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Simulation Study on the Feasibility of Current-mode SPECT for B-10 Concentration Estimation in Boron Neutron Capture Therapy

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JOURNAL OF INSTRUMENTATION 2019年第2期14卷

作者： Kanno, I. Nishimatsu, D. Funama, F. Kyoto Univ Grad Sch Engn Nishikyo Ku Kyoto 6158530 Japan

Boron neutron caputure therapy (BNCT) is a promising treatment for invasive tumors. The BNCT utilizes the energy deposition by alpha particle and Li-7 created by the neutron capture reaction of B-10. One of the problem of BNCT is the imaging of B-10 distribution during the treatment. The gamma rays with the energy of 0.478 MeV emitted by Li-7 can be exploited for this purpose. The photon counting of the gamma rays, however, is very difficult due to the high gamma ray background caused by 2.22 MeV gamma rays originated by the neutron reactions with H-1. To overcome this difficulty, the authors propose a method to measure gamma rays as electric current by a "transXend" detector, which had been invented by them for energy-resolved X-ray computed tomography. In this paper, the feasibility study on B-10 distribution imaging in a water phantom with a tumor region is shown by simulation studies. For establishing the relationship between electric currents induced in the transXend detector by gamma rays and B-10 concentration, the attenuation of gamma rays by the phantom should be taken into account. For this purpose, a neural network was employed. The results showed good agreement with the training data used for the neural network.

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) medical-image reconstruction methods and algorithms computer-aided diagnosis Solid state detectors

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Element-specific spectral imaging of multiple contrast agents: a phantom study

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JOURNAL OF INSTRUMENTATION 2018年第2期13卷 T02001-T02001页

作者： Panta, R. K. Bell, S. T. Healy, J. L. Aamir, R. Bateman, C. J. Moghiseh, M. Butler, A. P. H. Anderson, N. G. Univ Otago Dept Radiol 2 Riccarton Ave Christchurch 8140 New Zealand MARS Bioimaging Ltd 29a Clyde Rd Christchurch 8140 New Zealand Univ Canterbury Dept Phys & Astron Christchurch 8140 New Zealand Univ Canterbury Dept Biol Private Bag 4800 Christchurch 8140 New Zealand CERN European Ctr Nucl Res Geneva Switzerland Lincoln Univ Lincoln Agritech Ltd Engn Dr Christchurch 7460 New Zealand

This work demonstrates the feasibility of simultaneous discrimination of multiple contrast agents based on their element-specific and energy-dependent X-ray attenuation properties using a pre-clinical photon-counting spectral CT. We used a photon-counting based pre-clinical spectral CT scanner with four energy thresholds to measure the X-ray attenuation properties of various concentrations of iodine (9, 18 and 36 mg/ml), gadolinium (2, 4 and 8 mg/ml) and gold (2, 4 and 8 mg/ml) based contrast agents, calcium chloride (140 and 280 mg/ml) and water. We evaluated the spectral imaging performances of different energy threshold schemes between 25 to 82 keV at 118 kVp, based on K-factor and signal-to-noise ratio and ranked them. K-factor was defined as the X-ray attenuation in the K-edge containing energy range divided by the X-ray attenuation in the preceding energy range, expressed as a percentage. We evaluated the effectiveness of the optimised energy selection to discriminate all three contrast agents in a phantom of 33 mm diameter. A photon-counting spectral CT using four energy thresholds of 27, 33, 49 and 81 keV at 118 kVp simultaneously discriminated three contrast agents based on iodine, gadolinium and gold at various concentrations using their K-edge and energy-dependent X-ray attenuation features in a single scan. A ranking method to evaluate spectral imaging performance enabled energy thresholds to be optimised to discriminate iodine, gadolinium and gold contrast agents in a single spectral CT scan. Simultaneous discrimination of multiple contrast agents in a single scan is likely to open up new possibilities of improving the accuracy of disease diagnosis by simultaneously imaging multiple bio-markers each labelled with a nano-contrast agent.

关键词： Computerized Tomography (CT) and Computed Radiography (CR) X-ray detectors image reconstruction in medical imaging medical-image reconstruction methods and algorithms computer-aided software

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Comparison study of noise reduction algorithms in dual energy chest digital tomosynthesis

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JOURNAL OF INSTRUMENTATION 2018年第4期13卷 T04001-T04001页

作者： Lee, D. Kim, Y. -S. Choi, S. Lee, H. Choi, S. Kim, H. -J. Yonsei Univ Res Inst Hlth Sci Dept Radiat Convergence Engn 1 Yonseidae Gil Wonju 220710 Gangwon South Korea Yonsei Univ Coll Hlth Sci Dept Radiol Sci 1 Yonseidae Gil Wonju 220710 Gangwon South Korea

Dual energy chest digital tomosynthesis (CDT) is a recently developed medical technique that takes advantage of both tomosynthesis and dual energy X-ray images. However, quantum noise, which occurs in dual energy X-ray images, strongly interferes with diagnosis in various clinical situations. Therefore, noise reduction is necessary in dual energy CDT. In this study, noise-compensating algorithms, including a simple smoothing of high-energy images (SSH) and anti-correlated noise reduction (ACNR), were evaluated in a CDT system. We used a newly developed prototype CDT system and anthropomorphic chest phantom for experimental studies. The resulting images demonstrated that dual energy CDT can selectively image anatomical structures, such as bone and soft tissue. Among the resulting images, those acquired with ACNR showed the best image quality. Both coefficient of variation and contrast to noise ratio (CNR) were the highest in ACNR among the three different dual energy techniques, and the CNR of bone was significantly improved compared to the reconstructed images acquired at a single energy. This study demonstrated the clinical value of dual energy CDT and quantitatively showed that ACNR is the most suitable among the three developed dual energy techniques, including standard log subtraction, SSH, and ACNR.

关键词： medical-image reconstruction methods and algorithms computer-aided diagnosis X-ray radiography and digital radiography (DR)

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Performance characteristics of the MAMMOCARE PET system based on NEMA standard

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JOURNAL OF INSTRUMENTATION 2017年第1期12卷 C01014-C01014页

作者： Moliner, L. Correcher, C. Hellingman, D. Alamo, J. Carrilero, V. Orero, A. Gonzalez, A. J. Benlloch, J. M. Univ Politecn Valencia CSIC Inst Instrumentat Mol Imaging Cami Vera S-N Valencia Spain Oncovision SA Prince Felipe Res Ctr Eduardo Primo Yufera 3 Valencia Spain Netherlands Canc Inst Dept Nucl Med Plesmanlaan 121 Amsterdam Netherlands

In this work, we present the performance characteristics of the MAMMOCARE PET prototype based on an adaptation of the NU 42008 NEMA standard. MAMMOCARE is a project under the European Commission's 7th Framework programme to develop a breast biopsy system guided by a dedicated breast PET (dbPET) images. The PET system is formed by two rings with twelve detector modules each. The transaxial FOV is 170mm and the axial FOV is 94 mm. The system can separate the detectors up to 60mm in transaxial plane to allow the biopsy needle entrance. The acquisitions are reconstructed using the LMOS algorithm with tubeofresponse (TOR) backprojector, 1 iteration and 16 subsets. The voxel and pixel sizes are (1 x 1 x 1) mm(3) and (1.6 x 1.6) mm(2) respectively. The radial resolution measured is 1.62mm in the center of the FOV and 3.45mm at 50mm off the center in the radial direction using the closed configuration. In the open configuration the resolution reaches 1.85mm and 3.65mm at center and at 50mm offcenter. The adapted recovery coefficients (ARC) are measured for six hot rods inside a cylindrical phantom with a warm background. The ratio between hot and background regions is 10. The ARC values for the closed configuration are 0.32, 0.77 and 0.96 for the inserts with a diameter of 4.5 mm, 8.3mm and 25 mm, respectively. These values decrease to 0.16, 0.52 and 0.77 for the open configuration. The sensitivity measured using an energy window of 250 keV-750 keV is 3.6% and 2.5% for the closed and open configurations respectively. The NEC peak is 141 kcps@ 68MBq and 147 kcps@ 78MBq for closed and open configurations. The performance characteristics measured with the open ring configuration decreases with respect the closed configuration, however the values remain comparable to other dbPETs.

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

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Technological challenges in Magnetic Resonance Imaging: enhancing sensitivity, moving to quantitative imaging and searching for disease biomarkers

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JOURNAL OF INSTRUMENTATION 2018年第2期13卷 C02007-C02007页

作者： Retico, A. Natl Inst Nucl Phys Pisa Div Largo B Pontecorvo 3 I-56127 Pisa Italy

Diagnostic imaging based on the Nuclear Magnetic Resonance phenomenon has increasingly spread in the recent few decades, mainly owing to its exquisite capability in depicting a contrast between soft tissues, to its generally non-invasive nature, and to the priceless advantage of using non-ionizing radiation. Magnetic Resonance (MR)-based acquisition techniques allow gathering information on the structure (through Magnetic Resonance Imaging - MRI), the metabolic composition (through Magnetic Resonance Spectroscopy - MRS), and the functioning (through functional MRI - fMRI) of the human body. MR investigations are the methods of choice for studying the brain in vivo, including anatomy, structural wiring and functional connectivity, in healthy and pathological conditions. Alongside the efforts of the clinical research community in extending the acquisition protocols to allow the exploration of a large variety of pathologies affecting diverse body regions, some relevant technological improvements are on the way to maximize the impact of MR in medical diagnostic. The development of MR scanners operating at ultra-high magnetic field (UHF) strength (>= 7 tesla), is pushing forward the spatial resolution of MRI and the spectral resolution of MRS, and it is increasing the specificity of fMRI to grey matter signal. UHF MR systems are currently in use for research purposes only;nevertheless, UHF technological advances are positively affecting MR investigations at clinical field strengths. To overcome the current major limitation of MRI, which is mostly based on contrast between tissues rather than on absolute measurements of physical quantities, a new acquisition modality is under development, which is referred as Magnetic Resonance Fingerprinting technique. Finally, as neuroimaging data acquired worldwide are reaching the typical size of Big Data, dedicated technical solutions are required to mine large amount of information and to identify specific biomarkers of pathological

关键词： MRI (whole body, cardiovascular, breast, others) MR-angiography (MRA) medical-image reconstruction methods and algorithms computer-aided software Multi-modality systems

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Performance characteristics of the MAMMOCARE PET system based on NEMA standard

Performance characteristics of the MAMMOCARE PET system base...

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18th 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 diagnosis

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Proton therapy treatment monitoring with the DoPET system: activity range, positron emitters evaluation and comparison with Monte Carlo predictions

Proton therapy treatment monitoring with the DoPET system: a...

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19th International Workshop on Radiation Imaging Detectors (IWORID)

作者： Muraro, S. Battistoni, G. Belcari, N. Bisogni, M. G. Camarlinghi, N. Cristoforetti, L. Del Guerra, A. Ferrari, A. Fracchiolla, F. Morrocchi, M. Righetto, R. Sala, P. Schwarz, M. Sportelli, G. Topi, A. Rosso, V. Univ Pisa Dept Phys Pisa Italy INFN Pisa Italy INFN Milan Italy Trento Hosp Proton Therapy Dept Trento Italy CERN Geneva Switzerland INFN TIFPA Trento Italy Univ Siena Dept Phys Sci Earth & Environm Siena Italy INFN Siena Italy

Ion beam irradiations can deliver conformal dose distributions minimizing damage to healthy tissues thanks to their characteristic dose profiles. Nevertheless, the location of the Bragg peak can be affected by different sources of range uncertainties: a critical issue is the treatment verification. During the treatment delivery, nuclear interactions between the ions and the irradiated tissues generate beta(+) emitters: the detection of this activity signal can be used to perform the treatment monitoring if an expected activity distribution is available for comparison. Monte Carlo (MC) codes are widely used in the particle therapy community to evaluate the radiation transport and interaction with matter. In this work, FLUKA MC code was used to simulate the experimental conditions of irradiations performed at the Proton Therapy Center in Trento (IT). Several mono-energetic pencil beams were delivered on phantoms mimicking human tissues. The activity signals were acquired with a PET system (DoPET) based on two planar heads, and designed to be installed along the beam line to acquire data also during the irradiation. Different acquisitions are analyzed and compared with the MC predictions, with a special focus on validating the PET detectors response for activity range verification.

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

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Application and performance of an ML-EM algorithm in NEXT

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JOURNAL OF INSTRUMENTATION 2017年第8期12卷

作者： Simon, A. Lerche, C. Monrabal, F. Gomez-Cadenas, J. J. Alvarez, V. Azevedo, C. D. R. Benlloch-Rodriguez, J. M. Borges, F. I. G. M. Botas, A. Carcel, S. Carrion, J. V. Cebrian, S. Conde, C. A. N. Diaz, J. Diesburg, M. Escada, J. Esteve, R. Felkai, R. Fernandes, L. M. P. Ferrario, P. Ferreira, A. L. Freitas, E. D. C. Goldschmidt, A. Gonzalez-Diaz, D. Gutierrez, R. M. Hauptman, J. Henriques, C. A. O. Hernandez, A. I. Hernando Morata, J. A. Herrero, V. Jones, B. J. P. Labarga, L. Laing, A. Lebrun, P. Liubarsky, I. Lopez-March, N. Losada, M. Martin-Albo, J. Martinez-Lema, G. Martinez, A. McDonald, A. D. Monteiro, C. M. B. Mora, F. J. Moutinho, L. M. Munoz Vidal, J. Musti, M. Nebot-Guinot, M. Novella, P. Nygren, D. R. Palmeiro, B. Para, A. Perez, J. Querol, M. Renner, J. Ripoll, L. Rodriguez, J. Rogers, L. Santos, F. P. dos Santos, J. M. F. Sofka, C. Sorel, M. Stiegler, T. Toledo, J. F. Torrent, J. Tsamalaidze, Z. Veloso, J. F. C. A. Webb, R. White, J. T. Yahlali, N. CSIC Inst Fis Corpuscular IFIC Calle Catedrat Jose Beltran 2 Valencia 46980 Spain Univ Valencia Calle Catedrat Jose Beltran 2 Valencia 46980 Spain Forschungszentrum Julich Inst Neurosci & Med INM 4 Julich Germany Univ Aveiro Inst Nanostruct Nanomodelling & Nanofabricat i3N Campus Santiago P-3810193 Aveiro Portugal Univ Coimbra Dept Phys LIP P-3004516 Coimbra Portugal Univ Zaragoza Lab Fis Nucl & Astroparticulas Calle Pedro Cerbuna 12 E-50009 Zaragoza Spain Fermilab Natl Accelerator Lab POB 500 Batavia IL 60510 USA Univ Politecn Valencia CSIC Ctr Mixto Inst Instrumentac Imagen Mol I3M Camino Vera S-N E-46022 Valencia Spain Univ Coimbra Phys Dept LIBPhys Rua Larga P-3004516 Coimbra Portugal Lawrence Berkeley Natl Lab 1 Cyclotron Rd Berkeley CA 94720 USA Univ Santiago de Compostela Inst Gallego Fis Altas Energias Campus SurRua Xose Maria Suarez Nunez S-N Santiago De Compostela 15782 Spain Univ Antonio Narino Sede Circunvalar Ctr Invest Ciencias Basicas & Aplicadas Carretera 3 Este 47 A-15 Bogota Colombia Iowa State Univ Dept Phys & Astron 12 Phys Hall Ames IA 50011 USA Univ Texas Arlington Dept Phys POB 19059 Arlington TX 76019 USA Univ Autonoma Madrid Dept Fis Teor Campus Cantoblanco E-28049 Madrid Spain Univ Girona Escola Politecn Super Av Montilivi S-N Girona 17071 Spain Texas A&M Univ Dept Phys & Astron College Stn TX 77843 USA Joint Inst Nucl Res Joliot Curie 6 Dubna 141980 Russia Univ Oxford Oxford England Univ Texas Austin Austin TX 78712 USA

The goal of the NEXT experiment is the observation of neutrinoless double beta decay in Xe-136 using a gaseous xenon TPC with electroluminescent amplification and specialized photodetector arrays for calorimetry and tracking. The NEXT Collaboration is exploring a number of reconstruction algorithms to exploit the full potential of the detector. This paper describes one of them: the Maximum Likelihood Expectation Maximization (ML-EM) method, a generic iterative algorithm to find maximum-likelihood estimates of parameters that has been applied to solve many different types of complex inverse problems. In particular, we discuss a bi-dimensional version of the method in which the photosensor signals integrated over time are used to reconstruct a transverse projection of the event. First results show that, when applied to detector simulation data, the algorithm achieves nearly optimal energy resolution (better than 0.5% FWHM at the Q value of 136Xe) for events distributed over the full active volume of the TPC.

关键词： Gaseous imaging and tracking detectors image reconstruction in medical imaging Time projection Chambers (TPC) medical-image reconstruction methods and algorithms computer-aided software

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Basis material decomposition method for material discrimination with a new spectrometric X-ray imaging detector

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JOURNAL OF INSTRUMENTATION 2017年第8期12卷

作者： Brambilla, A. Gorecki, A. Potop, A. Paulus, C. Verger, L. Univ Grenoble Alpes CEA LETI DTBS LDET F-38000 Grenoble France

Energy sensitive photon counting X-ray detectors provide energy dependent information which can be exploited for material identification. The attenuation of an X-ray beam as a function of energy depends on the effective atomic number Zeff and the density. However, the measured attenuation is degraded by the imperfections of the detector response such as charge sharing or pile-up. These imperfections lead to non-linearities that limit the benefits of energy resolved imaging. This work aims to implement a basis material decomposition method which overcomes these problems. Basis material decomposition is based on the fact that the attenuation of any material or complex object can be accurately reproduced by a combination of equivalent thicknesses of basis materials. Our method is based on a calibration phase to learn the response of the detector for different combinations of thicknesses of the basis materials. The decomposition algorithm finds the thicknesses of basis material whose spectrum is closest to the measurement, using a maximum likelihood criterion assuming a Poisson law distribution of photon counts for each energy bin. The method was used with a ME100 linear array spectrometric X-ray imager to decompose different plastic materials on a Polyethylene and Polyvinyl Chloride base. The resulting equivalent thicknesses were used to estimate the effective atomic number Zeff. The results are in good agreement with the theoretical Zeff, regardless of the plastic sample thickness. The linear behaviour of the equivalent lengths makes it possible to process overlapped materials. Moreover, the method was tested with a 3 materials base by adding gadolinium, whose K-edge is not taken into account by the other two materials. The proposed method has the advantage that it can be used with any number of energy channels, taking full advantage of the high energy resolution of the ME100 detector. Although in principle two channels are sufficient, experimental measurements show t

关键词： Data processing methods Detection of explosives medical-image reconstruction methods and algorithms computer-aided diagnosis

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Imaging characterization of a new gamma ray detector based on CRY019 scintillation crystal for PET and SPECT applications

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JOURNAL OF INSTRUMENTATION 2017年第2期12卷 C02034-C02034页

作者： Polito, C. Pani, R. Trigila, C. Cinti, M. N. Fabbri, A. Frantellizzi, V. De Vincentis, G. Pellegrini, R. Pani, R. Sapienza Univ Morphogenesis & Tissue Engn SAIMLAL Dept Rome Italy Sapienza Univ Dept Phys Rome Italy Univ Roma Tre Dept Phys Rome Italy Univ Roma Tre Ist Nazl Fis Nucl Rome Italy Sapienza Univ Dept Mol Med Rome Italy Sapienza Univ Dept Radiol Oncol & Anatomopathol Sci Rome Italy Ist Nazl Fis Nucl Roma Sect 1 Rome Italy Sapienza Univ Dept Sci & Med Surg Biotechnol Rome Italy

In the last 40 years, in the field of Molecular Medicine imaging there has been a huge growth in the employment and in the improvement of detectors for PET and SPECT applications in order to reach accurate diagnosis of the diseases. The most important feature required to these detectors is an high quality of images that is usually obtained benefitting from the development of a wide number of new scintillation crystals with high imaging performances. In this contest, features like high detection efficiency, short decay time, great spectral match with photodetectors, absence of afterglow and low costs are surely attractive. However, there are other factors playing an important role in the realization of high quality images such as energy and spatial resolutions, position linearity and contrast resolution. With the aim to realize an high performace gamma ray detector for PET and SPECT applications, this work is focused on the evaluation of the imaging characteristics of a recently developed scintillation crystal, CRY019.

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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