2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)最新文献

{"title":"Design of a high dynamic range integrated charge to digital converter for online dosimetry in radiotherapy","authors":"L. Gallin-Martel, O. Rossetto, Y. Arnoud, B. Boyer, R. Delorme, R. Fabbro, M. Gallin-Martel, O. Guillaudin, A. Pélissier","doi":"10.1109/NSSMIC.2016.8069397","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069397","url":null,"abstract":"The Intensity Modulated Radiotherapy allows a more efficient dose delivery in the tumour leading to a reduction of the dose deposited in the nearby healthy organs. However, this technique requires additional resources to perform on line dosimetry and insure patient safety. A quasi transparent 2D transmission detector for monitoring the treatment X-ray beam has been developed. It includes a high performance embedded electronics relying on a Charge to Digital Converter designed in a CMOS 0.35 μm process. The Charge Balancing Integration technique coupled to an internal 6-bit Analog to Digital Converter allows high resolution and high dynamic range to be reached. This 16-channel, 16-bit converter exhibits a 6 fC LSB value, a nonlinearity better than 0.1 LSB and a RMS noise lower than 0.5 LSB.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116576400","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}

{"title":"Investigation of non-negativity constraint on basis images in half-rotation data reconstruction in spectral CT","authors":"Buxin Chen, Yan Liu, Zheng Zhang, Zhou Yu, Richard A. Thompson, E. Sidky, Xiaochuan Pan","doi":"10.1109/NSSMIC.2016.8069484","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069484","url":null,"abstract":"In conventional computed tomography (CT) reconstruction, a non-negativity constraint on the image values is often included. Such constraint reduces the feasible set in a constrained optimization problem and often results in faster search. In basis-material-based spectral CT reconstruction, the physical grounding for the non-negativity constraint of basis image values is no longer present. It is either not used [1] or relaxed to allow only small-magnitude negative values [2]. However, such constraint can still be applied as part of the decomposition model [3] and to reduce the feasible set and search space. We have developed an optimizationbased reconstruction method that integrates decomposition into reconstruction and allows for flexible spectral data acquisition [4], [5]. The non-negativity constraint was included in the previous reconstructions as it was part of the decomposition model for the phantom used. As we recently applied the method to half-plus-half rotation scans with a dual energy phantom containing iodine and calcium inserts, streak artifacts appeared in the images surrounding calcium inserts which also showed HU value biases. This has led us to re-evaluate the need for the non-negativity constraint in this particular problem and investigate its impact on the reconstruction in terms of visual comparison and bias evaluation.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115151385","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}

{"title":"Investigation of cooling structure design for PET detector thermal regulation methods","authors":"Brian J. Lee, Chen-Ming Chang, Inyong Kwon, C. Levin","doi":"10.1109/NSSMIC.2016.8069611","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069611","url":null,"abstract":"Temperature is an essential factor for stable performance of the positron emission tomography (PET). Some of the PET detector components produce significant heat (e.g. readout integrated circuits) that affects its performance. The temperature alters the breakdown voltage of photodetectors, which in turn affects the gain, cross talk, dark count rate and after-pulsing. One of the thermal regulation methods is to use an air/liquid cooling pipe embedded in a cold plate broadly distributing the temperature to the PC board; the gold vias in the board then conduct the temperature to the other side of the board. This paper concentrates on investigating the temperature distribution from various cooling structure configurations. The simulation software COMSOL was used with heat transfer and pipe flow modules to assess the thermal behavior of the cooling system. Two types of cooling pipe arrangements were simulated; a simple and a more complex curve arrangement. For the cold plates, a ceramic (92 W/m-K) and a thermally conductive plastic (10 W/m-K) were simulated. Full as well as “patchy” gold via configurations were also simulated. The simulation was performed for 300 seconds (real time) and the average and the standard deviation temperature of each SiPM was analyzed. With the complex cooling pipe arrangement, the temperature variation throughout all SiPMs was on average 37.9±5.2% higher for ceramic cold plates. For the cold plate materials, the ceramic showed 33.9±15.4% smaller thermal variation and −1.1±0.6% lower temperature compared to the thermally conductive plastic. The patchy vias resulted in 218.2±74.9% larger thermal variation when compared to the patchy vias. In summary, we have simulated various cooling pipe designs, cold plates and gold via distribution configurations to analyze the temperature variation across a PET detector PC board. The thermally conductive ceramic cold plate with as many vias as possible resulted in the most stable temperature variation.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115629258","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}

{"title":"Multitarget data association with higher-order motion models for tracking in proton CT instrumentation","authors":"Liyun Gong, Xujiong Ye, N. Allinson","doi":"10.1109/NSSMIC.2016.8069479","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069479","url":null,"abstract":"PRaVDA is an advanced imaging and dosimetry system for proton therapy with solid-state sensors throughout. The residual energy resolving detector (range telescope) can be composed of multiple layers of CMOS imagers. Such imagers, though operating at relatively low frame rates, can record many protons events per read cycle. The challenge is to identify the non-linear tracks of individual protons through the telescope. A multi-target data association with higher-order motion model (MDAMM) was designed for the proton events in each layer. Such algorithms focus more on motion constraints rather than appearance. We use a cost function based on Gaussian for MDAMM which is suitable for protons as they are laterally scattered. We factor in all trajectories of a protons path (through all layers) into a cost function in order to improve the quality of a candidate trajectory. Also to achieve a more efficiency and better target tracking for protons, each trajectory with its previously created tracking result is considered in the cost function.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124414416","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}

{"title":"Space-charge limited transport in CdTe-based X- and γ-ray detectors","authors":"O. Maslyanchuk, M. Solovan, V. Kulchynsky, V. Gnatyuk, T. Aoki","doi":"10.1109/NSSMIC.2016.8069947","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069947","url":null,"abstract":"The principle feature limiting spectrometric performance of CdTe and CdMnTe-based X/γ-ray detectors is the impossibility to increase the operating voltage to provide sufficient collection of charge carriers because of raising leakage current. We have carried out the detailed analysis of electrical characteristics of CdTe and CdMnTe-based detectors with two Ohmic contacts. It is shown that a rapid increase in leakage current at applying high bias voltage in the CdTe and CdMnTe crystals is caused by the current limited by space charge (SCLC). The same activation energy for the current of equilibrium holes and the current caused by nonequilibrium holes at high voltages confirms the fact that SCLC in the Ni/CdMnTe/Ni detector formed by injection of majority carriers (holes) due to lowering the barrier at an imperfect Ohmic contacts. This fact distinguishes Ni/CdMnTe/Ni detector from Pt/CdTe/Pt detector where SCLC formed by tunnel transitions of minority carriers from the Fermi level in the metal (or slightly below it) to the semiconductor through a thin insulating film between the crystal and metal contact. Comparison the measured and calculated current-voltage characteristics of CdMnTe crystal at different temperatures taking into account SCLC according to the Mott-Gurney theory allowed to determine the density of discrete trapping centers (1.4 × 1013 cm3) and energy of hole traps (0.39 eV) in the Ni/CdMnTe/Ni detector.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124466342","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}

{"title":"A combined partial volume reduction and super-resolution reconstruction for magnetic resonance images","authors":"Faezeh Fallah, Bin Yang, F. Schick, F. Bamberg","doi":"10.1109/NSSMIC.2016.8069548","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069548","url":null,"abstract":"Magnetic resonance imaging provides a superior soft tissue contrast and a noninvasive means for automatic diagnosis of tissue pathogenesis. However, like most imaging modalities, it suffers from a compromise between the achievable spatial resolution, scan time efficiency, and signal-to-noise-ratio. To address this difficulty, super-resolution techniques have been proposed to enhance the spatial resolution of images in the post-acquisition steps. Most of those methods are proposed for nonmedical images. Thus, they do not consider the specific requirements of medical imaging in respect of data fidelity. In the present work, we propose a novel approach for super-resolution estimation that simultaneously reduces partial volume effects in order to enhance the edges without introducing artefactual effects to medical images. In this method, instead of using an edge-preserving preconditioner an interpolation based on the reverse diffusion process of material has been incorporated into the iterative estimation of images of higher spatial resolution. The proposed scheme outperforms the edge-preserving preconditioner in terms of image fidelity and speed of estimation.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114644218","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}

{"title":"Quantitative Cerenkov luminescence imaging: Measurements and simulations","authors":"E. Ciarrocchi, N. Belcari, A. Cataldi, P. Erba, A. Guerra","doi":"10.1109/NSSMIC.2016.8069543","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069543","url":null,"abstract":"Cerenkov luminescence imaging (CLI) is an optical imaging modality recently proposed to image β emitting radionuclides through the Cerenkov light they produce in tissue. CLI has been suggested in particular for β− emitting isotopes, which are difficult to study by other means, and as a cost-effective alternative to PET, yet with reduced penetration depth and spatial resolution. In this work we tested the predictive capabilities of a Monte Carlo model developed within the Geant4 platform for the description of a CLI experiment. Our final goal is to use Monte Carlo simulations to quantitatively correlate the number of detected Cerenkov photons with the radionuclide distribution. The code could be used also as a tool for experiment planning, for example in evaluating CLI applications. To test the reliability of the Monte Carlo predictions, CLI measurements were performed with a simple geometry that can be easily simulated (a radionuclide diluted in water) and the CLI signal measured with an electron multiplying charge coupled device (EMCCD) was compared with the Monte Carlo prediction. We observed that, below a certain detection limit and for particular acquisition settings, the measured signal depended on the acquisition settings. Apart from these exceptions, the simulated CLI signal was systematically 0.8 times the measured one. This small and constant offset suggests that the code could have good predictive capabilities in water.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125233270","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}

{"title":"An automatic segmentation method for the measurement of the functional volume of oncological lesions on MR ADC maps","authors":"F. Gallivanone, M. Panzeri, C. Canevari, Interlenghi Matteo, C. Losio, Luca Gianolli, F. de Cobelli, Castiglioni Isabella","doi":"10.1109/NSSMIC.2016.8069430","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069430","url":null,"abstract":"Human cancers frequently display intra-tumor phenotypic heterogeneity, whose nature can have profound implications both for tumor development and therapeutic outcomes. Some recent research efforts have been devoted to develop advanced image processing methods able to extract imaging descriptors characterizing such intra-tumor phenotypic heterogeneity. However, most methods need to accurately define the lesion volume in order to extract imaging descriptors. This work aims at assessing a novel segmentation method to measure the functional volume of lesions on MR ADC maps. The method was validated in advanced breast cancer patients addressed to Neoadjuvant Chemotherapy and surgical intervention, undergoing pre-treatment FDG-PET and multi-parametric MR studies. PET metabolic volume (MTV), SUVmean, SUVmax, and Total Lesion Glycolysis (TLG) of lesions were measured using an already validated segmentation algorithm [Gallivanone et al., J. Instr. 2016]. The MR functional volume of lesions segmented on the ADC map resulted directly correlated to PET MTV. We defined a new parameter characterizing the MR total diffusion of lesions, the Total Lesion Diffusion (TLD) that resulted directly correlated to PET TLG. Furthermore, we assessed an inverse correlation between SUVmax and ADCmin within the PET and MR functional volumes, respectively. Textural indexes were also evaluated. Correlations (p<0.05) were found among the textural image descriptors related to the spatial distribution of the signal extracted within the PET and MR functional volumes. In conclusion, our segmentation method is effective to define the functional volume of lesions on ADC maps.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117062776","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}

{"title":"Construction of large-area micro-pattern gaseous detectors","authors":"P. Bernhard, A. Brogna, S. Caiazza, A. Düdder, P. Gülker, C. Kahra, T. Lin, M. Schott, Q. Weitzel, E. Yildirim","doi":"10.1109/NSSMIC.2016.8069756","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069756","url":null,"abstract":"Particle physics experiments often comprise tracking detectors with areas of up to a few square meters. If a spatial resolution of the order of 100μm and high-rate capability are required, Micro Pattern Gaseous Detectors (MPGD) are a cost-effective solution. However, the construction of large-area MPGDs is challenging, since tight fabrication tolerances have to be met to guarantee a stable and homogeneous performance. A precision granite table and an automated 3-D positioning system with an attached laser sensor, both inside a laminar-flow cell, have therefore been set up in the PRISMA Detector Lab at Mainz. Currently, this infrastructure is used to produce drift panels for the upgrade of the ATLAS muon spectrometer at CERN with Micro Mesh Gaseous Structure (Micromegas) detectors. In order to parallelize production steps, movable vacuum table boards with a surface planarity of about 20μm (root mean square) have been designed and built. We present preliminary results on the achieved precision of drift panel prototypes. These results are in particular relevant for future construction of large-area MPGDs, such as the Gas Electron Multiplier (GEM) detectors for experiments at the future MESA accelerator at Mainz.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117148568","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}

{"title":"Quantification accuracy of a new HRRT high throughput rat hotel using transmission-based attenuation correction: A phantom study","authors":"S. Keller, Elina N. L'Estrade, B. Dall, M. Palner, M. Herth","doi":"10.1109/NSSMIC.2016.8069467","DOIUrl":"https://doi.org/10.1109/NSSMIC.2016.8069467","url":null,"abstract":"Aim: To parallelize scanning and save time and cut costs of preclinical studies we have designed a new hotel holding 4 rats in the HRRT, which has a spatial resolution close to that of preclinical PET scanners. In this work we test the quantitative accuracy on phantoms in the hotel using different attenuation corrections methods on the HRRT. Material and Methods: The rat hotel has 4 compartments made of acrylic plastic with an 8 mm base plate and a 3 mm half-cylinder lid. Four 50 ml syringes filled with [18F]-FDG in water were used as phantoms and scanned in the rat hotel for 20 min. on the HRRT and a high statistics speed 10 transmission scan was acquired. Three μ-map processing/reconstruction methods — MAP-TR with either human head (HH) or water phantom (WP) prior and TXTV — were used and μ-maps and PET images reconstructed with each of the 3 μ-maps evaluated. Results: The μ-maps all underestimated the LAC of the acrylic plastic material as compared to CT, and the base plate thickness was underestimated. Activity concentrations were thus also underestimated: −4.6% using HH −8.7% using TXTV and −13.8% with WP. No noteworthy local variations were found. Conclusion: We found a global underestimation of PET activity, which was within a ±5% acceptance range using MAP-TR with the human head prior and a long transmission scan (speed 10). Fine tuning HH or TXTV parameters might give further improvements.","PeriodicalId":184587,"journal":{"name":"2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD)","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117152047","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}