Continuation Format Page
|
|
- Bernice Simmons
- 5 years ago
- Views:
Transcription
1 C.1 PET with submillimeter spatial resolution Figure 2 shows two views of the high resolution PET experimental setup used to acquire preliminary data [92]. The mechanics of the proposed system are similar to this system and constructed from non-magnetic materials. Two 512-pad (32x16 array, 1.4mm x 1.4mm x 1mm thick) silicon detectors were oriented horizontally to image a single slice. The detectors of the porposed system are the same detectors used here. To cut down background radiation, sources were placed in a shielded cavity and collimated with tungsten to a 1.5mm slice. The idea of this system is that photons from positron annihilation Compton scatter in the silicon pad detectors and the resulting Compton electron will be measured in the silicon pad detector. To collect the scattered photon for possible energy discrimination and additional timing information, the silicon detectors were flanked by four BGO scintillation detector modules scavenged from a CTI 931 PET scanner. No position information was available from these BGO detectors (although different scintillation detectors could provide additional position information). For the results described in this section the BGO scintillation detector system was not used. Because the detectors do not record the full sinogram, the object must be rotated using the computer controlled rotation stage on the instrument (For the updated instrument proposed in Section D.2 both the object and eventually the detectors will be capable of rotating around the tomograph axis for maximum flexibility in data acquisition relative to the orientation of the B-field.) Using a laser, detectors were aligned in a plane parallel to that of the slit using pitch and roll adjustments. The Figure 2: Experimental setup for high resolution PET data acquisitions. Left: disassembled showing silicon detectors, tungsten slice collimation, shielded source cavity, and rotating table. Laser is used to align silicon detectors coplanar with tungsten slit. Right: assembled device showing source shielding, protective plastic boxes for silicon detectors and position-insensitive BGO detectors ( end-caps ) for improved timing and energy resolution. 1mm thickness of each detector was then centered vertically on the open slit. Line sources were imaged at several rotational positions in the field-of-view and a ML calibration method was used to estimate the unknown geometric parameters of the instrument (detector positions, axis-of-rotation, etc.) Because of the large timewalk with our present version of the silicon detector readout electronics, which uses a 200 ns shaper in the fast-channel, a 200 ns time-window was used. Detectors were biased slightly less than depletion (due to bias supply limits) and were operated at a triggering threshold of ~20keV. Depending on the maximum distance of source activity from the isocenter, increments of the rotation stage for data acquisition ranged from 1º to 30º. For the initial studies we acquired an equal number of events at each view with each silicon detector read out in serial mode with all pads being readout. Figure 3 shows the initial results from the tomograph in Fig. 2 compared with those from the Concorde MicroPET R4. Shown at the left is an image of two hematocrit tubes filled with F-18 FDG acquired using the
2 MicroPET. Each tube had an inside diameter of 1.1mm, a wall-thickness of 0.2mm. The tubes were taped so that there was no space between them (separation between F-18 lines: 0.4mm). The measured resolution of the MicroPET R4 after accounting for the source size and using the MAP reconstruction algorithm that models detector blurring is ~1.6mm FWHM (volume resolution 4µl). The center image shows four pairs of the same sources at 5mm, 10mm, 15mm, and 20mm off-axis acquired using the high resolution PET setup and reconstructed using plain-vanilla maximum likelihood with no modeling of detector response. The scales are the same in the left and center images. The two line sources in each pair are clearly separated. Accounting for the source size, the resolution is 800µm x 800µm x 650µm (axial) FWHM (0.42µl). In contrast to systems without DOI resolution, performance is nearly constant across the FOV. To demonstrate that this is no resolution-recovery trick of the reconstruction, each pair of sources is apparent in the corresponding sinogram (Fig. 2, right). Recently, detectors having 1mm x 1mm x 1mm elements have been fabricated and should allow intrinsic resolution of approximately 650 µm FWHM including the effect of acolinearity. This result clearly demonstrates that prototype PET system is capable of achieving high (sub-millimeter) spatial resolutions. The significant remaining question is whether it is feasible for the detectors to operate in a large magnetic field. This is addressed in Section C.3. Figure 3: F-18 sources in two adjacent hematocrit tubes on-axis for MicroPET R4 (left) and for four pairs at 5mm, 10mm, 15mm, and 20mm off-axis for the high resolution PET test system shown in Fig 1 (center). Tubes have an internal diameter of 1.1mm and wall thickness of 0.2mm. MicroPET reconstructed using MAP algorithm; prototype high resolution PET using maximum likelihood with a simple system matrix that does not account for finite detector size. Resolution correcting for source size is approximately 1.6mm FWHM for MicroPET R4 and 800µm FWHM for the new instrument. Image at right is efficiency-corrected sinogram demonstrating the intrinsically high spatial resolution. Each hematocrit tube in each pair is evident at the appropriate projection angle. In the upcoming period we propose to use the above PET technique within its realm of applicability as a high resolution imaging tool to address the issue of positron range on image resolution. The results of this investigation should be applicable to all high resolution PET systems capable of operation at high magnetic field-strengths. C.2 Reduction of positron range in magnetic fields The importance of the positron distance of flight has been discussed in Section B. Here we discuss our preliminary simulation work using EGS-4 of the effect of strong magnetic fields on positron range. While the total distance traveled by a positron between emission and annihilation is not affected by an external magnetic field, the positrons no longer move in straight lines between scatter interactions with the material they travel through. The Lorentz force acts on the moving positrons forcing them onto a helical path thereby reducing the range which is defined as the distance between emission and annihilation points. The size of this effect depends on the direction of the positron relative to the magnetic field direction. It is largest for positrons traveling perpendicular to the direction of the magnetic field. Figure 4 shows simulated positron range distributions for different positron emitters in both water and lung tissue. Each configuration was simulated with and without a 7-T magnetic field. The reduction in range is clearly visible in Figure 4. The size of the effect depends both on the positron energy and the density of the material the positrons travel through. In order to
3 obtain quantitative results we project the range distribution onto an axis perpendicular to the magnetic field direction. An example for positrons emitted by Ga-68 in water is shown in Figure 5. Cusp-like distributions are observed in these studies similar to studies without magnetic field but with significantly reduced tails. Numerical results for different positron emitters are listed in Table 2. A substantial reduction in range can be obtained for radionuclides with large positron energies such as Tc-94m or Ga-68 but even for F-18 the average positron range can be reduced by strong magnetic fields in particular in less dense media such as lung tissue. In Water In Lung Tissue No Magnetic Field 7 T Magnetic Field No Magnetic Field 7 T Magnetic Field F-18 Ga-68 Tc-94m Figure 4: Simulated positron range distributions for F-18, Ga-68 and Tc-94m in water and lung tissue with and without a magnetic field. The range distribution is projected onto a plane perpendicular to the direction of the magnetic field.
4 Figure 5: Positron distance of flight in water for Ga-68, (a) without magnetic field, (b) projected onto a plane perpendicular to a 7-T magnetic field, (c) projected onto a plane parallel to a 7-T magnetic field, and (d) range projection onto an axis parallel and perpendicular to an 7-T magnetic field.
5 Isotope Max. Positron Energy [KeV] Tissue FWHM [mm] FWTM [mm] F C N O Ga Tc-94m 1428 Water Lung Water Lung Water Lung Water Lung Water Lung Water Lung Table 2 Simulated positron range in water and lung tissue for different positron-emitters in a 7T magnetic field perpendicular to the image plane. We conclude that embedding the PET FOV in a large magnetic field (7T) should reduce the positron range distribution in water and lung tissue and this effect should be observable with a PET system with sub-millimeter resolution. C.3 Magnetic field compatibility of proposed detectors In order to identify the issues associated with high field operation of a Compton PET system, we tested a silicon detector hybrid module similar to that which we propose to use for this investigation and similar to that used for the results in Section C.1. This module is shown is Figure 6. The silicon detector had 512-pads (32x16 array, 1.4mm x 1.4mm x 1mm thick) and was readout via four VaTaGP3 ASIC s. We chose to measure the pulse height spectrum of Am-241 to look for an effect due to the magnetic field. We initially setup to acquire an Am-241 spectrum in the 8T magnetic of the Ohio State University MRI facility. Within one minute of operation the hybrid failed. Upon further investigation we discovered that three wire bonds to the integrated circuit had broken on the high current lines which power the digital readout. These are shown in the right image of Figure 6. To understand this result we constructed a wire bond test system and operated it in the 8T magnetic field. We put 133mA through the test wire bonds which is roughly twice the peak current the real wires bonds have during readout operation.
6 Figure 6: Left Image: Photograph of the silicon detector module tested in an 8T magnetic field. Right Image: Photograph of the three broken wires (first, fourth, and sixth ones in) after the initial test in the 8T field. In the real device the current in the bond wires changes in magnitude with frequency. We found that for DC and high frequency operation we could not reproduce the breaking of bonds. However at roughly the readout frequency of the ASIC we were able to break bonds. Our solution was to encapsulate the wire bonds of the test setup. Upon testing this configuration we found that we did not break a wire bond after 18 hrs of continuous testing at the same frequency which previously had broken bonds. Figure 7: The Am-241 pulse height spectra obtained using a silicon pad detector and VaTaGP3 electronics operating in 0T (red curve) and 8T (black curve) magnetic fields. We repaired the broken detector system, encapsulated the wire bonds and took Am-241 spectra at 0, 2, 4, 6, and 8T. The total time in the 8T magnetic field was 8 hrs. No wire bonds were broken during the test nor were any other problems observed. For these tests the detector was operated at 100V and at a trigger threshold of approximately 20keV and each data run was a fixed number of events. Figure 7 shows the Am-241 results for data runs taken at 0T (red curve) and 8T (black curve). We observe no difference in the spectra obtained at 0T and at 8T. That the raw spectra appear nearly identical indicates that the trigger efficiency and energy
7 resolution did not change in the magnetic field. We conclude that the proposed silicon detector system will operate and have the same performance in the 7T field as we measure on the bench at 0T. C.4 Method for reducing effects of positron range in 3D As evident from the information above, while the magnetic field improves spatial resolution by reducing range in directions transverse to the field, it has little to no effect on the range of positrons emitted with significant momentum parallel to the magnetic field vector. The point spread functions resulting from this static magnetic confinement may actually exhibit worse imaging performance than using no confinement at all. To visualize this, refer to the projections of Monte Carlo generated PSFs for I-124 shown in Figure 8. The leftmost image is a planar projection of the PSF with no applied magnetic field. It has a sharp central peak and broad, diffuse -4 0 Tesla -4 9 Tesla XZ-Plane -4 9 Tesla XY-Plane Distance (mm) Distance (mm) Figure 8. Projections of the PSF due to range of I-124 positrons in water. Left: No magnetic confinement; PSF is isotropic. Center: Orientation of B-field vector is parallel to bottom of page. Note long tails extending in z-direction. Right: Orientation of B-field is into the page. tails that tend to average any out-of-plane structures resulting in an additional background haze in the slice being viewed. At 9T, projections of the resulting PSFs in two orthogonal directions are shown at the center and right. If one is viewing slices in the X-Y plane (rightmost image), resolution of in-plane structures will obviously be much better than with no magnetic field. However, notice the sharpness of the tails of the response function in the X-Z projection (center). Rather than a diffuse background, these sharp tails will generate artifacts in the slice being viewed from structures in adjacent planes. In short, while positron range will be reduced and images will exhibit improved spatial resolution, artifacts will be worse than with no magnetic field. The solution one that will improve spatial resolution in 3D to essentially that shown in the X-Y projection of Figure 8 is to acquire PET measurements in multiple orientations of the magnetic field vector relative to the object. It is of course difficult to change the orientation of a 9T magnet but it is much easier to orient the object in two or more directions relative to the magnetic field. The next significant question is once such PET information is obtained, how should it be reconstructed? The answer is particularly straightforward: a single estimate of the distribution of radiotracer is obtained by considering all measurements simultaneously. Specifically, the sets of projection data from each B-field orientation are combined using a maximum likelihood (or penalized likelihood or maximum a posteriori) image reconstruction that accounts correctly for uncertainties in the measurements. Although resolution recovery assuming the system response is modeled correctly is possible for all the above cases, the situation in which at least two orientations (preferably orthogonal) of a strong magnetic are used will provide a noise-resolution tradeoff superior to either the use of no field or a field oriented in only one direction. For the reconstructed images shown below, we assume the probability mass function of the measurements can be represented as a conditionally Poisson model where the conditioning is with respect to the unknown object:
8 y y A b ~ Poisson λ + (1) A b where y = [y 11,,y 1N ] T and y = [y 21,,y 2N ] T represent the recorded events for two orientations, which may be binned into histograms (or sinograms ) or instead may be just a list of the endpoints of each recorded coincidence (or other information-preserving transformation of the data). The matrices A and A represent the aperture function or system response of the tomograph in the two orientations of the magnetic field. For example, with the magnetic field vector parallel to the axis of the PET instrument, A would model a response function that has low uncertainty due to positron range in the x-y plane and high uncertainty along the axis of the tomograph. In contrast, A if the magnetic field vector is perpendicular to the previous orientation would model low uncertainty along the tomograph axis and high uncertainty in some orthogonal direction. The symbol λ=[λ 1,,λ M ] T is a discrete representation of the object e.g., voxels. More orientations of the field can be accommodated in the above model by augmenting the composite system matrix (in square brackets in (1)) with an additional A accounting for the correct orientation of the magnetic field relative to the object. As in similar models for PET the vectors b represent additive interference due to randoms and scatter. Once the reconstruction problem has been set up in this fashion, numerous methods can be used to obtain the estimate, the EM-algorithm being a particularly suitable choice for solving for the corresponding maximum likelihood or penalized maximum likelihood estimate. The key things to note are that (1) both sets of measurements arise from a single, unknown object λ that must be estimated, and (2) the system model must account for the PSF induced by the positron range for each orientation of the magnetic field. Calculations of image effect of range reduction The PSF for I-124 positron annihilations in water shown in Figure 8 was used to blur data from the simulated resolution phantom (rod diameters 4.8, 4.0, 3.2, 2.4, 1.6, and 1.2 mm). One million detected annihilations were recorded in a simulated single-slice PET scanner with resolution similar to the instrument that will be used for the experiments described in Section D, and then reconstructed using a maximum likelihood method (EM algorithm) that modeled the spatial resolution of the PET system but not the range of the positron. The corresponding image is shown in Figure 9 left below. Figure 9. Left: Reconstructed PET images for simulated data corresponding to resolution phantom filled with I-124 resolution phantom with no magnetic field. Right: Same phantom at 9T field strength with magnetic field vector perpendicular to the page. Both datasets have one million detected events. Intrinsic resolution of the PET scanner implied in the simulations is ~700µm FWHM similar to the instrument that will be used in the proposed investigation. This represents the ideal situation: artifacts from out-of-plane activity are non-existent The PSF modeling I-124 positron range at 9T field was also calculated and used to blur the phantom assuming the constant axis of the phantom (direction along rods) was oriented parallel to the B-field. This case will give the best resolution for such a phantom but it is unrealistic in practice since real objects tend not to have a constant activity distribution along one direction. Again, one million detected events were used to reconstruct the image in Figure 9 on the right. Notice the significantly improved spatial resolution. As noted, in reality this case is somewhat unrealistic (except for micro-jaszczak phantoms!).
9 Figure 10. Left: Orientation of B-field parallel to bottom of page. Center: orientation of B-field perpendicular to bottom of page. Right: Reconstruction from both orientations. Using the proposed acquisition and reconstruction method, datasets were simulated in two orientations of the B-field relative to the object; each orientation contains a mean of 500K events (1M total) and data were reconstructed using the ML technique described above. The leftmost image of Figure 10 is a reconstruction corresponding to a B-field to the right, the image in the center is a reconstruction from data acquired when the B-field is pointing toward the bottom of the page, and finally, the reconstruction on the right is made using both field orientations. These preliminary results are encouraging but the proposed work will quantify the actual advantages in terms of better noise-resolution tradeoffs as well as freedom from artifacts due to structures in adjacent planes using magnetic range confinement.
A. Specific Aims. Principal Investigator/Program Director (Last, First, Middle): Kagan, Harris
A. Specific Aims The long-term objective of this investigation is to develop PET instrumentation for molecular imaging of small animals that has unprecedented spatial resolution. Recent results (Section
More informationCorso di laurea in Fisica A.A Fisica Medica 5 SPECT, PET
Corso di laurea in Fisica A.A. 2007-2008 Fisica Medica 5 SPECT, PET Step 1: Inject Patient with Radioactive Drug Drug is labeled with positron (β + ) emitting radionuclide. Drug localizes
More informationImplementation and evaluation of a fully 3D OS-MLEM reconstruction algorithm accounting for the PSF of the PET imaging system
Implementation and evaluation of a fully 3D OS-MLEM reconstruction algorithm accounting for the PSF of the PET imaging system 3 rd October 2008 11 th Topical Seminar on Innovative Particle and Radiation
More informationIntroduction to Positron Emission Tomography
Planar and SPECT Cameras Summary Introduction to Positron Emission Tomography, Ph.D. Nuclear Medicine Basic Science Lectures srbowen@uw.edu System components: Collimator Detector Electronics Collimator
More informationMedical Imaging BMEN Spring 2016
Name Medical Imaging BMEN 420-501 Spring 2016 Homework #4 and Nuclear Medicine Notes All questions are from the introductory Powerpoint (based on Chapter 7) and text Medical Imaging Signals and Systems,
More informationCherenkov Radiation. Doctoral Thesis. Rok Dolenec. Supervisor: Prof. Dr. Samo Korpar
Doctoral Thesis Time-of-Flight Time-of-Flight Positron Positron Emission Emission Tomography Tomography Using Using Cherenkov Cherenkov Radiation Radiation Rok Dolenec Supervisor: Prof. Dr. Samo Korpar
More informationImage Acquisition Systems
Image Acquisition Systems Goals and Terminology Conventional Radiography Axial Tomography Computer Axial Tomography (CAT) Magnetic Resonance Imaging (MRI) PET, SPECT Ultrasound Microscopy Imaging ITCS
More informationDigital Image Processing
Digital Image Processing SPECIAL TOPICS CT IMAGES Hamid R. Rabiee Fall 2015 What is an image? 2 Are images only about visual concepts? We ve already seen that there are other kinds of image. In this lecture
More informationREMOVAL OF THE EFFECT OF COMPTON SCATTERING IN 3-D WHOLE BODY POSITRON EMISSION TOMOGRAPHY BY MONTE CARLO
REMOVAL OF THE EFFECT OF COMPTON SCATTERING IN 3-D WHOLE BODY POSITRON EMISSION TOMOGRAPHY BY MONTE CARLO Abstract C.S. Levin, Y-C Tai, E.J. Hoffman, M. Dahlbom, T.H. Farquhar UCLA School of Medicine Division
More informationSimulation of Internal Backscatter Effects on MTF and SNR of Pixelated Photon-counting Detectors
Simulation of Internal Backscatter Effects on MTF and SNR of Pixelated Photon-counting Detectors Alexander Korn, Juergen Giersch a and Martin Hoheisel b a Physikalisches Institut Universitaet Erlangen-Nuernberg,
More informationConflicts of Interest Nuclear Medicine and PET physics reviewer for the ACR Accreditation program
James R Halama, PhD Loyola University Medical Center Conflicts of Interest Nuclear Medicine and PET physics reviewer for the ACR Accreditation program Learning Objectives 1. Be familiar with recommendations
More information218 IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 44, NO. 2, APRIL 1997
218 IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 44, NO. 2, APRIL 1997 Compton Scatter and X-ray Crosstalk and the Use of Very Thin Intercrystal Septa in High-Resolution PET Detectors Craig S. Levin, Member,
More informationSlide 1. Technical Aspects of Quality Control in Magnetic Resonance Imaging. Slide 2. Annual Compliance Testing. of MRI Systems.
Slide 1 Technical Aspects of Quality Control in Magnetic Resonance Imaging Slide 2 Compliance Testing of MRI Systems, Ph.D. Department of Radiology Henry Ford Hospital, Detroit, MI Slide 3 Compliance Testing
More informationAn educational tool for demonstrating the TOF-PET technique
Nuclear Instruments and Methods in Physics Research A 471 (2001) 200 204 An educational tool for demonstrating the TOF-PET technique T.Bȧack a, *, J. Cederkȧall a, B. Cederwall a, A. Johnson a, A. Kerek
More informationJames R Halama, PhD Loyola University Medical Center
James R Halama, PhD Loyola University Medical Center Conflicts of Interest Nuclear Medicine and PET physics reviewer for the ACR Accreditation program Learning Objectives Be familiar with the tests recommended
More informationConstructing System Matrices for SPECT Simulations and Reconstructions
Constructing System Matrices for SPECT Simulations and Reconstructions Nirantha Balagopal April 28th, 2017 M.S. Report The University of Arizona College of Optical Sciences 1 Acknowledgement I would like
More informationSNIC Symposium, Stanford, California April The Hybrid Parallel Plates Gas Counter for Medical Imaging
The Hybrid Parallel Plates Gas Counter for Medical Imaging F. Anulli, G. Bencivenni, C. D Ambrosio, D. Domenici, G. Felici, F. Murtas Laboratori Nazionali di Frascati - INFN, Via E. Fermi 40, I-00044 Frascati,
More informationBME I5000: Biomedical Imaging
1 Lucas Parra, CCNY BME I5000: Biomedical Imaging Lecture 4 Computed Tomography Lucas C. Parra, parra@ccny.cuny.edu some slides inspired by lecture notes of Andreas H. Hilscher at Columbia University.
More information3-D PET Scatter Correction
Investigation of Accelerated Monte Carlo Techniques for PET Simulation and 3-D PET Scatter Correction C.H. Holdsworth, Student Member, IEEE, C.S. Levin", Member, IEEE, T.H. Farquhar, Student Member, IEEE,
More informationReview of PET Physics. Timothy Turkington, Ph.D. Radiology and Medical Physics Duke University Durham, North Carolina, USA
Review of PET Physics Timothy Turkington, Ph.D. Radiology and Medical Physics Duke University Durham, North Carolina, USA Chart of Nuclides Z (protons) N (number of neutrons) Nuclear Data Evaluation Lab.
More informationIntroduction to Emission Tomography
Introduction to Emission Tomography Gamma Camera Planar Imaging Robert Miyaoka, PhD University of Washington Department of Radiology rmiyaoka@u.washington.edu Gamma Camera: - collimator - detector (crystal
More information45 µm polystyrene bead embedded in scattering tissue phantom. (a,b) raw images under oblique
Phase gradient microscopy in thick tissue with oblique back-illumination Tim N Ford, Kengyeh K Chu & Jerome Mertz Supplementary Figure 1: Comparison of added versus subtracted raw OBM images 45 µm polystyrene
More informationarxiv:physics/ v1 [physics.ins-det] 18 Dec 1998
Studies of 1 µm-thick silicon strip detector with analog VLSI readout arxiv:physics/981234v1 [physics.ins-det] 18 Dec 1998 T. Hotta a,1, M. Fujiwara a, T. Kinashi b, Y. Kuno c, M. Kuss a,2, T. Matsumura
More informationValidation of GEANT4 for Accurate Modeling of 111 In SPECT Acquisition
Validation of GEANT4 for Accurate Modeling of 111 In SPECT Acquisition Bernd Schweizer, Andreas Goedicke Philips Technology Research Laboratories, Aachen, Germany bernd.schweizer@philips.com Abstract.
More informationEmission Computed Tomography Notes
Noll (24) ECT Notes: Page 1 Emission Computed Tomography Notes Introduction Emission computed tomography (ECT) is the CT applied to nuclear medicine. There are two varieties of ECT: 1. SPECT single-photon
More informationSPECT QA and QC. Bruce McBride St. Vincent s Hospital Sydney.
SPECT QA and QC Bruce McBride St. Vincent s Hospital Sydney. SPECT QA and QC What is needed? Why? How often? Who says? QA and QC in Nuclear Medicine QA - collective term for all the efforts made to produce
More information8/2/2017. Disclosure. Philips Healthcare (Cleveland, OH) provided the precommercial
8//0 AAPM0 Scientific Symposium: Emerging and New Generation PET: Instrumentation, Technology, Characteristics and Clinical Practice Aug Wednesday 0:4am :pm Solid State Digital Photon Counting PET/CT Instrumentation
More informationExtremely Fast Detector for 511 kev Gamma
Extremely Fast Detector for 511 kev Gamma V. Sharyy, D. Yvon, G. Tauzin, E.Delagnes, Ph. Abbon, J P. Bard, M. Kebbiri, M. Alokhina, C. Canot IRFU, CEA D. Breton, J. Maalmi LAL,IN2P3 Journée 2015 du Labex
More informationQuality control phantoms and protocol for a tomography system
Quality control phantoms and protocol for a tomography system Lucía Franco 1 1 CT AIMEN, C/Relva 27A O Porriño Pontevedra, Spain, lfranco@aimen.es Abstract Tomography systems for non-destructive testing
More informationCHAPTER 9: Magnetic Susceptibility Effects in High Field MRI
Figure 1. In the brain, the gray matter has substantially more blood vessels and capillaries than white matter. The magnified image on the right displays the rich vasculature in gray matter forming porous,
More informationC a t p h a n / T h e P h a n t o m L a b o r a t o r y
C a t p h a n 5 0 0 / 6 0 0 T h e P h a n t o m L a b o r a t o r y C a t p h a n 5 0 0 / 6 0 0 Internationally recognized for measuring the maximum obtainable performance of axial, spiral and multi-slice
More informationDevelopment of a high resolution animal PET with continuous crystals and SiPMs
Development of a high resolution animal PET with continuous crystals and SiPMs 1, John Barrio1, Jorge Cabello1,2, Ane Etxebeste1, Carlos Lacasta1, Josep F. Oliver1, Magdalena Rafecas1, Carles Solaz1, Vera
More informationEnhanced material contrast by dual-energy microct imaging
Enhanced material contrast by dual-energy microct imaging Method note Page 1 of 12 2 Method note: Dual-energy microct analysis 1. Introduction 1.1. The basis for dual energy imaging Micro-computed tomography
More informationGamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector
Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector K. Karafasoulis, K. Zachariadou, S. Seferlis, I. Papadakis, D. Loukas, C. Lambropoulos, C. Potiriadis Abstract Spectroscopic
More informationTechnological Advances and Challenges: Experience with Time-Of-Flight PET Combined with 3T MRI. Floris Jansen, GE Healthcare July, 2015
Technological Advances and Challenges: Experience with Time-Of-Flight PET Combined with 3T MRI Floris Jansen, GE Healthcare July, 2015 PET/MR 101 : challenges Thermal Workflow & Apps RF interactions?!!
More informationComputational Medical Imaging Analysis
Computational Medical Imaging Analysis Chapter 2: Image Acquisition Systems Jun Zhang Laboratory for Computational Medical Imaging & Data Analysis Department of Computer Science University of Kentucky
More informationIterative SPECT reconstruction with 3D detector response
Iterative SPECT reconstruction with 3D detector response Jeffrey A. Fessler and Anastasia Yendiki COMMUNICATIONS & SIGNAL PROCESSING LABORATORY Department of Electrical Engineering and Computer Science
More informationDiagnostic imaging techniques. Krasznai Zoltán. University of Debrecen Medical and Health Science Centre Department of Biophysics and Cell Biology
Diagnostic imaging techniques Krasznai Zoltán University of Debrecen Medical and Health Science Centre Department of Biophysics and Cell Biology 1. Computer tomography (CT) 2. Gamma camera 3. Single Photon
More informationPhase-Contrast Imaging and Tomography at 60 kev using a Conventional X-ray Tube
Phase-Contrast Imaging and Tomography at 60 kev using a Conventional X-ray Tube T. Donath* a, F. Pfeiffer a,b, O. Bunk a, W. Groot a, M. Bednarzik a, C. Grünzweig a, E. Hempel c, S. Popescu c, M. Hoheisel
More informationCharacterization of a Time-of-Flight PET Scanner based on Lanthanum Bromide
2005 IEEE Nuclear Science Symposium Conference Record M04-8 Characterization of a Time-of-Flight PET Scanner based on Lanthanum Bromide J. S. Karp, Senior Member, IEEE, A. Kuhn, Member, IEEE, A. E. Perkins,
More informationBiomedical Imaging. Computed Tomography. Patrícia Figueiredo IST
Biomedical Imaging Computed Tomography Patrícia Figueiredo IST 2013-2014 Overview Basic principles X ray attenuation projection Slice selection and line projections Projection reconstruction Instrumentation
More informationIntroduction to Biomedical Imaging
Alejandro Frangi, PhD Computational Imaging Lab Department of Information & Communication Technology Pompeu Fabra University www.cilab.upf.edu X-ray Projection Imaging Computed Tomography Digital X-ray
More informationPerformance Evaluation of radionuclide imaging systems
Performance Evaluation of radionuclide imaging systems Nicolas A. Karakatsanis STIR Users meeting IEEE Nuclear Science Symposium and Medical Imaging Conference 2009 Orlando, FL, USA Geant4 Application
More informationA new PET prototype for proton therapy: comparison of data and Monte Carlo simulations
A new PET prototype for proton therapy: comparison of data and Monte Carlo simulations V. Rosso, G.Battistoni, N. Belcari, N. Camarlinghi, A. Ferrari, S. Ferretti, A. Kraan, A. Mairani, N. Marino, J. E.
More informationFast Timing and TOF in PET Medical Imaging
Fast Timing and TOF in PET Medical Imaging William W. Moses Lawrence Berkeley National Laboratory October 15, 2008 Outline: Time-of-Flight PET History Present Status Future This work was supported in part
More informationChapter 36. Diffraction. Dr. Armen Kocharian
Chapter 36 Diffraction Dr. Armen Kocharian Diffraction Light of wavelength comparable to or larger than the width of a slit spreads out in all forward directions upon passing through the slit This phenomena
More informationFits you like no other
Fits you like no other BrightView X and XCT specifications The new BrightView X system is a fully featured variableangle camera that is field-upgradeable to BrightView XCT without any increase in room
More informationScatter Correction Methods in Dimensional CT
Scatter Correction Methods in Dimensional CT Matthias Baer 1,2, Michael Hammer 3, Michael Knaup 1, Ingomar Schmidt 3, Ralf Christoph 3, Marc Kachelrieß 2 1 Institute of Medical Physics, Friedrich-Alexander-University
More informationInterpolating Silicon Photomultipliers
Interpolating Silicon Photomultipliers Peter Fischer, Heidelberg University, Germany (Presenter) Claudio Piemonte, FBK, Italy We present the novel Interpolating Silicon PhotoMultiplier (ISiPM) topology
More informationPlane Wave Imaging Using Phased Array Arno Volker 1
11th European Conference on Non-Destructive Testing (ECNDT 2014), October 6-10, 2014, Prague, Czech Republic More Info at Open Access Database www.ndt.net/?id=16409 Plane Wave Imaging Using Phased Array
More informationHIGH-SPEED THEE-DIMENSIONAL TOMOGRAPHIC IMAGING OF FRAGMENTS AND PRECISE STATISTICS FROM AN AUTOMATED ANALYSIS
23 RD INTERNATIONAL SYMPOSIUM ON BALLISTICS TARRAGONA, SPAIN 16-20 APRIL 2007 HIGH-SPEED THEE-DIMENSIONAL TOMOGRAPHIC IMAGING OF FRAGMENTS AND PRECISE STATISTICS FROM AN AUTOMATED ANALYSIS P. Helberg 1,
More informationNovel Magnetic Field Mapping Technology for Small and Closed Aperture Undulators
Novel Magnetic Field Mapping Technology for Small and Closed Aperture Undulators Erik Wallen and Hyun-Wook Kim 06.06.2017 Outline Introduction - Measurement systems at LBNL - Activities at LBNL - Need
More informationImproving Positron Emission Tomography Imaging with Machine Learning David Fan-Chung Hsu CS 229 Fall
Improving Positron Emission Tomography Imaging with Machine Learning David Fan-Chung Hsu (fcdh@stanford.edu), CS 229 Fall 2014-15 1. Introduction and Motivation High- resolution Positron Emission Tomography
More informationin PET Medical Imaging
Fast Timing and TOF in PET Medical Imaging William W. Moses Lawrence Berkeley National Laboratory October 15, 2008 Outline: Time-of-Flight PET History Present Status Future This work was supported in part
More informationImprovement in the calibration techniques of approved dosimetry services in Spanish nuclear power plants of whole body counters with NaI detectors.
Improvement in the calibration techniques of approved dosimetry services in Spanish nuclear power plants of whole body counters with NaI detectors. E.Sollet (*), A.Felipe(**), JM.Perez (**), S. De Maria
More informationCT vs. VolumeScope: image quality and dose comparison
CT vs. VolumeScope: image quality and dose comparison V.N. Vasiliev *a, A.F. Gamaliy **b, M.Yu. Zaytsev b, K.V. Zaytseva ***b a Russian Sci. Center of Roentgenology & Radiology, 86, Profsoyuznaya, Moscow,
More informationSTATISTICAL positron emission tomography (PET) image
IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 23, NO. 9, SEPTEMBER 2004 1057 Accurate Estimation of the Fisher Information Matrix for the PET Image Reconstruction Problem Quanzheng Li, Student Member, IEEE,
More informationOptimization of CT Simulation Imaging. Ingrid Reiser Dept. of Radiology The University of Chicago
Optimization of CT Simulation Imaging Ingrid Reiser Dept. of Radiology The University of Chicago Optimization of CT imaging Goal: Achieve image quality that allows to perform the task at hand (diagnostic
More informationFits you like no other
Fits you like no other Philips BrightView X and XCT specifications The new BrightView X system is a fully featured variableangle camera that is field-upgradeable to BrightView XCT without any increase
More informationInvestigations of a novel small animal PET scanner with depth of interaction using GATE and a newly developed data rebinning application
University of Wollongong Research Online University of Wollongong Thesis Collection 1954-2016 University of Wollongong Thesis Collections 2009 Investigations of a novel small animal PET scanner with depth
More informationPhysical Optics. You can observe a lot just by watching. Yogi Berra ( )
Physical Optics You can observe a lot just by watching. Yogi Berra (1925-2015) OBJECTIVES To observe some interference and diffraction phenomena with visible light. THEORY In a previous experiment you
More informationDetection of Lesions in Positron Emission Tomography
Detection of Lesions in Positron Emission Tomography Bachelor Thesis Nina L.F. Bezem Study: Physics and Astronomy Faculty of Science Supervised by: Dr. Andre Mischke Utrecht University, Institute for Subatomic
More informationISO ISO ISO OHSAS ISO
ISO 9001 ISO 13485 ISO 14001 OHSAS 18001 ISO 27001 Pro-NM Performance 08-101 - standard version 08-103 - version with the PET Lid Phantom for NM and PET systems performance evaluation (collimator, artifacts,
More informationAlignment and Other Challenges in Reconstructing Cryotomograms with IMOD
Alignment and Other Challenges in Reconstructing Cryotomograms with IMOD Challenges in Cryotomography Alignment, alignment, alignment It can be hard to get fiducials onto/in the sample The low SNR makes
More informationarxiv: v2 [cond-mat.mtrl-sci] 5 Jan 2010
Gamma scattering scanning of concrete block for detection of voids. Shivaramu 1, Arijit Bose 2 and M. Margret 1 1 Radiological Safety Division, Safety Group, IGCAR, Kalpakaam - 63 12 (India) 2 Chennai
More informationComparison of 3D PET data bootstrap resampling methods for numerical observer studies
2005 IEEE Nuclear Science Symposium Conference Record M07-218 Comparison of 3D PET data bootstrap resampling methods for numerical observer studies C. Lartizien, I. Buvat Abstract Bootstrap methods have
More informationDiffraction. Single-slit diffraction. Diffraction by a circular aperture. Chapter 38. In the forward direction, the intensity is maximal.
Diffraction Chapter 38 Huygens construction may be used to find the wave observed on the downstream side of an aperture of any shape. Diffraction The interference pattern encodes the shape as a Fourier
More informationPositron Emission Tomography
Physics 656 Seminar on Physical Fundamentals of Medical Imaging Positron Emission Tomography Ahmed Qamesh Outline What is PET? PET mechanism Radionuclide and its synthesis Detection concept and Development
More informationChapter 38. Diffraction Patterns and Polarization
Chapter 38 Diffraction Patterns and Polarization Diffraction Light of wavelength comparable to or larger than the width of a slit spreads out in all forward directions upon passing through the slit This
More informationISOCS Characterization of Sodium Iodide Detectors for Gamma-Ray Spectrometry
ISOCS Characterization of Sodium Iodide Detectors for Gamma-Ray Spectrometry Sasha A. Philips, Frazier Bronson, Ram Venkataraman, Brian M. Young Abstract--Activity measurements require knowledge of the
More informationDesign and assessment of a novel SPECT system for desktop open-gantry imaging of small animals: A simulation study
Design and assessment of a novel SPECT system for desktop open-gantry imaging of small animals: A simulation study Navid Zeraatkar and Mohammad Hossein Farahani Research Center for Molecular and Cellular
More informationIdentification of Shielding Material Configurations Using NMIS Imaging
Identification of Shielding Material Configurations Using NMIS Imaging B. R. Grogan, J. T. Mihalczo, S. M. McConchie, and J. A. Mullens Oak Ridge National Laboratory, P.O. Box 2008, MS-6010, Oak Ridge,
More informationTORCH: A large-area detector for precision time-of-flight measurements at LHCb
TORCH: A large-area detector for precision time-of-flight measurements at LHCb Neville Harnew University of Oxford ON BEHALF OF THE LHCb RICH/TORCH COLLABORATION Outline The LHCb upgrade TORCH concept
More informationLCLS Undulator Quadrupole Fiducialization Plan
LCLS-TN-07-7 LCLS Undulator Quadrupole Fiducialization Plan Zachary Wolf, Michael Levashov, Eric Lundahl, Ed Reese, Catherine LeCocq, Robert Ruland Stanford Linear Accelerator Center August 14, 2007 Abstract
More informationApplying Hounsfield unit density calibration in SkyScan CT-analyser
1 Bruker-microCT Method note Applying Hounsfield unit density calibration in SkyScan CT-analyser Hounsfield units (HU) are a standard unit of x-ray CT density, in which air and water are ascribed values
More informationspecular diffuse reflection.
Lesson 8 Light and Optics The Nature of Light Properties of Light: Reflection Refraction Interference Diffraction Polarization Dispersion and Prisms Total Internal Reflection Huygens s Principle The Nature
More informationMethods for Quantitative Characterization of Large-Scale High Energy Computed Tomography Systems
More Info at Open Access Database www.ndt.net/?id=16704 Methods for Quantitative Characterization of Large-Scale High Energy Computed Tomography Systems Michael BÖHNEL 1, Andreas GRUBER 2, Nils REIMS 1,
More informationUvA-DARE (Digital Academic Repository) Motion compensation for 4D PET/CT Kruis, M.F. Link to publication
UvA-DARE (Digital Academic Repository) Motion compensation for 4D PET/CT Kruis, M.F. Link to publication Citation for published version (APA): Kruis, M. F. (2014). Motion compensation for 4D PET/CT General
More informationImpact of X-ray Scatter When Using CT-based Attenuation Correction in PET: A Monte Carlo Investigation
26 IEEE Nuclear Science Symposium Conference Record M6-349 Impact of X-ray Scatter When Using CT-based Attenuation Correction in PET: A Monte Carlo Investigation Habib Zaidi, Senior Member, IEEE and Mohammad
More informationCOUNT RATE AND SPATIAL RESOLUTION PERFORMANCE OF A 3-DIMENSIONAL DEDICATED POSITRON EMISSION TOMOGRAPHY (PET) SCANNER
COUNT RATE AND SPATIAL RESOLUTION PERFORMANCE OF A 3-DIMENSIONAL DEDICATED POSITRON EMISSION TOMOGRAPHY (PET) SCANNER By RAMI RIMON ABU-AITA A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY
More informationPHYSICS. Chapter 33 Lecture FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E RANDALL D. KNIGHT
PHYSICS FOR SCIENTISTS AND ENGINEERS A STRATEGIC APPROACH 4/E Chapter 33 Lecture RANDALL D. KNIGHT Chapter 33 Wave Optics IN THIS CHAPTER, you will learn about and apply the wave model of light. Slide
More informationMulti-slice CT Image Reconstruction Jiang Hsieh, Ph.D.
Multi-slice CT Image Reconstruction Jiang Hsieh, Ph.D. Applied Science Laboratory, GE Healthcare Technologies 1 Image Generation Reconstruction of images from projections. textbook reconstruction advanced
More information3/27/2012 WHY SPECT / CT? SPECT / CT Basic Principles. Advantages of SPECT. Advantages of CT. Dr John C. Dickson, Principal Physicist UCLH
3/27/212 Advantages of SPECT SPECT / CT Basic Principles Dr John C. Dickson, Principal Physicist UCLH Institute of Nuclear Medicine, University College London Hospitals and University College London john.dickson@uclh.nhs.uk
More informationWorkhorse ADCP Multi- Directional Wave Gauge Primer
Acoustic Doppler Solutions Workhorse ADCP Multi- Directional Wave Gauge Primer Brandon Strong October, 2000 Principles of ADCP Wave Measurement The basic principle behind wave the measurement, is that
More informationCHAPTER 11 NUCLEAR MEDICINE IMAGING DEVICES
CHAPTER 11 M.A. LODGE, E.C. FREY Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America 11.1. INTRODUCTION Imaging
More informationArion: a realistic projection simulator for optimizing laboratory and industrial micro-ct
Arion: a realistic projection simulator for optimizing laboratory and industrial micro-ct J. DHAENE* 1, E. PAUWELS 1, T. DE SCHRYVER 1, A. DE MUYNCK 1, M. DIERICK 1, L. VAN HOOREBEKE 1 1 UGCT Dept. Physics
More informationAX-PET : A novel PET concept with G-APD readout
AX-PET : A novel PET concept with G-APD readout Matthieu Heller CERN - PH/DT Marie Curie network MC-PAD Matthieu.heller@cern.ch On behalf of the AX-PET collaboration https://twiki.cern.ch/twiki/bin/view/axialpet
More informationLens Implementation on GATE for Optical Imaging Simulation
2017 IEEE NSS/MIC USA, Atlanta Lens Implementation on GATE for Optical Imaging Simulation Han Gyu Kang 1, Seong Hyun Song 1, Young Been Hang 1, Kyeong Min Kim 2, and Seong Jong Hong 1,3* 1.Dept. of Senior
More informationSUPPLEMENTARY INFORMATION
doi:10.1038/nature12009 Supplementary Figure 1. Experimental tilt series of 104 projections with a tilt range of ±72.6 and equal slope increments, acquired from a Pt nanoparticle using HAADF- STEM (energy:
More informationPHY 222 Lab 11 Interference and Diffraction Patterns Investigating interference and diffraction of light waves
PHY 222 Lab 11 Interference and Diffraction Patterns Investigating interference and diffraction of light waves Print Your Name Print Your Partners' Names Instructions April 17, 2015 Before lab, read the
More informationIndex. aliasing artifacts and noise in CT images, 200 measurement of projection data, nondiffracting
Index Algebraic equations solution by Kaczmarz method, 278 Algebraic reconstruction techniques, 283-84 sequential, 289, 293 simultaneous, 285-92 Algebraic techniques reconstruction algorithms, 275-96 Algorithms
More informationThe Design and Implementation of COSEM, an Iterative Algorithm for Fully 3-D Listmode Data
IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. 20, NO. 7, JULY 2001 633 The Design and Implementation of COSEM, an Iterative Algorithm for Fully 3-D Listmode Data Ron Levkovitz, Dmitry Falikman*, Michael Zibulevsky,
More informationMEDICAL IMAGE ANALYSIS
SECOND EDITION MEDICAL IMAGE ANALYSIS ATAM P. DHAWAN g, A B IEEE Engineering in Medicine and Biology Society, Sponsor IEEE Press Series in Biomedical Engineering Metin Akay, Series Editor +IEEE IEEE PRESS
More informationG3050 RadSearch: Radioactivity and Decommissioning Monitor
G3050 RadSearch: Radioactivity and Decommissioning Monitor 1. RadSearch overview RadSearch is a gamma radiation detection device based on medium-resolution gamma ray spectroscopy (MRGS). It is a real time,
More informationPerformance Evaluation of the Philips Gemini PET/CT System
Performance Evaluation of the Philips Gemini PET/CT System Rebecca Gregory, Mike Partridge, Maggie A. Flower Joint Department of Physics, Institute of Cancer Research, Royal Marsden HS Foundation Trust,
More informationHIGH RESOLUTION COMPUTED TOMOGRAPHY FOR METROLOGY
HIGH RESOLUTION COMPUTED TOMOGRAPHY FOR METROLOGY David K. Lehmann 1, Kathleen Brockdorf 1 and Dirk Neuber 2 1 phoenix x-ray Systems + Services Inc. St. Petersburg, FL, USA 2 phoenix x-ray Systems + Services
More informationModeling and Incorporation of System Response Functions in 3D Whole Body PET
Modeling and Incorporation of System Response Functions in 3D Whole Body PET Adam M. Alessio, Member IEEE, Paul E. Kinahan, Senior Member IEEE, and Thomas K. Lewellen, Senior Member IEEE University of
More informationWorkshop on Quantitative SPECT and PET Brain Studies January, 2013 PUCRS, Porto Alegre, Brasil Corrections in SPECT and PET
Workshop on Quantitative SPECT and PET Brain Studies 14-16 January, 2013 PUCRS, Porto Alegre, Brasil Corrections in SPECT and PET Físico João Alfredo Borges, Me. Corrections in SPECT and PET SPECT and
More informationMOHAMMAD MINHAZ AKRAM THE EFFECT OF SAMPLING IN HISTOGRAMMING AND ANALYTICAL RECONSTRUCTION OF 3D AX-PET DATA
MOHAMMAD MINHAZ AKRAM THE EFFECT OF SAMPLING IN HISTOGRAMMING AND ANALYTICAL RECONSTRUCTION OF 3D AX-PET DATA Master of Science Thesis Examiners: Prof. Ulla Ruotsalainen M.Sc. Uygar Tuna Examiners and
More informationUsing X-Ray Micro Tomography to assess the quality of Packaging Foil
Using X-Ray Micro Tomography to assess the quality of Packaging Foil Martin Koster 1, Gerard van Dalen 2, Robert Hoeve 3 1 Unilever Research 2 Unilever Research 3 Unilever Research, Olivier van Noortlaaan
More information