RESUMO
Recent epidemiological studies have shown that patients with right-sided breast cancer (RBC) treated with X-ray irradiation (IR) are more susceptible to developing cardiovascular diseases, such as arrhythmias, atrial fibrillation, and conduction disturbances after radiotherapy (RT). Our aim was to investigate the mechanisms induced by low to moderate doses of IR and to evaluate changes in the cardiac sympathetic nervous system (CSNS), atrial remodeling, and calcium homeostasis involved in cardiac rhythm. To mimic the RT of the RBC, female C57Bl/6J mice were exposed to X-ray doses ranging from 0.25 to 2 Gy targeting 40% of the top of the heart. At 60 weeks after RI, Doppler ultrasound showed a significant reduction in myocardial strain, ejection fraction, and atrial function, with a significant accumulation of fibrosis in the epicardial layer and apoptosis at 0.5 mGy. Calcium transient protein expression levels, such as RYR2, NAK, Kir2.1, and SERCA2a, increased in the atrium only at 0.5 Gy and 2 Gy at 24 h, and persisted over time. Interestingly, 3D imaging of the cleaned hearts showed an early reduction of CSNS spines and dendrites in the ventricles and a late reorientation of nerve fibers, combined with a decrease in SEMA3a expression levels. Our results showed that local heart IR from 0.25 Gy induced late cardiac and atrial dysfunction and fibrosis development. After IR, ventricular CSNS and calcium transient protein expression levels were rearranged, which affected cardiac contractility. The results are very promising in terms of identifying pro-arrhythmic mechanisms and preventing arrhythmias during RT treatment in patients with RBC.
Assuntos
Cálcio , Camundongos Endogâmicos C57BL , Sistema Nervoso Simpático , Animais , Camundongos , Sistema Nervoso Simpático/efeitos da radiação , Sistema Nervoso Simpático/metabolismo , Feminino , Cálcio/metabolismo , Raios X , Coração/efeitos da radiação , Coração/fisiopatologia , Remodelamento Atrial/efeitos da radiaçãoRESUMO
O odontoma é o mais comum tumor odontogênico, definido como malformação benigna, geralmente descoberto na segunda década de vida, durante a investigação de erupção tardia de dentes adjacentes ou retenção prolongada de dentes decíduos. O odontoma é subdividido em composto e complexo. O Odontoma classificado como Composto é constituído por um conjunto de estruturas similares a dentes, de formas e tamanhos diversos, cercados por uma área delgada radiolúcida. Já o Odontoma Complexo se assemelha a uma massa calcificada que apresenta a mesma radiopacidade do tecido dentário, também cercado por uma área delgada radiolúcida. Ocasionalmente, esses dois aspectos podem ser vistos em uma mesma lesão. Frequentemente os odontomas podem provocar um aumento de volume ósseo local devido ao seu desenvolvimento. O diagnóstico é feito através de exames radiográficos de rotina e quando necessário pode-se também lançar mão de Radiografias Panorâmicas e Tomografia Computadorizada Cone Beam com o intuito de verificar sua extensão, as malformações e alterações de erupção causadas aos dentes adjacentes, assim como a classificação do tumor. Este relato de caso apresenta um Odontoma Composto-Complexo em um paciente de 13 anos, do sexo masculino, atendido em 2016 na Clínica de Diagnóstico Bucal II da Universidade Federal Fluminense, que apresentou elementos dentários 22 e 23 impactados, retenção prolongada do elemento 63 e aumento de volume na região anterior do lado esquerdo da maxila. Para obtenção do diagnóstico foram realizadas: Radiografias Periapicais, Radiografia Panorâmica e Tomografia Computadorizada Cone Beam. O objetivo deste trabalho foi elucidar as formas de diagnóstico por imagem que foram utilizadas neste caso clínico e quais as vantagens de cada exame.
Odontomas are the most common type of odontogenic tumors, defined as a benign malformation, usually diagnosed in the second decade of life, during the investigation of late adjacent teeth eruption or a delay in exfoliation of deciduous teeth. They are divided into two types: compound and complex. The odontoma classified as compound is composed of multiple small tooth-like structures, in several shapes and sizes, surrounded by a thin radiolucent rim. On the other hand, complex odontomas resemble a mass of calcified tissue that presents the same dental tissue radiopacity, also surrounded by a thin radiolucent rim. Occasionally, both aspects can be seen in the same lesion. Often, odontomas can cause a local increase in bone volume due to their development. The diagnosis is made through routine radiographic examination and, when it is necessary, it is possible to make use of panoramic radiographies and cone beam computed tomography with the purpose of verifying its extension, malformations and erupted alterations caused to the adjacent teeth, as well as the tumor classification. This case report presents a Compound-Complex Odontoma in a 13-year-old male patient, treated in 2016 at the Oral Diagnosis Clinic II of the Federal Fluminense University. He presented impacted teeth 22 and 23, delayed eruption of tooth 63 and volume increase in the left anterior maxilla site. Aiming the patient's diagnosis, the following exams were necessary: periapical radiographies, panoramic radiography, cone beam computed tomography. The aim of this paper is to explain the different image diagnostic tools which were used in this clinical study and what are the advantages of each exam.
Assuntos
Humanos , Masculino , Adolescente , Dente Impactado , Raios X , Diagnóstico por Imagem , Radiografia Panorâmica , Odontoma , Tomografia Computadorizada de Feixe CônicoRESUMO
Bone mineral density (BMD) varies with aging and both systemic and local diseases; however, such evidence is lacking in feline medicine. This may be due to the need for general anesthesia in cats for direct BMD measurements using dual-energy X-ray absorptiometry (DXA) or quantitative computed tomography (QCT). In this study, computed digital absorptiometry (CDA), an indirect relative BMD-measuring method, was optimized to select an X-ray tube setting for the quantitative assessment of the feline knee joint. The knee joints of nine cats were radiographically imaged and processed using the CDA method with an aluminum density standard and five X-ray tube settings (from 50 to 80 kV; between 1.2 and 12 mAs). The reference attenuation of the X-ray beam for ten steps (S1-S10) of the density standard was recorded in Hounsfield units (HU), compared between X-ray tube settings, and used to determine the ranges of relative density applied for radiograph decomposition. The relative density decreased (p < 0.0001) with an increase in kV and dispersed with an increase in mAs. Then, the percentage of color pixels (%color pixels), representing ranges of relative density, was compared among S1-S10 and used for the recognition of background artifacts. The %color pixels was the highest for low steps and the lowest for high steps (p < 0.0001), regardless of X-ray tube settings. The X-ray tube setting was considered the most beneficial when it effectively covered the lowest possible HU ranges without inducing background artifacts. In conclusion, for further clinical application of the CDA method for quantitative research on knee joint OA in cats, 60 kV and 1.2 mAs settings are recommended.
Assuntos
Absorciometria de Fóton , Densidade Óssea , Articulação do Joelho , Animais , Gatos , Densidade Óssea/fisiologia , Absorciometria de Fóton/métodos , Articulação do Joelho/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Raios XRESUMO
The geographical origin of Panax ginseng significantly influences its nutritional value and chemical composition, which in turn affects its market price. Traditional methods for analyzing these differences are often time-consuming and require substantial quantities of reagents, rendering them inefficient. Therefore, hyperspectral imaging (HSI) in conjunction with X-ray technology were used for the swift and non-destructive traceability of Panax ginseng origin. Initially, outlier samples were effectively rejected by employing a combined isolated forest algorithm and density peak clustering (DPC) algorithm. Subsequently, random forest (RF) and support vector machine (SVM) classification models were constructed using hyperspectral spectral data. These models were further optimized through the application of 72 preprocessing methods and their combinations. Additionally, to enhance the model's performance, four variable screening algorithms were employed: SelectKBest, genetic algorithm (GA), least absolute shrinkage and selection operator (LASSO), and permutation feature importance (PFI). The optimized model, utilizing second derivative, auto scaling, permutation feature importance, and support vector machine (2nd Der-AS-PFI-SVM), achieved a prediction accuracy of 93.4 %, a Kappa value of 0.876, a Brier score of 0.030, an F1 score of 0.932, and an AUC of 0.994 on an independent prediction set. Moreover, the image data (including color information and texture information) extracted from color and X-ray images were used to construct classification models and evaluate their performance. Among them, the SVM model constructed using texture information from X -ray images performed the best, and it achieved a prediction accuracy of 63.0 % on the validation set, with a Brier score of 0.181, an F1 score of 0.518, and an AUC of 0.553. By implementing mid-level fusion and high-level data fusion based on the Stacking strategy, it was found that the model employing a high-level fusion of hyperspectral spectral information and X-ray images texture information significantly outperformed the model using only hyperspectral spectral information. This advanced model attained a prediction accuracy of 95.2 %, a Kappa value of 0.912, a Brier score of 0.027, an F1 score of 0.952, and an AUC of 0.997 on the independent prediction set. In summary, this study not only provides a novel technical path for fast and non-destructive traceability of Panax ginseng origin, but also demonstrates the great potential of the combined application of HSI and X-ray technology in the field of traceability of both medicinal and food products.
Assuntos
Algoritmos , Imageamento Hiperespectral , Panax , Máquina de Vetores de Suporte , Panax/classificação , Panax/química , Imageamento Hiperespectral/métodos , Luz , Raios XRESUMO
Within the scope of this investigation, we carried out experiments to investigate the potential of the Vision Transformer (ViT) in the field of medical image analysis. The diagnosis of osteoporosis through inspection of X-ray radio-images is a substantial classification problem that we were able to address with the assistance of Vision Transformer models. In order to provide a basis for comparison, we conducted a parallel analysis in which we sought to solve the same problem by employing traditional convolutional neural networks (CNNs), which are well-known and commonly used techniques for the solution of image categorization issues. The findings of our research led us to conclude that ViT is capable of achieving superior outcomes compared to CNN. Furthermore, provided that methods have access to a sufficient quantity of training data, the probability increases that both methods arrive at more appropriate solutions to critical issues.
Assuntos
Redes Neurais de Computação , Osteoporose , Osteoporose/diagnóstico por imagem , Humanos , Raios X , Processamento de Imagem Assistida por Computador/métodos , AlgoritmosRESUMO
Exposure to ionizing radiation can result in the development of a number of diseases, including cancer, cataracts and neurodegenerative pathologies. Certain occupational groups are exposed to both natural and artificial sources of radiation as a consequence of their professional activities. The development of non-invasive biomarkers to assess the risk of exposure to ionizing radiation for these groups is of great importance. In this context, our objective was to identify epigenetic and molecular biomarkers that could be used to monitor exposure to ionizing radiation. The impact of X-ray exposure on the miRNAs profile and the level of cf mtDNA were evaluated using the RT-PCR method. The levels of pro-inflammatory cytokines in their blood were quantified using the ELISA method. A significant decrease in miR-19a-3p, miR-125b-5p and significant increase in miR-29a-3p was observed in the blood plasma of individuals exposed to X-ray. High levels of pro-inflammatory cytokines and cf mtDNA were also detected. In silico identification of potential targets of these miRNAs was conducted using MIENTURNET. VDAC1 and ALOX5 were identified as possible targets. Our study identified promising biomarkers such as miRNAs and cf mtDNA that showed a dose-dependent effect of X-ray exposure.
Assuntos
Biomarcadores , DNA Mitocondrial , Epigênese Genética , MicroRNAs , Humanos , MicroRNAs/sangue , MicroRNAs/genética , DNA Mitocondrial/sangue , DNA Mitocondrial/genética , Epigênese Genética/efeitos da radiação , Biomarcadores/sangue , Raios X/efeitos adversos , Masculino , Exposição Ocupacional/efeitos adversos , Adulto , Pessoa de Meia-Idade , Citocinas/sangue , Citocinas/genética , FemininoRESUMO
BACKGROUND AND PURPOSE: Cone beam computed tomography (CBCT) is routinely used in radiotherapy to localize target volume. The aim of our study was to determine the biological effects of CBCT dose compared to subsequent therapeutic dose by using in vitro chromosome dosimetry. MATERIALS AND METHODS: Peripheral blood samples from five healthy volunteers were irradiated in two phantoms (water filled in-house made cylindrical, and Pure Image CTDI phantoms) with 6 MV FFF X-ray photons, the dose rate was 800 MU/min and the absorbed doses ranged from 0.5 to 8 Gy. Irradiation was performed with a 6 MV linear accelerator (LINAC) to generate a dose-response calibration curve. In the first part of the investigation, 1-5 CBCT imaging was used, in the second, only 2 Gy doses were delivered with a LINAC, and then, in the third part, a combination of CBCT and 2 Gy irradiation was performed mimicking online adapted radiotherapy treatment. Metaphases were prepared from lymphocyte cultures, using standard cytogenetic techniques, and chromosomal aberrations were evaluated. Estimate doses were calculated from chromosome aberrations using dose-response curves. RESULTS: Samples exposed to X-ray from CBCT imaging prior to treatment exhibited higher chromosomal aberrations and Estimate dose than the 2 Gy therapeutic (real) dose, and the magnitude of the increase depended on the number of CBCTs: 1-5 CBCT corresponded to 0.04-0.92 Gy, 1 CBCT + 2 Gy to 2.32 Gy, and 5 CBCTs + 2 Gy to 3.5 Gy. CONCLUSION: The estimated dose based on chromosomal aberrations is 24.8% higher than the physical dose, for the combination of 3 CBCTs and the therapeutic 2 Gy dose, which should be taken into account when calculating the total therapeutic dose that could increase the risk of a second cancer. The clinical implications of the combined radiation effect may require further investigation.
Assuntos
Aberrações Cromossômicas , Tomografia Computadorizada de Feixe Cônico , Linfócitos , Imagens de Fantasmas , Dosagem Radioterapêutica , Humanos , Tomografia Computadorizada de Feixe Cônico/métodos , Aberrações Cromossômicas/efeitos da radiação , Linfócitos/efeitos da radiação , Raios X , Relação Dose-Resposta à Radiação , Radiometria/métodosRESUMO
Objective.This work explores the enhancement of ionization clustering and its radial dependence around a gold nanoparticle (NP), indicative of the induction of DNA lesions, a potential trigger for cell-death.Approach.Monte Carlo track structure simulations were performed to determine (a) the spectral fluence of incident photons and electrons in water around a gold NP under charged particle equilibrium conditions and (b) the density of ionization clusters produced on average as well as conditional on the occurrence of at least one interaction in the NP using Associated Volume Clustering. Absorbed dose was determined for comparison with a recent benchmark intercomparison. Reported quantities are normalized to primary fluence, allowing to establish a connection to macroscopic dosimetric quantities.Main results.The modification of the electron spectral fluence by the gold NP is minor and mainly occurs at low energies. The net fluence of electrons emitted from the NP is dominated by electrons resulting from photon interactions. Similar to the known dose enhancement, increased ionization clustering is limited to a distance from the NP surface of up to200nm. The number of clusters per energy imparted is increased at distances of up to150nm, and accordingly the enhancement in clustering notably surpasses that of dose enhancement. Smaller NPs cause noticeable peaks in the conditional frequency of clusters between50nm-100nmfrom the NP surface.Significance.This work shows that low energy electrons emitted by NPs lead to an increase of ionization clustering in their vicinity exceeding that of energy imparted. While the electron component of the radiation field plays an important role in determining the background contribution to ionization clustering and energy imparted, the dosimetric effects of NPs are governed by the interplay of secondary electron production by photon interaction and their ability to leave the NP.
Assuntos
Ouro , Nanopartículas Metálicas , Método de Monte Carlo , Ouro/química , Nanopartículas Metálicas/química , Raios X , Elétrons , FótonsRESUMO
Objective.Proton therapy administers a highly conformal dose to the tumour region, necessitating accurate prediction of the patient's 3D map of proton relative stopping power (RSP) compared to water. This remains challenging due to inaccuracies inherent in single-energy computed tomography (SECT) calibration. Recent advancements in spectral x-ray CT (xCT) and proton CT (pCT) have shown improved RSP estimation compared to traditional SECT methods. This study aims to provide the first comparison of the imaging and RSP estimation performance among dual-energy CT (DECT) and photon-counting CT (PCCT) scanners, and a pCT system prototype.Approach.Two phantoms were scanned with the three systems for their performance characterisation: a plastic phantom, filled with water and containing four plastic inserts and a wood insert, and a heterogeneous biological phantom, containing a formalin-stabilised bovine specimen. RSP maps were generated by converting CT numbers to RSP using a calibration based on low- and high-energy xCT images, while pCT utilised a distance-driven filtered back projection algorithm for RSP reconstruction. Spatial resolution, noise, and RSP accuracy were compared across the resulting images.Main results.All three systems exhibited similar spatial resolution of around 0.54 lp/mm for the plastic phantom. The PCCT images were less noisy than the DECT images at the same dose level. The lowest mean absolute percentage error (MAPE) of RSP,(0.28±0.07)%, was obtained with the pCT system, compared to MAPE values of(0.51±0.08)%and(0.80±0.08)%for the DECT- and PCCT-based methods, respectively. For the biological phantom, the xCT-based methods resulted in higher RSP values in most of the voxels compared to pCT.Significance.The pCT system yielded the most accurate estimation of RSP values for the plastic materials, and was thus used to benchmark the xCT calibration performance on the biological phantom. This study underlined the potential benefits and constraints of utilising such a novelex-vivophantom for inter-centre surveys in future.
Assuntos
Imagens de Fantasmas , Plásticos , Prótons , Tomografia Computadorizada por Raios X , Processamento de Imagem Assistida por Computador/métodos , Animais , Bovinos , Calibragem , Raios XRESUMO
Deep learning-based 3D/2D surgical navigation registration techniques achieved excellent results. However, these methods are limited by the occlusion of surgical equipment resulting in poor accuracy. We designed a contrastive learning method that treats occluded and unoccluded X-rays as positive samples, maximizing the similarity between the positive samples and reducing interference from occlusion. The designed registration model has Transformer's residual connection (ResTrans), which enhances the long-sequence mapping capability, combined with the contrast learning strategy, ResTrans can adaptively retrieve the valid features in the global range to ensure the performance in the case of occlusion. Further, a learning-based region of interest (RoI) fine-tuning method is designed to refine the misalignment. We conducted experiments on occluded X-rays that contained different surgical devices. The experiment results show that the mean target registration error (mTRE) of ResTrans is 3.25 mm and the running time is 1.59 s. Compared with the state-of-the-art (SOTA) 3D/2D registration methods, our method offers better performance on occluded 3D/2D registration tasks.
Assuntos
Tomografia Computadorizada por Raios X , Humanos , Tomografia Computadorizada por Raios X/métodos , Aprendizado Profundo , Imageamento Tridimensional/métodos , Cirurgia Assistida por Computador/métodos , Raios XRESUMO
The effects of low-dose radiation exposure remain a controversial topic in radiation biology. This study compares early (0.5, 4, 24, 48, and 72 h) and late (5, 10, and 15 cell passages) post-irradiation changes in γH2AX, 53BP1, pATM, and p-p53 (Ser-15) foci, proliferation, autophagy, and senescence in primary fibroblasts exposed to 100 and 2000 mGy X-ray radiation. The results show that exposure to 100 mGy significantly increased γH2AX, 53BP1, and pATM foci only at 0.5 and 4 h post irradiation. There were no changes in p-p53 (Ser-15) foci, proliferation, autophagy, or senescence up to 15 passages post irradiation at the low dose.
Assuntos
Autofagia , Proliferação de Células , Senescência Celular , Reparo do DNA , Fibroblastos , Humanos , Fibroblastos/efeitos da radiação , Fibroblastos/metabolismo , Autofagia/efeitos da radiação , Senescência Celular/efeitos da radiação , Reparo do DNA/efeitos da radiação , Raios X/efeitos adversos , Proliferação de Células/efeitos da radiação , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Histonas/metabolismo , Relação Dose-Resposta à Radiação , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genética , Células Cultivadas , Dano ao DNA/efeitos da radiaçãoRESUMO
This research focused on the determination of scatter radiation levels in x-ray rooms during chest radiography. 108 patients were examined. Four x-ray machines (A, B, C, and D) were used during the research from three centers. Three positions were considered in this study; position Q just beside the (Bucky stand), position R, which is 150 cm from the left of the Bucky stand towards the door and position T, 200 cm from the Bucky stand to the radiographer's protective screen respectively. Two machines (A and B) from center 1 and one machine from center 2 (C) and one machine from center 3 (D). The body mass index (BMI) of the participants ranged from 20 to 25 kgm-2 with mean value of 23.97 kgm-2. The background radiation level was read using Radalert 100 m before any exposure, and the mean background level was 0.298 mR/h. The mean of the scatter radiation doses obtained from positions Q with respect to the four machines A, B, C, and D, were 0.109, 0.201, 0.204, 0.200 mR/h (9.166, 16.903, 17.156, 16.819 mSv/yr) and their standard deviations were ±0.052, ±0.053, ±0.064, and ±0.081 respectively. The results were comparable with previous studies. The study recommends staff education and training in determination of radiation levels for enhanced work safety.
Assuntos
Doses de Radiação , Radiografia Torácica , Espalhamento de Radiação , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Exposição Ocupacional/análise , Proteção Radiológica , Raios X , IdosoRESUMO
Visual perception of X-radiation is a well-documented, but poorly understood phenomenon. Scotopic rod cells and rhodopsin have been implicated in visual responses to X-rays, however, some evidence suggests that X-rays excite the retina via a different mechanism than visible light. While rhodopsin's role in X-ray perception is unclear, the possibility that it could function as an X-ray receptor has led to speculation that it could act as a transgenically expressed X-ray receptor. If so, it could be used to transduce transcranial X-ray signals and control the activity of genetically targeted populations of neurons in a less invasive version of optogenetics, X-genetics. Here we investigate whether human rhodopsin (hRho) is capable of transducing X-ray signals when expressed outside of the retinal environment. We use a live-cell cAMP GloSensor luminescence assay to measure cAMP decreases in hRho-expressing HEK293 cells in response to visible light and X-ray stimulation. We show that cAMP GloSensor luminescence decreases are not observed in hRho-expressing HEK293 cells in response to X-ray stimulation, despite the presence of robust responses to visible light. Additionally, irradiation had no significant effect on cAMP GloSensor responses to subsequent visible light stimulation. These results suggest that ectopically expressed rhodopsin does not function as an X-ray receptor and is not capable of transducing transcranial X-ray signals into neural activity for X-ray mediated, genetically targeted neuromodulation.
Assuntos
AMP Cíclico , Rodopsina , Humanos , Células HEK293 , Rodopsina/metabolismo , Rodopsina/genética , Raios X , AMP Cíclico/metabolismo , Luz , Estimulação Luminosa/métodosRESUMO
The radioprotective properties of copper chlorophyllin (100 and 150 µg/g), the standard antioxidant trolox (100 and 200 µg/g), and the standard radioprotector indralin (100 and 150 µg/g) were compared in male ICR mice (CD-1) subjected to whole-body irradiation (X-ray radiation) in doses of 6, 6.5, and 6.75 Gy. Animal survival was analyzed using the Kaplan-Meier method, and the significance of differences was evaluated using the log-rank test method. Dose change factors determined using the Phinney probit analysis were 1.1, 1.0, and 1.8 for chlorophyllin, trolox, and indralin at a dose of 100 µg/g body weight, respectively. The insignificant radioprotective properties of chlorophyllin and their absence in trolox when administered prophylactically do not rule out their possible radioprotective properties like a radiomodulator that protects the body after irradiation.
Assuntos
Antioxidantes , Clorofilídeos , Cromanos , Camundongos Endogâmicos ICR , Protetores contra Radiação , Irradiação Corporal Total , Animais , Protetores contra Radiação/farmacologia , Cromanos/farmacologia , Masculino , Camundongos , Clorofilídeos/farmacologia , Antioxidantes/farmacologia , Raios X , FenóisRESUMO
Objective.Time-of-flight (TOF) scatter rejection requires a total timing jitter, including the detector timing jitter and the x-ray source's pulses width, of 50 ps or less to mitigate most of the effects of scattered photons in radiography and CT imaging. However, since the total contribution of the source and detector to the timing jitter can be retrieved during an acquisition with nothing between the source and detector, it can be demonstrated that this contribution may be partially removed to improve the image quality.Approach.A scatter correction method using iterative deconvolution of the measured time point-spread function estimates the number of scattered photons detected in each pixel. To evaluate the quality of the estimation, GATE was used to simulate the radiography of a water cylinder with bone inserts, and a head and torso in a system with total timing jitters from 100 ps up to 500 ps full-width-at-half-maximum (FWHM).Main results.With a total timing jitter of 200 ps FWHM, 89% of the contrast degradation caused by scattered photons was recovered in a head and torso radiography, compared to 28% with a simple time threshold method. Corrected images using the estimation have a percent root-mean square error between 2% and 14% in both phantoms with timing jitters from 100 to 500 ps FWHM which is lower than the error achieved with scatter rejection alone at 100 ps FWHM.Significance.TOF x-ray imaging has the potential to mitigate the effects of the scattering contribution and offers an alternative to anti-scatter grids that avoids loss of primary photons. Compare to simple TOF scatter rejection using only a threshold, the deconvolution estimation approach has lower requirements on both the source and detector. These requirements are now within reach of state-of-the-art systems.
Assuntos
Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Espalhamento de Radiação , Humanos , Processamento de Imagem Assistida por Computador/métodos , Fatores de Tempo , Fótons , Tomografia Computadorizada por Raios X , Cabeça/diagnóstico por imagem , Raios XRESUMO
BACKGROUND AND AIM: Calibrated pelvic X-ray images are needed in the preoperative planning of total hip arthroplasty (THA) to predict component sizes. Errors and mismatch in the size of one or more components are reported, which can lead to clinically relevant complications. Our aim is to investigate whether we can solve the fundamental problem of X-ray calibration and whether traditional X-ray still has a place in preoperative planning despite improved radiological alternatives. METHODS: Based on geometric and radiographic principles, we estimate that the magnification factor is adapted to the X-ray device and depends strongly on the source-image distance of the device. We analyse the errors of the various calibration methods and investigate which narrow range can be expected to show that the center of rotation is sufficiently accurate. Based on the results of several CT-scans we defined an adapted magnification factor and validated the degree of measurement accuracy. RESULTS: The true magnification of objects on X-ray images depends mainly on the device settings. Stem size prediction is possible to a limited extent, with an error margin of 4.3%. Components can be predicted with a safety margin of one size up and down as with CT or 3D images. The prerequisite is that the source-image distance is greater than or equal to 120 cm, the table-image distance is known, and the object-image distance is estimated according to the patient's BMI. We defined a device-adapted magnification factor that simplifies the templating routine and can be used to obtain the most reliable preoperative dimensional measurements that can be expected from X-ray images. We found the error margin of the magnification factor with the highest degrees of prediction and precision. CONCLUSION: Preoperative planning is reliable and reproducible using X-ray images if calibration is performed with the device-adapted magnification factor suggested in this paper.
Assuntos
Artroplastia de Quadril , Humanos , Artroplastia de Quadril/métodos , Artroplastia de Quadril/instrumentação , Calibragem , Tomografia Computadorizada por Raios X/métodos , Cuidados Pré-Operatórios/métodos , Raios XRESUMO
Food crops around the world are commonly contaminated with Aspergillus flavus, which can produce the carcinogenic mycotoxin aflatoxin B1 (AFB1). The objective of this study is to test an X-ray irradiation sterilization method for studying AFB1 in contaminated maize samples in the laboratory. Maize that had been naturally contaminated with 300 ppb AFB1 by the growth of aflatoxigenic A. flavus was ground and then irradiated at 0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 kGy. A. flavus was quantified by dilution plating on potato dextrose agar (PDA) and modified Rose Bengal media (MDRB) for viability and qPCR for gene presence. AFB1 was quantified by HPLC and ELISA. A. flavus viability, but not gene copies, significantly decreased with increasing doses of radiation (PDA: p < 0.001; MDRB: p < 0.001; qPCR: p = 0.026). AFB1 concentration did not significantly change with increasing doses of radiation (HPLC: p = 0.153; ELISA: p = 0.567). Our results imply that X-ray irradiation is an effective means of reducing viable A. flavus without affecting AFB1 concentrations. Reducing the hazard of fungal spores and halting AFB1 production at the targeted dose are important steps to safely and reproducibly move forward research on the global mycotoxin challenge.
Assuntos
Aflatoxina B1 , Aspergillus flavus , Zea mays , Zea mays/microbiologia , Zea mays/efeitos da radiação , Aflatoxina B1/efeitos da radiação , Aspergillus flavus/efeitos da radiação , Aspergillus flavus/crescimento & desenvolvimento , Aspergillus flavus/metabolismo , Aspergillus flavus/efeitos dos fármacos , Raios X , Contaminação de Alimentos/prevenção & controle , Irradiação de Alimentos/métodos , Viabilidade Microbiana/efeitos da radiação , Viabilidade Microbiana/efeitos dos fármacosRESUMO
The morphological characteristics of the foot arch and the plantar soft tissue thickness are pivotal in assessing foot health, which is associated with various foot and ankle pathologies. By applying deep learning image segmentation techniques to lateral weight-bearing X-ray images, this study investigates the correlation between foot arch morphology (FAM) and plantar soft tissue thickness (PSTT), examining influences of age and sex. Specifically, we use the DeepLab V3+ network model to accurately delineate the boundaries of the first metatarsal, talus, calcaneus, navicular bones, and overall foot, enabling rapid and automated measurements of FAM and PSTT. A retrospective dataset containing 1497 X-ray images is analyzed to explore associations between FAM, PSTT, and various demographic factors. Our findings contribute novel insights into foot morphology, offering robust tools for clinical assessments and interventions. The enhanced detection and diagnostic capabilities provided by precise data support facilitate population-based studies and the leveraging of big data in clinical settings.
Assuntos
Aprendizado Profundo , Pé , Humanos , Feminino , Pé/diagnóstico por imagem , Pé/anatomia & histologia , Masculino , Adulto , Pessoa de Meia-Idade , Estudos Retrospectivos , Idoso , Adulto Jovem , Adolescente , Processamento de Imagem Assistida por Computador/métodos , Raios X , Radiografia/métodos , Idoso de 80 Anos ou maisRESUMO
This study aims to provide radiation reference levels in orthopaedic surgery. A total of 753 procedures were collected within 1 y. Categories containing several similar procedures were created based on four criteria: same anatomical area, same level of complexity, only single procedures, and at least 10 cases per category. Exposure was defined in terms of air kerma-area product, fluoroscopy time, and air kerma at the patient entrance reference point. For common procedures, median effective doses to patient were calculated using the Monte Carlo Software PCXMC. Most irradiating procedure in this study i.e. intramedullary nailing of the proximal femur was equivalent to an air kerma at the patient entrance reference point of 37.1 mGy, which is ~50 times lower than the threshold for acute deterministic effects of radiation. Optimization remains a must to reduce the dose while maintaining the image quality and reducing the likelihood of stochastic effects.
Assuntos
Método de Monte Carlo , Doses de Radiação , Humanos , Fluoroscopia/métodos , Procedimentos Ortopédicos , Raios X , Masculino , Feminino , AdultoRESUMO
Iodinated X-ray contrast media (ICM) was frequently detected in the aqueous environment. In this work, the applicability of three graphene-based nanomaterials (graphene nanosheets (GNS), graphene oxide (GO), and reduced graphene oxide (rGO)) for the adsorptive removal of the six ICMs including iohexol, iopamidol, iomeprol, iopromide, iodixanol and ioversol from aqueous solution was firstly evaluated by batch adsorption method. Among the three graphene-based nanomaterials, the GNS displayed the best adsorption performances for the adsorption of the six ICMs. The maximum uptakes of the six ICMs by the GNS (161.5 mg g-1 for iohexol, 267.2 mg g-1 for iodixanol, 197.7 mg g-1 for iopromide, 197.0 mg g-1 for iopamidol, 109.6 mg g-1 for iomeprol, and 168.2 mg g-1 for ioversol) can rapidly achieved within 10 min and indicate no dependence on pH in the range of 4-9. The results obtained from the calculations of isotherms, kinetics and thermodynamic supported the occurrence of a chemisorption of the GNS for the six ICMs. The π-π interactions between benzene ring of the ICMs and the sp2-hybridized two-dimensional sheet of GNS were deemed the predominant adsorption mechanism.