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Richtsmeier D, Rodesch PA, Iniewski K, Bazalova-Carter M. Material decomposition with a prototype photon-counting detector CT system: expanding a stoichiometric dual-energy CT method via energy bin optimization and K-edge imaging. Phys Med Biol 2024; 69:055001. [PMID: 38306974 DOI: 10.1088/1361-6560/ad25c8] [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: 03/30/2023] [Accepted: 02/01/2024] [Indexed: 02/04/2024]
Abstract
Objective.Computed tomography (CT) has advanced since its inception, with breakthroughs such as dual-energy CT (DECT), which extracts additional information by acquiring two sets of data at different energies. As high-flux photon-counting detectors (PCDs) become available, PCD-CT is also becoming a reality. PCD-CT can acquire multi-energy data sets in a single scan by spectrally binning the incident x-ray beam. With this, K-edge imaging becomes possible, allowing high atomic number (high-Z) contrast materials to be distinguished and quantified. In this study, we demonstrated that DECT methods can be converted to PCD-CT systems by extending the method of Bourqueet al(2014). We optimized the energy bins of the PCD for this purpose and expanded the capabilities by employing K-edge subtraction imaging to separate a high-atomic number contrast material.Approach.The method decomposes materials into their effective atomic number (Zeff) and electron density relative to water (ρe). The model was calibrated and evaluated using tissue-equivalent materials from the RMI Gammex electron density phantom with knownρevalues and elemental compositions. TheoreticalZeffvalues were found for the appropriate energy ranges using the elemental composition of the materials.Zeffvaried slightly with energy but was considered a systematic error. Anex vivobovine tissue sample was decomposed to evaluate the model further and was injected with gold chloride to demonstrate the separation of a K-edge contrast agent.Main results.The mean root mean squared percent errors on the extractedZeffandρefor PCD-CT were 0.76% and 0.72%, respectively and 1.77% and 1.98% for DECT. The tissue types in theex vivobovine tissue sample were also correctly identified after decomposition. Additionally, gold chloride was separated from theex vivotissue sample with K-edge imaging.Significance.PCD-CT offers the ability to employ DECT material decomposition methods, along with providing additional capabilities such as K-edge imaging.
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Affiliation(s)
- Devon Richtsmeier
- Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Pierre-Antoine Rodesch
- Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Kris Iniewski
- Redlen Techologies, 1763 Sean Heights, Saanichton, British Columbia V8M 1X6, Canada
| | - Magdalena Bazalova-Carter
- Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
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Kamal I, Razak HRA, Abdul Karim MK, Mashohor S, Liew JYC, Low YJ, Zaaba NA, Norkhairunnisa M, Rafi NASM. Mechanical and Imaging Properties of a Clinical-Grade Kidney Phantom Based on Polydimethylsiloxane and Elastomer. Polymers (Basel) 2022; 14:polym14030535. [PMID: 35160523 PMCID: PMC8840541 DOI: 10.3390/polym14030535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 02/01/2023] Open
Abstract
Medical imaging phantoms are considered critical in mimicking the properties of human tissue for calibration, training, surgical planning, and simulation purposes. Hence, the stability and accuracy of the imaging phantom play a significant role in diagnostic imaging. This study aimed to evaluate the influence of hydrogen silicone (HS) and water (H2O) on the compression strength, radiation attenuation properties, and computed tomography (CT) number of the blended Polydimethylsiloxane (PDMS) samples, and to verify the best material to simulate kidney tissue. Four samples with different compositions were studied, including samples S1, S2, S3, and S4, which consisted of PDMS 100%, HS/PDMS 20:80, H2O/PDMS 20:80, and HS/H2O/PDMS 20:40:40, respectively. The stability of the samples was assessed using compression testing, and the attenuation properties of sample S2 were evaluated. The effective atomic number of S2 showed a similar pattern to the human kidney tissue at 1.50 × 10−1 to 1 MeV. With the use of a 120 kVp X-ray beam, the CT number quantified for S2, as well measured 40 HU, and had the highest contrast-to-noise ratio (CNR) value. Therefore, the S2 sample formulation exhibited the potential to mimic the human kidney, as it has a similar dynamic and is higher in terms of stability as a medical phantom.
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Affiliation(s)
- Izdihar Kamal
- Department of Medical Imaging, School of Health Sciences, KPJ Healthcare University College, Nilai 71800, Negeri Sembilan, Malaysia; (I.K.); (N.A.Z.); (N.A.S.M.R.)
- Department of Physics, Faculty of Science, University of Putra Malaysia, Seri Kembangan 43400, Selangor, Malaysia; (J.Y.C.L.); (Y.J.L.)
| | - Hairil Rashmizal Abdul Razak
- Department of Radiology, Faculty of Medicine and Health Sciences, University of Putra Malaysia, Seri Kembangan 43400, Selangor, Malaysia;
| | - Muhammad Khalis Abdul Karim
- Department of Physics, Faculty of Science, University of Putra Malaysia, Seri Kembangan 43400, Selangor, Malaysia; (J.Y.C.L.); (Y.J.L.)
- Correspondence: ; Tel.: +60-192140612
| | - Syamsiah Mashohor
- Department of Computer and Communication Systems, Faculty of Engineering, University of Putra Malaysia, Seri Kembangan 43400, Selangor, Malaysia;
| | - Josephine Ying Chyi Liew
- Department of Physics, Faculty of Science, University of Putra Malaysia, Seri Kembangan 43400, Selangor, Malaysia; (J.Y.C.L.); (Y.J.L.)
| | - Yiin Jian Low
- Department of Physics, Faculty of Science, University of Putra Malaysia, Seri Kembangan 43400, Selangor, Malaysia; (J.Y.C.L.); (Y.J.L.)
| | - Nur Atiqah Zaaba
- Department of Medical Imaging, School of Health Sciences, KPJ Healthcare University College, Nilai 71800, Negeri Sembilan, Malaysia; (I.K.); (N.A.Z.); (N.A.S.M.R.)
- Diagnostic Imaging Services, KPJ Seremban Specialist Hospital, Lot 6219&6220, Jalan Toman 1 Kemayan Square, Seremban 70200, Negeri Sembilan, Malaysia
| | - Mazlan Norkhairunnisa
- Institute of Advanced Technology, University of Putra Malaysia, Seri Kembangan 43400, Selangor, Malaysia;
| | - Nur Athirah Syima Mohd Rafi
- Department of Medical Imaging, School of Health Sciences, KPJ Healthcare University College, Nilai 71800, Negeri Sembilan, Malaysia; (I.K.); (N.A.Z.); (N.A.S.M.R.)
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Al-Balushi MA, Ahmed NM, Zyoud SH, Mohammed Ali MK, Akhdar H, Aldaghri OA, Ibnaouf KH. Ionization Radiation Shielding Effectiveness of Lead Acetate, Lead Nitrate, and Bismuth Nitrate-Doped Zinc Oxide Nanorods Thin Films: A Comparative Evaluation. MATERIALS 2021; 15:ma15010003. [PMID: 35009152 PMCID: PMC8746144 DOI: 10.3390/ma15010003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/12/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022]
Abstract
The fabrication of Nano-based shielding materials is an advancing research area in material sciences and nanotechnology. Although bulky lead-based products remain the primary choice for radiation protection, environmental disadvantages and high toxicity limit their potentials, necessitating less costly, compatible, eco-friendly, and light-weight alternatives. The theme of the presented investigation is to compare the ionization radiation shielding potentialities of the lead acetate (LA), lead nitrate (LN), and bismuth nitrate (BN)-doped zinc oxide nanorods-based thin films (ZONRs-TFs) produced via the chemical bath deposition (CBD) technique. The impact of the selected materials' doping content on morphological and structural properties of ZONRs-TF was investigated. The X-ray diffractometer (XRD) analyses of both undoped and doped TFs revealed the existence of hexagonal quartzite crystal structures. The composition analysis by energy dispersive (EDX) detected the corrected elemental compositions of the deposited films. Field emission scanning electronic microscope (FESEM) images of the TFs showed highly porous and irregular surface morphologies of the randomly aligned NRs with cracks and voids. The undoped and 2 wt.% BN-doped TFs showed the smallest and largest grain size of 10.44 nm and 38.98 nm, respectively. The linear attenuation coefficient (µ) values of all the optimally doped ZONRs-TFs measured against the X-ray photon irradiation disclosed their excrement shielding potency. The measured µ values of the ZONRs-TFs displayed the trend of 1 wt.% LA-doped TF > 1 wt.% LN-doped TF > 3 wt.% BN-doped TF > undoped TFs). The values of μ of the ZONRs-TFs can be customized by adjusting the doping contents, which in turn controls the thickness and morphology of the TFs. In short, the proposed new types of the LA-, LN- and BN-doped ZONRs-TFs may contribute towards the development of the prospective ionization radiation shielding materials.
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Affiliation(s)
| | - Naser M. Ahmed
- School of Physics, Universiti Sains Malaysia (USM), Gelugor 11800, Malaysia; (M.A.A.-B.); (S.H.Z.)
- Correspondence: (N.M.A.); (H.A.)
| | - Samer H. Zyoud
- School of Physics, Universiti Sains Malaysia (USM), Gelugor 11800, Malaysia; (M.A.A.-B.); (S.H.Z.)
- Department of Mathematics and Sciences, Ajman University, Ajman P.O. Box 346, United Arab Emirates
- Nonlinear Dynamics Research Center (NDRC), Ajman University, Ajman P.O. Box 346, United Arab Emirates
| | - Mohammed Khalil Mohammed Ali
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia; (M.K.M.A.); (O.A.A.); (K.H.I.)
| | - Hanan Akhdar
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia; (M.K.M.A.); (O.A.A.); (K.H.I.)
- Correspondence: (N.M.A.); (H.A.)
| | - Osamah A. Aldaghri
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia; (M.K.M.A.); (O.A.A.); (K.H.I.)
| | - Khalid Hassan Ibnaouf
- Physics Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia; (M.K.M.A.); (O.A.A.); (K.H.I.)
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Manjunatha M, Umesh T. Effective atomic number of some rare earth compounds determined by the study of external bremsstrahlung. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2019. [DOI: 10.1016/j.jrras.2015.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- M.V. Manjunatha
- Department of Studies in Physics, University of Mysore, Manasagangothri, Mysore, Karnataka, 570006, India
| | - T.K. Umesh
- Department of Studies in Physics, University of Mysore, Manasagangothri, Mysore, Karnataka, 570006, India
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5
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Evaluation of radiological data of some saturated fatty acids using gamma ray spectrometry. Radiat Phys Chem Oxf Engl 1993 2016. [DOI: 10.1016/j.radphyschem.2015.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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6
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Measurements of mass attenuation coefficient, effective atomic number and electron density of some amino acids. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2013.12.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Bourque AE, Carrier JF, Bouchard H. A stoichiometric calibration method for dual energy computed tomography. Phys Med Biol 2014; 59:2059-88. [DOI: 10.1088/0031-9155/59/8/2059] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ghosh S, Das MK. Attenuation coefficients and absorbed gamma radiation energy of different varieties of potato, mango and prawn at different storage time and physiological condition. Food Chem 2014; 145:694-700. [PMID: 24128533 DOI: 10.1016/j.foodchem.2013.08.080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/18/2013] [Accepted: 08/19/2013] [Indexed: 11/19/2022]
Abstract
Attenuation coefficients of different varieties of gamma irradiated potato (Kufri Chandramukhi, Kufri Jyoti, and Kufri Sindhuri), mango (Himsagar, Langra, Dashehri and Fazli) and prawn (Tiger prawn and Fresh water prawn) of different storage time and physiological stages were determined. After six months storage attenuation coefficient of Kufri Chandramukhi was decreased by 30.8% with decrease of density and moisture content. Decreasing trend of attenuation coefficient during storage was more prominent (almost 50%) in other two varieties of potato. On the other hand in all four varieties, unripe mango consisted of significantly less (p ≤ 0.05) attenuation coefficient (around 11-14%) than the ripe one due to changes in physiological properties and density. Different varieties of prawn had different attenuation coefficients due to subtle differences in their proximate composition. Due to having different attenuation coefficients, different food components, even different varieties of same food component absorbed different gamma radiation energy though exposed to same radiation dose.
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Affiliation(s)
- Sayanti Ghosh
- Department of Food Technology and Biochemical Engineering, Jadavpur University, Kolkata 700032, India.
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Studies on mass attenuation coefficient, effective atomic number and electron density of some amino acids in the energy range 0.122–1.330MeV. Radiat Phys Chem Oxf Engl 1993 2013. [DOI: 10.1016/j.radphyschem.2013.07.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
A nonlinear model for the x-ray linear attenuation coefficient μ is employed for dual energy x-ray analysis (DEXA). Nonlinear simultaneous equations formed by μ and energy dependent model parameters are solved for the electron density N(e) and fourth compositional ratio R(4) which has the same 'units' as the atomic number. Computed tomography data was acquired at 20-35 keV using bending magnet synchrotron radiation, a double crystal monochromator, a rotation stage and an area detector. Test objects contained liquid samples as mixtures of ethanol, water and salt solutions with known density and composition. Various noise sources are identified and give μ uncertainties of 1-2%. A fan beam geometry allowed the detection of forward scattered radiation with measured μ being 6% lower than expectations for a narrow beam. Energy dependent model parameters were obtained by solving linear simultaneous equations formed by μ and material parameters based upon N(e) and R(4). DEXA accuracy was studied as a function of photon energy and sample composition. Propagation of errors analysis identifies the importance of the fractional compositional cross-products whose difference at the two beam energies should exceed 0.1, requiring 10 keV or more separation. For a reasonable approximation for the adjustable model parameters, the mean difference between the DEXA solution and true values (ΔN(e), ΔR(4)) are (1.0%, 0.5%) for soft tissue and (1.5%, 0.8%) for bone like samples.
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Affiliation(s)
- S M Midgley
- School of Physics, Monash University, Clayton, VIC 3080, Australia.
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Beaulieu L, Carlsson Tedgren A, Carrier JF, Davis SD, Mourtada F, Rivard MJ, Thomson RM, Verhaegen F, Wareing TA, Williamson JF. Report of the Task Group 186 on model-based dose calculation methods in brachytherapy beyond the TG-43 formalism: Current status and recommendations for clinical implementation. Med Phys 2012; 39:6208-36. [PMID: 23039658 DOI: 10.1118/1.4747264] [Citation(s) in RCA: 345] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Luc Beaulieu
- Département de Radio-Oncologie, Centre hospitalier universitaire de Québec, Québec, Québec G1R 2J6, Canada.
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Okunade AA. Parameters and computer software for the evaluation of mass attenuation and mass energy-absorption coefficients for body tissues and substitutes. J Med Phys 2007; 32:124-32. [PMID: 21157532 PMCID: PMC3000503 DOI: 10.4103/0971-6203.35725] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Accepted: 06/19/2007] [Indexed: 11/25/2022] Open
Abstract
The mass attenuation and energy-absorption coefficients (radiation interaction data), which are widely used in the shielding and dosimetry of X-rays used for medical diagnostic and orthovoltage therapeutic procedures, are strongly dependent on the energy of photons, elements and percentage by weight of elements in body tissues and substitutes. Significant disparities exist in the values of percentage by weight of elements reported in literature for body tissues and substitutes for individuals of different ages, genders and states of health. Often, interested parties are in need of these radiation interaction data for body tissues or substitutes with percentage by weight of elements and intermediate energies that are not tabulated in literature. To provide for the use of more precise values of these radiation interaction data, parameters and computer programs, MUA_T and MUEN_T are presented for the computation of mass attenuation and energy-absorption coefficients for body tissues and substitutes of arbitrary percentage-by-weight elemental composition and photon energy ranging between 1 keV (or k-edge) and 400 keV. Results are presented, which show that the values of mass attenuation and energy-absorption coefficients obtained from computer programs are in good agreement with those reported in literature.
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Affiliation(s)
- Akintunde A Okunade
- Department of Physics, Obafemi Awolowo University 220005, ILE-IFE Osun State, Nigeria
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Williamson JF, Li S, Devic S, Whiting BR, Lerma FA. On two-parameter models of photon cross sections: Application to dual-energy CT imaging. Med Phys 2006; 33:4115-29. [PMID: 17153391 DOI: 10.1118/1.2349688] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The goal of this study is to evaluate the theoretically achievable accuracy in estimating photon cross sections at low energies (20-1000 keV) from idealized dual-energy x-ray computed tomography (CT) images. Cross-section estimation from dual-energy measurements requires a model that can accurately represent photon cross sections of any biological material as a function of energy by specifying only two characteristic parameters of the underlying material, e.g., effective atomic number and density. This paper evaluates the accuracy of two commonly used two-parameter cross-section models for postprocessing idealized measurements derived from dual-energy CT images. The parametric fit model (PFM) accounts for electron-binding effects and photoelectric absorption by power functions in atomic number and energy and scattering by the Klein-Nishina cross section. The basis-vector model (BVM) assumes that attenuation coefficients of any biological substance can be approximated by a linear combination of mass attenuation coefficients of two dissimilar basis substances. Both PFM and BVM were fit to a modern cross-section library for a range of elements and mixtures representative of naturally occurring biological materials (Z = 2-20). The PFM model, in conjunction with the effective atomic number approximation, yields estimated the total linear cross-section estimates with mean absolute and maximum error ranges of 0.6%-2.2% and 1%-6%, respectively. The corresponding error ranges for BVM estimates were 0.02%-0.15% and 0.1%-0.5%. However, for photoelectric absorption frequency, the PFM absolute mean and maximum errors were 10.8%-22.4% and 29%-50%, compared with corresponding BVM errors of 0.4%-11.3% and 0.5%-17.0%, respectively. Both models were found to exhibit similar sensitivities to image-intensity measurement uncertainties. Of the two models, BVM is the most promising approach for realizing dual-energy CT cross-section measurement.
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Affiliation(s)
- Jeffrey F Williamson
- Department of Radiation Oncology, Virginia Commenwealth University, Richmond, Virginia 23284, USA.
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Midgley SM. Materials analysis using x-ray linear attenuation coefficient measurements at four photon energies. Phys Med Biol 2005; 50:4139-57. [PMID: 16177536 DOI: 10.1088/0031-9155/50/17/016] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The analytical properties of an accurate parameterization scheme for the x-ray linear attenuation coefficient are examined. The parameterization utilizes an additive combination of N compositional- and energy-dependent coefficients. The former were derived from a parameterization of elemental cross-sections using a polynomial in atomic number. The compositional-dependent coefficients are referred to as the mixture parameters, representing the electron density and higher order statistical moments describing elemental distribution. Additivity is an important property of the parameterization, allowing measured x-ray linear attenuation coefficients to be written as linear simultaneous equations, and then solved for the unknown coefficients. The energy-dependent coefficients can be determined by calibration from measurements with materials of known composition. The inverse problem may be utilized for materials analysis, whereby the simultaneous equations represent multi-energy linear attenuation coefficient measurements, and are solved for the mixture parameters. For in vivo studies, the choice of measurement energies is restricted to the diagnostic region (approximately 20 keV to 150 keV), where the parameterization requires N >or= 4 energies. We identify a mathematical pathology that must be overcome in order to solve the inverse problem in this energy regime. An iterative inversion strategy is presented for materials analysis using four or more measurements, and then tested against real data obtained at energies 32 keV to 66 keV. The results demonstrate that it is possible to recover the electron density to within +/-4% and fourth mixture parameter. It is also a key finding that the second and third mixture parameters cannot be recovered, as they are of minor importance in the parameterization at diagnostic x-ray energies.
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Affiliation(s)
- S M Midgley
- School of Physics, Monash University, Clayton, VIC 3800, Australia.
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