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- Allison, J, et al.
(författare)
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Geant4 developments and applications
- 2006
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Ingår i: IEEE TRANSACTIONS ON NUCLEAR SCIENCE. - 0018-9499. ; 53:1, s. 270-278
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Arce, P., et al.
(författare)
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Report on G4-Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Simulation Benchmarking Group
- 2021
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Ingår i: Medical Physics. - : Wiley. - 0094-2405 .- 2473-4209. ; 48:1, s. 19-56
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Tidskriftsartikel (refereegranskat)abstract
- Background: Geant4 is a Monte Carlo code extensively used in medical physics for a wide range of applications, such as dosimetry, micro- and nanodosimetry, imaging, radiation protection, and nuclear medicine. Geant4 is continuously evolving, so it is crucial to have a system that benchmarks this Monte Carlo code for medical physics against reference data and to perform regression testing. Aims: To respond to these needs, we developed G4-Med, a benchmarking and regression testing system of Geant4 for medical physics. Materials and Methods: G4-Med currently includes 18 tests. They range from the benchmarking of fundamental physics quantities to the testing of Monte Carlo simulation setups typical of medical physics applications. Both electromagnetic and hadronic physics processes and models within the prebuilt Geant4 physics lists are tested. The tests included in G4-Med are executed on the CERN computing infrastructure via the use of the geant-val web application, developed at CERN for Geant4 testing. The physical observables can be compared to reference data for benchmarking and to results of previous Geant4 versions for regression testing purposes. Results: This paper describes the tests included in G4-Med and shows the results derived from the benchmarking of Geant4 10.5 against reference data. Discussion: Our results indicate that the Geant4 electromagnetic physics constructor G4EmStandardPhysics_option4 gives a good agreement with the reference data for all the tests. The QGSP_BIC_HP physics list provided an overall adequate description of the physics involved in hadron therapy, including proton and carbon ion therapy. New tests should be included in the next stage of the project to extend the benchmarking to other physical quantities and application scenarios of interest for medical physics. Conclusion: The results presented and discussed in this paper will aid users in tailoring physics lists to their particular application.
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| 3. |
- Brauner, S., et al.
(författare)
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Reduced expression of TRIM21/Ro52 predicts poor prognosis in diffuse large B-cell lymphoma patients with and without rheumatic disease
- 2015
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 278:3, s. 323-332
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveTRIM21 (also known as Ro52) is an autoantigen in rheumatic disease and is predominantly expressed in leucocytes. Overexpression is associated with decreased proliferation, and the TRIM21 gene maps to a tumour suppressor locus. We therefore investigated the expression of TRIM21 in patients with diffuse large B-cell lymphoma (DLBCL) and its potential usefulness as a prognostic biomarker. Materials and methodsTRIM21 expression levels were assessed by immunohistochemistry in lymphoma biopsies from three cohorts of patients with DLBCL: 42 patients with rheumatic disease treated with a cyclophosphamide, vincristine, doxorubicin and prednisone (CHOP)-like regimen, 76 CHOP-treated and 196 rituximab-CHOP-treated nonrheumatic patients. Expression was correlated with clinical and biomedical parameters. TRIM21 expression was assessed in relation to lymphocyte proliferation by quantitative PCR and correlated with H-3-thymidine incorporation and propidium iodine staining. ResultsTRIM21 expression levels differed in the lymphomas compared to normal lymphoid tissue, with reduced expression correlating with shorter overall survival in all three cohorts. In the two larger cohorts, progression-free survival was assessed and was also found to correlate with TRIM21 expression. The association was independent of commonly used clinical prognostic scores, lymphoma subtype and several previously reported prognostic biomarkers. In agreement with this clinical observation, we noted an inverse correlation between TRIM21 expression and proliferation of leucocytes invitro. ConclusionsWe show that loss of TRIM21 expression is associated with more aggressive lymphoma and increased proliferation, whereas maintenance of TRIM21 expression is associated with better prognosis in patients with DLBCL. Based on our findings, we suggest that TRIM21 should be considered as a novel biomarker for lymphoma characterization and for predicting patient survival.
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| 4. |
- Champion, C., et al.
(författare)
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Dose point kernels in liquid water : An intra-comparison between GEANT4-DNA and a variety of Monte Carlo codes
- 2014
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 83, s. 137-141
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Tidskriftsartikel (refereegranskat)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.
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| 9. |
- Ivanchenko, M, et al.
(författare)
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Natural killer cells and type II interferon in Ro/SSA and La/SSB autoantibody-exposed newborns at risk of congenital heart block
- 2021
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Ingår i: Annals of the rheumatic diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 80:2, s. 194-202
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Tidskriftsartikel (refereegranskat)abstract
- Congenital heart block (CHB) with immune cell infiltration develops in the fetus after exposure to maternal Ro/La autoantibodies. CHB-related serology has been extensively studied, but reports on immune-cell profiles of anti-Ro/La-exposed neonates are lacking. In the current study, we characterised circulating immune-cell populations in anti-Ro/La+mothers and newborns, and explored potential downstream effects of skewed neonatal cell populations.MethodsIn total, blood from mothers (n=43) and neonates (n=66) was sampled at birth from anti-Ro/La+ (n=36) and control (n=30) pregnancies with or without rheumatic disease and CHB. Flow cytometry, microarrays and ELISA were used for characterising cells and plasma.ResultsSimilar to non-pregnant systemic lupus erythematosus and Sjögren-patients, anti-Ro/La+mothers had altered B-cell subset frequencies, relative T-cell lymphopenia and lower natural killer (NK)-cell frequencies. Surprisingly, their anti-Ro/La exposed neonates presented higher frequencies of CD56dimCD16hiNK cells (p<0.01), but no other cell frequency differences compared with controls. Type I and II interferon (IFN) gene-signatures were revealed in neonates of anti-Ro/La+ pregnancy, and exposure of fetal cardiomyocytes to type I IFN induced upregulation of several NK-cell chemoattractants and activating ligands. Intracellular flow cytometry revealed IFNγ production by NK cells, CD8+and CD4+T cells in anti-Ro/La exposed neonates. IFNγ was also detectable in their plasma.ConclusionOur study demonstrates an increased frequency of NK cells in anti-Ro/La exposed neonates, footprints of type I and II IFN and an upregulation of ligands activating NK cells in fetal cardiac cells after type I IFN exposure. These novel observations demonstrate innate immune activation in neonates of anti-Ro/La+pregnancy, which could contribute to the risk of CHB.
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