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Assessment of Radiation Doses for Paediatric Head, Chest, and Abdominopelvic Computed Tomography Examinations in a Teaching Hospital in Ghana

Amedzoame Bernard, Brobbey Isaac Frimpong, Djan Bismark, Acquah Isaac Kwesi, Tetteh Mercy Afadzi

Polish Journal of Medical Physics and Engineering

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2025

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Vol. 31, Iss. 3

256--262

EN

Introduction: With the increasing number of pediatric computed tomography (CT) examinations, there is a need to optimise protocols for children by adopting examination-specific protocols customised to the patient’s age, size, imaging region, and clinical indication. This study aimed to assess the radiation doses in pediatric CT examinations and compare them to international standards. Material and methods: A cross-sectional retrospective study design was adopted to probe patient records at the radiology department of a teaching hospital in Ghana. Thus, scan parameters, volume computed tomography dose index (CTDIvol), dose length product (DLP), as well as demographic data, were recorded from 496 pediatric patients (age 0-15 years) undergoing head, chest, and abdominopelvic CT examinations. Local Diagnostic Reference Levels (LDRLs) were established using the 75th percentile of patient dose values for each protocol and age group. These local levels were then compared with DRLs from other studies. Results: Head CT was the most performed examination (35.0%) compared to chest (32.0%) and abdominopelvic (33.0%). The male group recorded the highest (59.1%) percentage of CT examinations compared to the female group. While LDRL values from this study were generally lower than data from other studies, the CTDIvol and DLP for head scans of patients between 11 and 15 years were found to be higher than the data from other studies. Conclusions: Our study has established LDRLs for standard pediatric CT examinations in the teaching hospital. The LDRLs were generally lower than those reported in other studies, except for head scans in patients aged 11 to 15 years. These findings suggest that there are opportunities for further optimisation of pediatric CT imaging protocols at this facility.

2

Full-Field Force Mapping of Cutting Forces Driven by Local Density Variations in Norway Spruce Wood

Mellqvist Daniel, Buck Dietrich, Johansson Jimmy

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2025

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No. 131

44--53

EN

Full-Field Force Mapping of Cutting Forces Driven by Local Density Variations in Norway Spruce Wood. Local density variations in wood influence cutting performance. In this study, full-field force mapping was applied to investigate the relationship between density distribution and cutting forces. Cutting forces were measured using piezoelectric transducers during cutting of Norway spruce. X-ray computed tomography (CT) scans of the workpiece provided spatially resolved density data. Force maps were constructed by aligning recorded forces with kerf positions and CT data. Results showed that cutting forces increased in regions of higher density, particularly near knot boundaries and latewood zones. Inner knot areas exhibiting lower density correlated with reduced cutting forces. Normal-force patterns were less responsive to local density changes. No self-feeding behaviour was observed. The integrated CT–force mapping technique enables spatial analysis of cutting responses in relation to anatomical wood features.

3

Wykorzystanie tomografii komputerowej oraz SEM w ocenie morfologii przekrojów próbek azotanu(V) amonu

Biessikirski Andrzej, Kuterasiński Łukasz, Dworzak Michał, Kolano Malwina, Ruggiero-Mikołajczyk Małgorzata

Przemysł Chemiczny

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2024

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T. 103, nr 7

805--810

PL

Przedstawiono wyniki badań doświadczalnych związanych z analizą powierzchni morfologicznej w przekrojach granul porowaconego i rolniczego azotanu(V) amonu. Ocenę morfologii przeprowadzono z wykorzystaniem SEM oraz tomografii komputerowej. Przekroje próbek azotanu(V) amonu charakteryzowały się strukturą przypomi nająca pumeks. Wykazały występowanie niewielkiej liczby kanałów oraz brak chropowatości powierzchni krystalicznej. W przypadku porowaconego azotanu(V) amonu próbki charakteryzowały się zróżnicowaną budową wynikającą z różnych procesów produkcyjnych. Obie próbki wykazywały dużą liczbę porów, m.in. obecność porów kulistych i wydłużonych. Ponadto w przypadku AN-PP-2 w przekroju próbki widoczna była centralna pustka powietrzna, która nie znajdowała się na żadnym ze skanów dla AN-PP-1. Porowacony azotan(V) amonu charakteryzował się dużą porowatością, rzędu 60-70%, w po równaniu z porowatością rolniczego azotanu(V) amonu (ok. 49%). Przeprowadzone badania BET wykazały, że AN-PP-2 charakteryzował się największą powierzchnią właściwą, ok. 0,5 m²/g, co przy uwzględnieniu mocno rozwiniętej budowy morfologicznej potwierdza wysokie określane przez producenta współczynniki absorpcji.

EN

The morphology of cross sections of porous and agricultural NH₄NO₃ granules was analyzed by scanning electron microscopy (SEM), computed tomography and low-temperature nitrogen sorption. Agricultural NH₄NO₃ showed a pumice-like structure, characterized by a small number of channels and a smooth crystalline surface but samples of prilled NH₄NO₃ showed a significant presence of pores, including spherical and elongated pores. The porosity of prilled and agricultural NH₄NO₃ was 70 and 49%, resp. and BET surface area of both materials was 0.5 m²/g and 0.01 m²/g resp.

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Investigation of the effectiveness of eight different metal artifact reduction algorithms in reducing extracorporeal metal artifacts: a phantom study using the Gumbel method

Suzuki Keiko, Muto Hiroe

Polish Journal of Medical Physics and Engineering

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2024

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Vol. 30, Iss. 4

189--196

EN

Introduction: Metal Artifact Reduction (MAR) processing has been clinically applied to computed tomography (CT) images using various methods. Iterative MAR (iMAR) is an algorithm for reducing metal artifacts from implants and is tailored to the type, shape, and imaging site of a metal object. Various implants have been targeted using iMAR; however, there are some implants and metals that do not have a dedicated iMAR. The potential of iMAR for managing such artifacts has not yet been explored. Utilizing iMAR in unavoidable extracorporeal metal artifact cases could improve diagnosis. We aimed to assess whether the iMAR reduces extracorporeal metal artifacts and enhances image quality. Material and methods: CT was performed on a whole-body phantom with electrocardiogram (ECG) electrodes attached. Images were obtained without the iMAR and with eight different iMAR processings. The CT value profiles were perpendicular to the direction of artifact generation, and the maximum adjacent CT value difference was extracted from each CT value profile as the largest variation. The cumulative probabilities for the largest variations were obtained, and the location and scale parameters were calculated from the cumulative probability plots. Kruskal–Wallis tests and multiple comparisons were performed on nine different images. Results: Regarding the 100 cumulative probability plots of the largest variations obtained from each CT value profile, the coefficients of determination (R2) for all cumulative probability plots were as high as > 0.84, indicating that the features of the extracorporeal metal artifact generated from the ECG electrodes evaluated in this study asymptotically approached a Gumbel distribution. The location parameters showed no significant differences among the nine processed images (p > 0.11), whereas the scale parameters showed significant differences for neuro coil, shoulder implant, extremity implant, and thoracic coil iMAR-processed images compared with controls (p < 0.05). Conclusion: iMAR may improve diagnosis by reducing extracorporeal metal artifacts and enhancing image quality.

5

Analysis of the frequency and type of CT examinations performed in Poland in 2022

Pankowski Piotr, Wrzesień Małgorzata

Polish Journal of Medical Physics and Engineering

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2024

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Vol. 30, Iss. 1

11--17

EN

Introduction: Computed tomography (CT) is one of the most widely used diagnostic procedures in modern medicine. Despite many technical improvements, CT still exposes patients to significantly higher doses of radiation than other methods of diagnostic imaging. The presented analysis of the number of CT scans performed in Poland in 2022 aims to designate priorities in the process of optimising radiation protection and makes it possible to identify those examinations and patient groups for which action is particularly justified. Material and methods: The data presented is based on an analysis of the National Health Fund (NHF) database of medical services reimbursed in 2022. According to the NHF data, approximately 5.1 million CT examinations were performed. The coding of reimbursed medical procedures used by the NHF in 2022 included 45 different CT procedures. Results: The highest ratio of the number of examinations performed to the number of patients was found in the age group 59-75 years (average 1.35). This ratio varied according to examination type and was closest to 1 for spine and extremities examinations (between 1.1 and 1.2 on average). Irrespective of patients’ age and type of examination, the proportion of female and male patients fluctuates around 50%. Approximately 82% of head and neck examinations are single-phase CTs. Examinations with two or more phases account for about 17% and less than 1%, respectively. Conclusions: Over the past 10 years, both the number of CT scanners and the number of annually performed scans have doubled. Relative to the population size, this is a rate of about 22 scanners per one million people, an average level for European countries, ranging from a maximum of around 37 for Italy and Germany to around 20 for France, Spain, and Romania, according to Eurostat data.

6

Współczesne wyzwania i przyszłość algorytmów rekonstrukcyjnych w CT: aktualne problemy i kierunki rozwoju

Podolszańska Jolanta

Inżynier i Fizyk Medyczny

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2024

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Vol. 13, nr 5

495--501

PL

W ostatnich latach algorytmy rekonstrukcyjne w obrazowaniu medycznym przeszły znaczną ewolucję, w dużej mierze dzięki wykorzystaniu sztucznej inteligencji oraz technik głębokiego uczenia. Tradycyjne podejścia, takie jak filtracja wsteczna, są coraz częściej zastępowane przez iteracyjne algorytmy rekonstrukcyjne, które lepiej radzą sobie z redukcją szumów i artefaktów w obrazach niskiej dawki promieniowania. Kompresja danych oraz zastosowanie modeli hybrydowych, które łączą klasyczne metody z nowoczesnymi technologiami AI, umożliwiają szybszą i bardziej dokładną rekonstrukcję obrazów. Szczególną uwagę zwraca rozwijająca się technika kontrastu fazowego, która może zrewolucjonizować diagnostykę tkanek miękkich. W niniejszym artykule omawiane są najnowsze trendy i innowacje w zakresie algorytmów rekonstrukcyjnych, ze szczególnym naciskiem na ich zastosowanie w medycynie oraz przyszłe kierunki rozwoju.

EN

In recent years reconstruction algorithms in medical imaging have undergone significant evolution, largely using artificial intelligence and deep learning techniques. Traditional approaches such as filtrated back-projection are increasingly being replaced by iterative reconstruction algorithms that do a better job of reducing noise and artifacts in low-dose radiation images. Data compression and using hybrid models, which connect classical methods with innovative AI technologies, make possible faster and more efficient image reconstruction. Of note is the developing phase contrast technique, which has the potential to revolutionize soft tissue diagnostics. This article discusses the latest trends and innovations in reconstruction algorithms, with particular emphasis on their medical applications and future directions.

7

The assessment of the technical condition of a tire belt using computed tomography

Warczek Jan, Żak Krzysztof

Eksploatacja i Niezawodność

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2024

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Vol. 26, no. 2

art. no. 183177

EN

Car tire belting is a key structural element. Its operation in the tire determines the maintenance of the geometrical stability of the pneumatic wheel in conditions of variable operational loads. The belt creates a spatial composite structure in which the structural component is usually made of braided steel strands. The even arrangement of the fibers in the belt determines its mechanical properties. Under normal conditions, the belting is invisible in used tires and its technical condition is difficult to assess. The arrangement of the belt wires in the tire can be seen usingX-ray imaging, which was used in this work. In the conducted research, various configurations of the lamp settings and the detector of the measurement system were tested. On the basis of the tests performed, it is possible to assess irregularities in the belting resulting from manufacturing errors. However, a more important application of the obtained results is the possibility of assessing operating wear. Delamination in the belt detected during the tests reduce the safety of using such tires.

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Use of computed tomography to assess quality and structure of curved CFRP laminate samples produced by autoclave technology

Helizanowicz Barbara, Helizanowicz Damian, Krzemiński Łukasz, Matula Grzegorz

Composites Theory and Practice

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2024

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R. 24, nr 1

72--77

EN

Carbon fiber reinforced polymer (CFRP) composite laminates are widely used in parts with complex shapes with different curvatures. The curved regions are susceptible to the occurrence of manufacturing defects and premature in-service damage, thus the nondestructive inspection (NDI) of the curved regions is an important issue. X-ray computed tomography (CT) was used to assess the structure of CFRP composite laminate curved beams with different curvature geometry produced in the autoclave technology. The performed inspection allowed visualization of the structure of the curvatures on the ply level and the detection of defects such as foreign objects, voids, resin rich regions, wrinkles and changes in thickness. Also, the quantitative assessment of the defects and distances between the adjacent layers was carried out. The performed investigations show that X-ray CT is an adequate tool to visualize curved CFRP structures.

9

The use of computed tomography and scanning microscopy methods for assessing the alkaline reactivity of aggregate

Zapała-Sławeta Justyna

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 3

art. no. e149814

EN

The reaction of alkalis with aggregate containing reactive forms of silica (ASR) plays a significant role in shaping the durability of concrete, as the strongly hygroscopic reaction products generated lead to internal stress, causing its expansion and cracking. This study presents an extended analysis of corrosive processes occurring in mortars with reactive natural aggregate from Poland, using computed tomography and scanning microscopy methods. Numerous cracks in the grains and the surrounding cementitious matrix were observed, indicating a high degree of advancement of corrosive processes. Over time, the proportion of pores with reduced sphericity increased, indicating ongoing degradation of the mortars. The usefulness of computed tomography in studying the progress of ASR was demonstrated. Scanning microscopy confirmed that the cause of mortar degradation is the formed ASR gel with a typical composition, located within the volume of reactive grains, cracks propagating into the cementitious matrix, and accumulated in air voids.

10

Przetwarzanie i analiza danych w tomografii komputerowej dla celów diagnostyki technicznej

Zawada-Tomkiewicz Anna

Badania Nieniszczące i Diagnostyka

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2024

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nr 1-2

4--16

PL

W artykule zamieszczono wprowadzenie w metody radiologiczne wykorzystywane w tomografii komputerowej do badań nieniszczących. Zgodnie z normą PN-EN ISO 15708 zastosowanie CT ma duży potencjał do wykrywania rozwarstwienia oraz mikropęknięć, które nie są dostępne za pomocą innych urządzeń pomiarowych. Pozwala również na pełną ocenę powierzchni wewnętrznej i zewnętrznej części. CT jest jedyną metodą badań nieniszczących, która umożliwia połączenie testowania wad z testowaniem wymiarów. Artykuł skupia się na zagadnieniach związanych z jakością rekonstruowanych obrazów warstwowych oraz wpływem na jakość kwalifikacji testowanych wad i wymiarów.

EN

The article provides an introduction to radiological methods used in computed tomography for non-destructive testing. According to the PN-EN ISO 15708 standard, the use of CT has great potential for detecting delamination and microcracks that are not available using other measuring devices. It also allows for a complete assessment of the inner and outer surfaces of the part. CT is the only non-destructive testing method that allows defect testing to be combined with dimensional testing. The article focuses on issues related to the quality of reconstructed layered images and the impact on the quality of qualification of tested defects and dimensions.

11

Możliwości i korzyści zastosowania metody Small Punch Test w diagnostyce urządzeń przemysłowych

Nowak Marek, Baran Patryk

Badania Nieniszczące i Diagnostyka

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2024

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nr 3-4

26--29

PL

Dla zapewnienia bezpiecznej eksploatacji urządzeń technicznych konieczna jest wiedza o aktualnym ich stanie technicznym. Dotyczy to zarówno urządzeń w przemyśle energetycznym, petrochemicznym czy też chemicznym. W celu zapewnienia bezawaryjnej eksploatacji urządzeń prowadzone są badania z wykorzystaniem różnych metod nieniszczących. Katalog stosowanych metod jest co raz szerszy ze względu na rozwój różnych metod badawczych i potrzeby lepszej diagnostyki. Badania te prowadzone są w celu ujawniania uszkodzeń jak również istotne jest dostarczenie informacji o stanie materiału badanego obiektu. Dane dotyczące własności materiału pozyskuje się dzięki wykorzystaniu różnych metod badawczych, niekiedy mocno inwazyjnych. Alternatywą może być wykorzystanie metody Small Punch Test (SPT), która uważana jest za metodę małoinwazyjną. W artykule przedstawiono przykłady wykorzystania metody SPT w praktyce przemysłowej do wyznaczenia własności wytrzymałościowych materiałów jak również inne korzyści zastosowania tej metody. Pobranie niewielkiego wycinka materiału pozwala m.in. na realizację badań mikrostruktury za pomocą mikroskopu świetlnego i skaningowego mikroskopu elektronowego czy pomiarów twardości.

EN

In order to ensure safe operation of technical devices, knowledge of their current technical condition is necessary. This applies to devices in the energy as well petrochemical and chemical industries. In order to ensure failure-free operation of devices, the various non-destructive methods are used. The catalogue of methods used is becoming wider due to the development of various research methods and the needs for better diagnostics. These tests are carried out to detect damage and it is also important to provide information about material condition of tested object. Mechanical properties of the material are obtained through the use of various research methods, sometimes very invasive. An alternative may be the use of the Small Punch Test (SPT) method, which is considered a minimally invasive method. The article presents examples of the use of the SPT method in industrial practice to determine the strength properties of materials as well as other benefits of using this method. Taking a small sample of the material allows, among others, to carry out microstructure tests using a light microscope and a scanning electron microscope or hardness measurements.

12

3D printed anatomical models for preoperative planning of complex orthopaedic surgical operations of the lower limb

Valchanov P., Ivanov S.

Archives of Materials Science and Engineering

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2024

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Vol. 127, nr 2

73--85

EN

Purpose: Complex multifragmentary fractures of the pelvis and lower limb are a major challenge for operative orthopaedic surgery. The successful metallic osteosynthesis of the fractures requires an extensive planning process, which can be dramatically improved with the 3D printed anatomical models – replicas of the bones with high fidelity generated from CT and MRI imaging studies. The models represent the spatial properties of the skeleton with a dimensional error of approximately 8 μm/mm. They can be manufactured easily and with high reproducibility with commercial or open-access software and FDM 3D printing. Orthopaedic surgeons use the preoperative models as a highly accurate physical model of complex fractures and allow them to choose and prepare the optimal operation window, surgical tools, metallic implants, and as a template for recontouring (pre-bending) of fixation plates, which will be used during the surgery. The approach provides a new level of personalisation in operative orthopaedic surgery and significantly reduces the duration of the operation, the amount of blood loss and the intraoperative X-rays. The proper anatomical repositioning of the fracture is achieved at a higher rate in the surgeries, which are planned with 3D-printed anatomical models. The planning of surgical operations with 3D-printed models increases the overall effectiveness of the surgery, reduces the rate of post-surgical complications, and allows for a patient-specific approach. The paper will describe the methods for manufacturing accurate 3D-printed anatomical models representing complex fractures and their application for preoperative planning of orthopaedic operation. Design/methodology/approach: The anatomical 3D models were generated from CT datasets with open-access medical informatics software (3D Slicer) and 3D printed on an FDM 3D printer with minimal thermal deformation (Polylactate, PLA). The finished models were used for preoperative planning of complex orthopaedic operations, including high-energy multifragmentary hip, knee and ankle fractures. The preoperative planning included selecting surgical access, preparing tools and implants, and contouring (pre-bending) metal plates for metallic osteosynthesis. Several parameters, such as operation time, blood loss, intraoperative X-rays, and the achievement of anatomical reduction of the fractures, were observed in order to measure the quality of the operations. bones can be generated from tomographic imaging studies easily and accurately, even with open-source software. They can be utilised as a tool for preoperatively planning complex orthopaedical operations of the lower limb. Using 3D-printed models allows a patient-specific approach, which leads to good anatomical reduction and favourable functional results in complex surgeries regarding the pelvis, acetabulum, tibial plateau, and calcaneus. Practical implications: The methods described in the paper are routinely used for the preoperative planning of complex orthopaedical operations regarding the lower limb. In the future, they will be combined with the implementation of 3D-printed personalised titanium implants to achieve good anatomical reduction even for the most challenging multigragmental fractures. Originality/value: In the paper, we described the technical aspects and clinical considerations for the preoperative planning of complex orthopaedical operations, which can assist engineers and clinicians alike in implementing the useful method in clinical practice.

13

The Effect of Work Hardening on the Structure and Hardness of Hadfield Steel

Bańkowski Damian, Młynarczyk Piotr, Depczyński Wojciech P., Bolanowski Kazimierz

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

14--20

EN

The article aims to characterize Hadfield steel by analyzing its chemical composition, mechanical properties, and microstructure. The study focused on the twinning-induced work hardening of the alloy, which led to an increase in its hardness. The experimental data show that the material hardness at the surface improved considerably after solution heat treatment and work hardening, reaching more than 750 HV. By contrast, the hardness of the material core in the supersaturated condition was about 225 HV. The chemical and phase compositions of the material at the surface were compared with those of the core. The microstructural analysis of the steel revealed characteristic decarburization of the surface layer after solution heat treatment. The article also describes the effects of heat treatment on the properties and microstructure of Hadfield steel. The volumetric (qualitative) analysis of the computed tomography (CT) data of Hadfield steel subjected to heavy dynamic loading helped detect internal flaws, assess the material quality, and potentially prevent the structural failure or damage of the element tested.

14

Establishment of national diagnostic dose reference levels (DRLs) for routine computed tomography examinations in Jordan

Radaideh Khaldoon, Al-Radaideh Ali, Ramli Ramzun Maizan, Saleh Abdallah

Polish Journal of Medical Physics and Engineering

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2023

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Vol. 29, Iss. 1

26--34

EN

Background: Dose reference levels (DRLs) are used as indicators as well as guidance for dose optimization and to ensure justification of appropriate dose for a given clinical indication. The main aims of this study were to establish local DRLs for each CT imaging protocol as a reference point to evaluate the radiation dose indices and to compare our DRLs with those established in other countries and against the internationally reported guidelines. Materials and methods: 2000 CT dose reports of different adult imaging protocols from January 2021 until April 2022 were collected retrospectively at different hospitals in Jordan. Data were collected from CT scans that were performed using different types and models of CT scanners and included four adult non-enhanced, helical CT imaging protocols; Head, Chest, Abdomen-Pelvis, and Chest-Abdomen-Pelvis. Results: The average doses of CTDIvol, DLP, and effective dose were (65.11 mGy, 1232.71 mGy·cm, 2.83 mSv) for the head scan, (16.6 mGy, 586.6 mGy·cm, 8.21 mSv) for the chest scan, (17.91 mGy, 929.9 mGy·cm, 13.9 mSv) for the abdomen-pelvis scan, and (19.3 mGy, 1152 mGy·cm, 17.25 mSv) for the chest-abdomen-pelvis scan. In comparison with results from different international studies, DLP values measured in the present study were lower for the chest-abdomen-pelvis and abdomen-pelvis CT scans, and higher for the head CT and chest CT scans. Conclusions: It is very important that each country establishes its own DRLs and compares them with those reported by other countries, especially the developed ones. It is also important that these levels are regularly updated.

15

Analiza zatorowości płucnej w okresie pandemii COVID-19 na podstawie danych z pracowni TK 850-łóżkowego szpitala

Roczkowski Damian, Wojtasik Aneta

Inżynier i Fizyk Medyczny

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2023

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Vol. 12, nr 1

57--60

PL

Zatorowością płucną (ZP) nazywamy chorobę, podczas której dochodzi do zamknięcia bądź zwężenia tętnicy płucnej lub jej gałęzi przez materiał zakrzepowy. Celem pracy była analiza zatorowości płucnej w okresie przed (grupa A) i w czasie pandemii Covid-19 (grupa B). Porównawcza analiza obejmowała częstość występowania, płeć, wiek oraz lokalizację materiału zatorowego. Analizie statystycznej poddano 660 pacjentów. W okresie przed pandemią odsetek badań pacjentów z podejrzeniem zatorowości płucnej w stosunku do wszystkich badań TK wynosił 2,3%, a w czasie pandemii 4,9%. Potwierdzono obecność materiału zatorowego w grupie A w 32% przypadków, natomiast w grupie B w 30% przypadków. W porównaniu z całkowitą liczbą badań TK – przed pandemią zdiagnozowano zatorowość płucną u 0,7% wszystkich badanych pacjentów. Dla okresu w czasie pandemii odsetek ten wynosił 1,4%, przy czym jedynie w 15% byli to pacjenci ze zdiagnozowanym Covid-19. W grupie A odsetek kobiet wynosił 55% i 45% mężczyzn. W grupie B odpowiednio 51% kobiet i 49% mężczyzn; w przypadku pacjentów z COVID-19: 61% kobiet, 31% mężczyzn. Dla obu grup profil częstości występowania materiału zatorowego był taki sam – najczęściej obustronnie, następnie po stronie prawej i najrzadziej po stronie lewej. Odpowiedni odsetek wynosił: dla grupy A 69, 7 i 24%, a dla grupy B 63, 15 i 22%.

EN

Pulmonary embolism (PE) is a disease in which the pulmonary artery or its branches are blocked or narrowed by thrombotic material. The aim of the study was to analyze pulmonary embolism in the period before (group A) and during the Covid-19 pandemic (group B). Comparative analysis included incidence, gender, age and location of embolic material. 660 patients were subjected to statistical analysis. In the period before the pandemic, the percentage of examinations of patients with suspected pulmonary embolism in relation to all CT examinations was 2.3%, and during the pandemic it was 4.9%. The presence of embolic material was confirmed in group A in 32% of cases, and in group B in 30% of cases. Compared to the total number of CT scans, 0.7% of all patients tested had been diagnosed with pulmonary embolism before the pandemic. For the period during the pandemic, this percentage was 1.4%, with only 15% of patients diagnosed with COVID-19. In group A, the percentage of women was 55% and 45% of men. In group B, 51% of women and 49% of men, respectively; in the case of patients with Covid-19, 61% women, 31% men. For both groups, the profile of the incidence of embolic material was the same – most often bilaterally, then on the right side and least often on the left side. The corresponding percentages were: for group A 69, 7 and 24% and for group B 63, 15 and 22%.

16

Validation of a three-dimensional head phantom for imaging data

Podolszańska Jolanta

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2023

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T. 13, nr 3

29--32

EN

This paper presents the research results on the design of a three-dimensional head phantom for cone beam projection. The head model is based on a Shepp-Logan mathematical head model, which is used to simulate the operation of the CT scanner. The model is then compared with the reference data for structural similarity, reasoning, and shape. The geometric parameters of the obtained images are investigated. The reconstructed image is analyzed using the FDK method. The results show that the geometric parameters directly correlate with the number of projections. A mathematical framework of cone beam 3d reconstruction via the first derivative of the radon transform is presented.

PL

W artykule przedstawiono wyniki badań nad projektem trójwymiarowego fantomu głowy do projekcji wiązki stożkowej. Model głowy jest oparty na matematycznym modelu głowy Shepp-Logan, który jest używany do symulacji działania skanera CT. Model jest następnie porównywany z danymi referencyjnymi pod kątem podobieństwa strukturalnego, rozumowania i kształtu. Badane są parametry geometryczne uzyskanych obrazów. Zrekonstruowany obraz jest analizowany przy użyciu metody FDK. Wyniki pokazują, że parametry geometryczne mają bezpośredni związek z liczbą projekcji. Przedstawiono matematyczne ramy rekonstrukcji 3D wiązki stożkowej za pomocą pierwszej pochodnej transformaty radonowej.

17

Attention-guided multiple instance learning for COPD identification: To combine the intensity and morphology

Wu Yanan, Qi Shouliang, Feng Jie, Chang Runsheng, Pang Haowen, Hou Jie, Li Mengqi, Wang Yingxi, Xia Shuyue, Qian Wei

Biocybernetics and Biomedical Engineering

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2023

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Vol. 43, no. 3

568--585

EN

Chronic obstructive pulmonary disease (COPD) is a complex and multi-component respiratory disease. Computed tomography (CT) images can characterize lesions in COPD patients, but the image intensity and morphology of lung components have not been fully exploited. Two datasets (Dataset 1 and 2) comprising a total of 561 subjects were obtained from two centers. A multiple instance learning (MIL) method is proposed for COPD identification. First, randomly selected slices (instances) from CT scans and multi-view 2D snapshots of the 3D airway tree and lung field extracted from CT images are acquired. Then, three attention-guided MIL models (slice-CT, snapshot-airway, and snapshot-lung-field models) are trained. In these models, a deep convolution neural network (CNN) is utilized for feature extraction. Finally, the outputs of the above three MIL models are combined using logistic regression to produce the final prediction. For Dataset 1, the accuracy of the slice-CT MIL model with 20 instances was 88.1%. The backbone of VGG-16 outperformed Alexnet, Resnet18, Resnet26, and Mobilenet_v2 in feature extraction. The snapshotairway and snapshot-lung-field MIL models achieved accuracies of 89.4% and 90.0%, respectively. After the three models were combined, the accuracy reached 95.8%. The proposed model outperformed several state-of-the-art methods and afforded an accuracy of 83.1% for the external dataset (Dataset 2). The proposed weakly supervised MIL method is feasible for COPD identification. The effective CNN module and attention-guided MIL pooling module contribute to performance enhancement. The morphology information of the airway and lung field is beneficial for identifying COPD.

18

Computed Tomography and Scanning Electron Microscopy Analysis of a Friction Stir Welded Al-Cu Joint

Depczyński Wojciech P., Bańkowski Damian, Młynarczyk Piotr S.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

65--71

EN

The study aimed touse3D computed tomography (CT) to analyse a joint between two dissimilar materials produced by friction stir welding (FSW). As the materials joined, i.e., aluminum and copper, differ in properties (e.g., density and melting point), the weld is predicted to have an inhomogeneous microstructure. The investigations involved applying microfocus computed tomography (micro-CT) to visualize and analyze the volumetric structure of the joint. Volume rendering is extremely useful because, unlike computer modelling, which requires many simplifications, it helps create highly accurate representations of objects. Image segmentation into regions was performed through global gray-scale thresholding. The analysis also included elemental mapping of the weld cross-sections using scanning electron microscopy (SEM) and examination of its surface morphology by means of optical microscopy (OP). The joint finds its use in developing elements used in the chemical, energetics and aerospace industries, due to the excellent possibilities of combining many different properties, and above all, reducing the weight of the structure.

19

Supported by 2D and 3D Imaging Methods Investigation of the Influence of Fiber Orientation on the Mechanical Properties of the Composites Reinforced with Fibers in a Polymer Matrix

Saraczyn Robert, Deroszewska Martyna, Kowaluk Tomasz, Skołek Emilia, Rządkowski Witold, Myszka Dawid

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no. 3

170--183

EN

The aim of this study was to examine the behavior of the carbon fiber reinforced polymer (CFRP) composites depending on the fiber orientation and to understand the influence of microstructural discontinuities on mechanical properties. For the tests 210 gsm prepreg composite and 200 gsm carbon fabric with polymer matrix have been used. Samples were structured and later examined according to the ASTM-D3039 and ASTM-D3878 (equivalents are ISO 20975, ISO 527-4 and ISO 527-5). Accordingly, to the number of layers, three ways of the fibers arranging in relation to the applied force were used. Mechanical properties were determined in a static tensile test. The results of imaging studies, which included analyzes of Digital Image Correlation, Computed Tomography and Scanning Electron Microscopy, showed structural discontinuities, specific stress distribution and propagation of stresses depending on the production technology, which were correlated with the obtained strength results. The source of the gradual development of the degradation of the composite structure was observed in local microdamages and microcracks. As a result of a sub-critical crack growth within the resin matrix material, the defects are subject to a complex, multi-axial stress field on the micro-scale, even if the globally applied force is axial. Samples in which the load was applied along the axis of the fibers behave like an elastic material, while samples, where the force is applied at an angle to the axis of the fibers, tend to behave like an elastic-plastic material.

20

Evaluation of mandibular geometry in healthy children aged 0-1 year - a pilot study

Lipowicz Anna, Kawlewska Edyta, Larysz Dawid, Kostyra Patrycja, Graja Katarzyna, Joszko Kamil, Gzik-Zroska Bożena, Wolański Wojciech

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 3

93--102

EN

The main aim of the researches was the three-dimensional morphological assessment of the mandible in children. Materials&Methods: The research group consisted of 34 infants from 21 to 417 days of age (0-13 months). Models of the mandibles were developed on the basis of tomographic images. Characteristic anatomical points were marked on the models, on the basis of which characteristic distances and angles were calculated, determining the length, width and height of the mandible as well as its proportion and symmetry. Based on the obtained database, models of mandibular growth in the first year of life in three directions were also developed. Conclusion: The analysis of the results revealed some significant objective information on the growth and development of the normal mandible.