Pub Date : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829337
K. Usui, S. Kabuki, C. Kurokawa, S. Sugimoto, K. Sasai, E. Kunieda, K. Ogawa
To accomplish accurate irradiation to a target, image information about the target is very useful in radiotherapy. A kilo-voltage cone-beam computed tomography (kV-CBCT) system mounted on a linear accelerator can verify the accuracy of the set-up position and the size and location of the target on each treatment day. However, the gantry of the CBCT system is heavy and so requires a long data acquisition time. As a result, image distortion occurs in the case of a moving target. In this study, we proposed a method to reconstruct a target less affected by any motion of the target, and evaluated the proposed method with a moving phantom. In our method, CBCT images of the moving phantom were acquired, and the target position in two directions was detected with a template matching method using these projection images. And we selected data acquisition angles of the projection images in which the target was located in predefined regions in the projection images, and made a sinogram with the projection image of selected angles. A less blurred image was reconstructed with a filtered-backprojection method from the sinogram. The results of experiments showed that the blurring caused by the movement of the phantom was reduced with our proposed method.
{"title":"CBCT image reconstruction of a moving target with an on-board imaging system for radiation therapy","authors":"K. Usui, S. Kabuki, C. Kurokawa, S. Sugimoto, K. Sasai, E. Kunieda, K. Ogawa","doi":"10.1109/NSSMIC.2013.6829337","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829337","url":null,"abstract":"To accomplish accurate irradiation to a target, image information about the target is very useful in radiotherapy. A kilo-voltage cone-beam computed tomography (kV-CBCT) system mounted on a linear accelerator can verify the accuracy of the set-up position and the size and location of the target on each treatment day. However, the gantry of the CBCT system is heavy and so requires a long data acquisition time. As a result, image distortion occurs in the case of a moving target. In this study, we proposed a method to reconstruct a target less affected by any motion of the target, and evaluated the proposed method with a moving phantom. In our method, CBCT images of the moving phantom were acquired, and the target position in two directions was detected with a template matching method using these projection images. And we selected data acquisition angles of the projection images in which the target was located in predefined regions in the projection images, and made a sinogram with the projection image of selected angles. A less blurred image was reconstructed with a filtered-backprojection method from the sinogram. The results of experiments showed that the blurring caused by the movement of the phantom was reduced with our proposed method.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131450410","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829542
A. Lounis
To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Planar Pixel Sensor R&D Project was established comprising 18 institutes and more than 80 scientists. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edges to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. Most important of the recent accomplishments obtained in research institutes members of the R&D project is given. In addition, the production of prototype sensors also for the outer layers has seen significant progress within the recent months and first characterization results will be shown. On the topic of edge efficiencies, substantial achievements have been made in view of planar active edges. We will show results from successful productions with two vendors. In addition, the status of the SCP post-processing technology will be summarized; this process could be applied to most sensors independent of their manufacturer which enables the creation of almost active edges even for originally non-slim-edge sensors.
{"title":"Leading edge of the technological developments of Planar Pixel Sensors and prospects for ATLAS HL-LHC upgrade","authors":"A. Lounis","doi":"10.1109/NSSMIC.2013.6829542","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829542","url":null,"abstract":"To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Planar Pixel Sensor R&D Project was established comprising 18 institutes and more than 80 scientists. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edges to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. Most important of the recent accomplishments obtained in research institutes members of the R&D project is given. In addition, the production of prototype sensors also for the outer layers has seen significant progress within the recent months and first characterization results will be shown. On the topic of edge efficiencies, substantial achievements have been made in view of planar active edges. We will show results from successful productions with two vendors. In addition, the status of the SCP post-processing technology will be summarized; this process could be applied to most sensors independent of their manufacturer which enables the creation of almost active edges even for originally non-slim-edge sensors.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131987754","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829146
M. Pizzichemi
The EndoTOFPET-US collaboration is developing a multi-modal imaging tool combining Ultrasound with Time-Of-Flight Positron Emission Tomography into an endoscopic imaging device. The objective of the project is to obtain a coincidence time resolution of about 200ps FWHM and to achieve ~1mm spatial resolution for the PET head, while integrating all the components in a very compact detector suitable for endoscopic use. This scanner aims to be exploited for diagnostic and surgical oncology, as well as being instrumental in the clinical test of new biomarkers especially targeted for prostate and pancreatic cancer. The current status of the project is presented in this paper.
{"title":"EndoTOFPET-US: Towards a multi-modal endoscope for Ultrasound and Time of Flight PET","authors":"M. Pizzichemi","doi":"10.1109/NSSMIC.2013.6829146","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829146","url":null,"abstract":"The EndoTOFPET-US collaboration is developing a multi-modal imaging tool combining Ultrasound with Time-Of-Flight Positron Emission Tomography into an endoscopic imaging device. The objective of the project is to obtain a coincidence time resolution of about 200ps FWHM and to achieve ~1mm spatial resolution for the PET head, while integrating all the components in a very compact detector suitable for endoscopic use. This scanner aims to be exploited for diagnostic and surgical oncology, as well as being instrumental in the clinical test of new biomarkers especially targeted for prostate and pancreatic cancer. The current status of the project is presented in this paper.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"166 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132529024","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829122
Xue Rui, Y. Long, E. Asma, A. Alessio, Paul Kinahan, B. De Man
One advantage of a combined PET/CT scanner is that a fast CT acquisition provides a high quality attenuation correction map for PET reconstruction. A diagnostic CT system typically operates in a voltage range from 80 kVp to 140 kVp. The choice of optimal spectrum depends on the specific application. In diagnostic imaging, contrast, noise and dose all play important roles. The designated CT scan for PET attenuation correction has different image quality requirements compared to diagnostic CT. For example, at 511 keV, the contrast between different materials reduces significantly and there is typically no interest in distinguishing small contrast variations. On the other hand, it is important that the error on the attenuation map is small, and especially bias in the CT attenuation correction (CTAC) map could introduce significant artifacts in PET images which may affect clinical diagnosis. We are interested in operating the CT scanner at the lowest possible dose while still providing accurate attenuation correction. However, at these very low dose levels, the effects of electronic noise can become significant. In the study presented here, we analyzed the impacts of the X-ray tube voltage, current and filtration by metal filter on the quality of the CTAC by evaluating noise variance and bias at various dose levels.
{"title":"Analysis of optimal CT spectrum for PET attenuation correction","authors":"Xue Rui, Y. Long, E. Asma, A. Alessio, Paul Kinahan, B. De Man","doi":"10.1109/NSSMIC.2013.6829122","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829122","url":null,"abstract":"One advantage of a combined PET/CT scanner is that a fast CT acquisition provides a high quality attenuation correction map for PET reconstruction. A diagnostic CT system typically operates in a voltage range from 80 kVp to 140 kVp. The choice of optimal spectrum depends on the specific application. In diagnostic imaging, contrast, noise and dose all play important roles. The designated CT scan for PET attenuation correction has different image quality requirements compared to diagnostic CT. For example, at 511 keV, the contrast between different materials reduces significantly and there is typically no interest in distinguishing small contrast variations. On the other hand, it is important that the error on the attenuation map is small, and especially bias in the CT attenuation correction (CTAC) map could introduce significant artifacts in PET images which may affect clinical diagnosis. We are interested in operating the CT scanner at the lowest possible dose while still providing accurate attenuation correction. However, at these very low dose levels, the effects of electronic noise can become significant. In the study presented here, we analyzed the impacts of the X-ray tube voltage, current and filtration by metal filter on the quality of the CTAC by evaluating noise variance and bias at various dose levels.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130453698","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829601
M. Cascella, F. Grancagnolo, A. L’Erario, A. Miccoli, S. Rella, M. Spedicato, G. Tassielli
We present a novel low mass drift chamber concept, developed in order to fulfill the requirements imposed by the search for extremely rare processes, which require high resolutions (order of 50-200 keV/c) for particle momenta in a range (50-300 MeV/c) totally dominated by the multiple scattering contribution. The innovative concept in the chamber design is the separation of the gas containment and the mechanical support structure. We describe a geometry optimization procedure and a new semi-automatic wiring strategy with a feed-through-less wire anchoring system.
{"title":"Ultra light drift chambers for precision physics","authors":"M. Cascella, F. Grancagnolo, A. L’Erario, A. Miccoli, S. Rella, M. Spedicato, G. Tassielli","doi":"10.1109/NSSMIC.2013.6829601","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829601","url":null,"abstract":"We present a novel low mass drift chamber concept, developed in order to fulfill the requirements imposed by the search for extremely rare processes, which require high resolutions (order of 50-200 keV/c) for particle momenta in a range (50-300 MeV/c) totally dominated by the multiple scattering contribution. The innovative concept in the chamber design is the separation of the gas containment and the mechanical support structure. We describe a geometry optimization procedure and a new semi-automatic wiring strategy with a feed-through-less wire anchoring system.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134074002","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829792
I. Anokhin, M. Lerch, M. Petasecca, O. Zinets, A. Rosenfeld
Calculations of responses for experimentally studied silicon planar structures (epitaxial single-strip silicon diodes) have been carried out for various profiles of microbeams. The spatial distribution of responses on the microbeam radiation therapy (MRT) beams has been calculated taken into account both electrical field distribution inside of the detector and recombination in the diffusion region. Contributions to the responses from the space charge region (SCR) and the diffusion region are compared. It has been shown that the spatial resolution and the detector efficiency in edge on mode of the detector relative to X-ray microbeam can be higher than for the face on irradiation geometry. The response functions of diodes under MRT irradiation for a simple physical model have been obtained analytically. That allows calculating responses using the convolution procedure for different beam profiles.
{"title":"Silicon planar structures as detectors for microbeam radiation therapy","authors":"I. Anokhin, M. Lerch, M. Petasecca, O. Zinets, A. Rosenfeld","doi":"10.1109/NSSMIC.2013.6829792","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829792","url":null,"abstract":"Calculations of responses for experimentally studied silicon planar structures (epitaxial single-strip silicon diodes) have been carried out for various profiles of microbeams. The spatial distribution of responses on the microbeam radiation therapy (MRT) beams has been calculated taken into account both electrical field distribution inside of the detector and recombination in the diffusion region. Contributions to the responses from the space charge region (SCR) and the diffusion region are compared. It has been shown that the spatial resolution and the detector efficiency in edge on mode of the detector relative to X-ray microbeam can be higher than for the face on irradiation geometry. The response functions of diodes under MRT irradiation for a simple physical model have been obtained analytically. That allows calculating responses using the convolution procedure for different beam profiles.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133976670","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829761
A. Comerma, D. Gascón, L. Freixas, L. Garrido, R. Graciani, J. Marı́n, G. Martinez, J. Pérez, P. Rato Mendes, J. Castilla, J. Cela, José María Fernéndez-Varea, I. Sarasola
A front end application specific integrated circuit (ASIC) for the readout of common cathode Silicon Photo-Multipliers arrays is presented with the following features: wide dynamic range, high speed, multi channel, low input impedance current amplifier, low power (≈10mW per channel), common cathode connection, directly coupled input with common mode voltage control and separated timing and charge signal output.A 16 channel prototype with 16 independent outputs for energy and pile-up detection and a single fast timing output is described. The low jitter current mode processing together with a configurable differential current mode logic (CML) output provides a timing signal suitable for Time of Flight (TOF) applications, such as TOF-PET (Positron Emission Tomography). Each channel delivers a digital output of a Time Over Threshold (TOT) type with a pulse width proportional to peak current (charge) input. The current mode input stage features a novel double feedback; a low speed feedback loop keeps input node voltage constant while a higher speed feedback loop keeps input impedance low. Dedicated circuitry allows SiPM high over-voltage operation, thus maximizing Photon Detection Efficiency (PDE) and timing resolution. Design was submitted in June 2012 in Austria Microsystems (AMS) 0.35 μm HBT BiCMOS technology and is under test.
{"title":"FlexToT - Current mode ASIC for readout of common cathode SiPM arrays","authors":"A. Comerma, D. Gascón, L. Freixas, L. Garrido, R. Graciani, J. Marı́n, G. Martinez, J. Pérez, P. Rato Mendes, J. Castilla, J. Cela, José María Fernéndez-Varea, I. Sarasola","doi":"10.1109/NSSMIC.2013.6829761","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829761","url":null,"abstract":"A front end application specific integrated circuit (ASIC) for the readout of common cathode Silicon Photo-Multipliers arrays is presented with the following features: wide dynamic range, high speed, multi channel, low input impedance current amplifier, low power (≈10mW per channel), common cathode connection, directly coupled input with common mode voltage control and separated timing and charge signal output.A 16 channel prototype with 16 independent outputs for energy and pile-up detection and a single fast timing output is described. The low jitter current mode processing together with a configurable differential current mode logic (CML) output provides a timing signal suitable for Time of Flight (TOF) applications, such as TOF-PET (Positron Emission Tomography). Each channel delivers a digital output of a Time Over Threshold (TOT) type with a pulse width proportional to peak current (charge) input. The current mode input stage features a novel double feedback; a low speed feedback loop keeps input node voltage constant while a higher speed feedback loop keeps input impedance low. Dedicated circuitry allows SiPM high over-voltage operation, thus maximizing Photon Detection Efficiency (PDE) and timing resolution. Design was submitted in June 2012 in Austria Microsystems (AMS) 0.35 μm HBT BiCMOS technology and is under test.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127618388","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829666
T. Yanagida, Y. Fujimoto, H. Yagi, T. Yanagitani
Ceramic Ce 0.1% doped Gd3(Ga,Al)5O12 scintillator fabricated by Konoshima Chemical was evaluated. In X-ray induced radioluminescence, intense emission peak appeared around 530 nm. When 137Cs 662 keV γ-ray was irradiated, scintillation light yield turned out to be 70000 ph/MeV by using Si-APD. Scintillation decay timewas a typical value of Ce-doped garnet materials, ~ 100 ns.
{"title":"Scintillation properties of ceramic Ce-doped Gd3(Ga,Al)5O12","authors":"T. Yanagida, Y. Fujimoto, H. Yagi, T. Yanagitani","doi":"10.1109/NSSMIC.2013.6829666","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829666","url":null,"abstract":"Ceramic Ce 0.1% doped Gd<sub>3</sub>(Ga,Al)<sub>5</sub>O<sub>12</sub> scintillator fabricated by Konoshima Chemical was evaluated. In X-ray induced radioluminescence, intense emission peak appeared around 530 nm. When <sup>137</sup>Cs 662 keV γ-ray was irradiated, scintillation light yield turned out to be 70000 ph/MeV by using Si-APD. Scintillation decay timewas a typical value of Ce-doped garnet materials, ~ 100 ns.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131044901","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829173
D. Xia, Mi-Ae Park, S. Moore, S. Metzler
Recently, a square-pinhole collimator has been proposed for SPECT imaging since it can tile the projection onto the detector efficiently and the fields of view (FOVs) in transverse and axial directions become separable. In this work, we have conducted sensitivity and FOV experiments for eighteen fabricated platinum/iridium(Pt/Ir) inserts with sub-millimeter square-apertures. A sinqθ fit to the experimental sensitivity has been performed for these inserts. The mean (standard deviation) of fitted sensitivity exponents (q) and effective diameters (d) are 10.7 (1.3) and 0.35 mm (0.02 mm), which are close to the values obtained from the simulated sensitivity data generated using the geometric parameters of the designed inserts. From projections of the FOV on the detector, we have measured the acceptance angles in the transverse and axial directions. The measured mean (standard deviation) of transverse and axial half-acceptances are 17.33° (0.21°) and 15.03°(0.23°), which are in good agreement with the designed values (17.13° and 14.93°). These results show that the physical properties of the fabricated inserts with sub-millimeter aperture size match our design well.
近年来，人们提出了一种用于SPECT成像的方形针孔准直器，它可以有效地将投影平铺到探测器上，并且可以分离横向和轴向的视场。在这项工作中，我们对18个制造的亚毫米方形孔径铂/铱(Pt/Ir)插入物进行了灵敏度和视场实验。对这些插片进行了与实验灵敏度的sinqθ拟合。拟合的灵敏度指数(q)和有效直径(d)的均值(标准差)分别为10.7(1.3)和0.35 mm (0.02 mm)，与利用设计刀片几何参数生成的模拟灵敏度数据得到的值接近。根据视场在探测器上的投影，我们测量了横向和轴向的接收角。实测的横向和轴向半接受度均值(标准差)分别为17.33°(0.21°)和15.03°(0.23°)，与设计值(17.13°和14.93°)吻合较好。结果表明，制备的亚毫米孔径刀片的物理性能符合设计要求。
{"title":"Preliminary investigation of imaging properties for sub-millimeter square pinholes","authors":"D. Xia, Mi-Ae Park, S. Moore, S. Metzler","doi":"10.1109/NSSMIC.2013.6829173","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829173","url":null,"abstract":"Recently, a square-pinhole collimator has been proposed for SPECT imaging since it can tile the projection onto the detector efficiently and the fields of view (FOVs) in transverse and axial directions become separable. In this work, we have conducted sensitivity and FOV experiments for eighteen fabricated platinum/iridium(Pt/Ir) inserts with sub-millimeter square-apertures. A sinqθ fit to the experimental sensitivity has been performed for these inserts. The mean (standard deviation) of fitted sensitivity exponents (q) and effective diameters (d) are 10.7 (1.3) and 0.35 mm (0.02 mm), which are close to the values obtained from the simulated sensitivity data generated using the geometric parameters of the designed inserts. From projections of the FOV on the detector, we have measured the acceptance angles in the transverse and axial directions. The measured mean (standard deviation) of transverse and axial half-acceptances are 17.33° (0.21°) and 15.03°(0.23°), which are in good agreement with the designed values (17.13° and 14.93°). These results show that the physical properties of the fabricated inserts with sub-millimeter aperture size match our design well.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130932791","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 : 2013-10-01DOI: 10.1109/NSSMIC.2013.6829660
Y. Fujimoto, T. Yanagida, K. Kamada, J. Pejchal
Basic radiation response properties of lithium aluminate LiAlO2 crystals activated with transition metals like Ti, Mn and Cu were examined. When X-ray excited the crystals, intense emission peaks were observed at visible wavelength regions, they are ascribed to the Ti4+ charge transfer (Ti-doped), Mn2+ 3d5-3d5 (Mn-doped) and Cu+ 3d94s-3d10 (Cu-doped) transitions. The scintillation decay times were estimated to be about 1.8 μs (93 %) and 9.9 μs (7 %) for the Ti-doped crystal, 310 μs (96 %) and 2220 μs (4 %) for Mn-doped one, and 3.6 μs (52 %) and 19.6 μs (48 %) for Cu-doped one, respectively. In the 252Cf neutron irradiated pulse height spectra, Ti- and Cu- doped crystals showed higher light yield in comparison to that of GS20 commercial scintillator.
{"title":"Radiation response of transition metals-doped lithium aluminate crystals","authors":"Y. Fujimoto, T. Yanagida, K. Kamada, J. Pejchal","doi":"10.1109/NSSMIC.2013.6829660","DOIUrl":"https://doi.org/10.1109/NSSMIC.2013.6829660","url":null,"abstract":"Basic radiation response properties of lithium aluminate LiAlO<sub>2</sub> crystals activated with transition metals like Ti, Mn and Cu were examined. When X-ray excited the crystals, intense emission peaks were observed at visible wavelength regions, they are ascribed to the Ti<sup>4+</sup> charge transfer (Ti-doped), Mn<sup>2+</sup> 3d<sup>5</sup>-3d<sup>5</sup> (Mn-doped) and Cu<sup>+</sup> 3d<sup>9</sup>4s-3d<sup>10</sup> (Cu-doped) transitions. The scintillation decay times were estimated to be about 1.8 μs (93 %) and 9.9 μs (7 %) for the Ti-doped crystal, 310 μs (96 %) and 2220 μs (4 %) for Mn-doped one, and 3.6 μs (52 %) and 19.6 μs (48 %) for Cu-doped one, respectively. In the <sup>252</sup>Cf neutron irradiated pulse height spectra, Ti- and Cu- doped crystals showed higher light yield in comparison to that of GS20 commercial scintillator.","PeriodicalId":246351,"journal":{"name":"2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130980357","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}
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