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image reconstruction method in grating interferometer with phase stepping using grating position and dose fluctuation correction

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JOURNAL OF INSTRUMENTATION 2023年第7期18卷 P07006页

作者： Oh, Ohsung Kim, Daeseung Kim, Kyung Lee, Seung Wook Pusan Natl Univ Sch Mech Engn Busandaehak Ro 63beon Gil Busan 46241 South Korea

In this paper, we propose a method for reducing artifacts in X-ray and neutron grating interferometer imaging by optimizing the grating position and dose fluctuation. Grating interferometer can obtain additional information about the object, such as phase-contrast image and dark-field image, compared to traditional X-ray imaging. However, several errors such as inaccurate grating positions and non-uniform X-ray intensity can cause artifacts in the image and degrade image quality. The proposed method can reduce the artifacts by minimizing the value in the sample-free region in the transmission and dark-field images. We conducted experiments on both simulated and X-ray and neutron experimental data and demonstrated the effectiveness of our method.

关键词： image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided software Data processing methods X-ray radiography and digital radiography (DR)

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Designs of three different octagonal-shaped antennas for microwave-based breast cancer detection

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JOURNAL OF INSTRUMENTATION 2023年第9期18卷 P09013页

作者： Aydin, Emine Avsar Aydin, Ahmet Saribas, Gozde Adana Alparslan Turkes Sci & Technol Univ Dept Aerosp Engn Saricam Adana Turkiye Cukurova Univ Dept Biomed Engn Balcali Adana Turkiye

Today, there are numerous studies on Microwave Imaging methods. Thanks to these studies, the success and accuracy rate, especially in breast cancer diagnosis, increases. Microstrip antennas are used in the microwave imaging method. In this study, three different antenna models aimed to be used in microwave imaging methods were designed on the CST Studio Suite program. The designed antennas have been tested on the phantom model in the simulation environment. The test results were examined, and the designed antennas were produced using 3D printing technology. The built antennas were tested in the laboratory using the phantom and tumor-containing phantom models and obtained results were compared.

关键词： Manufacturing MRI (whole body, cardiovascular, breast, others), MR-angiography (MRA) Simulation methods and programs medical-image reconstruction methods and algorithms, computer-aided software

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Improvement of material decomposition and image quality in dual-energy radiography by reducing image noise

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JOURNAL OF INSTRUMENTATION 2016年第8期11卷 T08003-T08003页

作者： Lee, D. Kim, Y. -s. Choi, S. Lee, H. Choi, S. Jo, B. D. Jeon, P. -H. Kim, H. Kim, D. Kim, H. Kim, H. -J. Yonsei Univ Coll Hlth Sci Dept Radiat Convergence Engn 1 Yonseidae Gil Wonju 220710 Gangwon South Korea Yonsei Univ Dept Radiol Sci 1 Yonseidae Gil Wonju 220710 Gangwon South Korea Yonsei Univ Res Inst Hlth Sci 1 Yonseidae Gil Wonju 220710 Gangwon South Korea

Although digital radiography has been widely used for screening human anatomical structures in clinical situations, it has several limitations due to anatomical overlapping. To resolve this problem, dual-energy imaging techniques, which provide a method for decomposing overlying anatomical structures, have been suggested as alternative imaging techniques. Previous studies have reported several dual-energy techniques, each resulting in different image qualities. In this study, we compared three dual-energy techniques: simple log subtraction (SLS), simple smoothing of a high-energy image (SSH), and anti-correlated noise reduction (ACNR) with respect to material thickness quantification and image quality. To evaluate dual-energy radiography, we conducted Monte Carlo simulation and experimental phantom studies. The Geant 4 Application for Tomographic Emission (GATE) v 6.0 and tungsten anode spectral model using interpolation polynomials (TASMIP) codes were used for simulation studies and digital radiography, and human chest phantoms were used for experimental studies. The results of the simulation study showed improved image contrast-to-noise ratio (CNR) and coefficient of variation (COV) values and bone thickness estimation accuracy by applying the ACNR and SSH methods. Furthermore, the chest phantom images showed better image quality with the SSH and ACNR methods compared to the SLS method. In particular, the bone texture characteristics were well-described by applying the SSH and ACNR methods. In conclusion, the SSH and ACNR methods improved the accuracy of material quantification and image quality in dual-energy radiography compared to SLS. Our results can contribute to better diagnostic capabilities of dual-energy images and accurate material quantification in various clinical situations.

关键词： X-ray radiography and digital radiography (DR) medical-image reconstruction methods and algorithms, computer-aided software

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Study of position reconstruction of a LaBr3: Ce continuous scintillation crystal for medical applications

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JOURNAL OF INSTRUMENTATION 2013年第12期8卷 P12010-P12010页

作者： Fabbri, A. Sacco, D. Bennati, P. Baroncelli, A. Galasso, M. Cinti, M. N. Pellegrini, R. Pani, R. Cencelli, V. O. Univ Rome Roma Tre Dept Phys Rome Italy Univ Roma La Sapienza Dept Mol Med I-00185 Rome Italy Ist Nazl Fis Nucl Sez Roma Uno Rome Italy Ist Nazl Fis Nucl Sez Roma Tre Rome Italy INAIL Rome Italy

Many modern molecular imaging techniques, based on radiopharmaceuticals, can take advantage of sophisticated devices but are still based on the scintillation detector mechanism proposed by Anger. These devices can perform with millimeter spatial resolution and high detection efficiency, but the final performance is strongly affected by the algorithm used for the scintillation position detection. In this work, a detailed comparison of the effect on the imaging performances of three new position detection algorithms, in terms of spatial resolution, detection linearity and useful Field of View is performed on a prototype gamma detector. The detector, built by the authors, is based on a continuous LaBr3: Ce scintillation crystal coupled to an Hamamatsu MA-PMT H8500 and a single anode readout electronics. The experimental data are obtained scanning the detector surface with a Tc99m collimated source (0.4mm f) at 1.5mm step. The overall imaging performances of the device are also tested by mean of a bar phantom. We conclude that the Anger-like algorithms give a 50% uFoV with a 1.30mm +/- 0.05mm spatial resolution while the proposed algorithms give a 80% uFoV and 1.10mm +/- 0.06mm spatial resolution.

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

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Simulation and evaluation of a high resolution VIP PEM system with a dedicated LM-OSEM algorithm

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JOURNAL OF INSTRUMENTATION 2014年第5期9卷 C05011-C05011页

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

Over the last two decades there have been a growing number of designs for positron emission tomography (PET) cameras optimized to image the breast. These devices, commonly known as positron emission mammography (PEM) cameras allow much more spatial resolution by putting the photon detectors directly on the breast. PEM cameras have a compact geometry with a restricted field of view (FOV) thus exhibiting higher performance and lower cost than large whole body PET scanners. Typical PEM designs are based on scintillators such as bismuth germanate (BGO), lutetium oxorthosilicate (LSO) or lutetium yttrium orthosicilate (LYSO), and characterized by large parallax error due to deficiency of the depth of interaction (DOI) information from crystals. In the case of parallel geometry PEM, large parallax error results in poor image resolution along the vertical axis. In the framework of the Voxel Imaging PET (VIP) pathfinder project, we propose a high resolution PEM scanner based on pixelated solid-state CdTe detectors. The pixel PEM device with a millimeter-size pixel pitch provides an excellent spatial resolution in all directions 8 times better than standard commercial devices with a point spread function (PSF) of 1mm full width at half maximum (FWHM) and excellent energy resolution of down to 1.6% FWHM at 511 keV photons at room temperature. The system is capable to detect down to 1mm diameter hot spheres in warm background.

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

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Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

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JOURNAL OF INSTRUMENTATION 2017年第4期12卷 T04006-T04006页

作者： Lee, D. Choi, S. Lee, H. Kim, D. Choi, S. Kim, H. -J. Yonsei Univ Res Inst Hlth Sci Dept Radiat Convergence Engn 1 Yonseidae Gil Wonju 220710 Gangwon South Korea Yonsei Univ Dept Radiol Sci Coll Hlth Sci 1 Yonseidae Gil Wonju 220710 Gangwon South Korea

Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the similar to 20 degrees angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

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

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Measurement and simulative proof concerning the visibility loss in x-ray Talbot-Lau Moire imaging

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JOURNAL OF INSTRUMENTATION 2017年第12期12卷 T12007-T12007页

作者： Seifert, M. Gallersdoerfer, M. Horn, F. Ludwig, V. Schuster, M. Pelzer, G. Rieger, J. Michel, T. Anton, G. Friedrich Alexander Univ Erlangen Nuremberg ECAP Novel Detectors Med Phys Erwin Rommel Str 1 Erlangen Germany

X-ray grating-based phase-contrast imaging is a very promising imaging technique for medical imaging and non-destructive testing. Simultaneously to the attenuation properties additional information about the phase-shift and the scattering properties of an object can be gained. Nevertheless, to obtain this information multiple shots per image have to be taken in the so-called phase-stepping process. Thus, it often is a time consuming imaging procedure. In contrast, Moire imaging with a Talbot-Lau interferometer is a very fast single-shot imaging method. To obtain the Moire pattern which encodes the object information the interferometer has to be slightly detuned. This leads to a loss in visibility and therefore to a loss in image quality compared to the more time consuming phase-stepping method. Thus, it is important for the Moire imaging method to evaluate the mechanisms of visibility loss. In this publication we present measurements and simulations investigating the visibility loss due to detuning the Talbot-Lau interferometer. Thus, a deeper understanding of Moire imaging can be gained.

关键词： Analysis and statistical methods medical-image reconstruction methods and algorithms, computer-aided software Simulation methods and programs X-ray radiography and digital radiography (DR)

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Spectral micro-CT for simultaneous gold and iodine detection, and multi-material identification

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JOURNAL OF INSTRUMENTATION 2024年第4期19卷 C04023页

作者： Perion, P. Arfelli, F. Menk, R. H. Brombal, L. Univ Trieste Dept Phys Via Alfonso Valerio 2 Trieste Italy Ist Nazl Fis Nucl Div Trieste Via Alfonso Valerio 2 Trieste Italy Elettra Sincrotrone Trieste SS 14Km 1635 Area Sci Pk Trieste Italy Mid Sweden Univ Dept Comp & Elect Engn Holmgatan 10 Sundsvall Sweden

Multiple energy bin spectral micro -CT (SCT) is an advanced imaging technique that allows multi -material decomposition according to their specific absorption patterns at a sub -100 mu m scale. Typically, iodine is the preferred CT contrast agent for cardiovascular imaging, while gold nanoparticles have gained attention in recent years owing to their high absorption properties, biocompatibility and ability to target tumors. In this work, we demonstrate the potential for multi -material decomposition through SCT imaging of a test sample at the PEPI lab of INFN Trieste. The sample, consisting of gold, iodine, calcium, and water, was imaged using a Pixirad1/PixieIII chromatic detector with multiple energy thresholds and a wide spectrum (100 kV) produced by a micro -focus X-ray tube. The results demonstrate the simultaneous detection and separation of the four materials at a spatial scale of 35 mu m, suggesting the potential of this technique in improving material detectability and quantification in a range of pre -clinical applications, including cardiovascular and oncologic imaging.

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

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Online image corrections applied to a dedicated breast PET

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JOURNAL OF INSTRUMENTATION 2016年第3期11卷 C03035-C03035页

作者： Moliner, L. Gonzalez, A. J. Correcher, C. Benlloch, J. M. Univ Politecn Valencia CSIC Inst Instrumentat Mol Imaging I3M Cami Vera S-N E-46022 Valencia Spain Prince Felipe Res Ctr Oncovis Eduardo Primo Yufera 3 Valencia Spain

In this work, we present the online implementation of attenuation, scatter and random corrections using the LMEM algorithm for the dedicated breast PET named MAMMI. The attenuation correction is based on image segmentation, the random correction is derived from the rate estimation of single photon events and the scatter correction is determined by the dual energy window method. These three corrections are estimated and implemented in the reconstruction process without almost increasing the reconstruction time. The image quality is evaluated in terms of image uniformity and contrast using the reconstructed images of two custom-designed phantoms. When we apply the three corrections, the measured uniformity in the whole field of view is (10 +/- 1)% compared to (17 +/- 1)% without corrections. The adapted recovery contrast coefficients (normalized to 1) are approximately (0.80 +/- 0.02) in hot areas, improving the value of (0.66 +/- 0.07) obtained without corrections. The reconstruction processing time is also studied, finding an increment of around 7% when the three corrections are simultaneously included. Finally, 25 breast image datasets are also analyzed. The average acquisition time per patient is around 1200 seconds and the reconstruction times with corrections vary from 100 to 400 seconds using (1x1x1) mm(3) voxel size and from 300 to 1800 seconds using (0.5x0.5x0.5) mm(3) voxel size. These reconstructions are performed with a virtual pixel size of (1.6x1.6) mm(2) and twelve iterations.

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

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Preliminary evaluation of a monolithic detector module for integrated PET/MRI scanner with high spatial resolution

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JOURNAL OF INSTRUMENTATION 2015年第6期10卷 2015 JINST 10 C06006-2015 JINST 10 C06006页

作者： Pani, R. Gonzalez, A. J. Bettiol, M. Fabbri, A. Cinti, M. N. Preziosi, E. Borrazzo, C. Conde, P. Pellegrini, R. Di Castro, E. Majewski, S. Univ Roma La Sapienza Dept Mol Med I-00185 Rome Italy CSIC I3M Valencia 46022 Spain Univ Roma La Sapienza Postgrad Sch Med Phys I-00185 Rome Italy Univ Roma La Sapienza SAIMLAL Dept Doctorate Sch Biol & Mol Med Morphofunct Sci Biophys I-00185 Rome Italy Univ Roma La Sapienza Dept Radiol Sci Oncol & Pathol I-00185 Rome Italy W Virginia Univ Dept Radiol Ctr Adv Imaging Morgantown WV 26506 USA

The proposal of Mindview European Project concerns with the development of a very high resolution and high efficiency brain dedicated PET scanner simultaneously working with a Magnetic Resonance scanner, that expects to visualize neurotransmitter pathways and their disruptions in the quest to better diagnose schizophrenia. On behalf of this project, we propose a low cost PET module for the first prototype, based on monolithic crystals, suitable to be integrated with a head Radio Frequency (RF) coil. The aim of the suggested module is to achieve high performances in terms of efficiency, planar spatial resolution (expected about 1 mm) and discrimination of gamma Depth Of Interaction (DOI) in order to reduce the parallax error. Our preliminary results are very promising: a DOI resolution of about 3 mm, a spatial resolution ranging from about 1 to 1.5 mm and a good position linearity.

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

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