Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: radiological density

Sortuj według:

Ogranicz wyniki do:

Analysis of the accuracy of mapping in computed tomography

Ryniewicz Andrzej, Rysz Konrad, Bojko Łukasz

Journal of Engineering, Energy and Informatics

2021

No. 1

53--68

The aim of the study is to assess the accuracy of mapping the internal structure and shape of phantoms in computed tomography (CT) imaging, using reconstructive metrology and virtual measurements. The tests material is tomographic imaging of diagnostic phantoms: the head phantom used for monthly calibrations of computer tomographs and the specialized phantom for tests performed once a year. The Materialize Mimics computer program was used to measure the geometry of objects inside the phantoms and to measure the radiological density in the cross-sections of the tested patterns. It is a universal tool for assessing the accuracy of mapping in CT imaging. The results of the measurements were used to perform a complete statistical analysis. The values of standard deviations for the performed measurements did not exceed the limit value, which means that the tested tomograph meets the requirements for homogeneity of imaging and noise level specified in the Regulation of the Minister of Health. The proposed procedure is important for the target device, but can also be a tool for comparing the quality of different tomographs.

Celem pracy jest ocena dokładności odwzorowania struktury wewnętrznej i kształtu fantomów w obrazowaniu tomografią komputerową (CT), z zastosowaniem metrologii rekonstrukcyjnej i pomiarów wirtualnych. Materiałem badań jest obrazowanie tomograficzne fantomów diagnostycznych: fantomu głowy używanego do comiesięcznych kalibracji tomografów komputerowych i fantomu specjalistycznego do testów wykonywanych raz w roku. Do pomiarów geometrii obiektów znajdujących się wewnątrz fantomów oraz pomiarów gęstości radiologicznej w przekrojach badanych wzorców wykorzystano program komputerowy Materialise Mimics. Stanowi on uniwersalne narzędzie do oceny dokładności odwzorowania w obrazowaniu CT. Wyniki pomiarów wykorzystano do przeprowadzenia pełnej analizy statystycznej. Wartości odchyleń standardowych dla wykonanych pomiarów nie przekroczyły wartości granicznej, co oznacza, że badany tomograf spełnia wymogi odnośnie do jednorodności obrazowania i poziomu szumów, ujęte w Rozporządzeniu Ministra Zdrowia. Zaproponowana procedura jest istotna dla docelowego urządzenia, ale może również stanowić narzędzie do porównania jakości różnych tomografów.

Distribution of radiological density in bone regenerate in relation to cyclic displacements of bone fragments

Filipiak J., Krawczyk A., Morasiewicz L.

Acta of Bioengineering and Biomechanics

2009

Vol. 11, nr 3

3-9

We asked how bone fragment displacement could influence the distribution of radiological density in bone regenerate formed during the process of bone lengthening. The metatarsi of 21 sheep were lengthened by 20 mm by the Ilizarov method. The bone fragments were externally fixed with a specially designed ring external fixator equipped with linear actuator driver system. The test sheep were divided into three experimental groups: the G1 and G2 groups (N = 8) and the GR group (N = 5) - the reference group. In the case of sheep from the G1 and G2 groups, the lengthening was supplemented with mechanical stimulation of the regenerate in the form of cyclic bone fragment displacements (CBFDs) with the amplitudes of 1 mm (G1) and 2 mm (G1). Mechanical stimulation was applied over 30 days for 1 h per day with a frequency of 1 Hz. Eight weeks after the procedure the sheep were sacrificed in accordance with the required procedures. The analysis of the degree of bone regenerate mineralization involved the studies based on the CT scanning. The analysis of the results obtained is based on the paramenter called the degree of regenerate mineralization (RMD). The analysis of radiological density was carried out in the selected measurement areas. Such an area was located in three horizontal zones, taking into account the regenerate height, i.e. in its middle part (half regenerate length); the top part, 2 mm from the edge of the proximal fragment; and the bottom part, 2 mm from the edge of the distal fragment. The value of the RMD parameter varies significantly, depending on the bone regenerate area. The results obtained show that the CBFD = 2 mm accelerates the rate of mineralization of an eight-week-old regenerate. In the case of CBFD = 1 mm, the mineralization rate is lower by more than a dozen per cent.