1
|
Pinto MC, Mauter F, Michielsen K, Biniazan R, Kappler S, Sechopoulos I. A deep learning approach to estimate x-ray scatter in digital breast tomosynthesis: From phantom models to clinical applications. Med Phys 2023; 50:4744-4757. [PMID: 37394837 DOI: 10.1002/mp.16589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 05/17/2023] [Accepted: 06/12/2023] [Indexed: 07/04/2023] Open
Abstract
BACKGROUND Digital breast tomosynthesis (DBT) has gained popularity as breast imaging modality due to its pseudo-3D reconstruction and improved accuracy compared to digital mammography. However, DBT faces challenges in image quality and quantitative accuracy due to scatter radiation. Recent advancements in deep learning (DL) have shown promise in using fast convolutional neural networks for scatter correction, achieving comparable results to Monte Carlo (MC) simulations. PURPOSE To predict the scatter radiation signal in DBT projections within clinically-acceptable times and using only clinically-available data, such as compressed breast thickness and acquisition angle. METHODS MC simulations to obtain scatter estimates were generated from two types of digital breast phantoms. One set consisted of 600 realistically-shaped homogeneous breast phantoms for initial DL training. The other set was composed of 80 anthropomorphic phantoms, containing realistic internal tissue texture, aimed at fine tuning the DL model for clinical applications. The MC simulations generated scatter and primary maps per projection angle for a wide-angle DBT system. Both datasets were used to train (using 7680 projections from homogeneous phantoms), validate (using 960 and 192 projections from the homogeneous and anthropomorphic phantoms, respectively), and test (using 960 and 48 projections from the homogeneous and anthropomorphic phantoms, respectively) the DL model. The DL output was compared to the corresponding MC ground truth using both quantitative and qualitative metrics, such as mean relative and mean absolute relative differences (MRD and MARD), and to previously-published scatter-to-primary (SPR) ratios for similar breast phantoms. The scatter corrected DBT reconstructions were evaluated by analyzing the obtained linear attenuation values and by visual assessment of corrected projections in a clinical dataset. The time required for training and prediction per projection, as well as the time it takes to produce scatter-corrected projection images, were also tracked. RESULTS The quantitative comparison between DL scatter predictions and MC simulations showed a median MRD of 0.05% (interquartile range (IQR), -0.04% to 0.13%) and a median MARD of 1.32% (IQR, 0.98% to 1.85%) for homogeneous phantom projections and a median MRD of -0.21% (IQR, -0.35% to -0.07%) and a median MARD of 1.43% (IQR, 1.32% to 1.66%) for the anthropomorphic phantoms. The SPRs for different breast thicknesses and at different projection angles were within ± 15% of the previously-published ranges. The visual assessment showed good prediction capabilities of the DL model with a close match between MC and DL scatter estimates, as well as between DL-based scatter corrected and anti-scatter grid corrected cases. The scatter correction improved the accuracy of the reconstructed linear attenuation of adipose tissue, reducing the error from -16% and -11% to -2.3% and 4.4% for an anthropomorphic digital phantom and clinical case with similar breast thickness, respectively. The DL model training took 40 min and prediction of a single projection took less than 0.01 s. Generating scatter corrected images took 0.03 s per projection for clinical exams and 0.16 s for one entire projection set. CONCLUSIONS This DL-based method for estimating the scatter signal in DBT projections is fast and accurate, paving the way for future quantitative applications.
Collapse
Affiliation(s)
- Marta C Pinto
- Dept. of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Franziska Mauter
- Dept. of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
- Div. of Ionizing radiation, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
| | - Koen Michielsen
- Dept. of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Ioannis Sechopoulos
- Dept. of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
- Dutch Expert Centre for Screening (LRCB), Nijmegen, The Netherlands
- Technical Medicine Centre, University of Twente, Enschede, The Netherlands
| |
Collapse
|
2
|
Mettivier G, Sarno A, Varallo A, Russo P. Attenuation coefficient in the energy range 14–36 keV of 3D printing materials for physical breast phantoms. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac8966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 08/12/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. To measure the monoenergetic x-ray linear attenuation coefficient, μ, of fused deposition modeling (FDM) colored 3D printing materials (ABS, PLAwhite, PLAorange, PET and NYLON), used as adipose, glandular or skin tissue substitutes for manufacturing physical breast phantoms. Approach. Attenuation data (at 14, 18, 20, 24, 28, 30 and 36 keV) were acquired at Elettra synchrotron radiation facility, with step-wedge objects, using the Lambert–Beer law and a CCD imaging detector. Test objects were 3D printed using the Ultimaker 3 FDM printer. PMMA, Nylon-6 and high-density polyethylene step objects were also investigated for the validation of the proposed methodology. Printing uniformity was assessed via monoenergetic and polyenergetic imaging (32 kV, W/Rh). Main results. Maximum absolute deviation of μ for PMMA, Nylon-6 and HD-PE was 5.0%, with reference to literature data. For ABS and NYLON, μ differed by less than 6.1% and 7.1% from that of adipose tissue, respectively; for PET and PLAorange the difference was less than 11.3% and 6.3% from glandular tissue, respectively. PLAorange is a good substitute of skin (differences from −9.4% to +1.2%). Hence, ABS and NYLON filaments are suitable adipose tissue substitutes, while PET and PLAorange mimick the glandular tissue. PLAwhite could be printed at less than 100% infill density for matching the attenuation of glandular tissue, using the measured density calibration curve. The printing mesh was observed for sample thicknesses less than 60 mm, imaged in the direction normal to the printing layers. Printing dimensional repeatability and reproducibility was less 1%. Significance. For the first time an experimental determination was provided of the linear attenuation coefficient of common 3D printing filament materials with estimates of μ at all energies in the range 14–36 keV, for their use in mammography, breast tomosynthesis and breast computed tomography investigations.
Collapse
|
3
|
Okoh FO, Kabir NA, Yusof MFM, Mohammed ASA, Zainon R. Investigation of polyvinyl alcohol (PVAL) composite gels and the outcome of variation in breast phantom densities on image quality and dose in full-field digital mammography. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
4
|
Mohammad Rafiei M, Parsaei S, Kaur P, Singh KJ, Büyükyıldız M, Kurudirek M. A Monte Carlo investigation of some important radiation parameters and tissue equivalency for photons below 1 keV in human tissues. Biomed Phys Eng Express 2022; 8. [PMID: 34902852 DOI: 10.1088/2057-1976/ac428f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/13/2021] [Indexed: 11/11/2022]
Abstract
The attenuation coefficients are important input values in estimating not only the dose and exposure in radiotherapy and medical imaging, but also in the proper design of photon shields. While studies are widely available above 1 keV, the attenuation coefficients of human tissues for photon energies less than 1 keV have not been studied yet. In this study, the attenuation coefficients of water and some human tissues were estimated for low energy photons using the MCNP6.1 code in the energy region 0.1 keV-1 keV. Mass attenuation coefficients were estimated at photon energies of 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 and 1000 eV for water and ten human tissues (Soft, Breast, Lung, Bone, Brain, Eye lens, Ovary, Skin, Thyroid and Prostate). Results were compared with those available in literature and a fairly good agreement has been obtained. These data were then used to calculate the mean free path, half value layer, tenth value layer, effective atomic number and specific gamma-ray constant (useful for calculation of dose rate) as well. Moreover, for comparison the effective atomic number of the water has been obtained using the results of this work and using the data available in NIST database from 0.1 to 1 keV. In addition, the human tissues were compared with some tissue equivalent materials in terms of effective atomic number and specific gamma-ray constant to study the tissue equivalency from the results, the muscle-equivalent liquid with sucrose has been found to be the best tissue equivalent material for soft tissue, eye lens and brain with relative difference below 4.1%.
Collapse
Affiliation(s)
| | - Sara Parsaei
- Faculty of Physics, Shahid Bahonar University of Kerman, Kerman, Iran
| | - Parminder Kaur
- Department of Physics, Guru Nanak Dev University, Amritsar, 143005, India
| | - K J Singh
- Department of Physics, Guru Nanak Dev University, Amritsar, 143005, India
| | - Mehmet Büyükyıldız
- Department of Physics, Faculty of Engineering and Natural Sciences, Bursa Technical University, Bursa, Turkey
| | - Murat Kurudirek
- Technical Sciences Vocational College, Department of Electricity and Energy, Ataturk University, Erzurum, Turkey
| |
Collapse
|
5
|
Falchini G, Malezan A, Poletti M, Soria E, Pasqualini M, Perez R. Analysis of phosphorous content in cancer tissue by synchrotron micro-XRF. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2020.109157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
6
|
Conceição ALC, Perlich J, Haas S, Funari SS. SAXS-CT: a nanostructure resolving microscopy for macroscopic biologic specimens. Biomed Phys Eng Express 2020; 6:035012. [DOI: 10.1088/2057-1976/ab7cad] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
7
|
Chang TY, Lai KJ, Tu CY, Wu J. Three-layer heterogeneous mammographic phantoms for Monte Carlo simulation of normalized glandular dose coefficients in mammography. Sci Rep 2020; 10:2234. [PMID: 32042071 PMCID: PMC7010737 DOI: 10.1038/s41598-020-59317-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/27/2020] [Indexed: 12/15/2022] Open
Abstract
Normalized glandular dose (DgN) coefficients obtained using homogeneous breast phantoms are commonly used in breast dosimetry for mammography. However, glandular tissue is heterogeneously distributed in the breast. This study aimed to construct three-layer heterogeneous mammographic phantoms (THEPs) to examine the effect of glandular distribution on DgN coefficient. Each layer of THEPs was set to 25%, 50%, or 75% glandular fraction to emulate heterogeneous glandular distribution. Monte Carlo simulation was performed to attain mean glandular dose (MGD) and air kerma at 22-36 kVp and W/Al, W/Rh, and W/Ag target-filter combinations. The heterogeneous DgN coefficient was calculated as functions of the mean glandular fraction (MGF), breast thickness, tube voltage, and half-value layer. At 50% MGF, the heterogeneous DgN coefficients for W/Al, W/Rh, and W/Ag differed by 40.3%, 36.7%, and 31.2%. At 9-cm breast thickness, the DgN values of superior and inferior glandular distributions were 25.4% higher and 29.2% lower than those of uniform distribution. The proposed THEPs can be integrated with conventional breast dosimetry to consider the heterogeneous glandular distribution in clinical practice.
Collapse
Affiliation(s)
- Tien-Yu Chang
- Department of Radiology, Cheng Hsin General Hospital, Taipei, Taiwan
| | - Kuan-Jen Lai
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Chun-Yuan Tu
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
- Department of Radiology, Mackay Memorial Hospital, Taipei, Taiwan
| | - Jay Wu
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.
| |
Collapse
|
8
|
Frimaio A, Nascimento BC, Barrio RM, Campos LL, Costa PR. Reprint of “X-ray spectrometry applied for determination of linear attenuation coefficient of tissue-equivalent materials”. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2019.108553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
9
|
Soares L, Gobo M, Poletti M. Measurement of the linear attenuation coefficient of breast tissues using polienergetic x-ray for energies from 12 to 50 keV and a silicon dispersive detector. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2019.03.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
10
|
Characterization and applicability of low-density materials for making 3D physical anthropomorphic breast phantoms. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.108361] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
11
|
Piai A, Contillo A, Arfelli F, Bonazza D, Brombal L, Assunta Cova M, Delogu P, Di Trapani V, Donato S, Golosio B, Mettivier G, Oliva P, Rigon L, Taibi A, Tonutti M, Tromba G, Zanconati F, Longo R. Quantitative characterization of breast tissues with dedicated CT imaging. Phys Med Biol 2019; 64:155011. [PMID: 31234148 DOI: 10.1088/1361-6560/ab2c29] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A quantitative characterization of the soft tissues composing the human breast is achieved by means of a monochromatic CT phase-contrast imaging system, through accurate measurements of their attenuation coefficients within the energy range of interest for breast CT clinical examinations. Quantitative measurements of linear attenuation coefficients are performed on tomographic reconstructions of surgical samples, using monochromatic x-ray beams from a synchrotron source and a free space propagation setup. An online calibration is performed on the obtained reconstructions, in order to reassess the validity of the standard calibration procedure of the CT scanner. Three types of healthy tissues (adipose, glandular, and skin) and malignant tumors, when present, are considered from each sample. The measured attenuation coefficients are in very good agreement with the outcomes of similar studies available in the literature, although they span an energy range that was mostly neglected in the previous studies. No globally significant differences are observed between healthy and malignant dense tissues, although the number of considered samples does not appear sufficient to address the issue of a quantitative differentiation of tumors. The study assesses the viability of the proposed methodology for the measurement of linear attenuation coefficients, and provides a denser sampling of attenuation data in the energy range useful to breast CT.
Collapse
Affiliation(s)
- Anna Piai
- Department of Physics, University of Trieste, Via Valerio 2, 34127 Trieste, Italy. INFN Division of Trieste, Via Valerio 2, 34127 Trieste, Italy. Present address: Department of Physics, University of Milan, Via G. Celoria 16, 20133 Milano, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Frimaio A, Nascimento BC, Barrio RM, Campos LL, Costa PR. X-ray spectrometry applied for determination of linear attenuation coefficient of tissue-equivalent materials. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.03.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
13
|
He Y, Qin S, Dyer BA, Zhang H, Zhao L, Chen T, Zheng F, Sun Y, Shi L, Rong Y, Qiu J. Characterizing mechanical and medical imaging properties of polyvinyl chloride-based tissue-mimicking materials. J Appl Clin Med Phys 2019; 20:176-183. [PMID: 31207035 PMCID: PMC6612694 DOI: 10.1002/acm2.12661] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 04/25/2019] [Accepted: 05/23/2019] [Indexed: 01/09/2023] Open
Abstract
Polyvinyl chloride (PVC) is a commonly used tissue‐mimicking material (TMM) for phantom construction using 3D printing technology. PVC‐based TMMs consist of a mixture of PVC powder and dioctyl terephthalate as a softener. In order to allow the clinical use of a PVC‐based phantom use across CT and magnetic resonance imaging (MRI) imaging platforms, we evaluated the mechanical and physical imaging characteristics of ten PVC samples. The samples were made with different PVC‐softener ratios to optimize phantom bioequivalence with physiologic human tissue. Phantom imaging characteristics, including computed tomography (CT) number, MRI relaxation time, and mechanical properties (e.g., Poisson’s ratio and elastic modulus) were quantified. CT number varied over a range of approximately −10 to 110 HU. The relaxation times of the T1‐weighted and T2‐weighted images were 206.81 ± 17.50 and 20.22 ± 5.74 ms, respectively. Tensile testing was performed to evaluate mechanical properties on the three PVC samples that were closest to human tissue. The elastic moduli for these samples ranged 7.000–12.376 MPa, and Poisson’s ratios were 0.604–0.644. After physical and imaging characterization of the various PVC‐based phantoms, we successfully produced a bioequivalent phantom compatible with multimodal imaging platforms for machine calibration and image optimization/benchmarking. By combining PVC with 3D printing technologies, it is possible to construct imaging phantoms simulating human anatomies with tissue equivalency.
Collapse
Affiliation(s)
- Yaoyao He
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Shengxue Qin
- College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Brandon A Dyer
- Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, CA, USA
| | - Hongbin Zhang
- College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Lifen Zhao
- School of Material Science and Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Tiao Chen
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Department of Radiology, Hubei Cancer Hospital, Wuhan, China
| | - Fenglian Zheng
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Yong Sun
- Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Liting Shi
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Yi Rong
- Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, CA, USA
| | - Jianfeng Qiu
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| |
Collapse
|
14
|
Oliver PAK, Thomson RM. Investigating energy deposition in glandular tissues for mammography using multiscale Monte Carlo simulations. Med Phys 2019; 46:1426-1436. [PMID: 30657190 DOI: 10.1002/mp.13372] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/29/2018] [Accepted: 12/22/2018] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To investigate energy deposition in glandular tissues of the breast on macro- and microscopic length scales in the context of mammography. METHODS Multiscale mammography models of breasts are developed, which include segmented, voxelized macroscopic tissue structure as well as nine regions of interest (ROIs) embedded throughout the breast tissue containing explicitly-modelled cells. Using a 30 kVp Mo/Mo spectrum, Monte Carlo (MC) techniques are used to calculate dose to ∼mm voxels containing glandular and/or adipose tissues, as well as energy deposition on cellular length scales. ROIs consist of at least 1000 mammary epithelial cells and ∼200 adipocytes; specific energy (energy imparted per unit mass; stochastic analogue of the absorbed dose) is calculated within mammary epithelial cell nuclei. RESULTS Macroscopic dose distributions within segmented breast tissue demonstrate considerable variation in energy deposition depending on depth and tissue structure. Doses to voxels containing glandular tissue vary between ∼0.1 and ∼4 times the mean glandular dose (MGD, averaged over the entire breast). Considering microscopic length scales, mean specific energies for mammary epithelial cell nuclei are ∼30% higher than the corresponding glandular voxel dose. Additionally, due to the stochastic nature of radiation, there is considerable variation in energy deposition throughout a cell population within a ROI: for a typical glandular voxel dose of 4 mGy, the standard deviation of the specific energy for mammary epithelial cell nuclei is 85% relative to the mean. Thus, for a glandular voxel dose of 4 mGy at the centre of the breast, corresponding mammary epithelial cell nuclei will receive specific energies up to ∼9 mGy (considering the upper end of the 1σ standard deviation of the specific energy), while a ROI located 2 cm closer to the radiation source will receive specific energies up to ∼40 mGy. Energy deposition within mammary epithelial cell nuclei is sensitive to cell model details including cellular elemental compositions and nucleus size, underlining the importance of realistic cellular models. CONCLUSIONS There is considerable variation in energy deposition on both macro- and microscopic length scales for mammography, with glandular voxel doses and corresponding cell nuclei specific energies many times higher than the MGD in parts of the breast. These results should be considered for radiation-induced cancer risk evaluation in mammography which has traditionally focused on a single metric such as the MGD.
Collapse
Affiliation(s)
- Patricia A K Oliver
- Carleton Laboratory for Radiotherapy Physics, Physics Dept., Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Rowan M Thomson
- Carleton Laboratory for Radiotherapy Physics, Physics Dept., Carleton University, Ottawa, ON, K1S 5B6, Canada
| |
Collapse
|
15
|
Fredenberg E, Willsher P, Moa E, Dance DR, Young KC, Wallis MG. Measurement of breast-tissue x-ray attenuation by spectral imaging: fresh and fixed normal and malignant tissue. Phys Med Biol 2018; 63:235003. [PMID: 30465547 DOI: 10.1088/1361-6560/aaea83] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. In mammography, measurement of breast density, dose estimation, and differentiation between cysts and solid tumours are example applications requiring accurate data on tissue attenuation. Published attenuation data are, however, sparse and cover a relatively wide range. To supplement available data we have previously measured the attenuation of cyst fluid and solid lesions using photon-counting spectral mammography. The present study aims to measure the attenuation of normal adipose and glandular tissue, and to measure the effect of formalin fixation, a major uncertainty in published data. A total of 27 tumour specimens, seven fibro-glandular tissue specimens, and 15 adipose tissue specimens were included. Spectral (energy-resolved) images of the samples were acquired and the image signal was mapped to equivalent thicknesses of two known reference materials, from which x-ray attenuation as a function of energy can be derived. The spread in attenuation between samples was relatively large, partly because of natural variation. The variation of malignant and glandular tissue was similar, whereas that of adipose tissue was lower. Formalin fixation slightly altered the attenuation of malignant and glandular tissue, whereas the attenuation of adipose tissue was not significantly affected. The difference in attenuation between fresh tumour tissue and cyst fluid was smaller than has previously been measured for fixed tissue, but the difference was still significant and discrimination of these two tissue types is still possible. The difference between glandular and malignant tissue was close-to significant; it is reasonable to expect a significant difference with a larger set of samples. We believe that our studies have contributed to lower the overall uncertainty of breast tissue attenuation in the literature due to the relatively large sample sets, the novel measurement method, and by clarifying the difference between fresh and fixed tissue.
Collapse
Affiliation(s)
- Erik Fredenberg
- Philips Research, Knarrarnäsgatan 7, 164 85 Kista, Sweden. Philips Health Systems, Mammography Solutions, Torshamnsgatan 30A, 164 40 Kista, Sweden. Author to whom any correspondence should be addressed
| | | | | | | | | | | |
Collapse
|
16
|
Cho HM, Ding H, Kumar N, Sennung D, Molloi S. Calibration phantoms for accurate water and lipid density quantification using dual energy mammography. Phys Med Biol 2017; 62:4589-4603. [DOI: 10.1088/1361-6560/aa6f31] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
17
|
Abstract
The estimation of the mean glandular dose to the breast (MGD) for x-ray based imaging modalities forms an essential part of quality control and is needed for risk estimation and for system design and optimisation. This review considers the development of methods for estimating the MGD for mammography, digital breast tomosynthesis (DBT) and dedicated breast CT (DBCT). Almost all of the methodology used employs Monte Carlo calculated conversion factors to relate the measurable quantity, generally the incident air kerma, to the MGD. After a review of the size and composition of the female breast, the various mathematical models used are discussed, with particular emphasis on models for mammography. These range from simple geometrical shapes, to the more recent complex models based on patient DBCT examinations. The possibility of patient-specific dose estimates is considered as well as special diagnostic views and the effect of breast implants. Calculations using the complex models show that the MGD for mammography is overestimated by about 30% when the simple models are used. The design and uses of breast-simulating test phantoms for measuring incident air kerma are outlined and comparisons made between patient and phantom-based dose estimates. The most widely used national and international dosimetry protocols for mammography are based on different simple geometrical models of the breast, and harmonisation of these protocols using more complex breast models is desirable.
Collapse
Affiliation(s)
- David R Dance
- National Co-ordinating Centre for the Physics of Mammography (NCCPM), Royal Surrey County Hospital, Guildford GU2 7XX, United Kingdom and Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom
| | - Ioannis Sechopoulos
- Department of Radiology and Nuclear Medicine, Radboud University Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands and Dutch reference centre for screening (LRCB), PO Box 6873, 6503 GJ Nijmegen, The Netherlands
| |
Collapse
|
18
|
Ding H, Sennung D, Cho HM, Molloi S. Quantification of breast lesion compositions using low-dose spectral mammography: A feasibility study. Med Phys 2016; 43:5527. [PMID: 27782705 PMCID: PMC5035310 DOI: 10.1118/1.4962481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 08/23/2016] [Accepted: 08/29/2016] [Indexed: 01/15/2023] Open
Abstract
PURPOSE The positive predictive power for malignancy can potentially be improved, if the chemical compositions of suspicious breast lesions can be reliably measured in screening mammography. The purpose of this study is to investigate the feasibility of quantifying breast lesion composition, in terms of water and lipid contents, with spectral mammography. METHODS Phantom and tissue samples were imaged with a spectral mammography system based on silicon-strip photon-counting detectors. Dual-energy calibration was performed for material decomposition, using plastic water and adipose-equivalent phantoms as the basis materials. The step wedge calibration phantom consisted of 20 calibration configurations, which ranged from 2 to 8 cm in thickness and from 0% to 100% in plastic water density. A nonlinear rational fitting function was used in dual-energy calibration of the imaging system. Breast lesion phantoms, made from various combinations of plastic water and adipose-equivalent disks, were embedded in a breast mammography phantom with a heterogeneous background pattern. Lesion phantoms with water densities ranging from 0% to 100% were placed at different locations of the heterogeneous background phantom. The water density in the lesion phantoms was measured using dual-energy material decomposition. The thickness and density of the background phantom were varied to test the accuracy of the decomposition technique in different configurations. In addition, an in vitro study was also performed using mixtures of lean and fat bovine tissue of 25%, 50%, and 80% lean weight percentages as the background. Lesions were simulated by using breast lesion phantoms, as well as small bovine tissue samples, composed of carefully weighed lean and fat bovine tissues. The water densities in tissue samples were measured using spectral mammography and compared to measurement using chemical decomposition of the tissue. RESULTS The thickness of measured and known water contents was compared for various lesion configurations. There was a good linear correlation between the measured and the known values. The root-mean-square errors in water thickness measurements were 0.3 and 0.2 mm for the plastic phantom and bovine tissue backgrounds, respectively. CONCLUSIONS The results indicate that spectral mammography can be used to accurately characterize breast lesion composition in terms of their equivalent water and lipid contents.
Collapse
Affiliation(s)
- Huanjun Ding
- Department of Radiological Sciences, University of California, Irvine, California 92697
| | - David Sennung
- Department of Radiological Sciences, University of California, Irvine, California 92697
| | - Hyo-Min Cho
- Department of Radiological Sciences, University of California, Irvine, California 92697
| | - Sabee Molloi
- Department of Radiological Sciences, University of California, Irvine, California 92697
| |
Collapse
|
19
|
Fredenberg E, Kilburn-Toppin F, Willsher P, Moa E, Danielsson M, Dance DR, Young KC, Wallis MG. Measurement of breast-tissue x-ray attenuation by spectral mammography: solid lesions. Phys Med Biol 2016; 61:2595-612. [PMID: 26961507 DOI: 10.1088/0031-9155/61/7/2595] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. For instance, techniques to distinguish between cysts and solid tumours at mammography screening would be highly desirable to reduce recalls, but the development requires knowledge of the x-ray attenuation for cysts and tumours. We have previously measured the attenuation of cyst fluid using photon-counting spectral mammography. Data on x-ray attenuation for solid breast lesions are available in the literature, but cover a relatively wide range, likely caused by natural spread between samples, random measurement errors, and different experimental conditions. In this study, we have adapted a previously developed spectral method to measure the linear attenuation of solid breast lesions. A total of 56 malignant and 5 benign lesions were included in the study. The samples were placed in a holder that allowed for thickness measurement. Spectral (energy-resolved) images of the samples were acquired and the image signal was mapped to equivalent thicknesses of two known reference materials, which can be used to derive the x-ray attenuation as a function of energy. The spread in equivalent material thicknesses was relatively large between samples, which is likely to be caused mainly by natural variation and only to a minor extent by random measurement errors and sample inhomogeneity. No significant difference in attenuation was found between benign and malignant solid lesions. The separation between cyst-fluid and tumour attenuation was, however, significant, which suggests it may be possible to distinguish cystic from solid breast lesions, and the results lay the groundwork for a clinical trial. In addition, the study adds a relatively large sample set to the published data and may contribute to a reduction in the overall uncertainty in the literature.
Collapse
Affiliation(s)
- Erik Fredenberg
- Philips Health Systems, Mammography Solutions, Smidesvägen 5, 171 41 Solna, Sweden
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Ding H, Klopfer MJ, Ducote JL, Masaki F, Molloi S. Breast tissue characterization with photon-counting spectral CT imaging: a postmortem breast study. Radiology 2014; 272:731-8. [PMID: 24814180 DOI: 10.1148/radiol.14132732] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To investigate the feasibility of breast tissue characterization in terms of water, lipid, and protein contents with a spectral computed tomographic (CT) system based on a cadmium zinc telluride (CZT) photon-counting detector by using postmortem breasts. MATERIALS AND METHODS Nineteen pairs of postmortem breasts were imaged with a CZT-based photon-counting spectral CT system with beam energy of 100 kVp. The mean glandular dose was estimated to be in the range of 1.8-2.2 mGy. The images were corrected for pulse pile-up and other artifacts by using spectral distortion corrections. Dual-energy decomposition was then applied to characterize each breast into water, lipid, and protein contents. The precision of the three-compartment characterization was evaluated by comparing the composition of right and left breasts, where the standard error of the estimations was determined. The results of dual-energy decomposition were compared by using averaged root mean square to chemical analysis, which was used as the reference standard. RESULTS The standard errors of the estimations of the right-left correlations obtained from spectral CT were 7.4%, 6.7%, and 3.2% for water, lipid, and protein contents, respectively. Compared with the reference standard, the average root mean square error in breast tissue composition was 2.8%. CONCLUSION Spectral CT can be used to accurately quantify the water, lipid, and protein contents in breast tissue in a laboratory study by using postmortem specimens.
Collapse
Affiliation(s)
- Huanjun Ding
- From the Department of Radiological Sciences, University of California-Irvine, Medical Sciences I, B-140, Irvine, CA 92697
| | | | | | | | | |
Collapse
|
21
|
Fredenberg E, Dance DR, Willsher P, Moa E, von Tiedemann M, Young KC, Wallis MG. Measurement of breast-tissue x-ray attenuation by spectral mammography: first results on cyst fluid. Phys Med Biol 2013; 58:8609-20. [PMID: 24254377 DOI: 10.1088/0031-9155/58/24/8609] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. For instance, techniques to better characterize cysts at mammography screening would be highly desirable to reduce recalls, but the development is hampered by the lack of attenuation data for cysts. We have developed a method to measure x-ray attenuation of tissue samples using a prototype photon-counting spectral mammography unit. The method was applied to measure the attenuation of 50 samples of breast cyst fluid and 50 samples of water. Spectral (energy-resolved) images of the samples were acquired and the image signal was mapped to equivalent thicknesses of two known reference materials, which can be used to derive the x-ray attenuation as a function of energy. The attenuation of cyst fluid was found to be significantly different from water. There was a relatively large natural spread between different samples of cyst fluid, whereas the homogeneity of each individual sample was found to be good; the variation within samples did not reach above the quantum noise floor. The spectral method proved stable between several measurements on the same sample. Further, chemical analysis and elemental attenuation calculation were used to validate the spectral measurement on a subset of the samples. The two methods agreed within the precision of the elemental attenuation calculation over the mammographic energy range.
Collapse
|
22
|
Altman MB, Flynn MJ, Nishikawa RM, Chetty IJ, Barton KN, Movsas B, Kim JH, Brown SL. The potential of iodine for improving breast cancer diagnosis and treatment. Med Hypotheses 2012; 80:94-8. [PMID: 23171625 DOI: 10.1016/j.mehy.2012.10.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 10/12/2012] [Accepted: 10/28/2012] [Indexed: 11/25/2022]
Abstract
Early detection through modalities such as mammography remains pivotal in the fight against breast cancer. The detectability of breast cancer through mammography is rooted in the differential X-ray attenuation properties of cancerous and normal breast tissue. An unexplored component of the X-ray contrast between fibrous breast tissue and similarly composed tumor tissue is the presence of naturally localized iodine in the cancer but not healthy breast tissue. It is hypothesized that differing amounts of iodine are present in tumor versus normal breast tissue that leads to more easily detectable cancer due to an increased Z value of the tumor tissue relative to the healthy tissue, which results in enhanced differences in X-ray attenuation properties between the two tissues and thus greater radiographic contrast. The hypothesis is supported by experimental observations explaining how iodine could localize in the tumor tissue but not surrounding healthy tissue. Breast cancer cells express the sodium-iodide symporter (NIS), an ion pump which sequesters iodine in tumor cells. Healthy non-lactating breast tissue, in contrast, does not express NIS. Further evidence for the differential expression of NIS resulting in X-ray contrast enhancement in breast cancer is the established correlation between expression of insulin growth factor (IGF) and enhanced X-ray contrast, and the evidence that IGF is a promoter for NIS. Ultimately, if the expression of iodine can be shown to be a component of radiographic contrast between healthy and tumor breast tissue, this could be used to drive the development of new technology and techniques for use in the detection and treatment of breast cancer. The proof of this hypothesis could thus have a substantial impact in the fight against breast cancer.
Collapse
Affiliation(s)
- Michael B Altman
- Henry Ford Health System, Department of Radiation Oncology, 2799 W. Grand Blvd., Detroit, MI 48202, USA.
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Antoniassi M, Conceição A, Poletti M. Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation. Appl Radiat Isot 2012; 70:1351-4. [DOI: 10.1016/j.apradiso.2012.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 01/02/2012] [Accepted: 01/02/2012] [Indexed: 10/14/2022]
|
24
|
Freed M, Badal A, Jennings RJ, de las Heras H, Myers KJ, Badano A. X-ray properties of an anthropomorphic breast phantom for MRI and x-ray imaging. Phys Med Biol 2011; 56:3513-33. [PMID: 21606556 DOI: 10.1088/0031-9155/56/12/005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The purpose of this study is to characterize the x-ray properties of a dual-modality, anthropomorphic breast phantom whose MRI properties have been previously evaluated. The goal of this phantom is to provide a platform for optimization and standardization of two- and three-dimensional x-ray and MRI breast imaging modalities for the purpose of lesion detection and discrimination. The phantom is constructed using a mixture of lard and egg whites, resulting in a variable, tissue-mimicking structure with separate adipose- and glandular-mimicking components. The phantom can be produced with either a compressed or uncompressed shape. Mass attenuation coefficients of the phantom materials were estimated using elemental compositions from the USDA National Nutrient Database for Standard Reference and the atomic interaction models from the Monte Carlo code PENELOPE and compared with human values from the literature. The image structure was examined quantitatively by calculating and comparing spatial covariance matrices of the phantom and patient mammography images. Finally, a computerized version of the phantom was created by segmenting a computed tomography scan and used to simulate x-ray scatter of the phantom in a mammography geometry. Mass attenuation coefficients of the phantom materials were within 20% and 15% of the values for adipose and glandular tissues, respectively, which is within the estimation error of these values. Matching was improved at higher energies (>20 keV). Tissue structures in the phantom have a size similar to those in the patient data, but are slightly larger on average. Correlations in the patient data appear to be longer than those in the phantom data in the anterior-posterior direction; however, they are within the error bars of the measurement. Simulated scatter-to-primary ratio values of the phantom images were as high as 85% in some areas and were strongly affected by the heterogeneous nature of the phantom. Key physical x-ray properties of the phantom have been quantitatively evaluated and shown to be comparable to those of breast tissue. Since the MRI properties of the phantom have been previously evaluated, we believe it is a useful tool for quantitative evaluation of two- and three-dimensional x-ray and MRI breast imaging modalities for the purpose of lesion detection and characterization.
Collapse
Affiliation(s)
- Melanie Freed
- Division of Imaging and Applied Mathematics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993-0002, USA.
| | | | | | | | | | | |
Collapse
|
25
|
Tomal A, Poletti M, Caldas L. Evaluation of subject contrast and normalized average glandular dose by semi-analytical models. Appl Radiat Isot 2010; 68:755-9. [DOI: 10.1016/j.apradiso.2009.09.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|