1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference最新文献_第7页

High Integrity Digital Systems And Nuclear Safety 高完整性数字系统与核安全

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.701803

R. Brill

引用次数: 1

Composite Dual Window Scattering Correction Technique In PET PET复合双窗散射校正技术

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.701867

L. Shao, J. Karp, R. Freifelder

{"title":"Composite Dual Window Scattering Correction Technique In PET","authors":"L. Shao, J. Karp, R. Freifelder","doi":"10.1109/NSSMIC.1993.701867","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701867","url":null,"abstract":"Most current energy spectrum based scattering correction techniques in PET suffer from source distribution dependencies. As an alternative method to compensate for these problems, we propose a composite dual energy window (CDW) scattering correction technique, which is based on using the scatter kernels from both the scatter and the photopeak windows. The CDW technique can be broken down to two steps: convolution and energy window correction. In the convolution part, we can obtain the first order scatter projections for both the photopeak and scatter windows by using the calibrated scatter kernels. Then we find the object dependent scatter ratio by dividing the convolution-estimated scatter projections. By this simple division, the overestimation of scatters during convolution is mostly canceled out. In the second step, we simply use the measured scatter profiles in the scatter window and the estimated scatter ratio to obtain the scatter projection in the photopeak window. The CDW technique is evaluated with a Monte Carlo simulation program which simulates the UGM PENN-PET scanner. The results indicate that this technique is better than both the deconvolution-subtraction with one iteration and dual window scattering correction techniques.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126914261","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: 7

Post injection transmission scanning in a volume imaging PET camera 体成像PET相机注射后透射扫描

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.373525

R. Smith, J. Karp

{"title":"Post injection transmission scanning in a volume imaging PET camera","authors":"R. Smith, J. Karp","doi":"10.1109/NSSMIC.1993.373525","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.373525","url":null,"abstract":"Quantitative, low noise, measured attenuation correction has been established for the PENN PET 240H Volume Imaging Camera. This is achieved, without septa, using a narrow energy (450-570 keV) and sinogram position (2 cm wide mask) gate to minimize scatter contamination. Twelve minute transmission acquisitions with a 0.5 mCi rod source are adequate for this purpose. Post injection transmission scans (with emission activity in the FOV) suffer from emission contamination simulating transmitted gamma ray flux. This emission contamination may be measured by performing a transmission acquisition without a transmission source. This contamination is then subtracted from the measured post injection transmission scan. Emission activity within the FOV adds to detector deadtime so that more counts are lost than are added by the emission activity counts accepted into the transmission position gate. Thus there is a net loss of scan statistics when compared to pre-injection transmission scanning. Removal of emission contamination and compensation for this excess deadtime results in corrected attenuation coefficients. For residual activity levels typical of FDG whole-body cancer and cardiac studies the post injection measurements are within 4% of pre-injection values. This method is under refinement to correct for attenuation with higher levels of activity in the FOV.<<ETX>>","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125352313","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: 27

Microtomography using microfocus radiography system 使用微聚焦射线照相系统的微层析成像

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.373588

Joaquim Teixeira de Assis, T. Lopes, J.L. Rodridgues

引用次数: 0

A simple data loss model for positron camera systems 正电子相机系统的简单数据丢失模型

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.373634

L. Eriksson

引用次数: 42

Monte Carlo Simulation Of Pulse Height Spectra In Nuclear Logging Density Tools 核测井密度工具中脉冲高度谱的蒙特卡罗模拟

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.701675

W. Madigan

引用次数: 0

A rotating and squashing projector-backprojector pair for fan-beam and cone-beam iterative algorithms 扇形波束和锥波束迭代算法的旋转和压缩投影-反向投影对

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.373629

G. L. Zeng, Y. Hsieh, G. Gullberg

{"title":"A rotating and squashing projector-backprojector pair for fan-beam and cone-beam iterative algorithms","authors":"G. L. Zeng, Y. Hsieh, G. Gullberg","doi":"10.1109/NSSMIC.1993.373629","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.373629","url":null,"abstract":"The authors propose and implement a rotating-and-squashing projector-backprojector pair for fan-beam and cone-beam iterative algorithms. The motivation of their investigation is to significantly reduce both computation time and reconstruction artifacts when implementing attenuation, geometric and scatter correction models. At each projection angle, the authors' projector/backprojector first rotates the image volume so that the front face of the volume is parallel to the detector, then squashes the image volume so that the fan-beam and cone-beam rays are converted into parallel rays. In the authors' implementation, these two steps are combined and they only interpolate the voxel values once. The projection operation is achieved by a simple summation, and the backprojection operation is achieved by copying the projection array to the image volume. Another advantage of this projector/backprojector is that the system point response function can be deconvolved via the fast Fourier transform using the shift-invariant property of the point response function when the voxel-to-detector distance is constant. At each projection angle, the authors rotate and squash the image volume using interpolations. This causes smoothing of the image. However, this smoothing can be modeled as a point spread function and be deconvolved. The fan-beam and cone-beam rotating-and-squashing projector/backprojector have been implemented on a SPECT system for the EM-ML algorithm.<<ETX>>","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130653500","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: 6

Bias-variance tradeoffs analysis using uniform CR bound for a SPECT system 偏差-方差权衡分析使用统一的CR界为SPECT系统

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.373518

M. Usman, A. Hero, J. Fessler, W. Rogers

引用次数: 6

Atlas generated generalized ROIs for use in functional neuroimaging Atlas生成广义roi用于功能性神经成像

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.373606

L. Thurfjell, C. Bohm

引用次数: 2

An Unbiased Technique For Automatic Estimation Of Vessel Contours In Angiograms 血管造影中血管轮廓的无偏自动估计技术

1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference Pub Date : 1993-10-31 DOI: 10.1109/NSSMIC.1993.701843

M. Figueiredo, J. Leitão

{"title":"An Unbiased Technique For Automatic Estimation Of Vessel Contours In Angiograms","authors":"M. Figueiredo, J. Leitão","doi":"10.1109/NSSMIC.1993.701843","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701843","url":null,"abstract":"AbatTactAccurate and fully automatic assessment of artery dimensions in angiograms has been sought as a diagnostic tool, in particular for coronary heart disease. We propose a new technique to estimate vessel borders in angiographic images. Unlike in previous approaches, the obtained edge estimates are unbiased, this being of primordial importance since quantitative analysis is the goal. Another important feature of the proposed estimator is that no constant background is assumed, making it well suited for noxisubtracted angiograms. The key aspect of our approach is that the smoothness constraint is not used to smooth or i n some other way modify the estimates directly derived from the image (which would introduce bias) but rather elect (without modifying) candidate estimates. As a result, tlie selected points, if correct, are unbiased estimates. Even at low contrast segments and in tlie vicinity of artifacts, the true border points still correspond to (possibly faint) local maxima of the edge operator, wliicli can be correctly chosen if the surrounding context is taken into account. Robustness against unknown background is provided by tlie use a morphological edge detector rather than some linear operator such as a matched filter wliicli assumes flat background.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117224504","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