Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5874483
E. K. Fung, D. Weinzimmer, S. Strittmatter, Yiyun Huang, R. Carson
Segmentation in PET images is fraught with difficulty stemming from variable activity values and low SNR. Standard practice utilizes co-registered images from other modalities to provide anatomical information. Sometimes, this information may be missing or of limited usefulness. We present a method of extracting centerlines of rat spinal cords solely from dynamic PET images. The method relies on the unique temporal information in the voxel time activity curves (TAC) to improve segmentation results. Using techniques previously developed for carotid arteries, centerlines were modeled by B-splines to ensure smooth realistic curves. This method is highly automated, only requiring user definition of a small number of seed points. The method was applied to [11C]AFM studies which measure serotonin transporters in the cord. Initial analysis showed that the method yielded comparable results in standard uptake values (SUV) compared to manual delineation of regions of interest (ROI). It also demonstrated an improved outcome over segmentation based on intensity alone.
{"title":"Segmentation of rat spinal cord in PET using spatiotemporal information","authors":"E. K. Fung, D. Weinzimmer, S. Strittmatter, Yiyun Huang, R. Carson","doi":"10.1109/NSSMIC.2010.5874483","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5874483","url":null,"abstract":"Segmentation in PET images is fraught with difficulty stemming from variable activity values and low SNR. Standard practice utilizes co-registered images from other modalities to provide anatomical information. Sometimes, this information may be missing or of limited usefulness. We present a method of extracting centerlines of rat spinal cords solely from dynamic PET images. The method relies on the unique temporal information in the voxel time activity curves (TAC) to improve segmentation results. Using techniques previously developed for carotid arteries, centerlines were modeled by B-splines to ensure smooth realistic curves. This method is highly automated, only requiring user definition of a small number of seed points. The method was applied to [11C]AFM studies which measure serotonin transporters in the cord. Initial analysis showed that the method yielded comparable results in standard uptake values (SUV) compared to manual delineation of regions of interest (ROI). It also demonstrated an improved outcome over segmentation based on intensity alone.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"86 1","pages":"3605-3609"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78154454","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5874019
J. Barata, C. Conde
The drift velocities and the longitudinal and transverse diffusion coefficients for Ar+ ions in gaseous Ar/Ne mixtures, at atmospheric pressures, for Ar concentrations between 1 and 20%, and reduced electric field strengths, E/N, from 1 to 100 Td, corresponding to E/p, from about 0.329 to 32.9 V cm−1 Torr−1 at 293 K, are calculated by Monte Carlo simulation. The Monte Carlo simulations use a set of integral and differential elastic collision cross-sections for Ar+ ions with neutral Ar and Ne atoms. Differential and integral elastic collision cross-sections for Ar+ ions with neutral Ne atoms are calculated, and reported for center-of-mass energies between 1 meV and 10 eV, using a modified Tang and Toennies ion-atom interaction potential model to describe ab initio spectroscopic data for the ArNe+ molecular ion and the long-range interaction potentials. The phase shifts were calculated with the JWKB approximation. The cross-sections for the collision of Ar+ ions with Ar atoms used were the ones calculated before by the authors.
用蒙特卡罗模拟计算了在大气压下，当Ar浓度在1 ~ 20%之间时，氩气/氖混合物中Ar+离子的漂移速度和纵向和横向扩散系数，以及在293 K下电场强度E/N从1到100 Td，对应于E/p从0.329到32.9 V cm−1 Torr−1。蒙特卡罗模拟使用了一组Ar+离子与中性Ar和Ne原子的积分和微分弹性碰撞截面。利用改进的Tang和Toennies离子-原子相互作用势模型描述了ArNe+分子离子的从头算光谱数据和远程相互作用势，计算了Ar+离子与中性Ne原子的微分和积分弹性碰撞截面，并报道了质心能量在1 meV和10 eV之间。用JWKB近似计算相移。所使用的Ar+离子与Ar原子碰撞的横截面是作者之前计算的。
{"title":"Elastic cross-sections for low energy collision of Ar+ with Ne and Monte Carlo simulation of the transport of Ar+ ions in gaseous Ar/Ne mixtures","authors":"J. Barata, C. Conde","doi":"10.1109/NSSMIC.2010.5874019","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5874019","url":null,"abstract":"The drift velocities and the longitudinal and transverse diffusion coefficients for Ar<sup>+</sup> ions in gaseous Ar/Ne mixtures, at atmospheric pressures, for Ar concentrations between 1 and 20%, and reduced electric field strengths, E/N, from 1 to 100 Td, corresponding to E/p, from about 0.329 to 32.9 V cm<sup>−1</sup> Torr<sup>−1</sup> at 293 K, are calculated by Monte Carlo simulation. The Monte Carlo simulations use a set of integral and differential elastic collision cross-sections for Ar<sup>+</sup> ions with neutral Ar and Ne atoms. Differential and integral elastic collision cross-sections for Ar<sup>+</sup> ions with neutral Ne atoms are calculated, and reported for center-of-mass energies between 1 meV and 10 eV, using a modified Tang and Toennies ion-atom interaction potential model to describe ab initio spectroscopic data for the ArNe<sup>+</sup> molecular ion and the long-range interaction potentials. The phase shifts were calculated with the JWKB approximation. The cross-sections for the collision of Ar<sup>+</sup> ions with Ar atoms used were the ones calculated before by the authors.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"27 1","pages":"1476-1479"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78157546","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5874361
P. Olcott, Eric Gonzalez, A. Vandenbroucke, C. Levin
We present a mixture model of exponential distributions to describe the variation of the positron end-point in tissue. The physics of positron trajectories through tissue was simulated by a Monte-Carlo simulator based on elastic scattering from the nucleus, inelastic collisions with atomic electrons, hard elastic collisions producing delta electrons, and the positron emission energy spectra. Data from this comprehensive physics based Monte Carlo simulation was fed into the Expectation Maximization (EM) algorithm, and adapted to a binary mixture of exponential distributions. This binary mixture distribution provides a fast and accurate way to estimate positron-range for PET Monte Carlo simulation packages. For 18F and 15O point source simulations, the root mean square (rms) deviations within 2xFWHM between this mixture model and the full Monte Carlo simulation of positron endpoint probabilities was 4 and 7%, respectively.
{"title":"Mixture model for fast estimation of positron range","authors":"P. Olcott, Eric Gonzalez, A. Vandenbroucke, C. Levin","doi":"10.1109/NSSMIC.2010.5874361","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5874361","url":null,"abstract":"We present a mixture model of exponential distributions to describe the variation of the positron end-point in tissue. The physics of positron trajectories through tissue was simulated by a Monte-Carlo simulator based on elastic scattering from the nucleus, inelastic collisions with atomic electrons, hard elastic collisions producing delta electrons, and the positron emission energy spectra. Data from this comprehensive physics based Monte Carlo simulation was fed into the Expectation Maximization (EM) algorithm, and adapted to a binary mixture of exponential distributions. This binary mixture distribution provides a fast and accurate way to estimate positron-range for PET Monte Carlo simulation packages. For 18F and 15O point source simulations, the root mean square (rms) deviations within 2xFWHM between this mixture model and the full Monte Carlo simulation of positron endpoint probabilities was 4 and 7%, respectively.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"18 1","pages":"3058-3060"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81454458","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5874162
Chao Wang, Hongdi Li, S. An, Yuxuan Zhang, H. Baghaei, R. Ramirez, Shitao Liu, W. Wong
In the front-end circuit of a Positron Emission Tomography (PET) camera, adjusting the photomultipliers (PMT) gain by changing the voltage distribution in dynodes instead of changing the total high voltage is more convenient to realize, and this method is better in signal-to-noise-ratio (SNR) than using a variable-gain-amplifier (VGA) in the signal path which may induce extra noise. In this study, we revised the previous voltage divider design to achieve wider gain adjustable range which relaxes the PMT gain-spread requirement to reduce the PMT cost. An accurate test bench was used to measure the PMT transit time variation as a function of the relative gain. From the test result, within the adjustable gain range, the PMT transit time variation can be as large as several hundreds of picoseconds; and this is non-ignorable in the Time-of-Flight (TOF) applications. Hence, a time correction is required. A look-up-table (LUT) from the transit time variation vs. PMT relative gain curve is used to correct this transit time variation with the gain adjustment simultaneously without performing the time-consuming entire system timing recalibration.
{"title":"A study of transit time variation in the PMT with a gain programmable voltage divider for a TOF PET","authors":"Chao Wang, Hongdi Li, S. An, Yuxuan Zhang, H. Baghaei, R. Ramirez, Shitao Liu, W. Wong","doi":"10.1109/NSSMIC.2010.5874162","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5874162","url":null,"abstract":"In the front-end circuit of a Positron Emission Tomography (PET) camera, adjusting the photomultipliers (PMT) gain by changing the voltage distribution in dynodes instead of changing the total high voltage is more convenient to realize, and this method is better in signal-to-noise-ratio (SNR) than using a variable-gain-amplifier (VGA) in the signal path which may induce extra noise. In this study, we revised the previous voltage divider design to achieve wider gain adjustable range which relaxes the PMT gain-spread requirement to reduce the PMT cost. An accurate test bench was used to measure the PMT transit time variation as a function of the relative gain. From the test result, within the adjustable gain range, the PMT transit time variation can be as large as several hundreds of picoseconds; and this is non-ignorable in the Time-of-Flight (TOF) applications. Hence, a time correction is required. A look-up-table (LUT) from the transit time variation vs. PMT relative gain curve is used to correct this transit time variation with the gain adjustment simultaneously without performing the time-consuming entire system timing recalibration.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"22 1","pages":"2155-2157"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78963126","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5874323
Junjun Deng, S. Siegel, Mu Chen
In PET scanners, one or multiple collimated point sources are used to acquire transmission measurements to generate attenuation maps for emission tomography [1]. The transmission acquisition is, intrinsically, 3D cone beam geometry. The acquired list-mode data are transformed into sinograms in the histogram process. Thereafter, transmission images are reconstructed from the sinograms, which are then re-projected to generate an attenuation map. Conventionally, a 2D rebinning method is used to transform the list-mode data into 2D parallel beam sinograms [2], and, accordingly, 2D reconstruction algorithms are employed to generate transmission images. Due to the inaccuracy of the 2D rebinning method, only limited oblique Lines of Response (LOR) can be used, causing limited axial coverage. If more oblique LORs were to be accepted in the rebinning process, artifacts would be introduced in the transmission images that may result in inaccurate attenuation correction factors. To address this issue, a 3D cone-beam rebinning process is proposed to faithfully transform the list-mode data, and the associated reconstruction algorithms for cone-beam geometry have been adopted to generate the transmission images. The experimental results showed the new method produced better images, especially in the axial direction.
{"title":"3D cone-beam rebinning and reconstruction for animal PET transmission tomography","authors":"Junjun Deng, S. Siegel, Mu Chen","doi":"10.1109/NSSMIC.2010.5874323","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5874323","url":null,"abstract":"In PET scanners, one or multiple collimated point sources are used to acquire transmission measurements to generate attenuation maps for emission tomography [1]. The transmission acquisition is, intrinsically, 3D cone beam geometry. The acquired list-mode data are transformed into sinograms in the histogram process. Thereafter, transmission images are reconstructed from the sinograms, which are then re-projected to generate an attenuation map. Conventionally, a 2D rebinning method is used to transform the list-mode data into 2D parallel beam sinograms [2], and, accordingly, 2D reconstruction algorithms are employed to generate transmission images. Due to the inaccuracy of the 2D rebinning method, only limited oblique Lines of Response (LOR) can be used, causing limited axial coverage. If more oblique LORs were to be accepted in the rebinning process, artifacts would be introduced in the transmission images that may result in inaccurate attenuation correction factors. To address this issue, a 3D cone-beam rebinning process is proposed to faithfully transform the list-mode data, and the associated reconstruction algorithms for cone-beam geometry have been adopted to generate the transmission images. The experimental results showed the new method produced better images, especially in the axial direction.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"94 1","pages":"2885-2888"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87686070","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5873823
J. Winso, J. Rolando, W. H. Knight, E. S. Ackermann, V. Wijekumar, H. Yu
A novel technique has been developed under a DNDO SBIR Program to improve the quality and availability of law enforcement and first responder training in the use of Preventative Radiological/Nuclear Detection (PRND) equipment. This training method is implemented in a software system designated as RAILS (Realistic and Adaptive Interactive Learning System), which allows trainees to practice finding, identifying, and determining the threat level of radioactive sources in a 3D video game environment.
{"title":"Integration of radiation transport models in an interactive video game to train law enforcement and first responders on preventative RAD/NUC detection (PRND) methods","authors":"J. Winso, J. Rolando, W. H. Knight, E. S. Ackermann, V. Wijekumar, H. Yu","doi":"10.1109/NSSMIC.2010.5873823","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5873823","url":null,"abstract":"A novel technique has been developed under a DNDO SBIR Program to improve the quality and availability of law enforcement and first responder training in the use of Preventative Radiological/Nuclear Detection (PRND) equipment. This training method is implemented in a software system designated as RAILS (Realistic and Adaptive Interactive Learning System), which allows trainees to practice finding, identifying, and determining the threat level of radioactive sources in a 3D video game environment.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"59 1","pages":"560-565"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86819308","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5873917
A. Borisevitch, V. Dormenev, A. Fedorov, M. Korjik, T. Kuske, V. Mechinsky, O. Missevitch, R. Novotny, R. Rusack, A. Singovski
Scintillation crystals of the lead tungstate family — PWO, PWO-II — became widely used in electromagnetic calorimeters in high energy physics experiments at high luminosity accelerator facilities. During the operation of electromagnetic calorimeters a damage of the optical transmission of the crystals occurs due to creation of color centers. In addition to the recharge of a priori in the crystals existing defects by γ-radiation additional damage of the crystal matrix occurs due to hadrons. Therefore, radiation induced optical absorption can limit the energy resolution of the calorimeter. We have minimized radiation damage effects by technological efforts to obtain perfect crystals with a minimal concentration of the defects creating metastable color centers as well as the recoven' of color centers by stimulation with infrared light. In this paper we discuss the method of stimulated recovery of radiation induced absorption which can be even applied in situ. The mechanisms of the damage under γ- and hadronirradiation are described.
钨酸铅族的闪烁晶体PWO, PWO- ii -在高能物理实验中被广泛应用于电磁量热计中。在电磁量热计工作期间，由于色心的产生，晶体的光学传输受到损害。在γ辐射作用下，除了对存在缺陷的晶体进行先验充值外，还会发生强子对晶体基体的破坏。因此，辐射诱导的光吸收会限制量热计的能量分辨率。我们通过技术上的努力，以最小的缺陷浓度获得完美的晶体，创造亚稳态色中心，并通过红外光刺激恢复色中心，从而最大限度地减少了辐射损伤的影响。本文讨论了辐射诱导吸收的受激恢复方法，这种方法甚至可以在现场应用。描述了γ和强子辐照损伤的机理。
{"title":"Maintaining low radiation damage of lead tungstate scintillation crystals operating in high dose rate radiation environment","authors":"A. Borisevitch, V. Dormenev, A. Fedorov, M. Korjik, T. Kuske, V. Mechinsky, O. Missevitch, R. Novotny, R. Rusack, A. Singovski","doi":"10.1109/NSSMIC.2010.5873917","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5873917","url":null,"abstract":"Scintillation crystals of the lead tungstate family — PWO, PWO-II — became widely used in electromagnetic calorimeters in high energy physics experiments at high luminosity accelerator facilities. During the operation of electromagnetic calorimeters a damage of the optical transmission of the crystals occurs due to creation of color centers. In addition to the recharge of a priori in the crystals existing defects by γ-radiation additional damage of the crystal matrix occurs due to hadrons. Therefore, radiation induced optical absorption can limit the energy resolution of the calorimeter. We have minimized radiation damage effects by technological efforts to obtain perfect crystals with a minimal concentration of the defects creating metastable color centers as well as the recoven' of color centers by stimulation with infrared light. In this paper we discuss the method of stimulated recovery of radiation induced absorption which can be even applied in situ. The mechanisms of the damage under γ- and hadronirradiation are described.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"os-55 1","pages":"1010-1013"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87095793","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5873742
T. Yanagida, Y. Fujimoto, Y. Furuya, Y. Yokota, N. Kawaguchi, K. Kamada, J. Pejchal, Varely Chani, K. Fukuda, D. Totsuka, K. Uchiyama, Kuniyoshi Mori, Ken Kitano, M. Nikl, A. Yoshikawa
These instructions provide guidelines for preparing manuscripts for submission to the Conference Record (CR) of the 2010 IEEE Nuclear Science Symposium and Medical Imaging Conference. If you are using Microsoft Word 6.0 or later to prepare your manuscript, you should use this document as a template. Define all symbols used in the abstract. Do not cite references in the abstract.
这些说明提供了准备提交给2010年IEEE核科学研讨会和医学成像会议会议记录(CR)的手稿的指导方针。如果您使用Microsoft Word 6.0或更高版本来准备稿件，则应使用此文档作为模板。定义抽象中使用的所有符号。不要在摘要中引用参考文献。
{"title":"Development of pulsed X-ray tube equipped streak camera system to study scintillation phenomenon","authors":"T. Yanagida, Y. Fujimoto, Y. Furuya, Y. Yokota, N. Kawaguchi, K. Kamada, J. Pejchal, Varely Chani, K. Fukuda, D. Totsuka, K. Uchiyama, Kuniyoshi Mori, Ken Kitano, M. Nikl, A. Yoshikawa","doi":"10.1109/NSSMIC.2010.5873742","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5873742","url":null,"abstract":"These instructions provide guidelines for preparing manuscripts for submission to the Conference Record (CR) of the 2010 IEEE Nuclear Science Symposium and Medical Imaging Conference. If you are using Microsoft Word 6.0 or later to prepare your manuscript, you should use this document as a template. Define all symbols used in the abstract. Do not cite references in the abstract.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"10 1","pages":"185-187"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87743641","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5874257
A. Stolin, S. Majewski, R. Raylman, H. W. Hazard
We have implemented the low-profile SENSL 16ch SPMArray2 module in a small prototype of a beta/positron imager. The SiPM sensor has a 0.5–1mm thick plastic scintillator optically coupled via thin (1–2mm) glass window for better light spread between the sixteen 3mm SiPM pads to allow center of gravity position calculations of the scintillation light flashes. In the initial studies, aluminized Mylar foil and Teflon tape were used for a top surface reflector, and black Tedlar foil for a light-tight mechanical barrier. Sensitivity of 3–5 counts/sec per nanoCi was measured with one layer of 50 micron Teflon and 50 micron Tedlar each. For two Tedlar layers the sensitivity was lower by about 10 percent with the applied broad energy window. Intrinsic spatial resolution was estimated at approximately 2.5mm, with the un-collimated positron beam distribution limiting the measurement. The position information can be used as a finer indication when the hot spots are located within the ∼10mm×10mm useful FOV of the device. According to the initial plans, the imager will be evaluated as a tool assisting with checking the cancer margin adequacy in breast cancer excision (lumpectomy). Before surgery, the patient will obtain systemic injection of positron biomarker, such as F18-FDG, the same that was used to detect the cancer in the PET procedure. Attached to the surgeons fingertip, the imager will be used to scan the surface of the post-extraction cavity for residual positron activity as an indication of non-sufficient cancer margins, to allow for immediate in-situ correction. The imager is planned as another instrument in the set of complementary imaging and non-imaging tools to assist with breast cancer surgeries, not to replace other tools.
{"title":"Fingertip beta imager based on the SiPM technology","authors":"A. Stolin, S. Majewski, R. Raylman, H. W. Hazard","doi":"10.1109/NSSMIC.2010.5874257","DOIUrl":"https://doi.org/10.1109/NSSMIC.2010.5874257","url":null,"abstract":"We have implemented the low-profile SENSL 16ch SPMArray2 module in a small prototype of a beta/positron imager. The SiPM sensor has a 0.5–1mm thick plastic scintillator optically coupled via thin (1–2mm) glass window for better light spread between the sixteen 3mm SiPM pads to allow center of gravity position calculations of the scintillation light flashes. In the initial studies, aluminized Mylar foil and Teflon tape were used for a top surface reflector, and black Tedlar foil for a light-tight mechanical barrier. Sensitivity of 3–5 counts/sec per nanoCi was measured with one layer of 50 micron Teflon and 50 micron Tedlar each. For two Tedlar layers the sensitivity was lower by about 10 percent with the applied broad energy window. Intrinsic spatial resolution was estimated at approximately 2.5mm, with the un-collimated positron beam distribution limiting the measurement. The position information can be used as a finer indication when the hot spots are located within the ∼10mm×10mm useful FOV of the device. According to the initial plans, the imager will be evaluated as a tool assisting with checking the cancer margin adequacy in breast cancer excision (lumpectomy). Before surgery, the patient will obtain systemic injection of positron biomarker, such as F18-FDG, the same that was used to detect the cancer in the PET procedure. Attached to the surgeons fingertip, the imager will be used to scan the surface of the post-extraction cavity for residual positron activity as an indication of non-sufficient cancer margins, to allow for immediate in-situ correction. The imager is planned as another instrument in the set of complementary imaging and non-imaging tools to assist with breast cancer surgeries, not to replace other tools.","PeriodicalId":13048,"journal":{"name":"IEEE Nuclear Science Symposuim & Medical Imaging Conference","volume":"46 1","pages":"2595-2597"},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88315070","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}
Pub Date : 2010-10-01DOI: 10.1109/NSSMIC.2010.5874400
Mi-Ae Park, E. Lunsford, R. Zimmerman, S. Southekal, J. Frangioni, S. Moore
Increasing the number of pinholes in small-animal SPECT significantly improves its count sensitivity. When the detector(s) are small, however, overlapping of projections (multiplexing) from different pinholes is unavoidable and can amplify noise in reconstructed images. We have evaluated the performance of two multi-pinhole systems, one with and one without multiplexing, for a prototypical tumor-imaging task. We prepared seven beads (∼1.8-mm diameter) to mimic tumors labeled with Tc-99m. A uniform gelatin phantom was used to simulate normal background tissue. The tumor-to-normal tissue ratio was ∼6:1, and each bead contained ∼1 μCi. The first scanner, equipped with two 0.8-mm pinholes on each of three heads (HMS-0.8), acquired only non-overlapping projections. We also scanned the phantom using 1.6mm pinholes (HMS-1.6) The second scanner had 9 pinholes on each of four heads, and allowed multiplexing. To compensate for decay, the phantom was scanned for 50 min on HMS-0.8, 58 min on HMS-1.6, 82 min on NanoSPECT/CT with 1.4 mm pinholes (Nano-1.4), and 102 min with 1.0 mm pinholes (Nano-1.0). A total of 30 (24) angular projections were acquired with HMS (Nano); these were reconstructed using 10 OSEM subsets for HMS, and 4 subsets for Nano. The mean voxel value in each sphere, and the mean and standard deviation in a large VOI in the background, were used to compute the signal-to-noise ratio (SNR) and contrast of each bead. The relative noise in the background was also calculated. The systems with and without multiplexing yielded similar image quality and average bead SNR, especially for HMS-0.8 and Nano-1.0. Both systems yielded very similar SNR values, despite the fact that the multiplexed system acquired data using 36 pinholes, while the non-multiplexed system had only 6 pinholes. The multiplexed acquisition did not seem to adversely affect the image contrast of the spherical tumors.
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