26
|
Champion C, Glenn N, Berry T, Spence JC. Exploring women's responses to online media coverage of weight loss surgery. Clin Obes 2015; 5:281-7. [PMID: 26278398 DOI: 10.1111/cob.12110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/25/2015] [Accepted: 07/01/2015] [Indexed: 01/06/2023]
Abstract
The purpose of this study was to understand the reactions of women to online news articles about weight loss surgery and related reader comments. Focus groups were conducted; open-ended questions were asked to elicit responses to existing online news media content related to weight loss surgery. The participants described the online articles as predominantly supportive of weight loss surgery and in response they expressed a desire to see more critical content, including different and competing perspectives. Participants felt the online comments represented extreme perspectives and were predominately negative. These were therefore not viewed as helpful or informative. Nevertheless, readers viewed comments as a form of entertainment. Because of the aggressive and anonymous nature of reader comments in response to online news stories, the participants did not feel comfortable leaving comments themselves on the news sites. Findings highlight the importance of gathering readers' perspectives in response to interactive media content and, in particular, health information.
Collapse
|
27
|
Champion C, Quinto MA, Monti JM, Galassi ME, Weck PF, Fojón OA, Hanssen J, Rivarola RD. Water versus DNA: new insights into proton track-structure modelling in radiobiology and radiotherapy. Phys Med Biol 2015; 60:7805-28. [PMID: 26406277 DOI: 10.1088/0031-9155/60/20/7805] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Water is a common surrogate of DNA for modelling the charged particle-induced ionizing processes in living tissue exposed to radiations. The present study aims at scrutinizing the validity of this approximation and then revealing new insights into proton-induced energy transfers by a comparative analysis between water and realistic biological medium. In this context, a self-consistent quantum mechanical modelling of the ionization and electron capture processes is reported within the continuum distorted wave-eikonal initial state framework for both isolated water molecules and DNA components impacted by proton beams. Their respective probability of occurrence-expressed in terms of total cross sections-as well as their energetic signature (potential and kinetic) are assessed in order to clearly emphasize the differences existing between realistic building blocks of living matter and the controverted water-medium surrogate. Consequences in radiobiology and radiotherapy will be discussed in particular in view of treatment planning refinement aiming at better radiotherapy strategies.
Collapse
|
28
|
Quinto MA, Monti JM, Week PF, Fojón OA, Hanssen J, Rivarola RD, Champion C. TILDA-V: A full-differential code for proton tracking in biological matter. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/1742-6596/635/3/032063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
29
|
Jødal L, Le Loirec C, Champion C. Positron range in PET imaging: non-conventional isotopes. Phys Med Biol 2014; 59:7419-34. [PMID: 25386999 DOI: 10.1088/0031-9155/59/23/7419] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In addition to conventional short-lived radionuclides, longer-lived isotopes are becoming increasingly important to positron emission tomography (PET). The longer half-life both allows for circumvention of the in-house production of radionuclides, and expands the spectrum of physiological processes amenable to PET imaging, including processes with prohibitively slow kinetics for investigation with short-lived radiotracers. However, many of these radionuclides emit 'high-energy' positrons and gamma rays which affect the spatial resolution and quantitative accuracy of PET images. The objective of the present work is to investigate the positron range distribution for some of these long-lived isotopes. Based on existing Monte Carlo simulations of positron interactions in water, the probability distribution of the line of response displacement have been empirically described by means of analytic displacement functions. Relevant distributions have been derived for the isotopes (22)Na, (52)Mn, (89)Zr, (45)Ti, (51)Mn, (94 m)Tc, (52 m)Mn, (38)K, (64)Cu, (86)Y, (124)I, and (120)I. It was found that the distribution functions previously found for a series of conventional isotopes (Jødal et al 2012 Phys. Med. Bio. 57 3931-43), were also applicable to these non-conventional isotopes, except that for (120)I, (124)I, (89)Zr, (52)Mn, and (64)Cu, parameters in the formulae were less well predicted by mean positron energy alone. Both conventional and non-conventional range distributions can be described by relatively simple analytic expressions. The results will be applicable to image-reconstruction software to improve the resolution.
Collapse
|
30
|
Gholami Y, Toghyani M, Champion C, Kuncic Z. In silico radiobiology: Have we reached the limit of Monte Carlo simulations? ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/489/1/012011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
31
|
Monti J, Tachino C, Hanssen J, Fojón O, Galassi M, Champion C, Rivarola R. Distorted wave calculations for electron loss process induced by bare ion impact on biological targets. Appl Radiat Isot 2014; 83 Pt B:105-8. [DOI: 10.1016/j.apradiso.2012.12.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 12/26/2012] [Accepted: 12/27/2012] [Indexed: 10/27/2022]
|
32
|
Champion C, Incerti S, Perrot Y, Delorme R, Bordage MC, Bardiès M, Mascialino B, Tran HN, Ivanchenko V, Bernal M, Francis Z, Groetz JE, Fromm M, Campos L. Dose point kernels in liquid water: an intra-comparison between GEANT4-DNA and a variety of Monte Carlo codes. Appl Radiat Isot 2013; 83 Pt B:137-41. [PMID: 23478094 DOI: 10.1016/j.apradiso.2013.01.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 01/28/2013] [Accepted: 01/31/2013] [Indexed: 10/27/2022]
Abstract
Modeling the radio-induced effects in biological medium still requires accurate physics models to describe the interactions induced by all the charged particles present in the irradiated medium in detail. These interactions include inelastic as well as elastic processes. To check the accuracy of the very low energy models recently implemented into the GEANT4 toolkit for modeling the electron slowing-down in liquid water, the simulation of electron dose point kernels remains the preferential test. In this context, we here report normalized radial dose profiles, for mono-energetic point sources, computed in liquid water by using the very low energy "GEANT4-DNA" physics processes available in the GEANT4 toolkit. In the present study, we report an extensive intra-comparison of profiles obtained by a large selection of existing and well-documented Monte-Carlo codes, namely, EGSnrc, PENELOPE, CPA100, FLUKA and MCNPX.
Collapse
|
33
|
Allison J, Apostolakis J, Bagulya A, Champion C, Elles S, Garay F, Grichine V, Howard A, Incerti S, Ivanchenko V, Jacquemier J, Maire M, Mantero A, Nieminen P, Pandola L, Santin G, Sawkey D, Schälicke A, Urban L. Geant4 electromagnetic physics for high statistic simulation of LHC experiments. ACTA ACUST UNITED AC 2012. [DOI: 10.1088/1742-6596/396/2/022013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
34
|
Jødal L, Le Loirec C, Champion C. Positron range in PET imaging: an alternative approach for assessing and correcting the blurring. Phys Med Biol 2012; 57:3931-43. [PMID: 22643300 DOI: 10.1088/0031-9155/57/12/3931] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Positron range impairs resolution in PET imaging, especially for high-energy emitters and for small-animal PET. De-blurring in image reconstruction is possible if the blurring distribution is known. Furthermore, the percentage of annihilation events within a given distance from the point of positron emission is relevant for assessing statistical noise. This paper aims to determine the positron range distribution relevant for blurring for seven medically relevant PET isotopes, (18)F, (11)C, (13)N, (15)O, (68)Ga, (62)Cu and (82)Rb, and derive empirical formulas for the distributions. This paper focuses on allowed-decay isotopes. It is argued that blurring at the detection level should not be described by the positron range r, but instead the 2D projected distance δ (equal to the closest distance between decay and line of response). To determine these 2D distributions, results from a dedicated positron track-structure Monte Carlo code, Electron and POsitron TRANsport (EPOTRAN), were used. Materials other than water were studied with PENELOPE. The radial cumulative probability distribution G(2D)(δ) and the radial probability density distribution g(2D)(δ) were determined. G(2D)(δ) could be approximated by the empirical function 1 - exp(-Aδ(2) - Bδ), where A = 0.0266 (E(mean))(-1.716) and B = 0.1119 (E(mean))(-1.934), with E(mean) being the mean positron energy in MeV and δ in mm. The radial density distribution g(2D)(δ) could be approximated by differentiation of G(2D)(δ). Distributions in other media were very similar to water. The positron range is important for improved resolution in PET imaging. Relevant distributions for the positron range have been derived for seven isotopes. Distributions for other allowed-decay isotopes may be estimated with the above formulas.
Collapse
|
35
|
Champion C, Weck PF, Lekadir H, Galassi ME, Fojón OA, Abufager P, Rivarola RD, Hanssen J. Proton-induced single electron capture on DNA/RNA bases. Phys Med Biol 2012; 57:3039-49. [DOI: 10.1088/0031-9155/57/10/3039] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
36
|
Galassi ME, Champion C, Weck PF, Rivarola RD, Fojón O, Hanssen J. Quantum-mechanical predictions of DNA and RNA ionization by energetic proton beams. Phys Med Biol 2012; 57:2081-99. [DOI: 10.1088/0031-9155/57/7/2081] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
37
|
Delorme R, Agelou M, Champion C, Elleaume H, Taupin F, Flaender M, Ravanat J. 224 MODELING AND EXPERIMENTAL VALIDATION OF THE RADIATION – HEAVY ELEMENTS INTERACTIONS AT THE MICROMETER LEVEL IN PHOTON ACTIVATION RADIOTHERAPY. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)70193-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
38
|
Francis Z, Incerti S, Ivanchenko V, Champion C, Karamitros M, Bernal MA, Bitar ZE. Monte Carlo simulation of energy-deposit clustering for ions of the same LET in liquid water. Phys Med Biol 2011; 57:209-24. [DOI: 10.1088/0031-9155/57/1/209] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
39
|
Bernal MA, deAlmeida CE, Sampaio C, Incerti S, Champion C, Nieminen P. The invariance of the total direct DNA strand break yield. Med Phys 2011; 38:4147-53. [DOI: 10.1118/1.3597568] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
40
|
Incerti S, Ivanchenko A, Karamitros M, Mantero A, Moretto P, Tran HN, Mascialino B, Champion C, Ivanchenko VN, Bernal MA, Francis Z, Villagrasa C, Baldacchin G, Guèye P, Capra R, Nieminen P, Zacharatou C. Comparison of GEANT4 very low energy cross section models with experimental data in water. Med Phys 2010; 37:4692-708. [PMID: 20964188 DOI: 10.1118/1.3476457] [Citation(s) in RCA: 280] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The GEANT4 general-purpose Monte Carlo simulation toolkit is able to simulate physical interaction processes of electrons, hydrogen and helium atoms with charge states (H0, H+) and (He0, He+, He2+), respectively, in liquid water, the main component of biological systems, down to the electron volt regime and the submicrometer scale, providing GEANT4 users with the so-called "GEANT4-DNA" physics models suitable for microdosimetry simulation applications. The corresponding software has been recently re-engineered in order to provide GEANT4 users with a coherent and unique approach to the simulation of electromagnetic interactions within the GEANT4 toolkit framework (since GEANT4 version 9.3 beta). This work presents a quantitative comparison of these physics models with a collection of experimental data in water collected from the literature. METHODS An evaluation of the closeness between the total and differential cross section models available in the GEANT4 toolkit for microdosimetry and experimental reference data is performed using a dedicated statistical toolkit that includes the Kolmogorov-Smirnov statistical test. The authors used experimental data acquired in water vapor as direct measurements in the liquid phase are not yet available in the literature. Comparisons with several recommendations are also presented. RESULTS The authors have assessed the compatibility of experimental data with GEANT4 microdosimetry models by means of quantitative methods. The results show that microdosimetric measurements in liquid water are necessary to assess quantitatively the validity of the software implementation for the liquid water phase. Nevertheless, a comparison with existing experimental data in water vapor provides a qualitative appreciation of the plausibility of the simulation models. The existing reference data themselves should undergo a critical interpretation and selection, as some of the series exhibit significant deviations from each other. CONCLUSIONS The GEANT4-DNA physics models available in the GEANT4 toolkit have been compared in this article to available experimental data in the water vapor phase as well as to several published recommendations on the mass stopping power. These models represent a first step in the extension of the GEANT4 Monte Carlo toolkit to the simulation of biological effects of ionizing radiation.
Collapse
|
41
|
Champion C, Lekadir H, Galassi ME, Fojón O, Rivarola RD, Hanssen J. Theoretical predictions for ionization cross sections of DNA nucleobases impacted by light ions. Phys Med Biol 2010; 55:6053-67. [DOI: 10.1088/0031-9155/55/20/002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
42
|
Champion C. Electron impact ionization of liquid and gaseous water: a single-center partial-wave approach. Phys Med Biol 2009; 55:11-32. [DOI: 10.1088/0031-9155/55/1/002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
43
|
Champion C, Incerti S, Aouchiche H, Oubaziz D. A free-parameter theoretical model for describing the electron elastic scattering in water in the Geant4 toolkit. Radiat Phys Chem Oxf Engl 1993 2009. [DOI: 10.1016/j.radphyschem.2009.03.079] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
44
|
Hindié E, Champion C, Zanotti-Fregonara P, Rubello D, Moretti JL. Reply to: Determinants of (131)I radiation dose to thyroid follicular cells. Eur J Nucl Med Mol Imaging 2009; 36:1015-6. [PMID: 19399498 DOI: 10.1007/s00259-009-1144-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
45
|
Champion C, Boudrioua O, Cappello CD. Water molecule ionization by charged particles:a short review. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/101/1/012010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
46
|
Aouchiche H, Champion C, Oubaziz D. Electron and positron elastic scattering in gaseous and liquid water: A comparative study. Radiat Phys Chem Oxf Engl 1993 2008. [DOI: 10.1016/j.radphyschem.2007.09.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
47
|
Abbas I, Champion C, Zarour B, Lasri B, Hanssen J. Single and multiple cross sections for ionizing processes of biological molecules by protons and α-particle impact: a classical Monte Carlo approach. Phys Med Biol 2008; 53:N41-51. [DOI: 10.1088/0031-9155/53/4/n03] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
48
|
Elbast M, Wu TD, Guiraud-Vitaux F, Guerquin-Kern JL, Petiet A, Hindie E, Champion C, Croisy A, Colas-Linhart N. Kinetics of intracolloidal iodine in thyroid of iodine-deficient or equilibrated newborn rats. Direct imaging using secondary ion mass spectrometry. Cell Mol Biol (Noisy-le-grand) 2007; 53 Suppl:OL1018-OL1024. [PMID: 18184480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 11/11/2007] [Indexed: 05/25/2023]
Abstract
The most significant impact of the Chernobyl accident is the increased incidence of thyroid cancers among children. In order to accurately estimate the radiation dose provided by radioiodines, it is important to examine how the distribution of newly incorporated iodine varies with time and if this distribution varies according to the iodine status. The kinetic distribution of intra colloidal newly organified iodine in the rat immature thyroid was recorded and analysed using the ionic nanoprobe NanoSims50. Our observations imply that in case of radioiodine contamination, the energy deposits vary (i) with time, (ii) from one follicle to another, and (iii) from one cell to another inside the same follicle regardless the iodine status. The kinetic heterogeneity of iodine distribution must be take in account in thyroid dose evaluation.
Collapse
|
49
|
Champion C, Le Loirec C. Positron follow-up in liquid water: II. Spatial and energetic study for the most important radioisotopes used in PET. Phys Med Biol 2007; 52:6605-25. [DOI: 10.1088/0031-9155/52/22/004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
50
|
Hafied H, Eschenbrenner A, Champion C, Ruiz-López M, Cappello CD, Charpentier I, Hervieux PA. Electron momentum spectroscopy of the valence orbitals of the water molecule in gas and liquid phase: A comparative study. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.03.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|