Witold Skrzyński

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To evaluate the performance of computed tomography (CT) systems of various designs as a source of electron density (ρel) data for treatment planning of radiation therapy. Dependence of CT numbers on relative electron density of tissue-equivalent materials (HU-ρel relationship) was measured for several general-purpose CT systems (single-slice, multislice,(More)
Exposure doses to women undergoing screening mammography examinations should be kept as low as reasonably achievable, but they should ensure high enough image quality for adequate diagnosis. The aim of this study was to estimate the radiation risk according to the 'European guidelines for quality assurance in breast cancer screening and diagnosis', fourth(More)
Results of quality control (QC) tests for a period of over a year and patient doses were analysed for several computed tomography units in our centre. The results of the QC tests were generally within limits for all of the examined scanners, proving good and stable performance of the systems. The tests were not helpful in predicting breakdowns of the(More)
The purpose of this work is to compare the mean glandular dose (MGD) displayed by the mammography system and the MGD calculated according to the method proposed by Dance for women. This study also attempts to analyse whether the relationship between the calculated and the displayed values is constant and what factors influence this relationship. Material(More)
The aim of this work was to create a model of a wide-bore Siemens Somatom Sensation Open CT scanner for use with GMCTdospp, which is an EGSnrc-based software tool dedicated for Monte Carlo calculations of dose in CT examinations. The method was based on matching spectrum and filtration to half value layer and dose profile, and thus was similar to the method(More)
This paper presents the situation of the profession of medical physicists in Poland. The official recognition of the profession of medical physicist in Polish legislation was in 2002. In recent years, more and more Universities which have Physics Faculties introduce a medical physics specialty. At present, there are about 15 Universities which offer such(More)
BACKGROUND Different methods of image quality evaluation are routinely used for analogue and digital mammography systems in Poland. In the present study, image quality for several screen-film (SF), computed radiography (CR), and fully digital (DR) mammography systems was compared directly with the use of the ACR mammography accreditation phantom. (More)
The geometric accuracy of CT images is essential when they are used for planning radiation therapy. In this study, a method of quantitative testing of image rotation in CT is presented, based on the automated analysis of an image of a phantom half-filled with water. A plug-in was written for ImageJ software for automated detection of a water surface in an(More)
1H-NMR relaxation times are reported for native and thermally denatured lysozyme aqueous solutions measured as the function of the proton mole fraction in the sample. A two-exponential character of proton longitudinal relaxation function was observed for native lysozyme solutions: the fast component was attributed to the non-exchangeable protein protons,(More)
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