Jean Rinkel | Universidade Estadual de Campinas (original) (raw)

Papers by Jean Rinkel

Research paper thumbnail of Experimental evaluation of a physical based approach of scattered radiation correction in thoracic cone beam CT,” submitted to

Cone Beam Computerized Tomography (CBCT) enables threedimensional imaging with isotropic resoluti... more Cone Beam Computerized Tomography (CBCT) enables threedimensional imaging with isotropic resolution. X-ray scatter management is a challenging task for quantitative CBCT imaging: scattered radiation level is significantly high on cone beam systems compared to collimated fan beam systems. The effects of this scattered radiation are cupping artifacts, streaks, and quantification inaccuracies. At CEA-LETI, an original scatter management process without additional on-line acquisition has been developed, the API (Analytical transformation Plus Indexation based) method. The proposed method is composed of two steps: a scatter calibration is first performed through off-line acquisitions and is used to evaluate the level and a global shape of scattered radiation on on-line tomographic projections of the object. This global shape is adapted to the current acquisition with an analytical transformation issued from physical equations to evaluate the scattered radiation distribution on tomographi...

Research paper thumbnail of International Symposium on Digital Industrial Radiology and Computed Tomography- We.2.1 New Perspectives of X-ray Techniques for Explosive Detection Based on CdTe/CdZnTe Spectrometric Detectors

Abstract. Conventional explosive detection systems (EDS) based on X-ray technologies are using du... more Abstract. Conventional explosive detection systems (EDS) based on X-ray technologies are using dual-energy radiography; they provide only a crude material characterization. Recently emerged semiconductors based X-ray detectors offer new capabilities in energy discrimination. This study is aiming at evaluating their interest for EDS. LETI-LDET laboratory has developed several pixellated CdTe/CZT detectors. For X-ray spectral radiography, a detector capable to operate at count rates above 10 7 counts/mm 2 s has been implemented, and associated to a multidimensional spectra analysis. We present the performance get for material identification on experimental data. Two complementary X-ray techniques are used in EDS: diffraction and backscatter techniques. Adapted detector prototypes have been developed. Experimental spectra are presented, and a dedicated processing method introduced for backscatter. For all these techniques, we discuss how CdTe/CdZnTe based spectrometric detectors are we...

Research paper thumbnail of Method materials identification from radiographs x Multi Energies

The invention relates to a method for calibrating an identification of materials in X-ray radiogr... more The invention relates to a method for calibrating an identification of materials in X-ray radiography apparatus, comprising: a) determining at least one calibration material and, for each calibration material, at least a thickness of calibration of this material, b) measuring, for each calibration material and for current weights, coefficients of attenuation or transmission of X-radiation, c) calculation of statistical parameters from said coefficients, d) determining, for each calibration material and each calibration thickness, a probability distribution of presence probability, based on said statistical parameters.

Research paper thumbnail of New Perspectives of X-ray Techniques for Explosive Detection Based on CdTe/CdZnTe Spectrometric Detectors

Conventional explosive detection systems (EDS) based on X-ray technologies are using dual-energy ... more Conventional explosive detection systems (EDS) based on X-ray technologies are using dual-energy radiography; they provide only a crude material characterization. Recently emerged semiconductors based X-ray detectors offer new capabilities in energy discrimination. This study is aiming at evaluating their interest for EDS. LETI-LDET laboratory has developed several pixellated CdTe/CZT detectors. For X-ray spectral radiography, a detector capable to operate at count rates above 10counts/mms has been implemented, and associated to a multidimensional spectra analysis. We present the performance get for material identification on experimental data. Two complementary X-ray techniques are used in EDS: diffraction and backscatter techniques. Adapted detector prototypes have been developed. Experimental spectra are presented, and a dedicated processing method introduced for backscatter. For all these techniques, we discuss how CdTe/CdZnTe based spectrometric detectors are well-adapted.

Research paper thumbnail of Verfahren zur Schätzung der Streustrahlung bei einer Röntgentomographie

Research paper thumbnail of Method for estimation of scattered radiation tomography x-ray

Research paper thumbnail of Method and device for recognizing a material using its transmission function

The invention relates to a method for characterizing the nature of a material, comprising: - disp... more The invention relates to a method for characterizing the nature of a material, comprising: - disposing at least one sample (100) of this material between a source (1) of X-rays, and a detector; performing, using the X-ray source, N X-ray spectra transmitted through said material, each for a duration Δt; calculate the transmission function of this material as a function of the energy or the detection channel; in each of at least two energy zones, calculating the integral of the transmission function, thus forming at least a first transmission coefficient (α1) and a second transmission coefficient (α2).

Research paper thumbnail of Measuring method of the atomic number of an actual material

The invention relates to a method of estimating the effective atomic number of a material from a ... more The invention relates to a method of estimating the effective atomic number of a material from a transmission spectrum of said material. Is calculated in a first step (230) a likelihood function of effective atomic number and thickness of the material from the transmission spectrum and the calibration spectra, obtained in a preliminary calibration phase, for a plurality of sample calibration material of known effective atomic numbers and known thicknesses. then estimated (240) the effective atomic number (Z) of the material from the values ​​of the likelihood function.

Research paper thumbnail of Method and device for identifying material by spectral analysis of electromagnetic radiation through this material

Research paper thumbnail of Method for first broadcast spectrum extraction device and associated computer program

Research paper thumbnail of Correction for pile-up effect based on pixel-by-pixel calibration for tomography with Medipix3RX detector

Proceedings of Technology and Instrumentation in Particle Physics 2014 — PoS(TIPP2014), Jul 3, 2015

Research paper thumbnail of X-ray coherent diffraction imaging: Sequential inverse problems simulation

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Abstract Improvement of spatial coherence in third generation synchrotron beamlines made possible... more Abstract Improvement of spatial coherence in third generation synchrotron beamlines made possible the development of X-ray plane-wave coherent diffraction imaging technique (plane-wave cdi ), which enables 3D imaging at nanometric resolution. In this work, we first simulated the influence of detector geometry by comparing reconstruction quality of planar samples made of gold nanoparticles. We compared a commercially available detector geometry with the next Medipix3-based large area detector designed for the next fourth generation Brazilian synchrotron, sirius . The spatial resolution was highly improved, from 7.2 nm for the commercial geometry to 4.8 nm for the Medipix3 detector by keeping the same global image quality. Finally, global image qualities were compared by adjusting the sample-to-detectors distances at a given spatial resolution. For thick samples reconstruction at such high nanometric resolutions, the main limitation of current reconstruction approaches are due to the complex wave propagation within the sample, given by the inhomogeneous Helmholtz equation. We proposed an iterative method to reconstruct the complex refraction index. This method enables to keep the image quality almost constant beyond the resolution limit for thick samples made of gold nanoparticles in water.

Research paper thumbnail of Gold nanoparticles for X-ray microtomography of neurons

ACS Chemical Neuroscience

Research paper thumbnail of Caracterização de um detector espectrométrico de raios X e aplicação em detecção de nanopartículas de ouro em amostras biológicas

Revista dos Trabalhos de Iniciação Científica da UNICAMP

Usando fluorescência de raios-x, foram replicados os resultados obtidos por Silva et al, a fim de... more Usando fluorescência de raios-x, foram replicados os resultados obtidos por Silva et al, a fim de expandir a técnica para imageamento de nanopartículas de ouro em cérebros de ratos e investigou-se os limites a baixo fluxo de fótons.

Research paper thumbnail of Method of processing radiation spectra diffused through a material in order to obtain a primary diffuse radiation spectrum through said material, associated device and computer program

Research paper thumbnail of Method for Correcting the Stacking Phenomenon Applied to X-Ray Spectrums Acquired Using a Spectrometric Sensor

Research paper thumbnail of Measurement of Blood Flow Dynamics with X-Ray Computed Tomography: Dynamic CT Angiography

Research paper thumbnail of Method of estimating scattered radiation in X-ray tomography

Research paper thumbnail of Method of estimating scattered radiation in a two-dimensional detector

Research paper thumbnail of Correction du diffusé pour la reconstruction tomographique quantitative avec un capteur plan numérique

Http Www Theses Fr, 2006

La tomographie X en geometrie conique permet de realiser de la tomodensitometrie volumique par un... more La tomographie X en geometrie conique permet de realiser de la tomodensitometrie volumique par une simple rotation du systeme source-detecteur et d'obtenir des volumes reconstruits a resolution isotrope. Dans une telle geometrie, la detection est realisee par des capteurs plans numeriques. Une des principales limitations de ces derniers est que le rayonnement diffuse atteignant le capteur est bien plus important que pour les tomographes classiques a capteurs lineaires ou multibarrettes. Ce rayonnement diffuse cree des artefacts de sous-estimations des coefficients d'attenuation sur les images reconstruites. Dans cette these, nous proposons des methodes de pretraitement des donnees et de correction du diffuse pour realiser de la tomodensitometrie quantitative avec capteur plan et evaluons experimentalement ces methodes dans un contexte medical. Une premiere partie decrit comment mettre en oeuvre un banc de tomographie comportant un capteur plan. A cet effet, un protocole d'acquisition assurant la reproductibilite des acquisitions est defini. Des methodes de pretraitement numerique des acquisitions corrigeant les artefacts causes par le capteur sont proposees. Outre la correction des pixels defectueux, du niveau d'obscurite et de la non-uniformite de la reponse des differents pixels, des corrections indispensables a une bonne quantification sont developpees. Elles comprennent la correction de la non-linearite de la reponse des pixels et celle d'un signal parasite, appele diffuse capteur, qui regroupe les phenomenes de diffusion X et optique ayant lieu a l'interieur du capteur. Ces methodes sont validees experimentalement sur des fantomes representatifs d'un thorax. Dans une seconde partie, une nouvelle methode de correction du rayonnement diffuse par l'objet examine est proposee. Elle est basee sur une estimation des images de rayonnement diffuse associees a chaque angle de vue tomographique par un calibrage du diffuse genere�� par des objets de reference couple a une modelisation analytique du diffuse du premier ordre. Cette methode est validee sur des fantomes representatifs de thorax dans une configuration du banc experimental sans grille anti diffusante. Une adaptation de la methode avec grille anti diffusante est proposee et evaluee experimentalement.

Research paper thumbnail of Experimental evaluation of a physical based approach of scattered radiation correction in thoracic cone beam CT,” submitted to

Cone Beam Computerized Tomography (CBCT) enables threedimensional imaging with isotropic resoluti... more Cone Beam Computerized Tomography (CBCT) enables threedimensional imaging with isotropic resolution. X-ray scatter management is a challenging task for quantitative CBCT imaging: scattered radiation level is significantly high on cone beam systems compared to collimated fan beam systems. The effects of this scattered radiation are cupping artifacts, streaks, and quantification inaccuracies. At CEA-LETI, an original scatter management process without additional on-line acquisition has been developed, the API (Analytical transformation Plus Indexation based) method. The proposed method is composed of two steps: a scatter calibration is first performed through off-line acquisitions and is used to evaluate the level and a global shape of scattered radiation on on-line tomographic projections of the object. This global shape is adapted to the current acquisition with an analytical transformation issued from physical equations to evaluate the scattered radiation distribution on tomographi...

Research paper thumbnail of International Symposium on Digital Industrial Radiology and Computed Tomography- We.2.1 New Perspectives of X-ray Techniques for Explosive Detection Based on CdTe/CdZnTe Spectrometric Detectors

Abstract. Conventional explosive detection systems (EDS) based on X-ray technologies are using du... more Abstract. Conventional explosive detection systems (EDS) based on X-ray technologies are using dual-energy radiography; they provide only a crude material characterization. Recently emerged semiconductors based X-ray detectors offer new capabilities in energy discrimination. This study is aiming at evaluating their interest for EDS. LETI-LDET laboratory has developed several pixellated CdTe/CZT detectors. For X-ray spectral radiography, a detector capable to operate at count rates above 10 7 counts/mm 2 s has been implemented, and associated to a multidimensional spectra analysis. We present the performance get for material identification on experimental data. Two complementary X-ray techniques are used in EDS: diffraction and backscatter techniques. Adapted detector prototypes have been developed. Experimental spectra are presented, and a dedicated processing method introduced for backscatter. For all these techniques, we discuss how CdTe/CdZnTe based spectrometric detectors are we...

Research paper thumbnail of Method materials identification from radiographs x Multi Energies

The invention relates to a method for calibrating an identification of materials in X-ray radiogr... more The invention relates to a method for calibrating an identification of materials in X-ray radiography apparatus, comprising: a) determining at least one calibration material and, for each calibration material, at least a thickness of calibration of this material, b) measuring, for each calibration material and for current weights, coefficients of attenuation or transmission of X-radiation, c) calculation of statistical parameters from said coefficients, d) determining, for each calibration material and each calibration thickness, a probability distribution of presence probability, based on said statistical parameters.

Research paper thumbnail of New Perspectives of X-ray Techniques for Explosive Detection Based on CdTe/CdZnTe Spectrometric Detectors

Conventional explosive detection systems (EDS) based on X-ray technologies are using dual-energy ... more Conventional explosive detection systems (EDS) based on X-ray technologies are using dual-energy radiography; they provide only a crude material characterization. Recently emerged semiconductors based X-ray detectors offer new capabilities in energy discrimination. This study is aiming at evaluating their interest for EDS. LETI-LDET laboratory has developed several pixellated CdTe/CZT detectors. For X-ray spectral radiography, a detector capable to operate at count rates above 10counts/mms has been implemented, and associated to a multidimensional spectra analysis. We present the performance get for material identification on experimental data. Two complementary X-ray techniques are used in EDS: diffraction and backscatter techniques. Adapted detector prototypes have been developed. Experimental spectra are presented, and a dedicated processing method introduced for backscatter. For all these techniques, we discuss how CdTe/CdZnTe based spectrometric detectors are well-adapted.

Research paper thumbnail of Verfahren zur Schätzung der Streustrahlung bei einer Röntgentomographie

Research paper thumbnail of Method for estimation of scattered radiation tomography x-ray

Research paper thumbnail of Method and device for recognizing a material using its transmission function

The invention relates to a method for characterizing the nature of a material, comprising: - disp... more The invention relates to a method for characterizing the nature of a material, comprising: - disposing at least one sample (100) of this material between a source (1) of X-rays, and a detector; performing, using the X-ray source, N X-ray spectra transmitted through said material, each for a duration Δt; calculate the transmission function of this material as a function of the energy or the detection channel; in each of at least two energy zones, calculating the integral of the transmission function, thus forming at least a first transmission coefficient (α1) and a second transmission coefficient (α2).

Research paper thumbnail of Measuring method of the atomic number of an actual material

The invention relates to a method of estimating the effective atomic number of a material from a ... more The invention relates to a method of estimating the effective atomic number of a material from a transmission spectrum of said material. Is calculated in a first step (230) a likelihood function of effective atomic number and thickness of the material from the transmission spectrum and the calibration spectra, obtained in a preliminary calibration phase, for a plurality of sample calibration material of known effective atomic numbers and known thicknesses. then estimated (240) the effective atomic number (Z) of the material from the values ​​of the likelihood function.

Research paper thumbnail of Method and device for identifying material by spectral analysis of electromagnetic radiation through this material

Research paper thumbnail of Method for first broadcast spectrum extraction device and associated computer program

Research paper thumbnail of Correction for pile-up effect based on pixel-by-pixel calibration for tomography with Medipix3RX detector

Proceedings of Technology and Instrumentation in Particle Physics 2014 — PoS(TIPP2014), Jul 3, 2015

Research paper thumbnail of X-ray coherent diffraction imaging: Sequential inverse problems simulation

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Abstract Improvement of spatial coherence in third generation synchrotron beamlines made possible... more Abstract Improvement of spatial coherence in third generation synchrotron beamlines made possible the development of X-ray plane-wave coherent diffraction imaging technique (plane-wave cdi ), which enables 3D imaging at nanometric resolution. In this work, we first simulated the influence of detector geometry by comparing reconstruction quality of planar samples made of gold nanoparticles. We compared a commercially available detector geometry with the next Medipix3-based large area detector designed for the next fourth generation Brazilian synchrotron, sirius . The spatial resolution was highly improved, from 7.2 nm for the commercial geometry to 4.8 nm for the Medipix3 detector by keeping the same global image quality. Finally, global image qualities were compared by adjusting the sample-to-detectors distances at a given spatial resolution. For thick samples reconstruction at such high nanometric resolutions, the main limitation of current reconstruction approaches are due to the complex wave propagation within the sample, given by the inhomogeneous Helmholtz equation. We proposed an iterative method to reconstruct the complex refraction index. This method enables to keep the image quality almost constant beyond the resolution limit for thick samples made of gold nanoparticles in water.

Research paper thumbnail of Gold nanoparticles for X-ray microtomography of neurons

ACS Chemical Neuroscience

Research paper thumbnail of Caracterização de um detector espectrométrico de raios X e aplicação em detecção de nanopartículas de ouro em amostras biológicas

Revista dos Trabalhos de Iniciação Científica da UNICAMP

Usando fluorescência de raios-x, foram replicados os resultados obtidos por Silva et al, a fim de... more Usando fluorescência de raios-x, foram replicados os resultados obtidos por Silva et al, a fim de expandir a técnica para imageamento de nanopartículas de ouro em cérebros de ratos e investigou-se os limites a baixo fluxo de fótons.

Research paper thumbnail of Method of processing radiation spectra diffused through a material in order to obtain a primary diffuse radiation spectrum through said material, associated device and computer program

Research paper thumbnail of Method for Correcting the Stacking Phenomenon Applied to X-Ray Spectrums Acquired Using a Spectrometric Sensor

Research paper thumbnail of Measurement of Blood Flow Dynamics with X-Ray Computed Tomography: Dynamic CT Angiography

Research paper thumbnail of Method of estimating scattered radiation in X-ray tomography

Research paper thumbnail of Method of estimating scattered radiation in a two-dimensional detector

Research paper thumbnail of Correction du diffusé pour la reconstruction tomographique quantitative avec un capteur plan numérique

Http Www Theses Fr, 2006

La tomographie X en geometrie conique permet de realiser de la tomodensitometrie volumique par un... more La tomographie X en geometrie conique permet de realiser de la tomodensitometrie volumique par une simple rotation du systeme source-detecteur et d'obtenir des volumes reconstruits a resolution isotrope. Dans une telle geometrie, la detection est realisee par des capteurs plans numeriques. Une des principales limitations de ces derniers est que le rayonnement diffuse atteignant le capteur est bien plus important que pour les tomographes classiques a capteurs lineaires ou multibarrettes. Ce rayonnement diffuse cree des artefacts de sous-estimations des coefficients d'attenuation sur les images reconstruites. Dans cette these, nous proposons des methodes de pretraitement des donnees et de correction du diffuse pour realiser de la tomodensitometrie quantitative avec capteur plan et evaluons experimentalement ces methodes dans un contexte medical. Une premiere partie decrit comment mettre en oeuvre un banc de tomographie comportant un capteur plan. A cet effet, un protocole d'acquisition assurant la reproductibilite des acquisitions est defini. Des methodes de pretraitement numerique des acquisitions corrigeant les artefacts causes par le capteur sont proposees. Outre la correction des pixels defectueux, du niveau d'obscurite et de la non-uniformite de la reponse des differents pixels, des corrections indispensables a une bonne quantification sont developpees. Elles comprennent la correction de la non-linearite de la reponse des pixels et celle d'un signal parasite, appele diffuse capteur, qui regroupe les phenomenes de diffusion X et optique ayant lieu a l'interieur du capteur. Ces methodes sont validees experimentalement sur des fantomes representatifs d'un thorax. Dans une seconde partie, une nouvelle methode de correction du rayonnement diffuse par l'objet examine est proposee. Elle est basee sur une estimation des images de rayonnement diffuse associees a chaque angle de vue tomographique par un calibrage du diffuse genere�� par des objets de reference couple a une modelisation analytique du diffuse du premier ordre. Cette methode est validee sur des fantomes representatifs de thorax dans une configuration du banc experimental sans grille anti diffusante. Une adaptation de la methode avec grille anti diffusante est proposee et evaluee experimentalement.