| 1. |
- Reza, Salim, 1985-, et al.
(författare)
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Smart dosimetry by pattern recognition using a single photon counting detector system in time over threshold mode
- 2012
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The function of a dosimeter is to determine the absorbed dose of radiation, for those cases in which, generally, the particular type of radiation is already known. Lately, a number of applications have emerged in which all kinds of radiation are absorbed and are sorted by pattern recognition, such as the Medipix2 application in [1]. This form of smart dosimetry enables measurements where not only the total dosage is measured, but also the contributions of different types of radiation impacting upon the detector surface. Furthermore, the use of a photon counting system, where the energy deposition can be measured in each individual pixel, ensures measurements with a high degree of accuracy in relation to the pattern recognition. In this article a Timepix [2] detector system has been used in the creation of a smart dosimeter for Alpha, Beta and Gamma radiation. When a radioactive particle hits the detector surface it generates charge clusters and those impacting upon the detector surface are read out and image processing algorithms are then used to classify each charge cluster. The individual clusters are calculated and as a result, the dosage for each type of radiation is given. In some cases, several particles can impact in roughly the same place, forming overlapping clusters. In order to handle this problem, a cluster separation method has been added to the pattern recognition algorithm. When the clusters have been separated, they are classified by shape and sorted into the correct type of radiation. The algorithms and methods used in this dosimeter have been developed so as to be simple and computationally effective, in order to enable implementation on a portable device. © 2012 IOP Publishing Ltd and SISSA.
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| 2. |
- Wallin, Ewa, et al.
(författare)
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Acute brain lesions on MRI in relation to neurological outcome 6 months after cardiac arrest treated with hypothermia.
- 2015
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Ingår i: Resuscitation. - : Elsevier BV. - 0300-9572 .- 1873-1570. ; 96:Suppl1, s. 147-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Aim of the study: To document the acute magnetic resonance imaging (MRI) findings on the brain in cardiac arrest (CA) patients treated with therapeutic hypothermia (TH) and their relation to patients’ neurological outcome after 6 months.Method: A prospective observational study with MRI was performed regardless the level of consciousness in 56 post-CA patients treated with TH.Results: MRI of the brain was obtained at a median of 4 days (3-13 days). At 6 months, 32/56 had survived with good neurological outcome. The MMSE was performed in 28/32 (88%) patients with a median of 28 (24-30). Acute ischemic lesions were found on diffusion-weighted MRI (DWI) in 34 (61%) patients and were more common in patients with poor outcome (p=0.006). Acute ischemic injuries affected mostly gray matter, deep or cortical and with or without involvement of the underlying white matter. Very few lesions were pure white matter lesions. Lesions in the occipital and temporal lobes, deep gray matter and cerebellum were most associated with poor outcome. Reductions in the apparent diffusion coefficient (ADC) were more common in patients with poor outcome, particularly in the occipital lobes. None of the patients with an ADC below 600x10-6 mm2/s in any region survived to 6 months.Conclusions: In visual analyses of acute MRI, extensive acute lesions were found in the cortical regions and gray matter and were associated with poor outcome. In ADC measurements, low values were associated with poor outcome. Patients with good outcome showed a minor pathological pattern mainly in the frontal and parietal lobes.
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| 3. |
- Rezasson, Reza, 1985-, et al.
(författare)
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A fast and non-destructive alternative to the burnout method for paperboard quality inspections using phase-contrast X-ray imaging
- 2023
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Ingår i: TAPPI Journal. - : TAPPI. - 0734-1415. ; 22:2, s. 99-106
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Tidskriftsartikel (refereegranskat)abstract
- An X-ray based quality inspection method for paperboard was implemented and tested as a fastand non-destructive alternative to the burnout method. An argument against X-ray imaging for inspection of paperand paperboard has been that X-ray absorption is low in paper. To overcome this limitation, we used phase-contrastX-ray imaging (PCXI), which gives higher contrast than conventional attenuation-based imaging for low-absorbingmaterials such as paper. The suggested PCXI method was applied to previously prepared and quality rated samplesusing the burnout method.A strong similarity between the burnout images and the PCXI images was observed. In conclusion, further devel-opment of the phase-contrast X-ray method would provide an interesting option for replacing or complementing thestandard burnout method.
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