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Howell N, Middleton RJ, Sierro F, Fraser BH, Wyatt NA, Chacon A, Bambery KR, Livio E, Dobie C, Bevitt JJ, Davies J, Dosseto A, Franklin DR, Garbe U, Guatelli S, Hirayama R, Matsufuji N, Mohammadi A, Mutimer K, Rendina LM, Rosenfeld AB, Safavi-Naeini M. Neutron Capture Enhances Dose and Reduces Cancer Cell Viability in and out of Beam During Helium and Carbon Ion Therapy. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00368-7. [PMID: 38479560 DOI: 10.1016/j.ijrobp.2024.02.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 02/10/2024] [Accepted: 02/24/2024] [Indexed: 04/14/2024]
Abstract
PURPOSE Neutron capture enhanced particle therapy (NCEPT) is a proposed augmentation of charged particle therapy that exploits thermal neutrons generated internally, within the treatment volume via nuclear fragmentation, to deliver a biochemically targeted radiation dose to cancer cells. This work is the first experimental demonstration of NCEPT, performed using both carbon and helium ion beams with 2 different targeted neutron capture agents (NCAs). METHODS AND MATERIALS Human glioblastoma cells (T98G) were irradiated by carbon and helium ion beams in the presence of NCAs [10B]-BPA and [157Gd]-DOTA-TPP. Cells were positioned within a polymethyl methacrylate phantom either laterally adjacent to or within a 100 × 100 × 60 mm spread out Bragg peak (SOBP). The effect of NCAs and location relative to the SOBP on the cells was measured by cell growth and survival assays in 6 independent experiments. Neutron fluence within the phantom was characterized by quantifying the neutron activation of gold foil. RESULTS Cells placed inside the treatment volume reached 10% survival by 2 Gy of carbon or 2 to 3 Gy of helium in the presence of NCAs compared with 5 Gy of carbon and 7 Gy of helium with no NCA. Cells placed adjacent to the treatment volume showed a dose-dependent decrease in cell growth when treated with NCAs, reaching 10% survival by 6 Gy of carbon or helium (to the treatment volume), compared with no detectable effect on cells without NCA. The mean thermal neutron fluence at the center of the SOBP was approximately 2.2 × 109 n/cm2/Gy (relative biological effectiveness) for the carbon beam and 5.8 × 109 n/cm2/Gy (relative biological effectiveness) for the helium beam and gradually decreased in all directions. CONCLUSIONS The addition of NCAs to cancer cells during carbon and helium beam irradiation has a measurable effect on cell survival and growth in vitro. Through the capture of internally generated neutrons, NCEPT introduces the concept of a biochemically targeted radiation dose to charged particle therapy. NCEPT enables the established pharmaceuticals and concepts of neutron capture therapy to be applied to a wider range of deeply situated and diffuse tumors, by targeting this dose to microinfiltrates and cells outside of defined treatment regions. These results also demonstrate the potential for NCEPT to provide an increased dose to tumor tissue within the treatment volume, with a reduction in radiation doses to off-target tissue.
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Affiliation(s)
- Nicholas Howell
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Ryan J Middleton
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Frederic Sierro
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Benjamin H Fraser
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Naomi A Wyatt
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Andrew Chacon
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Keith R Bambery
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Elle Livio
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Christopher Dobie
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Joseph J Bevitt
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Justin Davies
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Anthony Dosseto
- Wollongong Isotope Geochronology Laboratory, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia
| | - Daniel R Franklin
- School of Electrical and Data Engineering, University of Technology Sydney, Ultimo, Australia
| | - Ulf Garbe
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Susanna Guatelli
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Ryoichi Hirayama
- National Institutes for Quantum Sciences and Technology, Chiba, Japan
| | | | - Akram Mohammadi
- National Institutes for Quantum Sciences and Technology, Chiba, Japan
| | - Karl Mutimer
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Louis M Rendina
- School of Chemistry, The University of Sydney, Sydney, Australia; The University of Sydney Nano Institute, Sydney, Australia
| | - Anatoly B Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Mitra Safavi-Naeini
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia.
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Kielly M, Caracciolo A, Chacon A, Vohradsky J, Di Vita D, Hamato A, Tashima H, Franklin DR, Yamaya T, Rosenfeld A, Carminati M, Fiorini C, Guatelli S, Safavi-Naeini M. First experimental demonstration of real-time neutron capture discrimination in helium and carbon ion therapy. Sci Rep 2024; 14:2601. [PMID: 38297114 PMCID: PMC10831067 DOI: 10.1038/s41598-024-52162-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 01/15/2024] [Indexed: 02/02/2024] Open
Abstract
This work provides the first experimental proof of an increased neutron capture photon signal following the introduction of boron to a PMMA phantom during helium and carbon ion therapies in Neutron Capture Enhanced Particle Therapy (NCEPT). NCEPT leverages [Formula: see text]B neutron capture, leading to the emission of detectable 478 keV photons. Experiments were performed at the Heavy Ion Medical Accelerator in Chiba, Japan, with two Poly(methyl methacrylate) (PMMA) targets, one bearing a boron insert. The BeNEdiCTE gamma-ray detector measured an increase in the 478 keV signal of 45 ± 7% and 26 ± 2% for carbon and helium ion irradiation, respectively. Our Geant4 Monte Carlo simulation model, developed to investigate photon origins, found less than 30% of detected photons originated from the insert, while boron in the detector's circuit boards contributed over 65%. Further, the model investigated detector sensitivity, establishing its capability to record a 10% increase in 478 keV photon detection at a target [Formula: see text]B concentration of 500 ppm using spectral windowing alone, and 25% when combined with temporal windowing. The linear response extended to concentrations up to 20,000 ppm. The increase in the signal in all evaluated cases confirm the potential of the proposed detector design for neutron capture quantification in NCEPT.
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Affiliation(s)
- Marissa Kielly
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Anita Caracciolo
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Andrew Chacon
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia
| | - James Vohradsky
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Davide Di Vita
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Akram Hamato
- Imaging Physics Group, Department of Advanced Nuclear Medicine Sciences, National Institutes for Quantum Science and Technology (QST), Inage-ku, Chiba, Japan
| | - Hideaki Tashima
- Imaging Physics Group, Department of Advanced Nuclear Medicine Sciences, National Institutes for Quantum Science and Technology (QST), Inage-ku, Chiba, Japan
| | - Daniel R Franklin
- School of Electrical and Data Engineering, University of Technology Sydney, Sydney, Australia
| | - Taiga Yamaya
- Imaging Physics Group, Department of Advanced Nuclear Medicine Sciences, National Institutes for Quantum Science and Technology (QST), Inage-ku, Chiba, Japan
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Marco Carminati
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Carlo Fiorini
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Susanna Guatelli
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Mitra Safavi-Naeini
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia.
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Jakubowski K, Chacon A, Tran LT, Stopic A, Garbe U, Bevitt J, Olsen S, Franklin DR, Rosenfeld A, Guatelli S, Safavi-Naeini M. A Monte Carlo model of the Dingo thermal neutron imaging beamline. Sci Rep 2023; 13:17415. [PMID: 37833371 PMCID: PMC10575880 DOI: 10.1038/s41598-023-44035-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
In this study, we present a validated Geant4 Monte Carlo simulation model of the Dingo thermal neutron imaging beamline at the Australian Centre for Neutron Scattering. The model, constructed using CAD drawings of the entire beam transport path and shielding structures, is designed to precisely predict the in-beam neutron field at the position at the sample irradiation stage. The model's performance was assessed by comparing simulation results to various experimental measurements, including planar thermal neutron distribution obtained in-beam using gold foil activation and [Formula: see text]B[Formula: see text]C-coated microdosimeters and the out-of-beam neutron spectra measured with Bonner spheres. The simulation results demonstrated that the predicted neutron fluence at the field's centre is within 8.1% and 2.1% of the gold foil and [Formula: see text]B[Formula: see text]C-coated microdosimeter measurements, respectively. The logarithms of the ratios of average simulated to experimental fluences in the thermal (E[Formula: see text] 0.414 eV), epithermal (0.414 eV < E[Formula: see text] 11.7 keV) and fast (E[Formula: see text] 11.7 keV) spectral regions were approximately - 0.03 to + 0.1, - 0.2 to + 0.15, and - 0.4 to + 0.2, respectively. Furthermore, the predicted thermal, epithermal and fast neutron components in-beam at the sample stage position constituted approximately 18%, 64% and 18% of the total neutron fluence.
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Affiliation(s)
- Klaudiusz Jakubowski
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
- Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Andrew Chacon
- Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Linh T Tran
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Attila Stopic
- Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Ulf Garbe
- Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Joseph Bevitt
- Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Scott Olsen
- Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Daniel R Franklin
- School of Electrical and Data Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Susanna Guatelli
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Mitra Safavi-Naeini
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia.
- Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia.
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Rutherford H, Saha Turai R, Chacon A, Franklin DR, Mohammadi A, Tashima H, Yamaya T, Parodi K, Rosenfeld AB, Guatelli S, Safavi-Naeini M. An inception network for positron emission tomography based dose estimation in carbon ion therapy. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac88b2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 08/10/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. We aim to evaluate a method for estimating 1D physical dose deposition profiles in carbon ion therapy via analysis of dynamic PET images using a deep residual learning convolutional neural network (CNN). The method is validated using Monte Carlo simulations of 12C ion spread-out Bragg peak (SOBP) profiles, and demonstrated with an experimental PET image. Approach. A set of dose deposition and positron annihilation profiles for monoenergetic 12C ion pencil beams in PMMA are first generated using Monte Carlo simulations. From these, a set of random polyenergetic dose and positron annihilation profiles are synthesised and used to train the CNN. Performance is evaluated by generating a second set of simulated 12C ion SOBP profiles (one 116 mm SOBP profile and ten 60 mm SOBP profiles), and using the trained neural network to estimate the dose profile deposited by each beam and the position of the distal edge of the SOBP. Next, the same methods are used to evaluate the network using an experimental PET image, obtained after irradiating a PMMA phantom with a 12C ion beam at QST’s Heavy Ion Medical Accelerator in Chiba facility in Chiba, Japan. The performance of the CNN is compared to that of a recently published iterative technique using the same simulated and experimental 12C SOBP profiles. Main results. The CNN estimated the simulated dose profiles with a mean relative error (MRE) of 0.7% ± 1.0% and the distal edge position with an accuracy of 0.1 mm ± 0.2 mm, and estimate the dose delivered by the experimental 12C ion beam with a MRE of 3.7%, and the distal edge with an accuracy of 1.7 mm. Significance. The CNN was able to produce estimates of the dose distribution with comparable or improved accuracy and computational efficiency compared to the iterative method and other similar PET-based direct dose quantification techniques.
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Chacon A, Kielly M, Rutherford H, Franklin DR, Caracciolo A, Buonanno L, D'Adda I, Rosenfeld A, Guatelli S, Carminati M, Fiorini C, Safavi-Naeini M. Detection and discrimination of neutron capture events for NCEPT dose quantification. Sci Rep 2022; 12:5863. [PMID: 35393505 PMCID: PMC8990023 DOI: 10.1038/s41598-022-09676-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/24/2022] [Indexed: 11/29/2022] Open
Abstract
Neutron Capture Enhanced Particle Therapy (NCEPT) boosts the effectiveness of particle therapy by capturing thermal neutrons produced by beam-target nuclear interactions in and around the treatment site, using tumour-specific \documentclass[12pt]{minimal}
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\begin{document}$$^{157}$$\end{document}157Gd-based neutron capture agents. Neutron captures release high-LET secondary particles together with gamma photons with energies of 478 keV or one of several energies up to 7.94 MeV, for \documentclass[12pt]{minimal}
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\begin{document}$$^{157}$$\end{document}157Gd, respectively. A key requirement for NCEPT’s translation is the development of in vivo dosimetry techniques which can measure both the direct ion dose and the dose due to neutron capture. In this work, we report signatures which can be used to discriminate between photons resulting from neutron capture and those originating from other processes. A Geant4 Monte Carlo simulation study into timing and energy thresholds for discrimination of prompt gamma photons resulting from thermal neutron capture during NCEPT was conducted. Three simulated \documentclass[12pt]{minimal}
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\begin{document}$$^3$$\end{document}3 cubic PMMA targets were irradiated by \documentclass[12pt]{minimal}
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\begin{document}$$^{12}$$\end{document}12C ion beams with a spread out Bragg peak (SOBP) depth range of 60 mm; one target is homogeneous while the others include \documentclass[12pt]{minimal}
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\begin{document}$$^3$$\end{document}3 neutron capture inserts (NCIs) of pure \documentclass[12pt]{minimal}
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\begin{document}$$^{157}$$\end{document}157Gd located at the distal edge of the SOBP. The arrival times of photons and neutrons entering a simulated \documentclass[12pt]{minimal}
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\begin{document}$$^3$$\end{document}3 ideal detector were recorded. A temporal mask of 50–60 ns was found to be optimal for maximising the discrimination of the photons resulting from the neutron capture by boron and gadolinium. A range of candidate detector and thermal neutron shielding materials were simulated, and detections meeting the proposed acceptance criteria (i.e. falling within the target energy window and arriving 60 ns post beam-off) were classified as true or false positives, depending on their origin. The ratio of true/false positives (\documentclass[12pt]{minimal}
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\begin{document}$$R_{TF}$$\end{document}RTF) was calculated; for targets with \documentclass[12pt]{minimal}
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\begin{document}$$^{157}$$\end{document}157Gd NCIs, the detector materials which resulted in the highest \documentclass[12pt]{minimal}
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\begin{document}$$R_{TF}$$\end{document}RTF were cadmium-shielded CdTe and boron-shielded LSO, respectively. The optimal irradiation period for both carbon and helium ions was 1 µs for the \documentclass[12pt]{minimal}
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\begin{document}$$^{157}$$\end{document}157Gd NCI.
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Affiliation(s)
- Andrew Chacon
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia
| | - Marissa Kielly
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Harley Rutherford
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Daniel R Franklin
- Faculty of Engineering and IT, University of Technology Sydney, Sydney, Australia
| | - Anita Caracciolo
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.,Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Luca Buonanno
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.,Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Ilenia D'Adda
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.,Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Susanna Guatelli
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia
| | - Marco Carminati
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.,Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Carlo Fiorini
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy.,Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano, Milan, Italy
| | - Mitra Safavi-Naeini
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia. .,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia.
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Caracciolo A, Buonanno L, Di Vita D, DrAdda I, Chacon A, Kielly M, Carminati M, Safavi-Naeini M, Fiorini C. BeNEdiCTE (Boron NEutron CapTurE): a Versatile Gamma-Ray Detection Module for Boron Neutron Capture Therapy. IEEE Trans Radiat Plasma Med Sci 2022. [DOI: 10.1109/trpms.2022.3154232] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ahmed AM, Chacon A, Rutherford H, Akamatsu G, Mohammadi A, Nishikido F, Tashima H, Yoshida E, Yamaya T, Franklin DR, Rosenfeld A, Guatelli S, Safavi-Naeini M. A validated Geant4 model of a whole-body PET scanner with four-layer DOI detectors. ACTA ACUST UNITED AC 2020; 65:235051. [DOI: 10.1088/1361-6560/abaa24] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rutherford H, Chacon A, Mohammadi A, Takyu S, Tashima H, Yoshida E, Nishikido F, Hofmann T, Pinto M, Franklin DR, Yamaya T, Parodi K, Rosenfeld AB, Guatelli S, Safavi-Naeini M. Dose quantification in carbon ion therapy using in-beam positron emission tomography. ACTA ACUST UNITED AC 2020; 65:235052. [DOI: 10.1088/1361-6560/abaa23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Mohammadi A, Tashima H, Iwao Y, Takyu S, Akamatsu G, Kang HG, Nishikido F, Yoshida E, Chacon A, Safavi-Naeini M, Parodi K, Yamaya T. Erratum: Influence of momentum acceptance on range monitoring of 11C and 15O ion beams using in-beam PET (2020 Phys. Med. Biol.
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125006). Phys Med Biol 2020; 65. [DOI: 10.1088/1361-6560/abc36a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 11/11/2022]
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Mohammadi A, Tashima H, Iwao Y, Takyu S, Akamatsu G, Kang HG, Nishikido F, Yoshida E, Chacon A, Safavi-Naeini M, Parodi K, Yamaya T. Influence of momentum acceptance on range monitoring of 11C and 15O ion beams using in-beam PET. Phys Med Biol 2020; 65:125006. [PMID: 32176873 DOI: 10.1088/1361-6560/ab8059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In heavy-ion therapy, the stopping position of primary ions in tumours needs to be monitored for effective treatment and to prevent overdose exposure to normal tissues. Positron-emitting ion beams, such as 11C and 15O, have been suggested for range verification in heavy-ion therapy using in-beam positron emission tomography (PET) imaging, which offers the capability of visualizing the ion stopping position with a high signal-to-noise ratio. We have previously demonstrated the feasibility of in-beam PET imaging for the range verification of 11C and 15O ion beams and observed a slight shift between the beam stopping position and the dose peak position in simulations, depending on the initial beam energy spread. In this study, we focused on the experimental confirmation of the shift between the Bragg peak position and the position of the maximum detected positron-emitting fragments via a PET system for positron-emitting ion beams of 11C (210 MeV u-1) and 15O (312 MeV u-1) with momentum acceptances of 5% and 0.5%. For this purpose, we measured the depth doses and performed in-beam PET imaging using a polymethyl methacrylate (PMMA) phantom for both beams with different momentum acceptances. The shifts between the Bragg peak position and the PET peak position in an irradiated PMMA phantom for the 15O ion beams were 1.8 mm and 0.3 mm for momentum acceptances of 5% and 0.5%, respectively. The shifts between the positions of two peaks for the 11C ion beam were 2.1 mm and 0.1 mm for momentum acceptances of 5% and 0.5%, respectively. We observed larger shifts between the Bragg peak and the PET peak positions for a momentum acceptance of 5% for both beams, which is consistent with the simulation results reported in our previous study. The biological doses were also estimated from the calculated relative biological effectiveness (RBE) values using a modified microdosimetric kinetic model (mMKM) and Monte Carlo simulation. Beams with a momentum acceptance of 5% should be used with caution for therapeutic applications to avoid extra dose to normal tissues beyond the tumour when the dose distal fall-off is located beyond the treatment volume.
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Affiliation(s)
- Akram Mohammadi
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Chacon A, James B, Tran L, Guatelli S, Chartier L, Prokopvich D, Franklin DR, Mohammadi A, Nishikido F, Iwao Y, Akamatsu G, Takyu S, Tashima H, Yamaya T, Parodi K, Rosenfeld A, Safavi‐Naeini M. Experimental investigation of the characteristics of radioactive beams for heavy ion therapy. Med Phys 2020; 47:3123-3132. [PMID: 32279312 DOI: 10.1002/mp.14177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 02/27/2020] [Accepted: 03/26/2020] [Indexed: 01/02/2023] Open
Affiliation(s)
- Andrew Chacon
- Centre for Medical Radiation Physics University of Wollongong, Wollongong NSW 2522 Australia
| | - Benjamin James
- Centre for Medical Radiation Physics University of Wollongong, Wollongong NSW 2522 Australia
| | - Linh Tran
- Centre for Medical Radiation Physics University of Wollongong, Wollongong NSW 2522 Australia
| | - Susanna Guatelli
- Centre for Medical Radiation Physics University of Wollongong, Wollongong NSW 2522 Australia
| | - Lachlan Chartier
- Australian Nuclear Science and Technology Organisation Lucas Heights NSW 2234 Australia
| | - Dale Prokopvich
- Australian Nuclear Science and Technology Organisation Lucas Heights NSW 2234 Australia
| | | | - Akram Mohammadi
- National Institute of Radiological Sciences (NIRS) National Institutes for Quantum and Radiological Science and Technology 4‐9‐1 Anagawa Inage‐ku Chiba 263‐8555 Japan
| | - Fumihiko Nishikido
- National Institute of Radiological Sciences (NIRS) National Institutes for Quantum and Radiological Science and Technology 4‐9‐1 Anagawa Inage‐ku Chiba 263‐8555 Japan
| | - Yuma Iwao
- National Institute of Radiological Sciences (NIRS) National Institutes for Quantum and Radiological Science and Technology 4‐9‐1 Anagawa Inage‐ku Chiba 263‐8555 Japan
| | - Go Akamatsu
- National Institute of Radiological Sciences (NIRS) National Institutes for Quantum and Radiological Science and Technology 4‐9‐1 Anagawa Inage‐ku Chiba 263‐8555 Japan
| | - Sodai Takyu
- National Institute of Radiological Sciences (NIRS) National Institutes for Quantum and Radiological Science and Technology 4‐9‐1 Anagawa Inage‐ku Chiba 263‐8555 Japan
| | - Hideaki Tashima
- National Institute of Radiological Sciences (NIRS) National Institutes for Quantum and Radiological Science and Technology 4‐9‐1 Anagawa Inage‐ku Chiba 263‐8555 Japan
| | - Taiga Yamaya
- National Institute of Radiological Sciences (NIRS) National Institutes for Quantum and Radiological Science and Technology 4‐9‐1 Anagawa Inage‐ku Chiba 263‐8555 Japan
| | - Katia Parodi
- Department of Medical Physics Ludwig‐Maximilians‐Universit at Munchen Garching b Munchen Germany
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics University of Wollongong, Wollongong NSW 2522 Australia
| | - Mitra Safavi‐Naeini
- Australian Nuclear Science and Technology Organisation Lucas Heights NSW 2234 Australia
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Chacon A, Barragan A, Judd T, Safi D. Adaptive Functioning (AF) Evaluations of Foreign Nationals Facing Capital Punishment. Arch Clin Neuropsychol 2019. [DOI: 10.1093/arclin/acz029.52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Objective
The US Supreme Court ruled against the application of the death penalty to individuals with intellectual disability (ID) (Atkins v. Virginia, 2002). Diagnostic criteria for ID require subnormal adaptive functioning (AF) in addition to IQ test scores (American Psychiatric Association [APA], 2013). The American Association on Intellectual and Developmental Disabilities (AAIDD) (2010, 2012) and APA (2013) recommend using culturally sensitive approaches. Assessing AF in immigrants is a challenge because their cultural backgrounds are different than those of the standardization samples of United States AF measures. When typical AF measures are not appropriate, AAIDD (2010) offers guidelines about appropriate sources such as school, work, and medical records, prior psychosocial evaluations, and qualitative adaptive behavior interviews with multiple informants. However, defendants facing the death penalty are often raised in impoverished areas with a paucity of pertinent documentation. This study identifies and discusses issues related to the use of self-report, selection of respondents, questions, collateral information, and clinical judgment in AF evaluations of immigrants facing the death penalty.
Case Description
We present a case study of an AF evaluation of a Mexican national seeking ID exemption from capital punishment.
Discussion
We offer a framework for developing and judging the quality of an AF evaluation that adheres to the (AAIDD) (2010, 2012) and APA (2013) guidelines, and includes 1) strengths and limitations of adaptive functioning in relation to others of his age group and culture; 2) reliable evidence concerning the individual’s history in specific periods of time; 3) an account of the individual’s cultural and linguistic differences; and 4) an account for potential bias on the respondents’ side.
References
Atkins v. Virginia, 536 U.S. 304 (2002). American Psychiatric Association. Diagnostic and statistical manual of mental disorders. fifth ed. Washington, DC: APA; 2013. American Psychological Association. (2016). Revision of ethical standard 3.04 of the “Ethical Principles of Psychologists and Code of Conduct” (2002, as amended 2010). American Psychologist, 71, 900. Schalock, R.L., Borthwick-Duffy, S.A.,Bradley, V. J., Buntix, W.H.E.,.Coulter, D.L., Craig, E.M…..Yeager, M.H. (2010). Intellectual disability: Definition, classification, and systems of supports. (11th ed.).Washington, DC: American Association on Intellectual and Developmental Disabilities. doi:978-1-935304-04-3. Schalock, R.L., Luckasson, R.A., Bradley, V., Buntinx, W.H.E., Lachapelle, Y., Shogren, K.A…Wehmeyer, M.L. (2012). Intellectual disability: Definition, classification, and system of supports: User's Guide. Washington, DC: American Association on Intellectual and Developmental Disabilities.
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Chacon A, Guatelli S, Rutherford H, Bolst D, Mohammadi A, Ahmed A, Nitta M, Nishikido F, Iwao Y, Tashima H, Yoshida E, Akamatsu G, Takyu S, Kitagawa A, Hofmann T, Pinto M, Franklin DR, Parodi K, Yamaya T, Rosenfeld A, Safavi-Naeini M. Comparative study of alternative Geant4 hadronic ion inelastic physics models for prediction of positron-emitting radionuclide production in carbon and oxygen ion therapy. Phys Med Biol 2019; 64:155014. [PMID: 31167173 DOI: 10.1088/1361-6560/ab2752] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The distribution of fragmentation products predicted by Monte Carlo simulations of heavy ion therapy depend on the hadronic physics model chosen in the simulation. This work aims to evaluate three alternative hadronic inelastic fragmentation physics options available in the Geant4 Monte Carlo radiation physics simulation framework to determine which model most accurately predicts the production of positron-emitting fragmentation products observable using in-beam PET imaging. Fragment distributions obtained with the BIC, QMD, and INCL + + physics models in Geant4 version 10.2.p03 are compared to experimental data obtained at the HIMAC heavy-ion treatment facility at NIRS in Chiba, Japan. For both simulations and experiments, monoenergetic beams are applied to three different block phantoms composed of gelatin, poly(methyl methacrylate) and polyethylene. The yields of the positron-emitting nuclei 11C, 10C and 15O obtained from simulations conducted with each model are compared to the experimental yields estimated by fitting a multi-exponential radioactive decay model to dynamic PET images using the normalised mean square error metric in the entrance, build up/Bragg peak and tail regions. Significant differences in positron-emitting fragment yield are observed among the three physics models with the best overall fit to experimental 12C and 16O beam measurements obtained with the BIC physics model.
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Affiliation(s)
- Andrew Chacon
- Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2522, Australia. Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
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Akamatsu G, Tashima H, Iwao Y, Wakizaka H, Maeda T, Mohammadi A, Takyu S, Nitta M, Nishikido F, Rutherford H, Chacon A, Safavi-Naeini M, Yoshida E, Yamaya T. Performance evaluation of a whole-body prototype PET scanner with four-layer DOI detectors. Phys Med Biol 2019; 64:095014. [PMID: 30978704 DOI: 10.1088/1361-6560/ab18b2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Parallax error caused by the detector crystal thickness degrades spatial resolution at the peripheral regions of the field-of-view (FOV) of a scanner. To resolve this issue, depth-of-interaction (DOI) measurement is a promising solution to improve the spatial resolution and its uniformity over the entire FOV. Even though DOI detectors have been used in dedicated systems with a small ring diameter such as for the human brain, breast and small animals, the use of DOI detectors for a large bore whole-body PET system has not been demonstrated yet. We have developed a four-layered DOI detector, and its potential for a brain dedicated system has been proven in our previous development. In the present work, we investigated the use of the four-layer DOI detector for a large bore PET system by developing the world's first whole-body prototype. We evaluated its performance characteristics in accordance with the NEMA NU 2 standard. Furthermore, the impact of incorporating DOI information was evaluated with the NEMA NU 4 image quality phantom. Point source images were reconstructed with a filtered back projection (FBP), and an average spatial resolution of 5.2 ± 0.7 mm was obtained. For the FBP image, the four-layer DOI information improved the radial spatial resolution by 48% at the 20 cm offset position. The peak noise-equivalent count rate (NECR) was 22.9 kcps at 7.4 kBq ml-1 and the scatter fraction was 44%. The system sensitivity was 5.9 kcps MBq-1. For the NEMA NU 2 image quality phantom, the 10 mm sphere was clearly visualized without any artifacts. For the NEMA NU 4 image quality phantom, we measured the phantom at 0, 10 and 20 cm offset positions. As a result, we found the image with four-layer DOI could visualize the 2 mm-diameter hot cylinder although it could not be recognized on the image without DOI. The average improvements in the recovery coefficients for the five hot rods (1-5 mm) were 0.3%, 4.4% and 26.3% at the 0, 10 and 20 cm offset positions, respectively (except for the 1 mm-diameter rod at the 20 cm offset position). Although several practical issues (such as adding end-shields) remain to be addressed before the scanner is ready for clinical use, we showed that the four-layer DOI technology provided higher and more uniform spatial resolution over the FOV and improved contrast for small uptake regions located at the peripheral FOV, which could improve detectability of small and distal lesions such as nodal metastases, especially in obese patients.
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Affiliation(s)
- Go Akamatsu
- National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan. Author to whom any correspondence should be addressed
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Hofmann T, Pinto M, Mohammadi A, Nitta M, Nishikido F, Iwao Y, Tashima H, Yoshida E, Chacon A, Safavi-Naeini M, Rosenfeld A, Yamaya T, Parodi K. Dose reconstruction from PET images in carbon ion therapy: a deconvolution approach. ACTA ACUST UNITED AC 2019; 64:025011. [DOI: 10.1088/1361-6560/aaf676] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Safavi-Naeini M, Chacon A, Guatelli S, Franklin DR, Bambery K, Gregoire MC, Rosenfeld A. Opportunistic dose amplification for proton and carbon ion therapy via capture of internally generated thermal neutrons. Sci Rep 2018; 8:16257. [PMID: 30390002 PMCID: PMC6215016 DOI: 10.1038/s41598-018-34643-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022] Open
Abstract
This paper presents Neutron Capture Enhanced Particle Therapy (NCEPT), a method for enhancing the radiation dose delivered to a tumour relative to surrounding healthy tissues during proton and carbon ion therapy by capturing thermal neutrons produced inside the treatment volume during irradiation. NCEPT utilises extant and in-development boron-10 and gadolinium-157-based drugs from the related field of neutron capture therapy. Using Monte Carlo simulations, we demonstrate that a typical proton or carbon ion therapy treatment plan generates an approximately uniform thermal neutron field within the target volume, centred around the beam path. The tissue concentrations of neutron capture agents required to obtain an arbitrary 10% increase in biological effective dose are estimated for realistic treatment plans, and compared to concentrations previously reported in the literature. We conclude that the proposed method is theoretically feasible, and can provide a worthwhile improvement in the dose delivered to the tumour relative to healthy tissue with readily achievable concentrations of neutron capture enhancement drugs.
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Affiliation(s)
- Mitra Safavi-Naeini
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia.
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia.
| | - Andrew Chacon
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
| | - Susanna Guatelli
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
| | - Daniel R Franklin
- Faculty of Engineering & IT, University of Technology Sydney, Sydney, Australia
| | - Keith Bambery
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia
| | - Marie-Claude Gregoire
- Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
| | - Anatoly Rosenfeld
- Centre for Medical Radiation Physics, University of Wollongong, Sydney, Australia
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Maza M, Melendez M, Masch R, Alfaro K, Chacon A, Gonzalez E, Soler M, Conzuelo-Rodriguez G, Gage JC, Alonzo TA, Castle PE, Felix JC, Cremer M. Acceptability of self-sampling and human papillomavirus testing among non-attenders of cervical cancer screening programs in El Salvador. Prev Med 2018; 114:149-155. [PMID: 29958860 DOI: 10.1016/j.ypmed.2018.06.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 05/21/2018] [Accepted: 06/25/2018] [Indexed: 10/28/2022]
Abstract
In a cross-sectional study carried out in El Salvador between February 2016 and July 2017, self-sampling and human papillomavirus (HPV) testing was found to be highly acceptable among 2019 women who had not attended a cervical cancer screening in at least 3 years. Within this population, HPV positivity rates differed according to age, marital status, number of children, and lifetime sexual partners. The proportion of women who tested HPV positive or who were diagnosed with cervical intraepithelial neoplasia grade 2 (CIN2) or more severe diagnoses (CIN2+) was similar to the general population of the area. Among the reasons for failing to participate in previous screening programs, non-attending women described logistic concerns, but also erroneous beliefs regarding HPV and cervical cancer, misconceptions regarding the screening procedure, discomfort with male providers, and confidentiality fears. The aim of this study was to identify opportunities and challenges that emerged from the use of self-sampling and HPV testing as part of a public cervical cancer control effort in a low-resource setting.
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Affiliation(s)
- M Maza
- Basic Health International, Colonia San Francisco, Avenida Las Camelias 14, San Salvador, El Salvador; Basic Health International, 25 Broadway, 9th Floor, New York, NY 10004, United States of America.
| | - M Melendez
- Basic Health International, Colonia San Francisco, Avenida Las Camelias 14, San Salvador, El Salvador; Basic Health International, 25 Broadway, 9th Floor, New York, NY 10004, United States of America.
| | - R Masch
- Basic Health International, Colonia San Francisco, Avenida Las Camelias 14, San Salvador, El Salvador; Basic Health International, 25 Broadway, 9th Floor, New York, NY 10004, United States of America.
| | - K Alfaro
- Basic Health International, Colonia San Francisco, Avenida Las Camelias 14, San Salvador, El Salvador; Basic Health International, 25 Broadway, 9th Floor, New York, NY 10004, United States of America.
| | - A Chacon
- Ministry of Health, San Salvador, El Salvador, Calle Arce 827, San Salvador, El Salvador
| | - E Gonzalez
- Ministry of Health, San Salvador, El Salvador, Calle Arce 827, San Salvador, El Salvador
| | - M Soler
- Basic Health International, Colonia San Francisco, Avenida Las Camelias 14, San Salvador, El Salvador; Basic Health International, 25 Broadway, 9th Floor, New York, NY 10004, United States of America.
| | - G Conzuelo-Rodriguez
- Basic Health International, Colonia San Francisco, Avenida Las Camelias 14, San Salvador, El Salvador; Basic Health International, 25 Broadway, 9th Floor, New York, NY 10004, United States of America.
| | - J C Gage
- National Cancer Institute, 9000 Rockville Pike, Bethesda, MD 20892, United States of America.
| | - T A Alonzo
- University of Southern California, 222 East Huntington Drive, Suite 100, Monrovia, CA 91016, United States of America.
| | - P E Castle
- Albert Einstein College of Medicine, 300 Morris Park Avenue, Bronx, NY 10461, United States of America
| | - J C Felix
- Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53226, United States of America.
| | - M Cremer
- Basic Health International, Colonia San Francisco, Avenida Las Camelias 14, San Salvador, El Salvador; Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, United States of America; Basic Health International, 25 Broadway, 9th Floor, New York, NY 10004, United States of America.
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Chacon A, Bauer A, Adams T, Rucker F, Brandl G, Georgii R, Garst M, Pfleiderer C. Uniaxial Pressure Dependence of Magnetic Order in MnSi. Phys Rev Lett 2015; 115:267202. [PMID: 26765018 DOI: 10.1103/physrevlett.115.267202] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Indexed: 06/05/2023]
Abstract
We report comprehensive small angle neutron scattering measurements complemented by ac susceptibility data of the helical order, conical phase, and Skyrmion lattice phase (SLP) in MnSi under uniaxial pressures. For all crystallographic orientations uniaxial pressure favors the phase for which a spatial modulation of the magnetization is closest to the pressure axis. Uniaxial pressures as low as 1 kbar applied perpendicular to the magnetic field axis enhance the Skyrmion lattice phase substantially, whereas the Skyrmion lattice phase is suppressed for pressure parallel to the field. Taken together we present quantitative microscopic information on how strain couples to magnetic order in the chiral magnet MnSi.
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Affiliation(s)
- A Chacon
- Physik-Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany
| | - A Bauer
- Physik-Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany
| | - T Adams
- Physik-Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany
| | - F Rucker
- Physik-Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany
| | - G Brandl
- Physik-Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, D-85748 Garching, Germany
| | - R Georgii
- Physik-Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, D-85748 Garching, Germany
| | - M Garst
- Institute for Theoretical Physics, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany
| | - C Pfleiderer
- Physik-Department, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany
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Savas JA, Ledon JA, Franca K, Chacon A, Nouri K. Pulsed dye laser-resistant port-wine stains: mechanisms of resistance and implications for treatment. Br J Dermatol 2013; 168:941-53. [PMID: 23290045 DOI: 10.1111/bjd.12204] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Port-wine stains (PWS) are among the most common congenital vascular malformations. Unlike capillary haemangiomas, these lesions do not involute spontaneously but rather become progressively more disfiguring as the patient ages. While benign in nature, the cosmetic deformity and attendant psychological and emotional distress prompt the majority of those afflicted to seek treatment. The pulsed dye laser (PDL) has long been considered the treatment of choice for these vascular lesions; however, very few patients achieve total clearance with PDL therapy and a significant number of lesions fail to respond at all. In order to address these recalcitrant cases, the mechanisms that contribute to treatment resistance must be understood and novel laser and light therapies must be employed. This review will address what is currently known about lesion-specific characteristics of PDL-resistant PWS as well as discuss current and future treatment options.
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Affiliation(s)
- J A Savas
- Department of Dermatology and Cutaneous Surgery, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA.
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Milde P, Kohler D, Seidel J, Eng LM, Bauer A, Chacon A, Kindervater J, Muhlbauer S, Pfleiderer C, Buhrandt S, Schutte C, Rosch A. Unwinding of a Skyrmion Lattice by Magnetic Monopoles. Science 2013; 340:1076-80. [DOI: 10.1126/science.1234657] [Citation(s) in RCA: 410] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Adams T, Chacon A, Wagner M, Bauer A, Brandl G, Pedersen B, Berger H, Lemmens P, Pfleiderer C. Long-wavelength helimagnetic order and skyrmion lattice phase in Cu2OSeO3. Phys Rev Lett 2012; 108:237204. [PMID: 23003986 DOI: 10.1103/physrevlett.108.237204] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/09/2012] [Indexed: 06/01/2023]
Abstract
We report a long-wavelength helimagnetic superstructure in bulk samples of the ferrimagnetic insulator Cu2OSeO3. The magnetic phase diagram associated with the helimagnetic modulation inferred from small-angle neutron scattering and magnetization measurements includes a skyrmion lattice phase and is strongly reminiscent of MnSi, FeGe, and Fe(1-x)Co(x)Si, i.e., binary isostructural siblings of Cu2OSeO3 that order helimagnetically. The temperature dependence of the specific heat of Cu2OSeO3 is characteristic of nearly critical spin fluctuations at the helimagnetic transition. This provides putative evidence for effective spin currents as the origin of enhancements of the magnetodielectric response instead of atomic displacements considered so far.
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Affiliation(s)
- T Adams
- Technische Universität München, Physik-Department E21, D-85748 Garching, Germany
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Flores Chávez M, Chacon A, Chacon de Petrola M, Pacheco de Toro M. Determination of Autologus Serum Skin Test and its Association with Clinical and Immunological Markers in Adult Patients with Chronic Urticaria Treated at the Regional Unit of Immunology at the "Dr. Enrique Tejera" Hospital from April to September 2007. J Allergy Clin Immunol 2009. [DOI: 10.1016/j.jaci.2008.12.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The management of benign prostatic hyperplasia has undergone a rapid evolution over the past decade from a surgical emphasis to a medical emphasis. Great strides in the development of alpha-adrenergic blockers, 5 alpha-reductase inhibitors and a variety of phytotherapeutics have fueled this evolution. This article reviews the past, present and future of the medical management of benign prostatic hyperplasia.
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Affiliation(s)
- A Chacon
- Division of Urology, University of California, San Diego, USA
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Calleja F, Eguaras MG, Chacon A, Vivancos R, Montero A, Concha M. Pulmonary valve endocarditis during puerperal sepsis. J Cardiovasc Surg (Torino) 1992; 33:292-4. [PMID: 1601910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A case of pulmonary valve endocarditis caused by Staphylococcus aureus during puerperal sepsis in a female patient is reported. The M-mode and two dimensional echocardiographic finding are described. A review of the literature shows that this entity is rare. A large vegetation in the leaflet of the pulmonary valve was excised and the patient recovered after a full course of antibiotics.
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Affiliation(s)
- F Calleja
- Department of Cardiovascular Surgery, Hospital Regional Reina Sofia, Cordoba, Spain
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Chacon A. Trachoma and Immigration. Public Health Pap Rep 1907; 33:163-166. [PMID: 19601358 PMCID: PMC2232429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Chacon A. Hygiene of the Sight. Public Health Pap Rep 1902; 28:311-313. [PMID: 19601070 PMCID: PMC2329481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Chacon A. Necessity of the Study by Sanitary Congresses of Measures for the Prevention of Blindness. Public Health Pap Rep 1896; 22:151-154. [PMID: 19600694 PMCID: PMC2329110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Chacon A. Prevention of Ophthalmia Neonatorum. Public Health Pap Rep 1892; 18:176-179. [PMID: 19600453 PMCID: PMC2266562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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