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- Bujila, Robert, et al.
(författare)
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A validation of SpekPy: A software toolkit for modelling X-ray tube spectra
- 2020
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Ingår i: Physica medica (Testo stampato). - : Elsevier BV. - 1120-1797 .- 1724-191X. ; 75, s. 44-54
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To validate the SpekPy software toolkit that has been developed to estimate the spectra emitted fromtungsten anode X-ray tubes. The model underlying the toolkit introduces improvements upon a well-knownsemi-empirical model of X-ray emission.Materials and methods: Using the same theoretical framework as the widely-used SpekCalc software, new electronpenetration data was simulated using the Monte Carlo (MC) method, alternative bremsstrahlung crosssectionswere applied, L-line characteristic emissions were included, and improvements to numerical methodsimplemented. The SpekPy toolkit was developed with the Python programming language. The toolkit was validatedagainst other popular X-ray spectrum models (50 to 120 kVp), X-ray spectra estimated with MC (30 to150 kVp) as well as reference half value layers (HVL) associated with numerous radiation qualities from standardlaboratories (20 to 300 kVp).Results: The toolkit can be used to estimate X-ray spectra that agree with other popular X-ray spectrum modelsfor typical configurations in diagnostic radiology as well as with MC spectra over a wider range of conditions.The improvements over SpekCalc are most evident at lower incident electron energies for lightly and moderatelyfiltered radiation qualities. Using the toolkit, estimations of the HVL over a large range of standard radiationqualities closely match reference values.Conclusions: A toolkit to estimate X-ray spectra has been developed and extensively validated for central-axisspectra. This toolkit can provide those working in Medical Physics and beyond with a powerful and user-friendlyway of estimating spectra from X-ray tubes.
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| 2. |
- Esposito, M, et al.
(författare)
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PRaVDA: The first solid-state system for proton computed tomography
- 2018
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Ingår i: Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB). - : Elsevier BV. - 1724-191X. ; 55, s. 149-154
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Karambatsakidou, A, et al.
(författare)
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Age-specific and gender-specific radiation risks in paediatric angiography and interventional cardiology: conversion coefficients and risk reference values
- 2020
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Ingår i: The British journal of radiology. - : British Institute of Radiology. - 1748-880X .- 0007-1285. ; 93:1110, s. 20190869-
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Tidskriftsartikel (refereegranskat)abstract
- To estimate risk for exposure-induced cancer death (REID), organ-specific risks of exposure-induced cancer death (REIDHT) and associated conversion coefficients (CCREID:KAP=REID/kerma-area product (KAP), CCREIDHT:KAP=REIDHT/KAP) in paediatric cardiac catheterizations using data from radiation dose structured reports (RDSR). A novel risk surveillance tool consisting of age-specific and gender-specific risk reference values (RRVs) related to population cancer risk is suggested. Methods: The PCXMC v.2.0 code is used together with exposure-related information from RDSR from a cohort of 238 children to assess cancer risks and related conversion coefficients. The KAP corresponding to 1 in 1000 of increased REID is used to define age-specific and gender-specific KAP values to monitor risk in such patient cohorts, here denoted as RRVs. Results: The REID estimates ranged from below 1 up to 300 in 100,000, and the RRVs for the different age groups and gender ranged from 0.77 Gycm2 and 2.1 Gycm2 for neonates (female, male) to 11 Gycm2 and 25 Gycm2 for 15-year-olds (female, male). The CCREID:KAP and CCREIDHT:KAP decreased biexponentially with increased age, being notably higher for female patients. Conclusions: Prominent risk contributing organs were the lungs and the (female) breast. The concept of age-specific and gender-specific RRVs related to population cancer risk is introduced and is intended to be used as a supporting tool for physicians performing such interventions. Advances in knowledge: Age-related and gender-related conversion coefficients for radiation risk, CCREID:KAP and CCREIDHT:KAP, are introduced and a novel risk surveillance concept, the RRV, is suggested for paediatric cardiac catheterizations.
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| 9. |
- Merzan, D., et al.
(författare)
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Evaluating the impact of scan settings on automatic tube current modulation in CT using a novel phantom
- 2017
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Ingår i: British Journal of Radiology. - : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 90:1069
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study was to make a comprehensive evaluation of how variable scan settings can affect the performance of automatic tube current modulation (ATCM) in recent CT scanners from the four major manufacturers. Methods: A phantom was designed and manufactured for the purpose of evaluating ATCM. The phantom was scanned with four categories of systematically varied settings (scan projection radiograph, technique and reconstruction parameters and phantom miscentring). The performance of ATCM, in terms of applied tube current and noise uniformity, for the scans with varied settings was compared with a reference scan using subjective and quantitative approaches. Results: The ATCM implemented by each manufacturer is based on different principles and any affect to the performance of the ATCM, when varying scan settings, will manifest differently among the vendors. The results are summarized in four tables corresponding to the categories of varied settings. Conclusion: The developed phantom proved useful for evaluating the ATCM. It is important to understand how different implementations (vendor specific) of ATCM perform in order to make informed decisions about the selection of scan settings when designing protocols. The resulting tables can serve as a reference for understanding the different implementations of ATCM and highlight settings that should be taken into consideration when adjusting an imaging protocol. Advances in knowledge: The results from this work can serve as a reference for how changes in geometry or scan settings can affect the performance of ATCM, in terms of tube current and noise.
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