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Longo R, Arfelli F, Bonazza D, Bottigli U, Brombal L, Contillo A, Cova MA, Delogu P, Di Lillo F, Di Trapani V, Donato S, Dreossi D, Fanti V, Fedon C, Golosio B, Mettivier G, Oliva P, Pacilè S, Sarno A, Rigon L, Russo P, Taibi A, Tonutti M, Zanconati F, Tromba G. Advancements towards the implementation of clinical phase-contrast breast computed tomography at Elettra. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:1343-1353. [PMID: 31274463 DOI: 10.1107/s1600577519005502] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/23/2019] [Indexed: 06/09/2023]
Abstract
Breast computed tomography (BCT) is an emerging application of X-ray tomography in radiological practice. A few clinical prototypes are under evaluation in hospitals and new systems are under development aiming at improving spatial and contrast resolution and reducing delivered dose. At the same time, synchrotron-radiation phase-contrast mammography has been demonstrated to offer substantial advantages when compared with conventional mammography. At Elettra, the Italian synchrotron radiation facility, a clinical program of phase-contrast BCT based on the free-space propagation approach is under development. In this paper, full-volume breast samples imaged with a beam energy of 32 keV delivering a mean glandular dose of 5 mGy are presented. The whole acquisition setup mimics a clinical study in order to evaluate its feasibility in terms of acquisition time and image quality. Acquisitions are performed using a high-resolution CdTe photon-counting detector and the projection data are processed via a phase-retrieval algorithm. Tomographic reconstructions are compared with conventional mammographic images acquired prior to surgery and with histologic examinations. Results indicate that BCT with monochromatic beam and free-space propagation phase-contrast imaging provide relevant three-dimensional insights of breast morphology at clinically acceptable doses and scan times.
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Affiliation(s)
- Renata Longo
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Fulvia Arfelli
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Deborah Bonazza
- Department of Medical Science, Cattinara Hospital, University of Trieste, 34149 Trieste, Italy
| | - Ubaldo Bottigli
- Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy
| | - Luca Brombal
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Adriano Contillo
- Department of Physics and Earth Science, University of Ferrara, 44122 Ferrara, Italy
| | - Maria A Cova
- Department of Medical Science, Cattinara Hospital, University of Trieste, 34149 Trieste, Italy
| | - Pasquale Delogu
- Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy
| | - Francesca Di Lillo
- Department of Physics `E. Pancini', University of Napoli `Federico II', 80126 Napoli, Italy
| | - Vittorio Di Trapani
- Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy
| | - Sandro Donato
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Diego Dreossi
- Elettra-Sincrotrone Trieste SCpA, 34149 Trieste, Italy
| | - Viviana Fanti
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | | | - Bruno Golosio
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Giovanni Mettivier
- Department of Physics `E. Pancini', University of Napoli `Federico II', 80126 Napoli, Italy
| | | | - Serena Pacilè
- Elettra-Sincrotrone Trieste SCpA, 34149 Trieste, Italy
| | - Antonio Sarno
- Department of Physics `E. Pancini', University of Napoli `Federico II', 80126 Napoli, Italy
| | - Luigi Rigon
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Paolo Russo
- Department of Physics `E. Pancini', University of Napoli `Federico II', 80126 Napoli, Italy
| | - Angelo Taibi
- Department of Physics and Earth Science, University of Ferrara, 44122 Ferrara, Italy
| | - Maura Tonutti
- ASUITS, Trieste University Hospital, Department of Radiology, 34100 Trieste, Italy
| | - Fabrizio Zanconati
- Department of Medical Science, Cattinara Hospital, University of Trieste, 34149 Trieste, Italy
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Direct Thermal Growth of Large Scale Cl-doped CdTe Film for Low Voltage High Resolution X-ray Image Sensor. Sci Rep 2018; 8:14810. [PMID: 30287874 PMCID: PMC6172199 DOI: 10.1038/s41598-018-33240-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/20/2018] [Indexed: 11/28/2022] Open
Abstract
Polycrystalline cadmium telluride (CdTe) X-ray photodetector with advanced performance was fabricated in a Schottky diode form by direct thermal deposition (evaporation) on pixelized complementary metal oxide semiconductor (CMOS) readout panel. Our CdTe X-ray detector shows such a variety of benefits as relatively low process temperature, low cost, low operation voltage less than 40 V, and higher sensitivity and spatial resolution than those of commercial a-Se detectors. CdTe has cubic Zinc Blende structure and maintains p-type conduction after growth in general. For low voltage operation, we succeeded in Cl doping at all stage of CdTe film deposition, and as a result, hole concentration of p-type CdTe was reduced to ~1012 cm−3 from ~1015 cm−3, and such concentration reduction could enable our Schottky diode with Ti electrode to operate at a reverse bias of less than 40 V. Our CdTe Schottky diode/CMOS pixel array as a direct conversion type imager demonstrates much higher resolution X-ray imaging in 7 × 9 cm2 large scale than that of CsI/CMOS array, an indirect conversion imager. To our limited knowledge, our results on polycrystalline CdTe Schottky diode/CMOS array would be very novel as a first demonstration of active pixel sensor system equipped with directly deposited large scale X-ray detector.
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Brombal L, Donato S, Brun F, Delogu P, Fanti V, Oliva P, Rigon L, Di Trapani V, Longo R, Golosio B. Large-area single-photon-counting CdTe detector for synchrotron radiation computed tomography: a dedicated pre-processing procedure. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:1068-1077. [PMID: 29979168 DOI: 10.1107/s1600577518006197] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
Large-area CdTe single-photon-counting detectors are becoming more and more attractive in view of low-dose imaging applications due to their high efficiency, low intrinsic noise and absence of a scintillating screen which affects spatial resolution. At present, however, since the dimensions of a single sensor are small (typically a few cm2), multi-module architectures are needed to obtain a large field of view. This requires coping with inter-module gaps and with close-to-edge pixels, which generally show a non-optimal behavior. Moreover, high-Z detectors often show gain variations in time due to charge trapping: this effect is detrimental especially in computed tomography (CT) applications where a single tomographic image requires hundreds of projections continuously acquired in several seconds. This work has been carried out at the SYRMEP beamline of the Elettra synchrotron radiation facility (Trieste, Italy), in the framework of the SYRMA-3D project, which aims to perform the world's first breast-CT clinical study with synchrotron radiation. An ad hoc data pre-processing procedure has been developed for the PIXIRAD-8 CdTe single-photon-counting detector, comprising an array of eight 30.7 mm × 24.8 mm modules tiling a 246 mm × 25 mm sensitive area, which covers the full synchrotron radiation beam. The procedure consists of five building blocks, namely dynamic flat-fielding, gap seaming, dynamic ring removal, projection despeckling and around-gap equalization. Each block is discussed and compared, when existing, with conventional approaches. The effectiveness of the pre-processing is demonstrated for phase-contrast CT images of a human breast specimen. The dynamic nature of the proposed procedure, which provides corrections dependent upon the projection index, allows the effective removal of time-dependent artifacts, preserving the main image features including phase effects.
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Affiliation(s)
- Luca Brombal
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Sandro Donato
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | | | - Pasquale Delogu
- Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy
| | - Viviana Fanti
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | | | - Luigi Rigon
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Vittorio Di Trapani
- Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy
| | - Renata Longo
- Department of Physics, University of Trieste, 34127 Trieste, Italy
| | - Bruno Golosio
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
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Vedantham S, Karellas A. Emerging Breast Imaging Technologies on the Horizon. Semin Ultrasound CT MR 2018; 39:114-121. [PMID: 29317033 DOI: 10.1053/j.sult.2017.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Early detection of breast cancers by mammography in conjunction with adjuvant therapy has contributed to reduction in breast cancer mortality. Mammography remains the "gold-standard" for breast cancer screening but is limited by tissue superposition. Digital breast tomosynthesis and more recently, dedicated breast computed tomography have been developed to alleviate the tissue superposition problem. However, all of these modalities rely upon x-ray attenuation contrast to provide anatomical images, and there are ongoing efforts to develop and clinically translate alternative modalities. These emerging modalities could provide for new contrast mechanisms and may potentially improve lesion detection and diagnosis. In this article, several of these emerging modalities are discussed with a focus on technologies that have advanced to the stage of in vivo clinical evaluation.
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Affiliation(s)
- Srinivasan Vedantham
- Department of Medical Imaging, University of Arizona College of Medicine, Banner University Medical Center, Tucson, AZ.
| | - Andrew Karellas
- Department of Medical Imaging, University of Arizona College of Medicine, Banner University Medical Center, Tucson, AZ
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Vedantham S, Shrestha S, Karellas A, Shi L, Gounis MJ, Bellazzini R, Spandre G, Brez A, Minuti M. Photon-counting hexagonal pixel array CdTe detector: Spatial resolution characteristics for image-guided interventional applications. Med Phys 2017; 43:2118. [PMID: 27147324 DOI: 10.1118/1.4944868] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
PURPOSE High-resolution, photon-counting, energy-resolved detector with fast-framing capability can facilitate simultaneous acquisition of precontrast and postcontrast images for subtraction angiography without pixel registration artifacts and can facilitate high-resolution real-time imaging during image-guided interventions. Hence, this study was conducted to determine the spatial resolution characteristics of a hexagonal pixel array photon-counting cadmium telluride (CdTe) detector. METHODS A 650 μm thick CdTe Schottky photon-counting detector capable of concurrently acquiring up to two energy-windowed images was operated in a single energy-window mode to include photons of 10 keV or higher. The detector had hexagonal pixels with apothem of 30 μm resulting in pixel pitch of 60 and 51.96 μm along the two orthogonal directions. The detector was characterized at IEC-RQA5 spectral conditions. Linear response of the detector was determined over the air kerma rate relevant to image-guided interventional procedures ranging from 1.3 nGy/frame to 91.4 μGy/frame. Presampled modulation transfer was determined using a tungsten edge test device. The edge-spread function and the finely sampled line spread function accounted for hexagonal sampling, from which the presampled modulation transfer function (MTF) was determined. Since detectors with hexagonal pixels require resampling to square pixels for distortion-free display, the optimal square pixel size was determined by minimizing the root-mean-squared-error of the aperture functions for the square and hexagonal pixels up to the Nyquist limit. RESULTS At Nyquist frequencies of 8.33 and 9.62 cycles/mm along the apothem and orthogonal to the apothem directions, the modulation factors were 0.397 and 0.228, respectively. For the corresponding axis, the limiting resolution defined as 10% MTF occurred at 13.3 and 12 cycles/mm, respectively. Evaluation of the aperture functions yielded an optimal square pixel size of 54 μm. After resampling to 54 μm square pixels using trilinear interpolation, the presampled MTF at Nyquist frequency of 9.26 cycles/mm was 0.29 and 0.24 along the orthogonal directions and the limiting resolution (10% MTF) occurred at approximately 12 cycles/mm. Visual analysis of a bar pattern image showed the ability to resolve close to 12 line-pairs/mm and qualitative evaluation of a neurovascular nitinol-stent showed the ability to visualize its struts at clinically relevant conditions. CONCLUSIONS Hexagonal pixel array photon-counting CdTe detector provides high spatial resolution in single-photon counting mode. After resampling to optimal square pixel size for distortion-free display, the spatial resolution is preserved. The dual-energy capabilities of the detector could allow for artifact-free subtraction angiography and basis material decomposition. The proposed high-resolution photon-counting detector with energy-resolving capability can be of importance for several image-guided interventional procedures as well as for pediatric applications.
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Affiliation(s)
- Srinivasan Vedantham
- Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Suman Shrestha
- Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Andrew Karellas
- Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Linxi Shi
- Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Matthew J Gounis
- Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Ronaldo Bellazzini
- Istituto Nazionale di Fisica Nucleare (INFN), Pisa 56127, Italy and Pixirad Imaging Counters s.r.l., L. Pontecorvo 3, Pisa 56127, Italy
| | - Gloria Spandre
- Istituto Nazionale di Fisica Nucleare (INFN), Pisa 56127, Italy and Pixirad Imaging Counters s.r.l., L. Pontecorvo 3, Pisa 56127, Italy
| | - Alessandro Brez
- Istituto Nazionale di Fisica Nucleare (INFN), Pisa 56127, Italy and Pixirad Imaging Counters s.r.l., L. Pontecorvo 3, Pisa 56127, Italy
| | - Massimo Minuti
- Istituto Nazionale di Fisica Nucleare (INFN), Pisa 56127, Italy and Pixirad Imaging Counters s.r.l., L. Pontecorvo 3, Pisa 56127, Italy
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