2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)最新文献_第7页

Storage characteristics of mixtures of KCl:Eu2+ phosphors and polyethylene powder by irradiation of fast neutrons 快中子辐照下KCl:Eu2+荧光粉与聚乙烯粉末混合物的贮存特性

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551116

K. Sakasai, K. Toh, T. Nakamura, K. Takakura, C. Konno, Y. Iwamoto

引用次数: 2

Image reconstruction and signal detectability in dual-head small animal PET 双头小动物PET图像重建与信号检测

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551784

Yu-Jiun Kao, Chun-Hao Kao, Yun Dong, C. Kao, Chin-Tu Chen, Weichung Wang, Cheng-Ying Chou

{"title":"Image reconstruction and signal detectability in dual-head small animal PET","authors":"Yu-Jiun Kao, Chun-Hao Kao, Yun Dong, C. Kao, Chin-Tu Chen, Weichung Wang, Cheng-Ying Chou","doi":"10.1109/NSSMIC.2012.6551784","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551784","url":null,"abstract":"Dual-head flat-panel positron emission tomography (PET) is the dedicated system for small-animal imaging because of its high spatial resolution and detection sensitivity. Unlike the conventional ring-based PET system, the dual-head system is versatile and can be reconfigured readily to accommodate different sample sizes and/or to achieve an optimal system performance. However, the unique imaging geometry also leads to severe depth-of-interaction (DOl) blurring. Monte Carlo simulation has been employed to account for DOl effects in the system response matrix with high accuracy, but the long simulation times make routine search for an optimal configuration impractical. To facilitate the system optimization while considering the parallax error, we employ an efficient numerical method to model the DOl effect in the system matrix for image reconstruction and accelerate the computation with the graphics processing units (GPUs). Among the system response matrices corresponding to different geometric configurations, a favorable one can be selected by exploiting the statistical detection theory. Computer simulation studies were carried out to validate and quantitatively evaluate the proposed method.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128609304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Standardization of 68Ga by means of a 4πβ-γ Software Coincidence System 用4πβ-γ软件符合系统对68Ga进行标准化

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551106

M. F. Koskinas, F. W. Lacerda, I. M. Yamazaki, F. Toledo, M. N. Takeda, M. S. Dias

引用次数: 1

Convergent iterative algorithms for joint reconstruction of activity and attenuation from time-of-flight PET data 从飞行时间PET数据中联合重建活动和衰减的收敛迭代算法

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551849

Sangtae Ahn, H. Qian, R. Manjeshwar

{"title":"Convergent iterative algorithms for joint reconstruction of activity and attenuation from time-of-flight PET data","authors":"Sangtae Ahn, H. Qian, R. Manjeshwar","doi":"10.1109/NSSMIC.2012.6551849","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551849","url":null,"abstract":"Joint reconstruction of activity and attenuation maps from emission data only, while being a long-standing problem in emission tomography, has been gaining recent interests because of its application to MR-based attenuation correction in PET/MR scanners where CT images are not available. Furthermore, recent studies showed that TOF (time-of-flight) information can substantially reduce, or completely remove in theory, crosstalk artifacts, which had been one of the hurdles preventing joint reconstruction techniques from being used clinically. Nonetheless, estimating both activity and attenuation from TOF emission data is a computationally challenging nonconvex optimization problem with high-dimensional data size. Therefore, as a tool for investigating and optimizing the joint estimation techniques for clinical use, we need numerical algorithms that are derived in a principled way and guaranteed to converge to a solution. Here, in a PL (penalized-likelihood) framework, we present a block alternating MM (minorization maximization) algorithm, which is provably globally convergent although the PL objective function is nonconcave. By using linear parameterization of attenuation maps, the algorithm applies to a variety of scenarios, depending on the type of and the degree of prior information, in a unified way. In addition, we provide a proof of the uniqueness of solutions to joint estimation problems for a continuous-space TOF PET system whose TOF kernels do not need to be Gaussian.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129244825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Reconstruction of gated dynamic cardiac SPECT data using spatiotemporal basis functions 利用时空基函数重建门控动态心脏SPECT数据

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551568

Uttam M. Shrestha, F. Alhassen, Youngho Seo, E. Botvinick, G. Gullberg

{"title":"Reconstruction of gated dynamic cardiac SPECT data using spatiotemporal basis functions","authors":"Uttam M. Shrestha, F. Alhassen, Youngho Seo, E. Botvinick, G. Gullberg","doi":"10.1109/NSSMIC.2012.6551568","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551568","url":null,"abstract":"Modeling of data from a dynamic acquisition is complicated by the combination of camera motion, organ motion, and the time-varying nature of the radionuclide distribution being imaged which results in inconsistent projection data sets. Our approach is to estimate the time varying radionuclide distribution directly from projection data. Entire tomographic slices or volumes are represented by a multiresolution spatiotemporal parameterization. The heart is modeled using spatiotemporal model that takes into account changes in the deformation of the heart as well as changes in the intensity of the signal caused by uptake and washout of the radiopharmaceutical from the heart and motion of the camera. We have developed an algorithm to reconstruct the continuous kinetics of the radiopharmaceutical by using spatiotemporal basis functions when the cardiac cycle of the heart is uniformly gated. The temporal basis functions are chosen to reflect the optimal tracer dynamics while the gate basis functions are assumed to be periodic with respect to the beating of the heart. Our preliminary results show that the fast gantry rotation of the SPECT camera can delineate the proper positioning of the myocardium in the reconstructed image while the 'out of phase' slow camera rotation smear out the motion of the heart.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129477196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Evaluation of the solid radioactive waste activity in nuclear medicine: Definition of shape factors to real geometries 核医学中固体放射性废物活性的评价:实际几何形状因子的定义

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551254

C. R. Brambilla, G. Hoff

{"title":"Evaluation of the solid radioactive waste activity in nuclear medicine: Definition of shape factors to real geometries","authors":"C. R. Brambilla, G. Hoff","doi":"10.1109/NSSMIC.2012.6551254","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551254","url":null,"abstract":"This work provides a critical analysis of the point source methodology applied in nuclear medicine radioactivity waste management routine. To evaluate the point source approximation used in the practice to determine the activity and its effect on activity and storage time was used deterministic and Monte Carlo calculations. The first step of this work was to validate the Monte Carlo Geant4 toolkit using measurements with standard calibration sources. After that the deterministic and Monte Carlo calculation was performed. In a realistic geometry the waste is not a point source but a box of dimensions (30.5 x 31.5 x 25.0) cm3. The impact on activity estimation comparing the real source point to the box geometry was observed from 20% up to 800% depending on the distance between the source and the detector and the selected radionuclide. The simple case evaluated in this work considering different radioisotopes proves that uses the point source approximation cause significant influence on the activity estimation. However it does not have significant impact in the storage time. The non significant influence in time storage can be explained by the activity limits recommend to release the radioactive waste that is significant smaller than the initial activity and the exponential behavior of the radioactive decay associated to value of the physical disintegration constant for the radionuclide commonly used on nuclear medicine applications.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129484115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

First results from the BNL/Penn PET-MRI system for whole body rodent imaging at 9.4T BNL/Penn PET-MRI系统对全身啮齿动物进行9.4T成像的第一个结果

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551626

M. Budassi, M. Purschke, J. Fried, T. Cao, S. Stoll, E. Gualtieri, J. Karp, P. O'connor, D. Schlyer, C. Woody, P. Vaska

引用次数: 4

Monolithic crystals on SiPM arrays in a prototype system with depth of interaction estimation 单片晶体在SiPM阵列上的原型系统与相互作用深度估计

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551740

J. Cabello, J. Gillam, J. Oliver, J. Barrio, M. Rafecas, G. Llosá

{"title":"Monolithic crystals on SiPM arrays in a prototype system with depth of interaction estimation","authors":"J. Cabello, J. Gillam, J. Oliver, J. Barrio, M. Rafecas, G. Llosá","doi":"10.1109/NSSMIC.2012.6551740","DOIUrl":"https://doi.org/10.1109/NSSMIC.2012.6551740","url":null,"abstract":"Increased sensitivity is one of the major challenges in novel detector development. While pixelated crystals are standard, the use of continuous crystals can provide increased active volume and thus sensitivity. Accurate estimation of the interaction positions of photons in continuous crystals requires a sophisticated algorithm. Additionally, including depth of interaction (Dol) in the reconstruction process can mitigate parallax effects near the edges of field of view, therefore Dol estimation is highly desirable. In this work, the interaction position coordinates in 3D are estimated adapting an already existing analytical model to our system with no additional hardware, training data sets or Monte Carlo simulations. The algorithm is implemented in a two-detector-head system comprised of continuous crystals coupled to SiPM arrays. Acquired data is stored in list-mode where the continuous nature of the interaction position is preserved. For image reconstruction, since the crystal is continuous, pre-computation of the system matrix elements would require discretization of the detected measurements. To avoid data discretization the system matrix elements are calculated on-the-fly. Spatial information is later on retained in the reconstruction algorithm by using a Siddon-like algorithm where the ray end-points correspond to the estimated interaction positions in continuous space, introducing the interaction position estimation uncertainty in the calculation of the system matrix elements. Reconstruction using continuous data is compared to reconstruction using artificially discretized data. Results show that the spatial resolution measured from a reconstructed point source using ML-EM obtained with a continuous crystal is superior to the spatial resolution obtained with a pixelated crystal.","PeriodicalId":187728,"journal":{"name":"2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129216035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Study of 3D reconstruction algorithm used in cosmic-ray muon radiography 宇宙射线介子摄影三维重建算法研究

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551058

Jianping Cheng, B. Yu, Ziran Zhao, Xuewu Wang

引用次数: 1

The trapezoidal clocking 梯形时钟

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Pub Date : 2012-10-01 DOI: 10.1109/NSSMIC.2012.6551424

Jinyuan Wu

引用次数: 1