Search

Jakość powietrza wewnętrznego istotnie wpływa na funkcjonowanie osób korzystających z zamkniętych przestrzeni. Celem badań było stworzenie prototypu zielonej instalacji mającej korzystnie oddziaływać na mikroklimat pomieszczenia dzięki odpowiedniemu doborowi roślin, a także stworzeniu systemu praktycznie bezobsługowego, działającego również przy niedoborach światła dziennego. W ramach studium literaturowego wytypowano szereg roślin z grupy tzw. oczyszczaczy powietrza. W pracy koncepcyjnej stworzono projekt, a następnie dwa prototypy zielonej instalacji w celu sprawdzenia słuszności założeń. Wykonano analizy mikrobiologiczne powietrza w pomieszczeniu ze względu na fakt, że hodowle roślin stanowią dodatkowe źródło mikroorganizmów w powietrzu pomieszczeń.

W edukacji akademickiej coraz większą popularność zdobywa metoda zwana Project Based Learning (PBL). Jej istotą jest pozyskiwanie przez studentów pracujących w grupie kompetencji i wiedzy poprzez samodzielną pracę projektową przy jedynie mentorskim udziale nauczycieli. Na Politechnice Śląskiej metoda ta jest wdrażana od kilku lat. W ramach relacjonowanego PBL, zrealizowanego w semestrze zimowym roku akademickiego 2020/2021, zadaniem studentów było w pierwszej kolejności rozpoznanie charakterystycznych potrzeb oraz ograniczeń osób niewidomych i słabowidzących (z wykorzystaniem metody badań ankietowych), a następnie opracowanie zgodnie z zasadami projektowania uniwersalnego koncepcji architektonicznej imitującej tor przeszkód – tytułowej ścieżki adaptacyjnej.

Histopathological analysis is the current gold standard in breast cancer diagnosis and management, however, as imaging technology improves, the amount of potential diagnostic information that may be demonstrable radiologically should also increase. We aimed to evaluate the potential clinical usefulness of 3-D phase-contrast micro-computed tomography (micro-CT) imaging at high spatial resolutions as an adjunct to conventional histological microscopy. Ten breast tissue specimens, 2 mm in diameter, were scanned at the SYRMEP beamline of the Elettra Synchrotron using the propagation-based phase-contrast micro-tomography method. We obtained $1.2~\mu \text{m}$ pixel size images, which were analyzed and compared with corresponding histological sections examined under light microscopy. To evaluate the effect of spatial resolution on breast cancer diagnosis, scans with four different pixel sizes were also performed. Our comparative analysis revealed that high-resolution images can enable, at a near-histological level, detailed architectural assessment of tissue that may permit increased breast cancer diagnostic sensitivity and specificity when compared with current imaging practices. The potential clinical applications of this method are also discussed.

Propagation-based phase-contrast CT (PB-CT) is a novel imaging technique that visualises variations in both X-ray attenuation and refraction. This study aimed to compare the clinical image quality of breast PB-CT using synchrotron radiation with conventional absorption-based CT (AB-CT), at the same radiation dose. Seven breast mastectomy specimens were scanned and evaluated by a group of 14 radiologists and medical imaging experts who assessed the images based on seven radiological image quality criteria. Visual grading characteristics (VGC) were used to analyse the results and the area under the VGC curve was obtained to measure the differences between the two techniques. For six image quality criteria (overall quality, perceptible contrast, lesion sharpness, normal tissue interfaces, calcification visibility and image noise), PB-CT images were superior to AB-CT images of the same dose (AUCVGC: 0.704 to 0.914, P≤.05). For the seventh criteria (artefacts), PB-CT images were also rated better than AB-CT images (AUCVGC: 0.647) but the difference was not significant. The results of this study provide a solid basis for future experimental and clinical protocols of breast PB-CT.

To evaluate and compare the image quality of propagation-based phase-contrast computed tomography (PB-CT) using synchrotron radiation and conventional cone-beam breast computed tomography (CBBCT) based on various radiological image quality criteria. Eight excised breast tissue samples of various sizes and containing different lesion types were scanned using PB-CT at a synchrotron facility and using CBBCT at a university-affiliated breast imaging centre. PB-CT scans were performed at two different mean glandular dose (MGD) levels: standard (5.8 mGy) and low (1.5 mGy), for comparison with CBBCT scans at the standard MGD (5.8 mGy). Image quality assessment was carried out using six quality criteria and six independent medical imaging experts in a reading room with mammography workstations. The interobserver agreement between readers was evaluated using intraclass correlation coefficient (ICC), and image quality was compared between the two breast imaging modalities using the area under the visual grading characteristic curve (AUCVGC). Interobserver agreement between the readers showed moderate reliability for five image criteria (ICC: ranging from 0.488 to 0.633) and low reliability for one criterion (image noise) (ICC 0.307). For five image quality criteria (overall quality, perceptible contrast, lesion sharpness, normal tissue interfaces, and calcification visibility), both standard-dose PB-CT images (AUCVGC 0.958 to 1, p ≤ .05) and low dose PB-CT images (AUCVGC 0.785 to 0.834, p ≤ .05) were of significantly higher image quality than standard-dose CBBCT images. Synchrotron-based PB-CT can achieve a significantly higher radiological image quality at a substantially lower radiation dose compared with conventional CBBCT. • PB-CT using synchrotron radiation results in higher image quality than conventional CBBCT for breast imaging. • PB-CT using synchrotron radiation requires a lower radiation dose than conventional CBBCT for breast imaging. • PB-CT can help clinicians diagnose patients with breast cancer.

The aim of this study was to optimise the experimental protocol and data analysis for in-vivo breast cancer x-ray imaging. Results are presented of the experiment at the SYRMEP beamline of Elettra Synchrotron using the propagation-based phase-contrast mammographic tomography method, which incorporates not only absorption, but also x-ray phase information. In this study the images of breast tissue samples, of a size corresponding to a full human breast, with radiologically acceptable x-ray doses were obtained, and the degree of improvement of the image quality (from the diagnostic point of view) achievable using propagation-based phase-contrast image acquisition protocols with proper incorporation of x-ray phase retrieval into the reconstruction pipeline was investigated. Parameters such as the x-ray energy, sample-to-detector distance and data processing methods were tested, evaluated and optimized with respect to the estimated diagnostic value using a mastectomy sample with a malignant lesion. The results of quantitative evaluation of images were obtained by means of radiological assessment carried out by 13 experienced specialists. A comparative analysis was performed between the x-ray and the histological images of the specimen. The results of the analysis indicate that, within the investigated range of parameters, both the objective image quality characteristics and the subjective radiological scores of propagation-based phase-contrast images of breast tissues monotonically increase with the strength of phase contrast which in turn is directly proportional to the product of the radiation wavelength and the sample-to-detector distance. The outcomes of this study serve to define the practical imaging conditions and the CT reconstruction procedures appropriate for low-dose phase-contrast mammographic imaging of live patients at specially designed synchrotron beamlines.

PURPOSE Propagation-based phase-contrast computed tomography (PB-CT) is a method for three-dimensional x-ray imaging that utilizes refraction, as well as absorption, of x rays in the tissues to increase the signal-to-noise ratio (SNR) in the resultant images, in comparison with equivalent conventional absorption-only x-ray tomography (CT). Importantly, the higher SNR is achieved without sacrificing spatial resolution or increasing the radiation dose delivered to the imaged tissues. The present work has been carried out in the context of the current development of a breast CT imaging facility at the Australian Synchrotron. METHODS Seven unfixed complete mastectomy samples with and without breast cancer lesions have been imaged using absorption-only CT and PB-CT techniques under controlled experimental conditions. The radiation doses delivered to the mastectomy samples during the scans were comparable to those approved for mammographic screening. Physical characteristics of the reconstructed images, such as spatial resolution and SNR, have been measured and compared with the results of the radiological quality assessment of the complete absorption CT and PB-CT image stacks. RESULTS Despite the presence of some image artefacts, the PB-CT images have outperformed comparable absorption CT images collected at the same radiation dose, in terms of both the measured objective image characteristics and the radiological image scores. The outcomes of these experiments are shown to be consistent with predictions of the theory of PB-CT imaging and previous reported experimental studies of this imaging modality. CONCLUSIONS The results presented in this paper demonstrate that PB-CT holds a high potential for improving on the quality and diagnostic value of images obtained using existing medical x-ray technologies, such as mammography and digital breast tomosynthesis (DBT). If implemented at suitable synchrotron imaging facilities, PB-CT can be used to complement existing imaging modalities, leading to more accurate breast cancer diagnosis.

In this study we demonstrate the first direct comparison between synchrotron x-ray propagation-based CT (PB-CT) and cone-beam breast-CT (CB-CT) on human mastectomy specimens (N = 12) including different benign and malignant lesions. The image quality and diagnostic power of the obtained data sets were compared and judged by two independent expert radiologists. Two cases are presented in detail in this paper including a comparison with the corresponding histological evaluation. Results indicate that with PB-CT it is possible to increase the level of contrast-to-noise ratio (CNR) keeping the same level of dose used for the CB-CT or achieve the same level of CNR reached by CB-CT at a lower level of dose. In other words, PB-CT can achieve a higher diagnostic potential compared to the commercial breast-CT system while also delivering a considerably lower mean glandular dose. Therefore, we believe that PB-CT technique, if translated to a clinical setting, could have a significant impact in improving breast cancer diagnosis.

LiF:Mg,Cu,P thermoluminescent glow-curve, which shape up to a dose of 1 Gy is remarkably invariable, at higher doses undergoes very strong changes. The most important of them is an occurrence of a new high-temperature peak B, which shows a peculiar property: its position shifts towards higher temperatures with increasing doses. In this work, the possibility of exploiting this shift of peak position for ultra-high-dose dosimetry is studied. The performed investigations, after irradiations with 6 MeV electron doses ranging up to 1.2 MGy confirmed that this property may be indeed successfully used for dosimetry. For doses exceeding about 40 kGy, i.e. for glow-curves for which peak B is well visible, the method based on the simple evaluation of the position of the global maximum of a glow-curve produced very good results. The use of peak position as a measure of the dose makes the proposed method extraordinary resistant to applications at high-temperature conditions. It was found, that it is possible to perform correct measurement of the absorbed dose with detectors subjected before the readout to a pre-heat even up to 350 °C.

Phase-contrast imaging of the breast is expected to deliver significantly improved image quality and diagnostic value at a reduced radiation dose compared to present-day 2D X-ray mammography, digital breast tomosynthesis (DBT) and computed tomography (CT) and become a viable method for early diagnosis of breast cancer in women. This paper builds upon the evaluation of a novel protocol to evaluate 3D mammographic phase contrast imaging for the detection of breast cancer undertaken with a purpose designed phantom and selected breast cancer specimens. Following evaluation, propagation-based phase contrast imaging was demonstrated to have high contrast to noise ratio alongside an important reduction in radiation dose. The challenge now is to shift the focus of research to real clinic solutions, with the worldfirst demonstration of X-ray in-line full field phase-contrast mammographic tomography (PCT) with cancer patients through an international collaboration of a multi-disciplinary team.

Rationale and Objectives This study employs clinical/radiological evaluation in establishing the optimum imaging conditions for breast cancer imaging using the X-ray propagation-based phase-contrast tomography. Materials and Methods Two series of experiments were conducted and in total 161 synchrotron-based computed tomography (CT) reconstructions of one breast mastectomy specimen were produced at different imaging conditions. Imaging factors include sample-to-detector distance, X-ray energy, CT reconstruction method, phase retrieval algorithm applied to the CT projection images and maximum intensity projection. Observers including breast radiologists and medical imaging experts compared the quality of the reconstructed images with reference images approximating the conventional (absorption) CT. Various radiological image quality attributes in a visual grading analysis design were used for the radiological assessments. Results The results show that the application of the longest achievable sample-to-detector distance (9.31 m), the lowest employed X-ray energy (32 keV), the full phase retrieval, and the maximum intensity projection can significantly improve the radiological quality of the image. Several combinations of imaging variables resulted in images with very high-quality scores. Conclusion The results of the present study will support future experimental and clinical attempts to further optimize this innovative approach to breast cancer imaging.

The aim of this study was to highlight the advantages that propagation-based phase-contrast computed tomography (PB-CT) with synchrotron radiation can provide in breast cancer diagnostics. For the first time, a fresh and intact mastectomy sample from a 60 year old patient was scanned on the IMBL beamline at the Australian Synchrotron in PB-CT mode and reconstructed. The clinical picture was described and characterized by an experienced breast radiologist, who underlined the advantages of providing diagnosis on a PB-CT volume rather than conventional two-dimensional modalities. Subsequently, the image quality was assessed by 11 breast radiologists and medical imaging experts using a radiological scoring system. The results indicate that, with the radiation dose delivered to the sample being equal, the accuracy of a diagnosis made on PB-CT images is significantly higher than one using conventional techniques.

In search of origin and mechanism of the high-dose high-temperature TL emission with presence of the peak ‘B’ about thirty batches of LiF:Mg,Cu,P detectors with different dopants' concentration were produced and comprehensive studies of their high-dose TL features have been performed. Within each step of the research, these characteristics were compared with the high-dose TL properties of the typical MCP-N detectors' batch highly exposed simultaneously with the detectors from batches of varying dopants concentration. We determined the effect of concentration of specific dopants on the TL peak ‘B’. It was found that both magnesium and copper are necessary to obtain high-dose TL signal, however, the important for high-dose TL features seems to be also concentration of phosphorus. In the framework of this study we present results of magnesium and copper concentration changes to the TL signal after high-doses of electron radiation.