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Analytic digital tomosynthesis reconstruction in partial sampling with a multislit collimator using a prior sinogram interpolation method

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JOURNAL OF INSTRUMENTATION 2019年第1期14卷 C01015-C01015页

作者： Park, S. Kim, G. Park, C. Lee, D. Cho, H. Kim, K. Kang, S. Kim, W. Lim, H. Lee, H. Jeon, D. Park, J. Lim, Y. Seo, C. Yonsei Univ iTOMO Grp Dept Radiat Convergence Engn 1 Yonseidae Gil Wonju 26493 Gangwon Do South Korea

This study investigated analytic digital tomosynthesis (DTS) reconstruction in partial sampling with a multislit collimator that partially blocks the x-ray beam to the patient during projection data acquisition, thereby reducing excessive radiation dose to patients. Partially-sampled DTS images reconstructed using the analytic filtered-backprojection (FBP) algorithm usually suffer from severe bright-band artifacts around multislit edges of the collimator due to incomplete spatial sampling. In this study, a new prior sinogram interpolation method was introduced to the analytic DTS reconstruction in partial sampling to alleviate such artifacts. To verify the proposed DTS method, we conducted a systematic simulation and investigated image characteristics. Three multislit collimator layouts of C(2/2), C(3/3), and C(4/4) with a 50% duty cycle were designed and used in the simulation. Here C(n/n) denotes a collimator layout that blocks the x-ray beam over n detector pixels vertically with a n-pixel interval. All projections were obtained at a tomographic angle of theta = +/- 40 degrees and an angle step of Delta theta = 2 degrees and used to reconstruct DTS images using the FBP algorithm. Our results indicate that the proposed sinogram interpolation method effectively minimized bright-band artifacts in analytic DTS reconstruction in partial sampling, thus maintaining the image quality.

关键词： computerized Tomography (CT) and Computed Radiography (CR) medical-image reconstruction methods and algorithms, computer-aided software

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Using triple gamma coincidences with a pixelated semiconductor Compton-PET scanner: a simulation study

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JOURNAL OF INSTRUMENTATION 2016年第1期11卷

作者： Kolstein, M. Chmeissani, M. Barcelona Inst Sci & Technol IFAE Campus UAB E-08193 Bellaterra Barcelona Spain

The Voxel Imaging PET (VIP) Pathfinder project presents a novel design using pixelated semiconductor detectors for nuclear medicine applications to achieve the intrinsic image quality limits set by physics. The conceptual design can be extended to a Compton gamma camera. The use of a pixelated CdTe detector with voxel sizes of 1 x 1 x 2mm(3) guarantees optimal energy and spatial resolution. However, the limited time resolution of semiconductor detectors makes it impossible to use Time Of Flight (TOF) with VIP PET. TOF is used in order to improve the signal to noise ratio (SNR) by using only the most probable portion of the Line-Of-Response (LOR) instead of its entire length. To overcome the limitation of CdTe time resolution, we present in this article a simulation study using beta(+)-gamma emitting isotopes with a Compton-PET scanner. When the beta(+) annihilates with an electron it produces two gammas which produce a LOR in the PET scanner, while the additional gamma, when scattered in the scatter detector, provides a Compton cone that intersects with the aforementioned LOR. The intersection indicates, within a few mm of uncertainty along the LOR, the origin of the beta-gamma decay. Hence, one can limit the part of the LOR used by the image reconstruction algorithm.

关键词： Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) Multi-modality systems medical-image reconstruction methods and algorithms, computer-aided software Compton imaging

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Development of a novel gamma probe for detecting radiation direction

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JOURNAL OF INSTRUMENTATION 2016年第1期11卷 C01002-C01002页

作者： Pani, R. Pellegrini, R. Cinti, M. N. Longo, M. Donnarumma, R. D'Alessio, A. Borrazzo, C. Pergola, A. Ridolfi, S. De Vincentis, G. Univ Roma La Sapienza Dept Sci & Med & Surg Biotechnol Piazzale Aldo Moro 5 I-00185 Rome Italy Ist Nazl Fis Nucl Sez Roma Piazzale Aldo Moro 2 I-00185 Roma Rome Italy Univ Roma La Sapienza Dept Mol Med Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Postgrad Sch Med Phys Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Piazzale Aldo Moro 5 I-00185 Rome Italy Ars Mensurae Via Vincenzo Comparini 101 I-00188 Rome Italy Univ Roma La Sapienza Dept Radiol Sci Oncol & Anat Pathol Piazzale Aldo Moro 5 I-00185 Rome Italy

Spatial localization of radioactive sources is currently a main issue interesting different fields, including nuclear industry, homeland security as well as medical imaging. It is currently achieved using different systems, but the development of technologies for detecting and characterizing radiation is becoming important especially in medical imaging. In this latter field, radiation detection probes have long been used to guide surgery, thanks to their ability to localize and quantify radiopharmaceutical uptake even deep in tissue. Radiolabelled colloid is injected into, or near to, the tumor and the surgeon uses a hand-held radiation detector, the gamma probe, to identify lymph nodes with radiopharmaceutical uptkake. The present work refers to a novel scintigraphic goniometric probe to identify gamma radiation and its direction. The probe incorporates several scintillation crystals joined together in a particular configuration to provide data related to the position of a gamma source. The main technical characteristics of the gamma locator prototype, i.e. sensitivity, spatial resolution and detection efficiency, are investigated. Moreover, the development of a specific procedure applied to the images permits to retrieve the source position with high precision with respect to the currently used gamma probes. The presented device shows a high sensitivity and efficiency to identify gamma radiation taking a short time (from 30 to 60 s). Even though it was designed for applications in radio-guided surgery, it could be used for other purposes, as for example homeland security.

关键词： Intra-operative probes Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided software

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Evaluation of the Intel Xeon Phi Co-processor to accelerate the sensitivity map calculation for PET imaging

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JOURNAL OF INSTRUMENTATION 2015年第7期10卷

作者： Dey, T. Rodrigue, P. Philips Res Oncol Solut NL-5656 AE Eindhoven Netherlands

We aim to evaluate the Intel Xeon Phi coprocessor for acceleration of 3D Positron Emission Tomography (PET) image reconstruction. We focus on the sensitivity map calculation as one computational intensive part of PET image reconstruction, since it is a promising candidate for acceleration with the Many Integrated Core (MIC) architecture of the Xeon Phi. The computation of the voxels in the field of view (FoV) can be done in parallel and the 10(3) to 10(4) samples needed to calculate the detection probability of each voxel can take advantage of vectorization. We use the ray tracing kernels of the Embree project to calculate the hit points of the sample rays with the detector and in a second step the sum of the radiological path taking into account attenuation is determined. The core components are implemented using the Intel single instruction multiple data compiler (ISPC) to enable a portable implementation showing efficient vectorization either on the Xeon Phi and the Host platform. On the Xeon Phi, the calculation of the radiological path is also implemented in hardware specific intrinsic instructions (so-called 'intrinsics') to allow manually-optimized vectorization. For parallelization either OpenMP and ISPC tasking (based on pthreads) are evaluated. Our implementation achieved a scalability factor of 0.90 on the Xeon Phi coprocessor (model 5110P) with 60 cores at 1 GHz. Only minor differences were found between parallelization with OpenMP and the ISPC tasking feature. The implementation using intrinsics was found to be about 12% faster than the portable ISPC version. With this version, a speedup of 1.43 was achieved on the Xeon Phi coprocessor compared to the host system (HP SL250s Gen8) equipped with two Xeon (E5-2670) CPUs, with 8 cores at 2.6 to 3.3 GHz each. Using a second Xeon Phi card the speedup could be further increased to 2.77. No significant differences were found between the results of the different Xeon Phi and the Host implementations. The examina

关键词： Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided software Computing (architecture, farms, GRID for recording, storage, archiving, and distribution of data)

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image fusion scheme for differential phase contrast mammography

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JOURNAL OF INSTRUMENTATION 2013年第7期8卷 C07011-C07011页

作者： Wang, Z. Clavijo, C. A. Roessl, E. van Stevendaal, U. Koehler, T. Hauser, N. Stampanoni, M. Paul Scherrer Inst Swiss Light Source Villigen Switzerland Univ Zurich Inst Biomed Engn Zurich Switzerland Swiss Fed Inst Technol Zurich Switzerland Philips Technol GmbH Hamburg Germany Kantonsspital Baden Dept Gynecol & Obstet Interdisciplinary Breast Ctr Baden Baden Switzerland

Latest progresses in breast imaging using differential phase contrast technique pose the question how to fuse multiple information (yielded by the absorption, differential phase, and scattering signals) into a single, but more informative image for clinical diagnosis and evaluation. In this work, we propose an image fusion scheme based on the multiple-resolution (MR) framework. The three signals are first transformed into multiple bands presenting information at different frequency and then a two-step processing follows: section 3.2 an intra-band processing enhances the local signal-to-noise ratio using a novel noise estimation method and context modeling;section 3.3 an inter-band processing weights each band by considering their characteristics and contributions, as well as suppressing the global noise level. The fused image, which looks similar to conventional mammogram but with significantly enhanced detail features, is then reconstructed by inverse transform. This fused image is compatible with clinical settings and enables the radiologists to use their years of diagnosis experiences in mammography.

关键词： X-ray mammography and scinto- and MRI-mammography medical-image reconstruction methods and algorithms, computer-aided software X-ray radiography and digital radiography (DR) Multi-modality systems

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Diffraction enhanced imaging computed tomography (DEI-CT) at the BMIT facility at the Canadian Light Source

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JOURNAL OF INSTRUMENTATION 2013年第8期8卷 C08002-C08002页

作者： Webb, M. A. Belev, G. Wysokinski, T. W. Chapman, D. Canadian Light Source Saskatoon SK S7N 2V3 Canada Univ Saskatchewan Dept Anat & Cell Biol Saskatoon SK S7N 5E5 Canada

A synchrotron source such as available at the Canadian Light Source provides the ability to use a large number of imaging techniques. Computed tomography (CT) can be a extension of many X-ray imaging techniques. The ability to turn two dimensional projections into three dimensional structures is a powerful method of data analysis. CT also allows the user to slice the data in any desired direction without the need to cut up the sample. Diffraction enhanced imaging (analyzer based imaging) uses a crystal to measure refraction of the sample which may give significantly larger contrast than absorption alone. Measurements typically involve make images at multiple positions of the analyzer crystal and then using the images to extract the absorption, refraction components. Multiple-image radiology increases the number of images and adds the ultra-small-angle scatter. This paper will discuss the practical and technical aspects of extending diffraction enhanced imaging (DEI) to three dimensions (DEI-CT). A combination of hardware and software is used to provide a stable x-ray beam for the duration of potentially long measurement times and thus enable measurement of good quality diffraction enhanced imaging computed tomography (DEI-CT) data.

关键词： computerized Tomography (CT) and Computed Radiography (CR) medical-image reconstruction methods and algorithms, computer-aided software

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Evaluation of list-mode ordered subset expectation maximization image reconstruction for pixelated solid-state compton gamma camera with large number of channels

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JOURNAL OF INSTRUMENTATION 2014年第4期9卷

作者： Kolstein, M. De Lorenzo, G. Chmeissani, M. Univ Autonoma Barcelona IFAE E-08193 Bellaterra Spain

The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated solid-state technology for nuclear medicine applications. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 10(6)). For Compton camera, especially with a large number of readout channels, image reconstruction presents a big challenge. In this work, results are presented for the List-Mode Ordered Subset Expectation Maximization (LM-OSEM) image reconstruction algorithm on simulated data with the VIP Compton camera design. For the simulation, all realistic contributions to the spatial resolution are taken into account, including the Doppler broadening effect. The results show that even with a straight-forward implementation of LM-OSEM, good images can be obtained for the proposed Compton camera design. Results are shown for various phantoms, including extended sources and with a distance between the field of view and the first detector plane equal to 100 mm which corresponds to a realistic nuclear medicine environment.

关键词： image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided software Compton imaging

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Proton Computed Tomography: iterative image reconstruction and dose evaluation

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JOURNAL OF INSTRUMENTATION 2017年第1期12卷 C01034-C01034页

作者： Civinini, C. Bonanno, D. Brianzi, M. Carpinelli, M. Cirrone, G. A. P. Cuttone, G. Lo Presti, D. Maccioni, G. Pallotta, S. Randazzo, N. Scaringella, M. Romano, F. Sipala, V. Talamonti, C. Vanzi, E. Bruzzi, M. Ist Nazl Fis Nucl Florence Div Florence Italy Ist Nazl Fis Nucl Catania Div Catania Italy Ist Nazl Fis Nucl Lab Nazl Sud Catania Italy Univ Sassari Chem & Pharm Dept Sassari Italy Univ Catania Dept Phys & Astron Catania Italy Ist Nazl Fis Nucl Cagliari Div Cagliari Italy Univ Florence Biomed Expt & Clin Sci Dept Florence Italy Azienda Osped Univ Careggi SOD Fis Med Florence Italy Azienda Osped Univ Senese Fis Sanit Siena Italy Univ Florence Dept Phys & Astron Florence Italy

Proton Computed Tomography (pCT) is a medical imaging method with a potential for increasing accuracy of treatment planning and patient positioning in hadron therapy. A pCT system based on a Silicon microstrip tracker and a YAG:Ce crystal calorimeter has been developed within the INFN Prima-RDH collaboration. The prototype has been tested with a 175 MeV proton beam at The Svedberg Laboratory (Uppsala, Sweden) with the aim to reconstruct and characterize a tomographic image. Algebraic iterative reconstruction methods (ART), together with the most likely path formalism, have been used to obtain tomographies of an inhomogeneous phantom to eventually extract density and spatial resolutions. These results will be presented and discussed together with an estimation of the average dose delivered to the phantom and the dependence of the image quality on the dose. Due to the heavy computation load required by the algebraic algorithms the reconstruction programs have been implemented to fully exploit the high calculation parallelism of Graphics Processing Units. An extended field of view pCT system is in an advanced construction stage. This apparatus will be able to reconstruct objects of the size of a human head making possible to characterize this pCT approach in a pre-clinical environment.

关键词： Instrumentation for hadron therapy Instrumentation for particle-beam therapy medical-image reconstruction methods and algorithms, computer-aided software

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Cerenkov luminescence imaging guided selective-reconstruction for a flexible dual-head PET

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JOURNAL OF INSTRUMENTATION 2017年第4期12卷 P04005-P04005页

作者： Yang, D. Chen, X. Zhang, C. Wan, L. Meng, F. Xie, Q. Liang, J. Xidian Univ Engn Res Ctr Mol 266 Xinglong Sect Xifeng Rd Xian 710071 Shaanxi Peoples R China Xidian Univ Neuro Imaging Minist Educ 266 Xinglong Sect Xifeng Rd Xian 710071 Shaanxi Peoples R China Xidian Univ Sch Life Sci & Technol 266 Xinglong Sect Xifeng Rd Xian 710071 Shaanxi Peoples R China Hangzhou Dianzi Univ Inst Informat & Control Xiasha Higher Educ Zone Hangzhou 310018 Zhejiang Peoples R China Huazhong Univ Sci & Technol Sch Life Sci & Technol 1037 Luoyu Rd Wuhan 430074 Hubei Peoples R China

Dual-head PET can simply and flexibilly adjust its architecture to fit the size of the imaging object, making it great potential for simultaneous multi-modality molecular imaging. In this paper, we proposed conceptally dual-modality imaging system of distance-adjustable dual-head PET and Cerenkov luminescence imaging (CLI), and implemented a CLI guided selectivere-construction method. In the selective-reconstruction, we reconstructed the information inside a predefined region of interest using a fine voxel, whereas reconstructed other regions using a coarse voxel. We used CLI data as a priori information to outline the predefined region of interest. Simultaneously, for reducing the computaion burden, an attenuation map with a coarse voxel size was used for the attenuation correction. We demonstrated the feasibility and effectiveness of our proposed method with Monte Carlo based simulations by reconstructing phantom consisted of two hot rods. Experiment results show that an most improved efficiency over 70 times speedup with an MSE of 5.2235.

关键词： image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided diagnosis medical-image reconstruction methods and algorithms, computer-aided software Multi-modality systems

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Assessment of the effects of different sample perfusion procedures on phase-contrast tomographic images of mouse spinal cord

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JOURNAL OF INSTRUMENTATION 2018年第3期13卷 C03027-C03027页

作者： Stefanutti, E. Sierra, A. Miocchi, P. Massimi, L. Brun, F. Maugeri, L. Bukreeva, I. Nurmi, A. Provinciali, G. Begani Tromba, G. Grohn, O. Giove, F. Cedola, A. Fratini, M. IRCCS Fdn Santa Lucia Via Ardeatina 306-354 I-00142 Rome Italy Univ Eastern Finland Biomed Imaging Unit AI Virtanen Inst Mol Sci Neulaniementie 2 FIN-70211 Kuopio Finland Sapienza Univ CNR Inst Nanotechnol Phys Dept Piazzale Aldo Moro 2 I-00185 Rome Italy Charles River Discovery Serv Microkatu 1 Kuopio 70210 Finland Sapienza Univ Phys Dept Piazzale Aldo Moro 2 I-00185 Rome Italy Elettra Synchrotron Radiat Trieste SCpA Area Sci Pk I-34149 Trieste Italy Museo Stor Fis Ctr Fermi Piazza Viminale 1 I-00184 Rome Italy Ctr Studi & Ric Enrico Fermi Piazza Viminale 1 I-00184 Rome Italy

Synchrotron X-ray Phase Contrast micro-Tomography (SXrPC mu T) is a powerful tool in the investigation of biological tissues, including the central nervous system (CNS), and it allows to simultaneously detect the vascular and neuronal network avoiding contrast agents or destructive sample preparations. However, specific sample preparation procedures aimed to optimize the achievable contrast-and signal-to-noise ratio (CNR and SNR, respectively) are required. Here we report and discuss the effects of perfusion with two different fixative agents (ethanol and paraformaldehyde) and with a widely used contrast medium (MICROFIL (R)) on mouse spinal cord. As a main result, we found that ethanol enhances contrast at the grey/white matter interface and increases the contrast in correspondence of vascular features and fibres, thus providing an adequate spatial resolution to visualise the vascular network at the microscale. On the other hand, ethanol is known to induce tissue dehydration, likely reducing cell dimensions below the spatial resolution limit imposed by the experimental technique. Nonetheless, neurons remain well visible using either perfused paraformaldehyde or MICROFIL (R) compound, as these latter media do not affect tissues with dehydration effects. Paraformaldehyde appears as the best compromise: it is not a contrast agent, like MICROFIL (R), but it is less invasive than ethanol and permits to visualise well both cells and blood vessels. However, a quantitative estimation of the relative grey matter volume of each sample has led us to conclude that no significant alterations in the grey matter extension compared to the white matter occur as a consequence of the perfusion procedures tested in this study.

关键词： medical-image reconstruction methods and algorithms, computer-aided diagnosis medical-image reconstruction methods and algorithms, computer-aided software

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