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TOF capability evaluation on a panel PET for human body imaging

JOURNAL OF INSTRUMENTATION 2013年第4期8卷

作者： Xiao, P. Cao, X. Wan, L. Li, Y. Xie, Q. Huazhong Univ Sci & Technol Dept Biomed Engn Wuhan 430074 Hubei Peoples R China Wuhan Natl Lab Optoelect Wuhan 430074 Hubei Peoples R China

Due to its unique structure, parallel panel configuration may lead to novel applications for positron emission tomography (PET). The major challenge of panel PET imaging is the limited angle problem, to which the time-of-flight (TOF) information seems to be a promising solution. This work investigated the required TOF capability of a panel PET design, which has a feasible size of field of view (FOV) for human torso. Such a system's corresponding angular coverage can vary from 70 to 102 degrees. The recovery ability of small lesions was assessed, and the contrast recovery coefficient (CRC) and signal-to-noise ratio (SNR) were analyzed, with a full ring PET as the benchmark system. We also varied the timing resolution and the distance between panels, to evaluate their impacts on image quality. Encouraging results were obtained in simulation study. Distortions and artifacts caused by the limited angular coverage were greatly reduced with timing resolutions better than 300 ps. The recovery ability of small lesions in most part of FOV was desirable. Meanwhile, varying panel distance in the range of 25 to 45 cm seemed to have trivial influence, when timing resolution was fixed at 300 ps. That means that such changes of panel distance might not affect the requirement on TOF capability, allowing more flexibility in panel PET's design and applications.

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

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Preparation and osteogenic properties of magnesium calcium phosphate biocement scaffolds for bone regeneration

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JOURNAL OF INSTRUMENTATION 2013年第7期8卷

作者： Li, X. Niu, Y. Guo, H. Chen, H. Li, F. Zhang, J. Chen, W. Wu, Z. Deng, Y. Wei, J. Liu, C. E China Univ Sci & Technol Key Lab Ultrafine Mat Minist Educ Shanghai 200237 Peoples R China Second Mil Med Univ Dept Orthopaed Changhai Hosp Shanghai 200433 Peoples R China Chinese Acad Sci Shanghai Inst Appl Phys Shanghai Synchrotron Radiat Facil Shanghai 201800 Peoples R China Shanghai 8th Peoples Hosp Dept Pharmaceut Shanghai 200235 Peoples R China

The regenerative treatment of large osseous defects remains a formidable challenge in today. In the present study, we have synthesized biodegradable magnesium calcium phosphate biocement (MCPB) scaffolds with interconnected macroporous structure (100-600 mu m), as well as good bioactivity, biocompatibility and proper degradatibility. The results revealed that the porosity increased from 52% to 80% of MCPB scaffolds while the compressive strength decreased from 6.1MPa to 1.2MPa. We further assessed the effects of scaffolds on the rabbit femur cavity defect model in vivo by using synchrotron radiation X-ray microCT and microCT imaging, indicating that the MCPB scaffolds underwent gradually degradation and promoted the extensive neo-bone formation.

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

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Automated identification of the lung contours in positron emission tomography

Automated identification of the lung contours in positron em...

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14th International Workshop on Radiation Imaging Detectors

作者： Nery, F. Silvestre Silva, J. Ferreira, N. C. Caramelo, F. J. Faustino, R. Univ Coimbra ICNAS Inst Nucl Sci Appl Hlth Coimbra Portugal Univ Coimbra Instrumentat Ctr Fac Sci & Technol Coimbra Portugal Polytech Inst Portalegre Sch Technol & Management Portalegre Portugal Univ Coimbra Fac Med IBILI Inst Biomed Res Light & Image Coimbra Portugal

Positron Emission Tomography (PET) is a nuclear medicine imaging technique that permits to analyze, in three dimensions, the physiological processes in vivo. One of the areas where PET has demonstrated its advantages is in the staging of lung cancer, where it offers better sensitivity and specificity than other techniques such as CT. On the other hand, accurate segmentation, an important procedure for computer aided Diagnostics (CAD) and automated image analysis, is a challenging task given the low spatial resolution and the high noise that are intrinsic characteristics of PET images. This work presents an algorithm for the segmentation of lungs in PET images, to be used in CAD and group analysis in a large patient database. The lung boundaries are automatically extracted from a PET volume through the application of a marker-driven watershed segmentation procedure which is robust to the noise. In order to test the effectiveness of the proposed method, we compared the segmentation results in several slices using our approach with the results obtained from manual delineation. The manual delineation was performed by nuclear medicine physicians that used a software routine that we developed specifically for this task. To quantify the similarity between the contours obtained from the two methods, we used figures of merit based on region and also on contour definitions. Results show that the performance of the algorithm was similar to the performance of human physicians. Additionally, we found that the algorithm-physician agreement is similar (statistically significant) to the inter-physician agreement.

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

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A proton Computed Tomography system for medical applications

A proton Computed Tomography system for medical applications

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14th International Workshop on Radiation Imaging Detectors

作者： Sipala, V. Bruzzi, M. Bucciolini, M. Carpinelli, M. Cirrone, G. A. P. Civinini, C. Cuttone, G. Lo Presti, D. Pallotta, S. Pugliatti, C. Randazzo, N. Romano, F. Scaringella, M. Stancampiano, C. Talamonti, C. Tesi, M. Vanzi, E. Zani, M. Univ Sassari I-07100 Sassari Italy INFN Cagliari I-09042 Monserrato CA Italy Univ Florence Dept Energet I-50139 Florence Italy INFN Florence I-50019 Sesto Fiorentino FI Italy Univ Florence Dept Clin Physiopathol I-50134 Florence Italy Azienda Osped Univ Careggi I-50134 Florence Italy Lab Nazl Sud INFN I-95123 Catania Italy Univ Catania Dept Phys I-95123 Catania Italy INFN Catania I-95123 Catania Italy Ctr Studi & Ric I-00184 Rome Italy Museo Stor Fis Enrico Fermi I-00184 Rome Italy

Proton Computed Tomography (pCT) can improve the accuracy of both patient positioning and dose calculation in proton therapy, enabling to accurately reconstruct the electron density distribution of irradiated tissues. A pCT prototype, equipped with a silicon tracker and a YAG:Ce calorimeter, has been manufactured by an Italian collaboration. First tests under proton beam allowed obtaining good quality tomographic images of a non-homogeneous phantom. Manufacturing of a new large area system with real-time data acquisition is under way.

关键词： Instrumentation for hadron therapy computerized Tomography (CT) and Computed Radiography (CR) medical-image reconstruction methods and algorithms, computer-aided so

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Evaluation of Origin Ensemble algorithm for image reconstruction for pixelated solid-state detectors with large number of channels

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JOURNAL OF INSTRUMENTATION 2013年第4期8卷 P04030页

作者： Kolstein, M. De Lorenzo, G. Mikhaylova, E. Chmeissani, M. Arino, G. Calderon, Y. Ozsahin, I. Uzun, D. 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 PET scanners, conventional algorithms like Filtered Back-Projection (FBP) and Ordered Subset Expectation Maximization (OSEM) are straightforward to use and give good results. However, FBP presents difficulties for detectors with limited angular coverage like PEM and Compton gamma cameras, whereas OSEM has an impractically large time and memory consumption for a Compton gamma camera with a large number of channels. In this article, the Origin Ensemble (OE) algorithm is evaluated as an alternative algorithm for image reconstruction. Monte Carlo simulations of the PET design are used to compare the performance of OE, FBP and OSEM in terms of the bias, variance and average mean squared error (MSE) image quality metrics. For the PEM and Compton camera designs, results obtained with OE are presented.

关键词： computerized Tomography (CT) and Computed Radiography (CR) Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided so Compton imaging

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X-ray biomedical imaging beamline at SSRF

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JOURNAL OF INSTRUMENTATION 2013年第8期8卷

作者： Xie, H. Deng, B. Du, G. Fu, Y. He, Y. Guo, H. Peng, G. Xue, Y. Zhou, G. Ren, Y. Wang, Y. Chen, R. Tong, Y. Xiao, T. Chinese Acad Sci Shanghai Inst Appl Phys Shanghai Synchrotron Radiat Facil SSRF Shanghai 201204 Peoples R China

Since May 6, 2009, the X-ray biomedical imaging beamline at Shanghai Synchrotron Radiation Facility (SSRF) has been formally opened to users. The beamline is composed of a wiggler source with the intensity of magnetic field of 2.0 Tesla, a double crystal monochromator (DCM) cooled with liquid nitrogen, a 6-axis filter for high heat load reducing on the downstream optics such as Be window and DCM. The photon energy range for the monochromatic beam is 8-72.5keV. Three sets of digital X-ray detectors are provided to users with the pixel size range being 0.37-13 mu m. Several imaging methods such as micro-CT, in-line phase contrast imaging could be applied in biomedicine, material science and paleontology studies. The spatial resolution of 0.8 mu m and the temporal resolution of 1 ms could be realized. By the end of 2012, the beamline has provided more than 13900 hours beamtime for users, while over half of the research proposals come from biomedicine field. Nearly 2000 person-times have come and done their experiments at the beamline. More than 470 user proposals have been perfomed and more than 110 papers from users have been published. some typical experimental results on biomedical applications will be introduced.

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

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Melatonin mitigate cerebral vasospasm after experimental subarachnoid hemorrhage: a study of synchrotron radiation angiography

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JOURNAL OF INSTRUMENTATION 2013年第6期8卷

作者： Cai, J. He, C. Chen, L. Han, T. Huang, S. Huang, Y. Bai, Y. Bao, Y. Zhang, H. Ling, F. Guangdong Prov Hosp Tradit Chinese Med Guangzhou Higher Educ Mega Ctr Dept Neurosurg Affiliated Hosp Guangzhou 510006 Guangdong Peoples R China Capital Med Univ Xuanwu Hosp Dept Neurosurg Beijing 100053 Peoples R China Guangdong Prov Hosp Tradit Chinese Med Dept Neurol Guangzhou 510120 Guangdong Peoples R China Seventh Hosp Fuzhou Dept Surg Fuzhou 350001 Peoples R China Guangzhou Univ Chinese Med Postdoctoral Res Ctr Guangzhou 510006 Guangdong Peoples R China Guangzhou Univ Chinese Med Sch Clin Med 2 Guangzhou 510120 Guangdong Peoples R China

Cerebral vasospasm (CV) after subarachnoid hemorrhage (SAH) is a devastating and unsolved clinical issue. In this study, the rat models, which had been induced SAH by prechiasmatic cistern injection, were treated with melatonin. Synchrotron radiation angiography (SRA) was employed to detect and evaluate CV of animal models. Neurological scoring and histological examinations were used to assess the neurological deficits and CV as well. Using SRA techniques and histological analyses, the anterior cerebral artery diameters of SAH rats with melatonin administration were larger than those without melatonin treatment (p < 0.05). The neurological deficits of SAH rats treated with melatonin were less than those without melatonin treatment (p < 0.05). We concluded that SRA was a precise and in vivo tool to observe and evaluate CV of SAH rats;intraperitoneally administration of melatonin could mitigate CV after experimental SAH.

关键词： medical-image reconstruction methods and algorithms, computer-aided so X-ray radiography and digital radiography (DR) Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) Intra-operative probes

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2D image reconstruction of a human chest by using Calderon's method and the adjacent current pattern

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JOURNAL OF INSTRUMENTATION 2013年第3期8卷

作者： Cao, Z. Xu, L. Beihang Univ Minist Educ Sch Instrument Sci & Optoelect Engn Deparment Measurement & ControlKey Lab Precis Op Beijing 100191 Peoples R China

In this paper, Calderon's method is applied to a chest-like sensing region, as monitored by electrical impedance tomography. This method provides a direct algorithm for image reconstruction, where the gray value at any pixel of the reconstructed image is computed using a direct and independent approach. The major calculations of image reconstruction in Calderon's method are implemented for a circular boundary and, as a result, the complicated calculations of the scattering transform, as required by non-circular boundaries, are avoided. A unique conformal transformation is used to map a unit disk onto a sensing region with a non-circular boundary, such as a chest-like region. A new method to calculate the Dirichlet-to-Neumann map is also introduced, which is used to compute the scattering transform. The feasibility of the proposed method has been validated by testing the construction of phantoms with chest-like boundaries. Data collected from the chest of a male subject has been used to visualize lung movement, as monitored by the electrical impedance tomography system.

关键词： image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided so Data reduction methods

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Automated identification of the lung contours in positron emission tomography

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JOURNAL OF INSTRUMENTATION 2013年第3期8卷

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

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Understanding refraction contrast using a comparison of absorption and refraction computed tomographic techniques

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JOURNAL OF INSTRUMENTATION 2013年第5期8卷

作者： Wiebe, S. Rhodes, G. Wei, Z. Rosenberg, A. Belev, G. Chapman, D. Univ Saskatchewan Dept Med Imaging Saskatoon SK Canada Univ Saskatchewan Div Biomed Engn Saskatoon SK Canada Univ Saskatchewan Dept Anat & Cell Biol Saskatoon SK Canada Univ Saskatchewan Dept Pediat Saskatoon SK Canada Canadian Light Source Saskatoon SK Canada

Refraction x-ray contrast is an imaging modality used primarily in a research setting at synchrotron facilities, which have a biomedical imaging research program. The most common method for exploiting refraction contrast is by using a technique called Diffraction Enhanced Imaging (DEI). The DEI apparatus allows the detection of refraction between two materials and produces a unique "edge enhanced" contrast appearance, very different from the traditional absorption x-ray imaging used in clinical radiology. In this paper we aim to explain the features of x-ray refraction contrast as a typical clinical radiologist would understand. Then a discussion regarding what needs to be considered in the interpretation of the refraction image takes place. Finally we present a discussion about the limitations of planar refraction imaging and the potential of DEI Computed Tomography. This is an original work that has not been submitted to any other source for publication. The authors have no commercial interests or conflicts of interest to disclose.

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

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