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Thien TC, Nemallapudi MV. Determination of lutetium density in LYSO crystals: methodology and PET detector applications. Phys Med Biol 2024; 69:075024. [PMID: 38529716 DOI: 10.1088/1361-6560/ad2e6e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 02/28/2024] [Indexed: 03/27/2024]
Abstract
Objective. Lutetium yttrium oxyorthosilicate (LYSO) scintillation crystals are used in positron emission tomography (PET) due to their high gamma attenuation, fair energy resolution, and fast scintillation decay time. The enduring presence of the176Lu isotope, characterized by a half-life of 37.9 billion years, imparts a consistent radiation background (BG) profile that depends on the geometry and composition attributes of the LYSO crystals.Approach. In this work, we proposed a methodology for estimating the composition of LYSO crystals in cases where the exact Lutetium composition remains unknown. The connection between BG spectrum intensity and intrinsic radioactivity enables precise estimation of Lutetium density in LYSO crystal samples. This methodology was initially applied to a well-characterized LYSO crystal sample, yielding results closely aligned with the known composition. The composition estimation approach was extended to several samples of undisclosed LYSO crystals, encompassing single crystal and crystal array configurations. Furthermore, we model the background spectrum observed in the LYSO-based detector and validate the observed spectra via simulations.Main results. The estimated Lutetium composition exhibited adequate consistency across different samples of the same LYSO material, with variations of less than 1%. The result of the proposed approach coupled with the simulation successfully models the background radiation spectra in various LYSO-based detector geometries.Significance. The implications of this work extend to the predictive assessment of system behaviors and the autonomous configuration parameters governing LYSO-based detectors.
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Affiliation(s)
- T C Thien
- Department of Physics, National Central University, Taiwan
- Institute of Physics, Academia Sinica, Taiwan
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Kalaitzidis P, Gustafsson J, Hindorf C, Ljungberg M. Validation of a computational chain from PET Monte Carlo simulations to reconstructed images. Heliyon 2022; 8:e09316. [PMID: 35520630 PMCID: PMC9062260 DOI: 10.1016/j.heliyon.2022.e09316] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/25/2021] [Accepted: 04/19/2022] [Indexed: 01/21/2023] Open
Abstract
The study aimed to create a pipeline from Monte Carlo simulated projections of a Gate PET system to reconstructed images. The PET system was modelled after the GE Discovery MI (DMI) PET/CT, and the simulated projections were reconstructed with the stand-alone reconstruction software CASToR. Attenuation correction, normalisation calibration, random estimation, and scatter estimation for the simulations were computed with in-house programs. The pipeline was compared in both projection and image space with data acquired on a clinical DMI and reconstructed with GE's off-line PET reconstruction software (PET Toolbox) and CASToR. The simulated and measured data were compared for the number of prompt coincidences, scatter fraction, contrast recovery coefficient (CRC), signal-to-noise ratio (SNR), background variability, residual lung error, and image profiles. A slight discrepancy was noted in the projection space, but good agreements were generally achieved in image space between simulated and measured data. The CRC was found to be 81 % for Gate – CASToR, 84 % for GE – CASToR, and 84 % for GE - PET Toolbox for the largest sphere of the NEMA image quality (IQ) phantom, and the SNR was found to be 98 for Gate – CASToR, 91 for GE – CASToR, and 93 for GE – PET Toolbox. Profiles drawn over the spheres for the NEMA IQ phantom and the Data Spectrum (DS) phantom show a good match between measurement and simulation. The results indicate feasibility to utilise the pipeline as a tool for off-line simulation-based studies. A complete pipeline introduces possibilities to study the impact of single parameters in the whole chain from simulation to reconstructed images.
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Affiliation(s)
- Philip Kalaitzidis
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden
- Corresponding author.
| | | | - Cecilia Hindorf
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Solna, Stockholm, Sweden
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Antonecchia E, Bäcker M, Cafolla D, Ciardiello M, Kühl C, Pagnani G, Wang J, Wang S, Zhou F, D'Ascenzo N, Gialanella L, Pisante M, Rose G, Xie Q. Design Study of a Novel Positron Emission Tomography System for Plant Imaging. FRONTIERS IN PLANT SCIENCE 2022; 12:736221. [PMID: 35116047 PMCID: PMC8805640 DOI: 10.3389/fpls.2021.736221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Positron Emission Tomography is a non-disruptive and high-sensitive digital imaging technique which allows to measure in-vivo and non invasively the changes of metabolic and transport mechanisms in plants. When it comes to the early assessment of stress-induced alterations of plant functions, plant PET has the potential of a major breakthrough. The development of dedicated plant PET systems faces a series of technological and experimental difficulties, which make conventional clinical and preclinical PET systems not fully suitable to agronomy. First, the functional and metabolic mechanisms of plants depend on environmental conditions, which can be controlled during the experiment if the scanner is transported into the growing chamber. Second, plants need to be imaged vertically, thus requiring a proper Field Of View. Third, the transverse Field of View needs to adapt to the different plant shapes, according to the species and the experimental protocols. In this paper, we perform a simulation study, proposing a novel design of dedicated plant PET scanners specifically conceived to address these agronomic issues. We estimate their expected sensitivity, count rate performance and spatial resolution, and we identify these specific features, which need to be investigated when realizing a plant PET scanner. Finally, we propose a novel approach to the measurement and verification of the performance of plant PET systems, including the design of dedicated plant phantoms, in order to provide a standard evaluation procedure for this emerging digital imaging agronomic technology.
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Affiliation(s)
- Emanuele Antonecchia
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- Istituto Neurologico Mediterraneo, NEUROMED I.R.C.C.S, Pozzilli, Italy
| | - Markus Bäcker
- Institute for Medical Engineering and Research Campus STIMULATE, University of Magdeburg, Magdeburg, Germany
| | - Daniele Cafolla
- Istituto Neurologico Mediterraneo, NEUROMED I.R.C.C.S, Pozzilli, Italy
| | | | - Charlotte Kühl
- Institute for Medical Engineering and Research Campus STIMULATE, University of Magdeburg, Magdeburg, Germany
| | - Giancarlo Pagnani
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
| | - Jiale Wang
- School of Information and Communication Engineering, University of Electronics Science and Technology of China, Chengdu, China
- Yangtze Delta Region Institute of University of Science and Technology of China, Quzhou, China
| | - Shuai Wang
- School of Information and Communication Engineering, University of Electronics Science and Technology of China, Chengdu, China
- Yangtze Delta Region Institute of University of Science and Technology of China, Quzhou, China
| | - Feng Zhou
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Nicola D'Ascenzo
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- Istituto Neurologico Mediterraneo, NEUROMED I.R.C.C.S, Pozzilli, Italy
| | - Lucio Gialanella
- Department of Mathematics and Physics, University of Campania L. Vanvitelli, Caserta, Italy
| | - Michele Pisante
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
| | - Georg Rose
- Institute for Medical Engineering and Research Campus STIMULATE, University of Magdeburg, Magdeburg, Germany
| | - Qingguo Xie
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- Istituto Neurologico Mediterraneo, NEUROMED I.R.C.C.S, Pozzilli, Italy
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei, China
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Ko K, Choi H, Yi Y, Kim W, Kim J, Hwang J, Ko E, Cho G. Discrete Convolution-Based Energy Spectrum Configuring Method for the Analysis of the Intrinsic Radiation of 176Lu. SENSORS 2021; 21:s21217040. [PMID: 34770347 PMCID: PMC8587293 DOI: 10.3390/s21217040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/15/2021] [Accepted: 10/21/2021] [Indexed: 11/16/2022]
Abstract
There has been considerable interest in inorganic scintillators based on lutetium due to their favorable physical properties. Despite their advantages, lutetium-based scintillators could face issues because of the natural occurring radioisotope of 176Lu that is contained in natural lutetium. In order to mitigate its potential shortcomings, previous works have studied to understand the energy spectrum of the intrinsic radiation of 176Lu (IRL). However, few studies have focused on the various principal types of photon interactions with matter; in other words, only the full-energy peak according to the photoelectric effect or internal conversion have been considered for understanding the energy spectrum of IRL. Thus, the approach we have used in this study considers other principal types of photon interactions by convoluting each energy spectrum with combinations for generating the spectrum of the intrinsic radiation of 176Lu. From the results, we confirm that the method provides good agreement with the experiment. A significant contribution of this study is the provision of a new approach to process energy spectra induced by mutually independent radiation interactions as a single spectrum.
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Affiliation(s)
- Kilyoung Ko
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (K.K.); (H.C.); (W.K.); (J.K.); (J.H.); (E.K.)
| | - Hyunwoong Choi
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (K.K.); (H.C.); (W.K.); (J.K.); (J.H.); (E.K.)
| | - Yongsun Yi
- Department of Nuclear Engineering, Khalifa University of Science Technology and Research, Abu Dhabi P.O. Box 127788, United Arab Emirates;
| | - Wonku Kim
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (K.K.); (H.C.); (W.K.); (J.K.); (J.H.); (E.K.)
| | - Junhyeok Kim
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (K.K.); (H.C.); (W.K.); (J.K.); (J.H.); (E.K.)
| | - Jisung Hwang
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (K.K.); (H.C.); (W.K.); (J.K.); (J.H.); (E.K.)
| | - Eunbie Ko
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (K.K.); (H.C.); (W.K.); (J.K.); (J.H.); (E.K.)
| | - Gyuseong Cho
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (K.K.); (H.C.); (W.K.); (J.K.); (J.H.); (E.K.)
- Correspondence:
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Domínguez-Jiménez DY, Alva-Sánchez H. Energy spectra due to the intrinsic radiation of LYSO/LSO scintillators for a wide range of crystal sizes. Med Phys 2021; 48:1596-1607. [PMID: 33475160 DOI: 10.1002/mp.14729] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/22/2020] [Accepted: 12/21/2020] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Most detectors in current positron emission tomography (PET) scanners and prototypes use lutetium oxyorthosilicate (LSO) or lutetium yttrium oxyorthosilicate (LYSO) scintillators. The aim of this work is to provide a complete set of background energy spectra, due to the scintillator intrinsic radioactivity, for a wide range of crystal sizes. METHODS An analytical model, developed and validated in a previous work, was used to obtain the background energy spectra of square base cuboids of different dimensions. The model uses the photon absorption probabilities of the three gamma rays (88, 202, and 307 keV) emitted following the beta decay of 176 Lu to 176 Hf excited states. These probabilities were obtained for each crystal size considered in this work from Monte Carlo simulations using the PENELOPE code. The probabilities are then used to normalize and shift the beta spectrum to the corresponding energy value of the simultaneous detection of one, two, or three gamma rays in the scintillator. The simulated cuboids had side lengths of 5, 10, 20, 30, 40, 50, and 60 mm and crystal thickness T = 2.5, 5, 10, 15, and 20 mm. From these results a complete set of energy spectra, including intermediate dimensions, were obtained. In addition, LYSO and LSO were compared in terms of their analytical background energy spectra for two crystal sizes. The analytical spectra were convolved using a variable Gaussian kernel to account for the energy resolution of a typical detector. A parameterization of the photon absorption probabilities for each gamma ray energy as a function of the cuboid volume to surface area ratio was obtained. RESULTS A data set of L(Y)SO background energy spectra was obtained and is available for the reader as 2D histograms. The model accurately predicts the structure of the energy spectra including the relative peak and valley intensities. The data allow visualizing how the structure evolves with increasing crystal length and thickness. Lutetium yttrium oxyorthosilicate and LSO present very similar background energy spectra for the range of sizes studied in this work and therefore the data generated can be confidently used for both scintillator materials. The filtered spectra showed a variable shift in the main peaks, depending on crystal size, alerting that to achieve a correct detector calibration using the background spectrum is not straight forward and requires precise data analysis and measurements. In addition, we found that square base L(Y)SO cuboids with same volume to surface area ratio have background spectra with the same structure. CONCLUSIONS We present the energy spectra of L(Y)SO crystal of different sizes which will be very useful for industry and research groups developing and simulating detectors for positron imaging applications in terms of calibration, quality assurance, crystal maps, detector fine gain tuning, background reduction and other applications using the long-lived 176 Lu source. We analyzed the data produced in this work and found that crystal cuboids with equal volume to surface area ratio produce the same background energy spectra, a conclusion that simplifies its calculation and clarifies why the same energy spectrum is observed under different experimental setups.
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Affiliation(s)
| | - Héctor Alva-Sánchez
- Instituto de Física, Universidad Nacional Autónoma de México, A.P. 20-364, Mexico City, 01000, Mexico
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Lara-Camacho VM, Hernández-Acevedo EM, Alva-Sánchez H, Murrieta-Rodríguez T, Martínez-Dávalos A, Moranchel M, Rodríguez-Villafuerte M. Experimental validation of the ANTS2 code for modelling optical photon transport in monolithic LYSO crystals. Phys Med 2021; 81:215-226. [PMID: 33482439 DOI: 10.1016/j.ejmp.2020.12.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/11/2020] [Accepted: 12/31/2020] [Indexed: 11/16/2022] Open
Abstract
In this work the scintillation energy spectra originating from the background radioactivity from polished monolithic lutetium yttrium oxyorthosilicate coupled to position-sensitive silicon photomultipliers (SiPM) was studied using the open source Monte Carlo simulation package ANTS2. Two crystal sizes, fully and partially covering the photosensor area, three surface crystal wrappings (black, specular or diffuse) and the full signal formation process in the photosensor were considered. The simulation results were validated with experimental data acquired under the same geometric and detector operating conditions. In all cases ANTS2 simulated spectra have very good agreement with experimental results, reproducing the expected shape, with correct onset and end at 88 and 1190 keV, respectively, as well as sharp edges at the reference energies of 88, 88 + 202, 88 + 307 and 88 + 202 + 307 keV. The normalized root-mean square error between simulated and measured spectra varied between 4.3% and 10.4%.
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Affiliation(s)
- Víctor Manuel Lara-Camacho
- Instituto de Física, Universidad Nacional Autónoma de México, A. P. 20-364, Ciudad de México 01000, Mexico; Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ciudad de México 07738, Mexico
| | | | - Héctor Alva-Sánchez
- Instituto de Física, Universidad Nacional Autónoma de México, A. P. 20-364, Ciudad de México 01000, Mexico
| | - Tirso Murrieta-Rodríguez
- Instituto de Física, Universidad Nacional Autónoma de México, A. P. 20-364, Ciudad de México 01000, Mexico
| | - Arnulfo Martínez-Dávalos
- Instituto de Física, Universidad Nacional Autónoma de México, A. P. 20-364, Ciudad de México 01000, Mexico
| | - Mario Moranchel
- Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ciudad de México 07738, Mexico
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