164 research outputs found
SPECT-CT fusion: a new diagnostic tool for endocrinology
Wstęp: Wprowadzenie standardu DICOM do wszystkich
urządzeń diagnostyki obrazowej umożliwiło fuzję obrazów
tomografii emisyjnej pojedynczego fotonu (SPECT, single
photon emission computed tomography), tomografii komputerowej
(CT, computed tomography), magnetycznego rezonansu
jądrowego (MRI, magnetic resonanse imaging) i innych typów
danych obrazowania biomedycznego. Fuzję można wykonywanywać
w dwojaki sposób, za pomocą dedykowanych
skanerów hybrydowych lub przez oprogramowanie niezwiązane
z konkretnym urządzeniem.
Technologia fuzji posiada niezmierny potencjał w diagnostyce
obrazowej do wykrywania licznych stanów, takich jak
choroby nowotworowe, choroba Alzheimera oraz inne zaburzenia
nerwowe.
W ośrodku autorów ponad 2 lata temu stopniowo wprowadzono
fuzję SPECT-CT w diagnostyce klinicznej wielu
schorzeń endokrynologicznych oraz onkologicznych. Użyto
danych obrazowych SPECT oraz CT wykonanych na oddzielnych
i niezależnych urządzeniach (dwugłowicowej
gamma-kamerze E.Cam-Duet firmy Siemens i szesnastorzędowym
tomografie komputerowym Somatom Sensation firmy
Siemens).
Materiał i metody: Prosty i szybki algorytm o niskiej złożoności
obliczeniowej zastosowano do wykonania fuzji kolejnych
81 przypadków. Trzydziestu dwóch pacjentów zakwalifikowano
do fuzji SPECT-CT po terapeutycznym leczeniu
131I u chorych po amputacji tarczycy z powodu raka, 12 - po
podaniu radioaktywnych analogów somatostatyny, 7 - po
terapeutycznym podaniu 131 I MIBG, 6 - po diagnostycznym podaniu MIBG z 131I lub 123I, 3 - po scyntygrafii przytarczyc
oraz 2 - po scyntygrafii kości.
Najbardziej powszechnym wskazaniem do fuzji była potrzeba
scharakteryzowania podejrzanych zmian wykrytych
na skanach CT poprzez zachodzące w nich zmiany metaboliczne.
Lokalizacja anatomiczna ognisk gromadzenia widzianych
na obrazach SPECT oraz ocena efektów terapii
radioizotopowej były kolejnymi najczęstszymi przyczynami
wskazań.
Wyniki: Obserwowane błędy nałożenia wynikały z tak zwanych
czynników ludzkich: nieprecyzyjnego wyboru położenia
markerów, ruchów oddechowych oraz przemieszczenia
markerów między kolejnymi badaniami. Fuzję ponad
74% chorych określono jako "bardzo dobrą" lub "dobrą".
Wnioski: Wybór chorych, wyszkolenie personelu (zwłaszcza
techników i fizyków) oraz współpraca z radiologiem to
najbardziej istotne czynniki, które umożliwiają właściwe zastosowanie
oraz interpretację fuzji obrazów SPECT-CT.Introduction: The introduction of the DICOM format in all
diagnostic imaging devices allowed coregistering SPECT,
CT, MR and other types of biomedical imaging. Fusion can
be performed by dedicated hybrid devices or by means of
software. The fusion algorithm consists of two steps: coregistration
and simultaneous visualization. Our center gradually
implemented SPECT-CT fusion in clinical diagnostic
work-up of several endocrinologic and oncologic diseases
more than 2 years ago.
Material and methods: An easy and fast algorithm in terms
of computational complexity of image fusion was presented
and applied to 81 consecutive cases. Thirty-two patients
were scheduled to SPECT-CT fusion after thyroidectomy
and 131I treatment for thyroid cancer, twelve after somatostatine
receptor scintigraphy, seven after 131I MIBG therapy,
six after diagnostic MIBG scintigraphy with 123I or 131I, three
after parathyroid scintigraphy and two after bone scan.
The most common indication to the fusion was the need of
metabolic characterization of suspected lesions detected on
CT scan. The anatomic localization of a focal uptake seen
on SPECT and the evaluation of the radiometabolic therapy
effect folloved.
Results: A variance of error level observed was a result of
human factor, decision on marker’s placement, respiratory movements and marker’s displacement between acquisitions.
However, 74% of patients in our series have fusion
results classified as "very good" or "good".
Conclusions: The selection of patients, the training of the
personel and the cooperation with radiologists are the most
important factors for a correct application and interpretation
of the SPECT-CT image fusion
Thermal and epithermal neutrons in the vicinity of the Primus Siemens biomedical accelerator
In this paper, the thermal and epithermal neutron fluence distributions in the vicinity of the Primus Siemens
accelerator are presented. The measurements were carried out by the use of the neutron activation method for 15 MV X-rays and electron beams of 18 MeV and 21 MeV. From the radiation safety point of view for the hospital personnel, it is important to know the thermal and epithermal neutron fluence distribution in the vicinity of the accelerator because the neutrons interacting with atoms of a medium by various processes induce the activity of objects (accelerator, other apparatus etc.) and walls in the treatment room. The thermal and epithermal neutron capture, particularly, in high atomic number materials of the accelerator head can be a significant source of gamma radiation and it has to be taken into account for estimation of the work safety of the personnel. Values of the neutron fluence were normalized to the maximum photon (or electron) dose Dmax,γ (e) measured at the central axis of therapeutic X-ray (or electron) beam in a water phantom. The thermal neutron fluences measured during the 15 MV X-ray emission varied between 1.1 × 105 n · cm−2· Gy−1 and 4.4 × 105 n · cm−2· Gy−1 whereas the epithermal neutron fluences ranged from 0.2 × 105 n · cm−2· Gy−1 to 1.8 × 105 n · cm−2· Gy−1. In the case of electron beams, the neutron fluence measurements were performed only at the
isocentre. The obtained thermal and epithermal neutron fluences were 1.2 × 104 n · cm−2· Gy−1 and 0.6 × 104 n · cm−2· Gy−1, respectively, for the 18 MeV electrons. In the the case of the 21 MeV electron beams the thermal neutron fluence was 2.0 × 104 n · cm−2· Gy−1 whereas the epithermal neutron fluence was 0.8 × 104 n · cm−2· Gy−1
IMPROVEMENT OF THE MECHANICAL PROPERTIES OF MOBILE PLATFORM STAINLESS CONSTRUCTION ELEMENTS
Stainless steel could be treated as the main material used to construct various means of transport, including mobile platforms and tank trucks. An austenitic steel known as 316L steel (1.4401) has high resistance to atmospheric corrosion, natural waters, water vapor, alkaline solutions, and acids, even at elevated temperatures. This steel is weldable, although it is also prone to various types of welding cracks. Many factors influence the quality and mechanical properties of a joint. The most significant of these is the appropriate selection of welding parameters, which should be determined precisely and separately for each type of sheet, depending on its thickness and geometric features. The aim of the present article is to study the influence of main TIG (Tungsten inert gas) welding parameters on the creation of proper joints used in the construction of mobile truck platforms or tank trucks. The proper selection of parameters enables the production of welds with good functional properties. A novelty of this article is the proposal to weld each layer of a thick joint with different parameters, which has an important influence on the mechanical properties of the joint. It is expected that the new material and technological solution will yield a joint with good corrosion resistance and increased mechanical properties. This is important in the responsible construction of means of transport, using the example of mobile platforms and tank trucks. Different tests verifying the properties of joints, including non-destructive testing, tensile strength tests, and fatigue tests, as well as a hardness probe, were applied
Manufacturing and characterization of epoxy resin with Fe3O4 and SiO2 particles
Thermosetting polymers are very popular in the automotive and aeronautic industry, in particular epoxy resin is widely used as matrix thermoset in carbon and glass fibre reinforced composites. The properties of these epoxy-based polymers can be improved with the addition of particulate or small fibre materials in order to construct a lightweight material with enhanced mechanical and structural response. This work aimed to manufacture and characterize epoxy resin reinforced composites with iron (II,
III) oxide (magnetite, Fe3O4) in amounts of 0.25, 0.5 and 1 wt%, and 2 and 4 wt% of fumed silicon dioxide (silica, SiO2). Mechanical properties were investigated by three-point bending flexural test, fracture toughness, flexural stress relaxation. In addition, apparent porosity, apparent density and Differential Scanning Calorimetry tests were performed. The results showed that the addition of Fe3O4 does not contribute significantly to the improvement of mechanical properties. However, fumed SiO2 promotes a considerable improvement in the mechanical properties.
Keywords: Composite, epoxy resin, Fe3O4, SiO2, mechanical propertie
Knowledge centers as an innovative knowledge transfer mechanism : lesson learned from the program implemented in Lesser Poland
The aim of the paper is to present the lessons learnt from the "SPIN" regional public project. The project was implemented in the region of Lesser Poland. The objective of the project was to increase the intensity of knowledge transfer from universities to enterprises. The goal was achieved by establishing four Centres for Knowledge Transfer at major universities. Each of them was dedicated to a specific
domain of knowledge - regional smart specialization - biotechnology, translational medicine, smart grids and energy-saving buildings. The paper discusses the implementation and effects of the project. The most important conclusions stemming from the project concern the fact that the context of the implementation needs to be taken into account during the project as well as the importance of leadership. More attention should also be devoted to the motivation and skills of those involved in the implementation
IMPACT ANALYSIS OF MICRO-JET COOLING FOR STRESS CONCENTRATION IN A CRANE BUMPER DURING A COLLISION
In the structure of crane bumpers, there is a need to join various types of steel. Usually, low-alloy steel structures are used for this purpose, which can be represented by S355J2 steel. The tensile strength of S355J2 low-alloy steel is slightly below 600 MPa, and the tensile strength of S355J2 steel is at the high level of 200 J at ambient temperature. The impact strength of this steel in negative temperatures is also good at over 47 J at -60 °C, so it meets the 6th class of impact toughness. Welding structures, after classic gas metal arc welding (GMAW) processes, meet only the second impact toughness class. An improved GMAW process was used by micro-jet cooling application to raise the mechanical properties of the joints. The microstructure and main properties of the joints were carefully analyzed. The influence of using the new suggested welding process on the various properties of the welds is presented (UTS – ultimate tensile strength, YS – yield strength, Poisson ratio, elongation, Young’s modulus). Then, the effects of tests for use in crane bumper construction were checked by using a hybrid finite element method (FEM) analysis
Vocational education : barrier or chance on the labour market? : results of the Human Capital Study
Rozdział zawiera wyniki analizy sytuacji pracowników z wykształceniem zawodowym na rynku pracy w Polsce, a jego najważniejszym celem jest ocena szans rynkowych, jakie obecnie stwarza ukończenie szkoły zawodowej. Sytuację pracowników, które posiadają ten rodzaj wykształcenia przedstawiono z dwóch perspektyw - pracodawców i pracowników. Najpierw scharakteryzowano więc poziom zgłaszanego przez pracodawców zapotrzebowania na pracowników z wykształceniem zawodowym, występujące trudności rekrutacyjne, rodzaj stawianych tym pracownikom wymagań. Odniesiono się także do tego, jak pracodawcy postrzegają możliwości rozwoju kompetencji pracowników z wykształceniem zawodowym oraz jakie formy uczenia się uznają za właściwe dla tej grupy. Następnie, przyjmując perspektywę pracowników, pokazano, jak osoby z wykształceniem zawodowym radzą sobie na ryku pracy pod względem poziomu zatrudnienia, stabilności tego zatrudnienia, miejsca w hierarchii stanowisk pracy, poziomu zarobków. Pokazano też, jak pracownicy ci oceniają przydatność wiedzy i umiejętności wyniesionych ze szkoły oraz własne kompetencje uniwersalne. W rozdziale wykorzystano wyniki badania pracodawców, ludności i ofert pracy z projektu Bilans Kapitału Ludzkiego z lat 2010-2017.The chapter presents the results of the analysis of the condition of people with vocational education in the labour market in Poland. Main goal is to analyse chances of people with that level of education in the labour market. Their chances are presented from two perspectives - employers and workers. In the first part, the demand for employees with vocational education is described, followed by characteristic of requirements of employers towards them, as well as the recruitment problems indicated by the employers. The first part of the chapter shows also how employers perceive the competences’ development opportunities of employees with vocational education and what forms of learning they consider appropriate for this group. The second part focuses on the employees' perspective and presents how people with vocational education cope in the labour market in terms of employment level, job stability, position in the hierarchy of occupations and earnings. It also shows how those employees assess the usefulness of knowledge and skills acquired at school and their own general competences. Analyses presented in the chapter are based on the data from surveys of employers, general population and research of the job offers carried out in Study of Human Capital in Poland project in 2010-2017
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