Imaging Purposes Research Articles

Patient-specific tumor and respiratory monitoring phantom design for quality controls of stereotactic ablative body radiotherapy in lung cancer cases.

The design, production and adaptability to clinical routine of a patient-specific tumor and respiratory monitoring phantom (TRMP) was investigated using 3D printer technology. TRMP and GTV modelling were done using 4D-CT images of the inhalation phase. The model was converted to STL (Stereolithography) format and printed with STH (Strong Herbal) biopolymer with HU (Hounsfield Unit) suitable for imaging purposes. The assembly of TRMP motorized parts and mechanical equipment has been completed and made suitable for clinical use. In the first part of the study, the deviations of radio-opaque markers attached to the TRMP sternum to perform mechanical quality control tests and T1-7 costal vertebrae in CC, AP, and LAT directions were evaluated. In the second part of the study, in order to evaluate the usability of the TRMP in quality assurance (QA), point dose measurements with BeO OSL dosimetry and EBT3 gafchromic film measurements were taken in Trilogy® radiotherapy accelerator and CyberKnife® robotic radiosurgery accelerator. In this study, we present a highly flexible TMRP capable of performing independent internal and external motions. TRMP was successfully tested in different treatment accelerators, both mechanically and dosimetrically.

POSTMODERN DÖNEMDE TÜKETİCİYİ ANLAMAK, REKLAMLARDA KULLANILAN ARKETİPLERİN POSTMODERN TÜKETİCİ İLE İLİŞKİSİ: TÜRKİYENİN EN DEĞERLİ 20 MARKASININ YOUTUBE REKLAMLARININ ÖRNEĞİ

Postmodern culture, which developed after the modern period, is in a structure in which postfordist consumption understanding is adopted instead of fordist consumption and consumption for image purposes is at the forefront. In this context, brands create their images in order to be remembered in the current culture and to create a lifestyle for the continuity of consumption. The creation process of images, on the other hand, is through advertisements where the continuous production and consumption of high reality and commodities is made, and it shows a common development with postmodern culture brand images. Within the scope of the study, a descriptive approach and content analysis method were preferred in order to make sense of how brand images are produced through advertisements in the postmodern period and to deal with the constructing dimension. Accordingly, the top 10 brands in the ranking of the Brand Finance 2021 Turkey Report were selected as a sample and the ads of the selected brands between 1 June 2021 and 5 June 2021 with the theme of world environment day were analyzed. As a result of the analysis, within the framework of advertising and consumption; brand images in the postmodern period, where there are higher realities, fragmented consumer structure, production and consumption change places and the subject is decentralized; Impressions can be evaluated in various ways such as symbolism, personification, meanings and messages and psychological elements. Looking at the general position, it has been concluded that the structural features of postmodernity are effective in creating and creating brand image characters, and in this respect, it shapes brand images.

Amplified spontaneous emission and gain in highly concentrated Rhodamine-doped peptide derivative

Bioinspired fluorescence, being widely explored for imaging purposes, faces challenges in delivering bright biocompatible sources. While quite a few techniques have been developed to reach this goal, encapsulation of high-quantum yield fluorescent dyes in natural biological forms suggest achieving superior light-emitting characteristics, approaching amplified spontaneous emission and even lasing. Here we compare gain capabilities of highly concentrated Rhodamine B solutions with a newly synthesized biocompatible peptide derivative hybrid polymer/peptide material, RhoB-PEG1300-F6, which contains the fluorescent covalently bound dye. While concentration quenching effects limit the maximal achievable gain of dissolved Rhodamine B, biocompatible conjugation allows elevating amplification coefficients towards moderately high values. In particular, Rhodamine B, anchored to the peptide derivative material, demonstrates gain of 22–23 cm−1 for a 10−2 M solution, while a pure dye solution possesses 25% smaller values at the same concentration. New biocompatible fluorescent agents pave ways to demonstrate lasing in living organisms and can be further introduced to therapeutic applications, if proper solvents are found.

Enhancement of medical images using fuzzy logic

Image enhancement is one of the most critical subjects in computer vision and image processing fields. It can be considered as means to enrich the perception of images for human viewers. All kinds of images typically suffer from different problems such as weak contrast and noise. The primary purpose of image enhancement is to change an image's visual appearance. Many algorithms have recently been proposed for enhancing medical images. Image enhancement is still deemed a challenging task. In this paper, the fuzzy c-means clustering (FCM) technique is utilized to enhance the medical images. The method of enhancement consists of two stages. The proposed algorithm conducts a cluster test on the image pixels. It then increases the difference of gray level between the diverse objects to accomplish the enhancement purpose of the medical images. The experimental results have been tested using various images. The algorithm enhanced the small target of the image to a reasonable limit and revealed favorable performance. The results of image enhancement techniques were evaluated by using terms of different criteria such as peak signal to noise ratio (PSNR), mean square error (MSE) and average information contents (AIC), showing promising performance.

Electromagnetic and imaging properties of chiral dispersive spherical interfaces under bimodal propagation using ABCD matrices.

The properties of thick lenses are altered substantially in the presence of chirality and material dispersion. Recent work has involved examining of a chiral thick lens by re-deriving the related ABCD matrices based on standard paraxial and meridional conditions. A salient feature of a chiral thick lens is the inherent bimodal propagation via circular polarizations. Additionally, determination of image intensities requires the electromagnetic transmission properties expressed via the Fresnel coefficients. Three different scenarios are considered, viz., first-order frequency-dependent material dispersion of the dielectric permittivity, the lens material being chiral, and the case of an air gap (shaped like a thick lens) embedded in a chiral host. Under chirality, two sets of ABCD matrices are derived for right- and left-circularly polarized modes. The analyses and results are compared with the standard achiral problem. For imaging purposes, a simple 1D colored transparency is placed as an object before the thick lens in each scenario, with the transmission across the spherical boundaries examined via the ABCD parameters; also, the plane-wave amplitude transmitted across the system under different chirality bands and physical parameters is examined using the corresponding Fresnel coefficients. Under dispersion, image characteristics such as foci, location, magnification, and amplitude are controlled by narrow sidebands around a monochromatic carrier and the chirality. It is found that significant differences arise in the three imaging systems leading to the comparisons presented here.

A novel method for sensitivity modelling of optical gas imaging thermal cameras with warm filters

ABSTRACT The work proposes a novel method for sensitivity modelling of uncooled thermal cameras for optical gas imaging purposes. Such cameras use warm interference filters for better gas leak contrast at the cost of decreased sensitivity. With the presented method, it is possible to estimate this sensitivity without the need for physically installing a filter inside the camera. It can be done for any chosen background temperature and an arbitrary filter with known spectral transmission characteristic, which is often found in the filter manufacturer’s documentation. The proposed method requires prior measurement of the camera calibration curve before filter installation. In addition, this method may be used for estimating, how camera noise equivalent temperature difference will change after filter installation. With the aid of new parameter gas equivalent blackbody digital level difference, one may also verify, whether in particular measurement scenario gas leak will be visible or not. The performance of the proposed method is validated with five different filters and broadband uncooled thermal imaging camera.

High-Intensity Focused Ultrasound: A Review of Mechanisms and Clinical Applications.

High Intensity Focused Ultrasound (HIFU) is an emerging and increasingly useful modality in the treatment of cancer and other diseases. Although traditional use of ultrasound at lower frequencies has primarily been for diagnostic imaging purposes, the development of HIFU has allowed this particular modality to expand into therapeutic use. This non-invasive and acoustic method involves the use of a piezoelectric transducer to deliver high-energy pulses in a spatially coordinated manner, while minimizing damage to tissue outside the target area. This review describes the history of the development of diagnostic and therapeutic ultrasound and explores the biomedical applications utilizing HIFU technology including thermally ablative treatment, therapeutic delivery mechanisms, and neuromodulatory phenomena. The application of HIFU across various tumor types in multiple organ systems is explored in depth, with particular attention to successful models of HIFU in the treatment of various medical conditions. Basic mechanisms, preclinical models, previous clinical use, and ongoing clinical trials are comparatively discussed. Recent advances in HIFU across multiple medical fields reveal the growing importance of this biomedical technology for the care of patients and for the development of possible pathways for the future use of HIFU as a commonplace treatment modality.

Personalised Profiling of Innate Immune Memory Induced by Nano-Imaging Particles in Human Monocytes.

Engineered nanoparticles used for medical purposes must meet stringent safety criteria, which include immunosafety, i.e., the inability to activate possibly detrimental immune/inflammatory effects. Even medical nanomaterials devoid of direct immunotoxic or inflammatory effects may have an impact on human health if able to modify innate memory, which is the ability to “prime” future immune responses towards a different, possibly more detrimental reactivity. Although innate memory is usually protective, anomalous innate memory responses may be at the basis of immune pathologies. In this study, we have examined the ability of two nanomaterials commonly used for diagnostic imaging purposes, gold and iron oxide nanoparticles, to induce or modulate innate memory, using an in vitro model based on human primary monocytes. Monocytes were exposed in culture to nanoparticles alone or together with the bacterial agent LPS (priming phase/primary response), then rested for six days (extinction phase), and eventually challenged with LPS (memory/secondary response). The memory response to the LPS challenge was measured as changes in the production of inflammatory (TNFα, IL-6) and anti-inflammatory cytokines (IL-10, IL-1Ra), as compared to unprimed monocytes. The results show that both types of nanoparticles can have an effect in the induction of memory, with changes observed in the cytokine production. By comparing nanomaterials of different shapes (spherical vs. rod-shaped gold particles) and different size (17 vs. 22 nm diameter spherical iron oxide particles), it was evident that innate memory could be differentially induced and modulated depending on size, shape and chemical composition. However, the main finding was that the innate memory effect of the particles was strongly donor-dependent, with monocytes from each donor showing a distinct memory profile upon priming with the same particles, thereby making impossible to draw general conclusions on the particle effects. Thus, in order to predict the effect of imaging nanoparticles on the innate memory of patients, a personalised profiling would be required, able to take in consideration the peculiarities of the individual innate immune reactivity.

Rollback reconstruction for TDC enhanced perfusion imaging

Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis. However, the low rotational speed of the C-arm (6–8 s per circle) is a challenge for applying perfusion imaging in C-arm cone beam computed tomography (CBCT). Traditional reconstruction methods cannot remove the artifacts caused by the slow rotational speed or acquire enough sample points to restore the time density curve (TDC). This paper presents a dynamic rollback reconstruction method for CBCT. The proposed method can improve the temporal resolution by increasing the sample points used for calculating the TDC. Combined with existing techniques, the algorithm allows slow-rotating scanners to be used for perfusion imaging purposes. In the experiments, the proposed method was compared with other dynamic reconstruction algorithms based on standard reconstruction and the temporal interpolation approach. The presented algorithm could improve the temporal resolution without increasing the X-ray exposure time or contrast agent.

Manually scanned single fiber optical coherence tomography for skin cancer characterization

Optical coherence tomography (OCT) is a cross-sectional imaging modality based on low coherence light interferometry. Within dermatology, it has found applications for in vivo diagnostic imaging purposes, as well as to guide Mohs micrographic surgery (MMS), due to its ability to visualize skin morphology up to several millimeters in depth. However, standard OCT probes have a large footprint and capture an extended area of the skin, making it difficult to precisely pinpoint clinically relevant location being imaged. Mohs surgeons stand to benefit from a handheld in vivo imaging device that can accurately trace surgical margins. In this study, we demonstrate the use of a single fiber OCT (sfOCT) instrument. Our imaging system features a miniature common path single fiber probe, and a novel speckle decorrelation technique that generates distortion free 2D images from manual scanning.By manually moving the single-fiber probe across the region of interest, the user can perform a lateral OCT scan while visualizing the location of the probe during data acquisition. Using the sfOCT, we have identified normal skin morphology, qualitatively correlated features of basal cell carcinoma and squamous cell carcinoma with histopathology, and quantified the disruption of the dermo-epidermal junction OCT pattern in skin tumors—each demonstrating the potential of utilizing sfOCT to differentiate tumor from normal skin. Using this imaging tool, a Mohs surgeon can enhance determination of surgical margins for the first stage of MMS, potentially decreasing the time and number of stages required for complete tumor removal.

Covert and Secure Communication Using Multiple Invisible Stego Images by Split-Logical Algorithm

The use of the web is developing for surreptitious and non-surreptitious communication with the expansion of brilliant innovations. In this circumstance, there is a need to improve the security level of the covert information. Our motive is to propose a unique algorithm by using steganography along with cryptography which provides a better solution for secret communication and improves security with more levels. In this paper, the two-level stationary wavelet transform technique is applied to cover image to acquire HH2 sub-band alongside the remaining sub-bands. The data are implanted into the HH2 sub-band of the cover image by utilizing the random pixel embedded strategy to accomplish the stego image. To improve the security of the stego image, the surreptitious text data are changed into cipher form with a novel cryptography algorithm that incorporates unique data conversion and gray-code techniques. The resultant stego image undergoes to split-logical algorithm to create numerous imperceptible stego images. The main purpose of imperceptible stego images is to provide better security to covert information and also it increases the payload capacity. The concept of generating imperceptible stego images is, each of them will be treated as a stego image for hackers. But original stego image is reconstructed by combining all generated imperceptible stego images. These imperceptible stego images are ready to oppose the diverse steganalysis assaults like visual, noise, rotational assaults, and so forth.

Halogenation at the Phenylalanine Residue of Monomethyl Auristatin F Leads to a Favorable cis/trans Equilibrium and Retained Cytotoxicity.

Halogenation can be utilized for the purposes of labeling and molecular imaging, providing a means to, e.g., follow drug distribution in an organism through positron emission tomography (PET) or study the molecular recognition events unfolding by nuclear magnetic resonance (NMR) spectroscopy. For cancer therapeutics, where often highly toxic substances are employed, it is of importance to be able to track the distribution of the drugs and their metabolites in order to ensure minimal side effects. Labeling should ideally have a negligible disruptive effect on the efficacy of a given drug. Using a combination of NMR spectroscopy and cytotoxicity assays, we identify a site susceptible to halogenation in monomethyl auristatin F (MMAF), a widely used cytotoxic agent in the antibody–drug conjugate (ADC) family of cancer drugs, and study the effects of fluorination and chlorination on the physiological solution structure of the auristatins and their cytotoxicity. We find that the cytotoxicity of the parent drug is retained, while the conformational equilibrium is shifted significantly toward the biologically active trans isomer, simultaneously decreasing the concentration of the inactive and potentially disruptive cis isomer by up to 50%. Our results may serve as a base for the future assembly of a multifunctional toolkit for the assessment of linker technologies and exploring bystander effects from the warhead perspective in auristatin-derived ADCs.

Imaging calibration of AstroSat Cadmium Zinc Telluride Imager (CZTI)

AstroSat is India's first space-based astronomical observatory, launched on September 28, 2015. One of the payloads aboard AstroSat is the Cadmium Zinc Telluride Imager (CZTI), operating at hard X-rays. CZTI employs a two-dimensional coded aperture mask for the purpose of imaging. In this paper, we discuss various image reconstruction algorithms adopted for the test and calibration of the imaging capability of CZTI and present results from CZTI on-ground as well as in-orbit image calibration.

Optical modulation frequency mediated tunable response time and responsivity in graphene-PbS QD based hybrid photodetectors

Graphene/lead sulfide (PbS) quantum dot (QD) hybrid infrared photodetectors have gained a lot of attention in recent times due to their high resolution and cost effective fabrication process. In spite of exhibiting remarkably high responsivity, such hybrid detectors are slow as a result of their internal gain mechanism process. In this work, we present a convenient strategy to modulate the correlation between their responsivity and response time giving access to high resolution fast photodetectors in the broadband wavelength range for imaging purpose. Using a layer-by-layer deposition technique including simultaneous ligand exchange and surface passivation at each layer, homogeneous PbS QD films on chemical vapour deposition grown single layer graphene could be achieved. The obtained hybrid phototransistors exhibit a high responsivity of 108 A W−1 and sensitivity down to 0.1 pW incident light power in the near-infrared wavelength range. By modulating the incident light at a modulation frequency up to 50 kHz, we achieve a response time as low as 5 μs while preserving a much higher responsivity (144 A W−1) compared to existing commercial room temperature infrared photodetectors.

English

BACKGROUND The purpose of imaging is multifaceted, ranging from selecting the most appropriate patients for treatment, to avoiding those who are unlikely to benefit. In the present situation, imaging methods basically include cross-sectional imaging by computed tomography (CT) or magnetic resonance imaging (MRI). The target of the assessment is the vessels that supply the brain parenchyma and its associated part at the same / distant perfusion level. In this study, we wanted to evaluate the diagnostic accuracy of diffusion-weighted MR imaging with nonenhanced CT in the diagnosis of hyperacute stroke. METHODS This prospective study was conducted in Radiology Department at Narayan Medical College Rohtas, Bihar. The study group includes a sample of 45 patients who had come to the Department of Radiology within 6 hours of onset of stroke symptoms. Non-enhanced computed tomography (NECT) and MRI were done in all the patients and the results were studied. Study subjects were recruited as following inclusion and exclusion criteria. Data was collected, entered and analysed using Microsoft Excel, Epi Info and statistical package for social sciences (SPSS) software. RESULTS The hyperintense ischemic lesions on diffusion-weighted imaging (DWI) were typically more visually distinct and easier to distinguish than the EIS on CT scans, resulting in better overall values. When the five regions were looked at separately, DWI had higher sensitivity than CT studies, which was close to the overall EIS ranking. The basal ganglia and the insular ribbon had the greatest sensitivity in both modalities. Eight of the 14 patients were classified in the consensus rating of CT and DW imaging, resulting in a sensitivity of 57 percent for both methods, with a bad value of 0.40 for CT and a good value of 0.68 for DW imaging. CONCLUSIONS DW imaging had a higher sensitivity and interrater agreement than CT imaging in detecting early infarction. KEYWORDS Stroke, Computed tomography, MRI, Ischaemia

A case for mandatory ultrasound training for rural general practitioners: a commentary.

Point-of-care ultrasound is a rapidly evolving technology that enables rapid diagnostic imaging to be performed at a patient's bedside, reducing time to diagnosis and minimising the need for patient transfers. This has significant applications for rural emergency and general practice, and could potentially prevent unnecessary transfers of patients from rural communities to more urban centres for the purpose of diagnostic imaging, reducing costs and preventing disruption to patients' lives. Meta-analyses on point-of-care ultrasound have reported extremely high sensitivity and specificity when detecting lung pathology, and the potential applications of the technology are substantial. A significant application of the technology is in the care of rural paediatric patients, where acute lower respiratory pathology is the most common cause of preventable deaths, hospitalisations, and emergency medical retrievals from remote communities for children under five. Although widely available, point-of-care ultrasound technology is not widely utilised in Australian emergency departments and general practices. Issues with comprehensive training, maintenance of skills, upskilling and quality assurance programs prevent physicians from feeling confident when utilising the technology. In Canada, point-of-care ultrasound training is part of the core competency training in the Royal College of Physicians of Canada emergency medicine fellowship program. Point-of-care ultrasound is widely used in rural practice, although lack of training, funding, maintenance of skills and quality assurance were still listed as barriers to use. Point-of-care ultrasound is a highly sensitive and specific technology with wide potential applications. Issues with quality control and maintenance of skills are preventing widespread use. Coupling point-of-care ultrasound with telemedicine could help increase the usability and accessibility of the technology by reducing the issues associated with maintenance of skills and quality assurance.

Optical properties of an extended gravitational lens

We continue to study the optical properties of the solar gravitational lens (SGL). The aim is prospective applications of the SGL for imaging purposes. We investigate the solution of Maxwell's equations for the electromagnetic (EM) field, obtained on the background of a static gravitational field of the Sun. We now treat the Sun as an extended body with a gravitational field that can be described using an infinite series of gravitational multipole moments. Studying the propagation of monochromatic EM waves in this extended solar gravitational field, we develop a wave-optical treatment of the SGL that allows us to study the caustics formed in an image plane in the SGL's strong interference region. We investigate the EM field in several important regions, namely i) the area in the inner part of the caustic and close to the optical axis, ii) the region outside the caustic, and iii) the region in the immediate vicinity of the caustic, especially around its cusps and folds. We show that in the first two regions the physical behavior of the EM field may be understood using the method of stationary phase. However, in the immediate vicinity of the caustic the method of stationary phase is inadequate and a wave-optical treatment is necessary. Relying on the angular eikonal method, we develop a new approach to describe the EM field accurately in all regions, including the immediate vicinity of the caustics and especially near the cusps and folds. The method allows us to investigate the EM field in this important region, which is characterized by rapidly oscillating behavior. Our results are new and can be used to describe gravitational lensing by realistic astrophysical objects, such as stars, spiral and elliptical galaxies.

An Innovative Approach for Denoising of the Digital Video Stream

Everyday tones of video signals are generated, transmitted, and analyzed. The video contents are created for educational purposes, entertainment purposes, surveillance purposes, medical imaging purposes, weather forecasting, satellite imaging, and many other significant places. During the different phases of video content preparation, transmission, and analysis some unwanted signals get interfered with the true contents. Particularly, the medical imaging signals, since they are weak signals, are more prone to unwanted interferences. Such unwanted interference of the noise signals makes it difficult to analyze the critical information in the video contents and hence, the need for denoising process arises. A decent video denoising framework assures visual improvement in the video signals or it serves as the significant pre-processing step in the video processing steps like compression and analysis. Through this paper, we are about to disclose an efficient video denoising framework that takes the noisy video signal in the form of frames per second and performs the video denoising using shot detection, compensation, intensity calculations, and motion estimation process.

Multi detector computed tomography in maxillofacial injuries

Background: Imaging is an important step after the clinical evaluation in the workup of patients with facial trauma .It helps to define the extent of injury and to plan the surgical, interventional, or conservative therapy. Multidetector computed tomography (MDCT) is the imaging technique of choice to detect and characterize the number of fractures, fragments, the degree of dislocation, and the involvement of anatomical structures. It provides a three-dimensional (3D) mapping of the smallest fractures and abnormalities in a short period of time in trauma and emergency setting.Results: The study included 30 patients with mean age of 41.07± 13.92 years with age range of 21 – 68 years. In most of the cases the mode of injury was road traffic accidents among 23(76.7%). Fracture maxilla in 63.3% followed by mandible in 56.7% was the most common bone involved in facial fractures. Hemosinus (56.7%) was the most common associated finding in the patients who presented with facial trauma. Brain contusions were the next common finding seen in 30% patients. Medial wall of the orbit was the most common wall involved in orbital fractures. The mandibular injuries were most common in the condyle and the body of the mandible. Le Fort fracture lines were identified in 17 patients with the most common Le Fort line being the Le Fort II & Le Fort III which was seen 7 patients (23.3%) each.Conclusion: The complex anatomy of the facial bones requires multiplanar imaging techniques for a proper evaluation. The main purpose of diagnostic imaging is to detect and localize the exact number, site of facial fractures and soft tissue injuries. 3D images are useful, although variable for different bones, in the assessment of complex fractures involving the face. Coronal images are useful adjunct in detection of facial fractures. MDCT offers excellent spatial resolution, which in turn enables exquisite multiplanar reformations, and 3-D reconstructions, allowing enhanced diagnostic accuracy and surgical planning.

Fabrication and testing of Novel 20 gas gaps double-stack Multi-gap Resistive Plate Chamber (MRPC) with multi-layer Copper converters and reduced HV for high energy gamma detection

Resistive Plate Chambers (RPCs) are cost-effective detectors with fast signal, excellent time and spatial resolution for charged particle detection. These detectors can be also good candidates for medical imaging purposes like PET. Although, low efficiency of gaseous detectors limits their usage for high energy gamma detection, but it is possible to improve the detection efficiency by proper gamma to electron converter material and multi-layers of RPCs (MRPCs). In common RPCs, increasing the number of layers is limited by the large amount of applied High Voltage (HV). To overcome this problem, which is important for secure medical imaging system, the double-stack mode configuration is used in such a way that the RPCs are physically serial, but electrically parallel. In this work, A 20 gap MRPC with 160μ m of Copper converters and 150μ m gas gaps is fabricated. For this purpose, each metal sheet sandwiched between two thin resistive glasses. The metal electrodes are also used to apply separate HV to each gas gap. By using the proposed configuration, the applied HV can be reduced to 1.2kV for whole system. The simulation results show that the detection efficiency for 661keV Cs-137 gammas with 160μ m of Copper converter is around %5, which is in good agreement with experimental results.