statistical Iterative Reconstruction (ASIR, GE Healthcare, Waukesha, WI, USA) algorithm, in order to evaluate a possible employment of this algorithm in low dose chest CT imaging with CAD analysis. We analysed both clinical and phantom CT images. Noise, noise power spectrum (NPS) and modulation transfer function (MTF) were estimated for different inserts in the phantom images. Image contrast and contrast-to-noise ratio (CNR) of different nodules contained in clinical chest images were evaluated. Noise decreases non-linearly when increasing the ASIR blending level of reconstruction. ASIR modified the NPS. The MTF for ASIR-reconstructed images depended on tube load, contrast and blending level. Both image contrast and CNR increased with the ASIR blending level.
BioMed Research International, 2022
The purpose of this study was to investigate the effect of image preprocessing on radiomic featur... more The purpose of this study was to investigate the effect of image preprocessing on radiomic features estimation from computed tomography (CT) imaging of locally advanced rectal cancer (LARC). CT images of 20 patients with LARC were used to estimate 105 radiomic features of 7 classes (shape, first-order, GLCM, GLDM, GLRLM, GLSZM, and NGTDM). Radiomic features were estimated for 6 different isotropic resampling voxel sizes, using 10 interpolation algorithms (at fixed bin width) and 6 different bin widths (at fixed interpolation algorithm). The intraclass correlation coefficient (ICC) and the coefficient of variation (CV) were calculated to assess the variability in radiomic features estimation due to preprocessing. A repeated measures correlation analysis was performed to assess any linear correlation between radiomic feature estimate and resampling voxel size or bin width. Reproducibility of radiomic feature estimate, when assessed through ICC analysis, was nominally excellent ( ICC &...
CT images of the Catphan 504 phantom.
Poster: "EuroSafe Imaging 2018 / ESI-0036 / RADIOMA Project (IOnizing RADiation in MAmmograp... more Poster: "EuroSafe Imaging 2018 / ESI-0036 / RADIOMA Project (IOnizing RADiation in MAmmography): an Italian proposal for the development of an innovative dose index in mammography" by: "D. Caramella1, G. Aringhieri1, C. Sottocornola2, M. E. Fantacci2, P. Barca2, F. Paolicchi3, A. C. Traino3; 1Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Universita di Pisa Pisa/IT, 2Dipartimento Di Fisica E. Fermi Universita di Pisa Pisa/IT, 3Azienda Ospedaliero Universitaria Pisana Pisa/IT"
Applied Sciences, 2021
Given the inherent characteristics of nonlinearity and nonstationarity of iterative reconstructio... more Given the inherent characteristics of nonlinearity and nonstationarity of iterative reconstruction algorithms in computed tomography (CT) imaging, this study aimed to perform, for the first time, a voxel-based characterization of noise properties in CT imaging with the ASiR-V and ASiR algorithms as compared with conventional filtered back projection (FBP). Multiple repeated scans of the Catphan-504 phantom were carried out. CT images were reconstructed using FBP and ASiR/ASiR-V with different blending levels of reconstruction (20%, 40%, 60%, 80%, 100%). Noise maps and their nonuniformity index (NUI) were obtained according to the approach proposed by the report of AAPM TG-233. For the homogeneous CTP486 module, ASiR-V/ASiR allowed a noise reduction of up to 63.7%/52.9% relative to FBP. While the noise reduction values of ASiR-V-/ASiR-reconstructed images ranged up to 33.8%/39.9% and 31.2%/35.5% for air and Teflon contrast objects, respectively, these values were approximately 60%/50...
2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA), 2018
Digital mammography represents the most sensitive technique to detect and diagnose breast cancer ... more Digital mammography represents the most sensitive technique to detect and diagnose breast cancer and is hence the preferred method for clinical and screening diagnostic tests. Nevertheless, the absorbed dose in a mammographic procedure can not be neglected even due to the highly radiosensitivity of the breast. In this work we developed a practical method to assess the average absorbed dose both in digital mammography and digital breast tomosynthesis. A new dose index is here proposed as an easily evaluable dosimetric quantity according to the requests of the European Directive 2013/59 EURATOM.
Proceedings of the 14th International Joint Conference on Biomedical Engineering Systems and Technologies, 2021
X-ray breast imaging techniques are an essential part of breast cancer screening programs and the... more X-ray breast imaging techniques are an essential part of breast cancer screening programs and their improvements lead to gain in performance and accuracy. Radiation dose estimate and control play an important role in digital mammography and digital breast tomosynthesis investigations, since the risk of radioinduced cancer to the gland must be contained and dose delivered to the gland must be declared in the medical report. The actual dosimetric protocols suggest the assessment of radiation dose by means of Monte Carlo calculation on digital breast phantoms, providing the assumption of the homogeneous mixture of glandular and adipose tissues within the breast organ, leading to a drastic approximation. In line with the trend of other research groups, with the aim of improving the Monte Carlo model, in the current work a new heterogeneous digital breast model is proposed, involving a voxelized approach and disengaging from the concept of homogeneous phantom. The proposed model is based on new findings in the literature and after a validation process, the model is adopted to evaluate mean glandular dose discrepancies with the traditional model which is adopted in clinic for decades.
Proceedings of the 13th International Joint Conference on Biomedical Engineering Systems and Technologies, 2020
The aim of this work is to characterize 3D-printing materials to be used for breast physical phan... more The aim of this work is to characterize 3D-printing materials to be used for breast physical phantoms in mammography and digital breast tomosynthesis QA procedures or research. Our approach involves both Monte Carlo (MC) calculations and experimental measurements. Using a GEANT4-based application, MC simulations are involved in order to compare transmission properties of the digital "standard breast", which is composed by the external skin layer and the breast tissue inside, with those of typical printable materials. Substitute materials for skin layer and breast tissue have been identified and a 3D-printed physical breast phantom has been derived. Finally, a comparison between MC results and experimental measurements has been performed with the Hologic Selenia® Dimensions® mammography unit using XR-QA2 radiochromic films.
Physical and Engineering Sciences in Medicine, 2020
Digital breast tomosynthesis (DBT) has recently gained interest both for breast cancer screening ... more Digital breast tomosynthesis (DBT) has recently gained interest both for breast cancer screening and diagnosis. Its employment has increased also in conjunction with digital mammography (DM), to improve cancer detection and reduce false positive recall rate. Synthetic mammograms (SMs) reconstructed from DBT data have been introduced to replace DM in the DBT + DM approach, for preserving the benefits of the dual-acquisition modality whilst reducing radiation dose and compression time. Therefore, different DBT models have been commercialized and the effective potential of each system has been investigated. In particular, wide-angle DBT was shown to provide better depth resolution than narrow-angle DBT, while narrow-angle DBT allows better identification of microcalcifications compared to wide-angle DBT. Given the increasing employment of SMs as supplement to DBT, a comparison of image quality between SMs obtained in narrow-angle and wide-angle DBT is of practical interest. Therefore, the aim of this phantom study was to evaluate and compare the image quality of SMs reconstructed from 15° (SM 15) and 40° (SM 40) DBT in a commercial system. Spatial resolution, noise and contrast properties were evaluated through the modulation transfer function (MTF), noise power spectrum, maps of signalto-noise ratio (SNR), image contrast, contrast-to-noise ratio (CNR) and contrast-detail (CD) thresholds. SM 40 expressed higher MTF than SM 15 , but also lower SNR and CNR levels. SM 15 and SM 40 were characterized by slight different texture, and a different behavior in terms of contrast was found. SM 15 provided better CD performances than SM 40. These results suggest that the employment of wide/narrow-angle DBT + SM images should be optimized based on the specific image task.
Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies, 2018
According to the World Health Organization (WHO), breast cancer is the most common cancer in wome... more According to the World Health Organization (WHO), breast cancer is the most common cancer in women, constituting 29% of all cancers related to the female population. In this context, Full Field Digital Mammography (FFDM) is the reference imaging technique for breast cancer early detection and diagnosis and it is widely employed in screening programs. Therefore, the absorbed radiation dose for each examination shall be evaluated in order to ensure proper radiation exposures for the patient. In addition, the new European Directive 59/2013/EURATOM requires that dosimetric data referred to the radiation exposure should be inserted in the radiological report. For these reasons, we designed a multidisciplinary research project with the intention of realizing and validating a new method for calculating the Average Absorbed Breast Dose (2ABD) by the patient during a mammography procedure. The innovative aspect regards the availability of a quantitative and personalized dosimetric parameter, providing an index that is patient-specific rather than related to the X-ray machine output, directly related to the risk of radiation. Specifically, in this work we present our scientific approach as well as the initial results.
Copyright © 2021 Di Martino, Barca, Barone, Bortoli, Borgheresi, De Stefano, Di Francesco, Failla... more Copyright © 2021 Di Martino, Barca, Barone, Bortoli, Borgheresi, De Stefano, Di Francesco, Faillace, Giuliano, Grasso, Linsalata, Marfisi, Migliorati, Pacitti, Palumbo, and Felici. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Approved by: Frontiers Editorial Office, Frontiers Media SA, Switzerland
Applied Sciences, 2021
Quantitative analyses in nuclear medicine are increasingly used, both for diagnostic and therapeu... more Quantitative analyses in nuclear medicine are increasingly used, both for diagnostic and therapeutic purposes. The Partial Volume Effect (PVE) is the most important factor of loss of quantification in Nuclear Medicine, especially for evaluation in Region of Interest (ROI) smaller than the Full Width at Half Maximum (FWHM) of the PSF. The aim of this work is to present a new approach for the correction of PVE, using a post-reconstruction process starting from a mathematical expression, which only requires the knowledge of the FWHM of the final PSF of the imaging system used. After the presentation of the theoretical derivation, the experimental evaluation of this method is performed using a PET/CT hybrid system and acquiring the IEC NEMA phantom with six spherical “hot” ROIs (with diameters of 10, 13, 17, 22, 28, and 37 mm) and a homogeneous “colder” background. In order to evaluate the recovery of quantitative data, the effect of statistical noise (different acquisition times), tomo...
Frontiers in Physics, 2020
Various in vivo experimental works carried out on different animals and organs have shown that it... more Various in vivo experimental works carried out on different animals and organs have shown that it is possible to reduce the damage caused to healthy tissue still preserving the therapeutic efficacy on the tumor tissue, by drastically reducing the total time of dose delivery (<200 ms). This effect, called the FLASH effect, immediately attracted considerable attention within the radiotherapy community, due to the possibility of widening the therapeutic window and treating effectively tumors which appear radioresistant to conventional techniques. Despite the experimental evidence, the radiobiological mechanisms underlying the FLASH effect and the beam parameters contributing to its optimization are not yet known in details. In order to fully understand the FLASH effect, it might be worthy to investigate some alternatives which can further improve the tools adopted so far, in terms of both linac technology and dosimetric systems. This work investigates the problems and solutions conc...
Frontiers in Physics, 2020
European Radiology Experimental, 2020
Background: To propose a practical and simple method to individually evaluate the average absorbe... more Background: To propose a practical and simple method to individually evaluate the average absorbed dose for digital breast tomosynthesis. Methods: The method is based on the estimate of incident air kerma (k a,i) on the breast surface. An analytical model was developed to calculate the k a,i from the tube voltage, tube load, breast thickness, x-ray tube yield, and anode-filter combination. A homogeneous phantom was employed to simulate the breast in experimental measurements and to assess the dose-depth relationship. The k a,i values were employed to calculate the "average absorbed breast dose" (2ABD) index. Four mammographic units were used to develop and test our method under many conditions close to clinical settings. The average glandular dose (AGD) calculated following the method described by Dance et al., and the 2ABD computed through our method (i.e., from the exposure parameters) were compared in a number of conditions. Results: A good agreement was obtained between the k a,i computed through our model and that measured under different clinical conditions: discrepancies < 6% were found in all conditions. 2ABD matches with a good accuracy the AGD for a 100% glandular-breast: the minimum, maximum, and mean differences were < 0.1%, 7%, and 2.4%, respectively; the discrepancies increase with decreasing breast glandularity. Conclusions: The proposed model, based on only few exposure parameters, represents a simple way to individually calculate an index, 2ABD, which can be interpreted as the average absorbed dose in a homogeneous phantom, approximating a 100% glandular breast. The method could be easily implemented in any mammographic device performing DBT.