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Combined SRCT & FXCT - The next steps

JOURNAL OF INSTRUMENTATION 2016年第3期11卷 C03048-C03048页

作者： Hall, C. Acres, R. G. Winnett, A. Wang, F. Australian Synchrotron Imaging & Med Beamline Clayton Vic 3168 Australia Swinburne Univ Dept Chem & Biotechnol Hawthorn Vic 3122 Australia

One of the goals in developing synchrotron radiation x-ray computed tomography (SRCT) for biomedical specimens, is allowing particular tissues and cell types to be marked in the images. This is equivalent to the staining in histology, which enables researchers to visualise and measure tissue structure and biochemical processes within the specimen. Some progress in this direction for SRCT is being made, using a variety of contrast agents that alter the natural x-ray attenuation of the marked tissue [1]. However there are limits to the usefulness of these attenuation altering techniques. Often high concentrations of potentially disruptive chemicals are required with reduced compatibility for in-vivo studies. Another image highlighting technique which might prove more sensitive is x-ray fluorescence imaging. In this case usually endogenous elemental markers are visualised. We would like to develop a lower resolution, but wider field of view means of three-dimensional (3-D) fluorescence imaging compatible with SRCT. We have previously proposed a technique in which x-ray fluorescence CT (FXCT) and SRCT data can be collected simultaneously [3]. This work resulted in proof of concept modelling, and a simple experiment test system. We show data here which demonstrate a two-dimensional (2-D) reconstruction of an iodine fluorescence map from a phantom. Measurements were performed with a fixed beam modulating mask using the Imaging and medical beam line (IMBL) at the Australian Synchrotron. Fluorescence data was obtained during a CT scan using a single point detector, while transmission data was simultaneously collected using an area detector. A maximum likelihood expectation maximisation (MLEM) iterative algorithm was used to reconstruct the fluorescence map. We report on technique development and now believe compressive sensing (CS) imaging techniques suit SRCT and may overcome the issues encountered so far in combining SRCT and FXCT.

关键词： X-ray fluorescence (XRF) systems medical-image reconstruction methods and algorithms, computer-aided software Simulation methods and programs

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Proton Computed Tomography: iterative image reconstruction and dose evaluation

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JOURNAL OF INSTRUMENTATION 2017年第1期12卷 C01034-C01034页

作者： Civinini, C. Bonanno, D. Brianzi, M. Carpinelli, M. Cirrone, G. A. P. Cuttone, G. Lo Presti, D. Maccioni, G. Pallotta, S. Randazzo, N. Scaringella, M. Romano, F. Sipala, V. Talamonti, C. Vanzi, E. Bruzzi, M. Ist Nazl Fis Nucl Florence Div Florence Italy Ist Nazl Fis Nucl Catania Div Catania Italy Ist Nazl Fis Nucl Lab Nazl Sud Catania Italy Univ Sassari Chem & Pharm Dept Sassari Italy Univ Catania Dept Phys & Astron Catania Italy Ist Nazl Fis Nucl Cagliari Div Cagliari Italy Univ Florence Biomed Expt & Clin Sci Dept Florence Italy Azienda Osped Univ Careggi SOD Fis Med Florence Italy Azienda Osped Univ Senese Fis Sanit Siena Italy Univ Florence Dept Phys & Astron Florence Italy

Proton Computed Tomography (pCT) is a medical imaging method with a potential for increasing accuracy of treatment planning and patient positioning in hadron therapy. A pCT system based on a Silicon microstrip tracker and a YAG:Ce crystal calorimeter has been developed within the INFN Prima-RDH collaboration. The prototype has been tested with a 175 MeV proton beam at The Svedberg Laboratory (Uppsala, Sweden) with the aim to reconstruct and characterize a tomographic image. Algebraic iterative reconstruction methods (ART), together with the most likely path formalism, have been used to obtain tomographies of an inhomogeneous phantom to eventually extract density and spatial resolutions. These results will be presented and discussed together with an estimation of the average dose delivered to the phantom and the dependence of the image quality on the dose. Due to the heavy computation load required by the algebraic algorithms the reconstruction programs have been implemented to fully exploit the high calculation parallelism of Graphics Processing Units. An extended field of view pCT system is in an advanced construction stage. This apparatus will be able to reconstruct objects of the size of a human head making possible to characterize this pCT approach in a pre-clinical environment.

关键词： Instrumentation for hadron therapy Instrumentation for particle-beam therapy medical-image reconstruction methods and algorithms, computer-aided software

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Cerenkov luminescence imaging guided selective-reconstruction for a flexible dual-head PET

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JOURNAL OF INSTRUMENTATION 2017年第4期12卷 P04005-P04005页

作者： Yang, D. Chen, X. Zhang, C. Wan, L. Meng, F. Xie, Q. Liang, J. Xidian Univ Engn Res Ctr Mol 266 Xinglong Sect Xifeng Rd Xian 710071 Shaanxi Peoples R China Xidian Univ Neuro Imaging Minist Educ 266 Xinglong Sect Xifeng Rd Xian 710071 Shaanxi Peoples R China Xidian Univ Sch Life Sci & Technol 266 Xinglong Sect Xifeng Rd Xian 710071 Shaanxi Peoples R China Hangzhou Dianzi Univ Inst Informat & Control Xiasha Higher Educ Zone Hangzhou 310018 Zhejiang Peoples R China Huazhong Univ Sci & Technol Sch Life Sci & Technol 1037 Luoyu Rd Wuhan 430074 Hubei Peoples R China

Dual-head PET can simply and flexibilly adjust its architecture to fit the size of the imaging object, making it great potential for simultaneous multi-modality molecular imaging. In this paper, we proposed conceptally dual-modality imaging system of distance-adjustable dual-head PET and Cerenkov luminescence imaging (CLI), and implemented a CLI guided selectivere-construction method. In the selective-reconstruction, we reconstructed the information inside a predefined region of interest using a fine voxel, whereas reconstructed other regions using a coarse voxel. We used CLI data as a priori information to outline the predefined region of interest. Simultaneously, for reducing the computaion burden, an attenuation map with a coarse voxel size was used for the attenuation correction. We demonstrated the feasibility and effectiveness of our proposed method with Monte Carlo based simulations by reconstructing phantom consisted of two hot rods. Experiment results show that an most improved efficiency over 70 times speedup with an MSE of 5.2235.

关键词： image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided diagnosis medical-image reconstruction methods and algorithms, computer-aided software Multi-modality systems

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GATE simulation of a new design of pinhole SPECT system for small animal brain imaging

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JOURNAL OF INSTRUMENTATION 2017年第1期12卷 C01085-C01085页

作者： Ozsahin, D. Uzun Blackberg, L. El Fakhri, G. Sabet, H. Harvard Med Sch Massachusetts Gen Hosp Dept Radiol 55 Fruit St Boston MA 02115 USA Near East Univ TRNC Dept Biomed Engn Near East Blvd CY-99138 Nicosia Cyprus Uppsala Univ Dept Phys & Astron Box 516 SE-75120 Uppsala Sweden

Small animal SPECT imaging has gained an increased interest over the past decade since it is an excellent tool for developing new drugs and tracers. Therefore, there is a huge effort on the development of cost-effective SPECT detectors with high capabilities. The aim of this study is to simulate the performance characteristics of new designs for a cost effective, stationary SPECT system dedicated to small animal imaging with a focus on mice brain. The conceptual design of this SPECT system platform, Stationary Small Animal SSA-SPECT, is to use many pixelated CsI:TI detector modules with 0.4 mm x 0.4 mm pixels in order to achieve excellent intrinsic detector resolution where each module is backed by a single pinhole collimator with 0.3 mm hole diameter. In this work, we present the simulation results of four variations of the SSA-SPECT platform where the number of detector modules and FOV size is varied while keeping the detector size and collimator hole size constant. Using the NEMA NU-4 protocol, we performed spatial resolution, sensitivity, image quality simulations followed by a Derenzo-like phantom evaluation. The results suggest that all four SSA-SPECT systems can provide better than 0.063% system sensitivity and < 1.5 mm FWHM spatial resolution without resolution recovery or other correction techniques. Specifically, SSA-SPECT-1 showed a system sensitivity of 0.09% in combination with 1.1 mm FWHM spatial resolution.

关键词： Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc) Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) Gamma detectors (scintillators, CZT, HPG, HgI etc) medical-image reconstruction methods and algorithms, computer-aided software

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Development of correction methods for variable pinhole single-photon emission computed tomography

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JOURNAL OF INSTRUMENTATION 2016年第2期11卷 C02060-C02060页

作者： Bae, S. Bae, J. Lee, H. Lee, K. Korea Univ Dept Bioconvergence Engn 145 Anam Ro Seoul South Korea Korea Univ Res Inst Global Hlth Technol 145 Anam Ro Seoul South Korea Korea Univ Sch Biomed Engn 145 Anam Ro Seoul South Korea

We propose a novel pinhole collimator in which the pinhole shape can be changed in real-time, and a new single-photon emission computed tomography (SPECT) system that utilizes this variable pinhole (VP) collimator. The acceptance angle and distance between the collimator and the object of VP SPECT are varied so that the optimum value of the region-of-interest (ROI) can be obtained for each rotation angle. Because of these geometrical variations, new correction methods are required for image reconstruction. In this study, we developed two correction methods. The first is the sensitivity-correction algorithm, which minimizes the variation of a system matrix caused by varying the acceptance angle for each rotation angle. The second is the acquisition-time-correction method, which reduces the variation of uniformity caused by varying the distance between the collimator and the object for each rotation angle. A 3D maximum likelihood expectation maximization (MLEM) algorithm was applied to image reconstruction, and two digital phantoms were studied to evaluate the resolution and sensitivity of the images obtained using the proposed methods. The images obtained by using the proposed correction methods show higher uniformity and resolution than those obtained without using these methods. In particular, the results of the resolution phantom study show that hot rods (0.8-mm-diameter) can be clearly distinguished using the proposed correction methods. A quantitative analysis of the ROI phantom revealed that the mean square error (MSE) was 0.42 without the acquisition-time-correction method, and 0.04 with the acquisition-time-correction method. The MSEs of the resolution phantom without and with the acquisition-time-correction method were calculated as 55.14 and 14.69, respectively.

关键词： Data processing methods Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided software

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Position algorithm for monolithic scintillation crystals based on charge projection readout

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JOURNAL OF INSTRUMENTATION 2016年第1期11卷 C01061-C01061页

作者： Pani, R. Bettiol, M. Preziosi, E. Cinti, M. N. Borrazzo, C. Pellegrini, R. Di Castro, E. Fabbri, A. Univ Roma La Sapienza Dept Sci & Med & Surg Biotechnol Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Dept Mol Med Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Morphofunct Sci Biophys Doctorate Sch Biol & Mol Med SAIMLAL Dept Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Post Grad Sch Med Phys Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Dept Radiol Sci Oncol & Pathol Piazzale Aldo Moro 5 I-00185 Rome Italy

Nuclear medicine imaging devices commonly use multi-element photo detection systems, composed of an array of N x N elements, each one providing an individual signal. Many strategies have been developed to reduce the number of readout channels, one of the main approaches is the Rows and Columns (R/C) projection logic. In this paper we proposed a modified version of Raised To the Power (RTP) algorithm adapted to R/C logic. In order to validate its efficiency a linear scanning irradiation on two 49 x 49 mm(2) LaBr3:Ce (0.5%) crystals with different thickness (4 mm and 10 mm) was carried out. Imaging performance analysis was made in terms of position linearity, Field-of-View (FoV) enlargement and spatial resolution. Imaging results from Anger Logic, RTP algorithm based on single element readout and RTP algorithm based on R/C readout were compared. A notable advantage of using RTP algorithms instead of Anger Logic was found: the FoV widens from about 30% to more than 70% of the detector area whereas the spatial resolution is highly improved, especially for off-center interactions, both for 4 mm-thick and 10 mm-thick crystals. Furthermore, imaging performance with the R/C readout is just slightly different from the single element one (FoV reduction less than 7% and SR worsening less than 10%). The R/C adapted RTP algorithm opens doors to high imaging performance with a substantial reduction of complexity and cost in the readout electronics.

关键词： Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided software

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Development of correction methods for variable pinhole single-photon emission computed tomography

Development of correction methods for variable pinhole singl...

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17th International Workshop on Radiation Imaging Detectors

关键词： Data processing methods Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided software

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Development of a novel gamma probe for detecting radiation direction

Development of a novel gamma probe for detecting radiation d...

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17th International Workshop on Radiation Imaging Detectors

作者： Pani, R. Pellegrini, R. Cinti, M. N. Longo, M. Donnarumma, R. D'Alessio, A. Borrazzo, C. Pergola, A. Ridolfi, S. De Vincentis, G. Univ Roma La Sapienza Dept Sci & Med & Surg Biotechnol Piazzale Aldo Moro 5 I-00185 Rome Italy Ist Nazl Fis Nucl Sez Roma Piazzale Aldo Moro 2 I-00185 Roma Rome Italy Univ Roma La Sapienza Dept Mol Med Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Postgrad Sch Med Phys Piazzale Aldo Moro 5 I-00185 Rome Italy Univ Roma La Sapienza Piazzale Aldo Moro 5 I-00185 Rome Italy Ars Mensurae Via Vincenzo Comparini 101 I-00188 Rome Italy Univ Roma La Sapienza Dept Radiol Sci Oncol & Anat Pathol Piazzale Aldo Moro 5 I-00185 Rome Italy

Spatial localization of radioactive sources is currently a main issue interesting different fields, including nuclear industry, homeland security as well as medical imaging. It is currently achieved using different systems, but the development of technologies for detecting and characterizing radiation is becoming important especially in medical imaging. In this latter field, radiation detection probes have long been used to guide surgery, thanks to their ability to localize and quantify radiopharmaceutical uptake even deep in tissue. Radiolabelled colloid is injected into, or near to, the tumor and the surgeon uses a hand-held radiation detector, the gamma probe, to identify lymph nodes with radiopharmaceutical uptkake. The present work refers to a novel scintigraphic goniometric probe to identify gamma radiation and its direction. The probe incorporates several scintillation crystals joined together in a particular configuration to provide data related to the position of a gamma source. The main technical characteristics of the gamma locator prototype, i.e. sensitivity, spatial resolution and detection efficiency, are investigated. Moreover, the development of a specific procedure applied to the images permits to retrieve the source position with high precision with respect to the currently used gamma probes. The presented device shows a high sensitivity and efficiency to identify gamma radiation taking a short time (from 30 to 60 s). Even though it was designed for applications in radio-guided surgery, it could be used for other purposes, as for example homeland security.

关键词： Intra-operative probes Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided software

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Development of a proton Computed Tomography detector system

Development of a proton Computed Tomography detector system

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17th International Workshop on Radiation Imaging Detectors

作者： Naimuddin, Md. Coutrakon, G. Blazey, G. Boi, S. Dyshkant, A. Erdelyi, B. Hedin, D. Johnson, E. Krider, J. Rukalin, V. Uzunyan, S. A. Zutshi, V. Fordt, R. Sellberg, G. Rauch, J. E. Roman, M. Rubinov, P. Wilson, P. Univ Delhi Dept Phys & Astrophys Delhi 110007 India No Illinois Univ Dept Phys De Kalb IL 60115 USA Fermilab Natl Accelerator Lab POB 500 Batavia IL 60510 USA

computer tomography is one of the most promising new methods to image abnormal tissues inside the human body. Tomography is also used to position the patient accurately before radiation therapy. Hadron therapy for treating cancer has become one of the most advantegeous and safe options. In order to fully utilize the advantages of hadron therapy, there is a necessity of performing radiography with hadrons as well. In this paper we present the development of a proton computed tomography system. Our second-generation proton tomography system consists of two upstream and two downstream trackers made up of fibers as active material and a range detector consisting of plastic scintillators. We present details of the detector system, readout electronics, and data acquisition system as well as the commissioning of the entire system. We also present preliminary results from the test beam of the range detector.

关键词： Instrumentation for hadron therapy computerized Tomography (CT) and Computed Radiography (CR) medical-image reconstruction methods and algorithms, computer-aided software

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Position algorithm for monolithic scintillation crystals based on charge projection readout

Position algorithm for monolithic scintillation crystals bas...

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17th International Workshop on Radiation Imaging Detectors

关键词： Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided software

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