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Background: Electromagnetic induction hyperthermia is a promising method to treat the deep-seated tumors such as brain and prostatic tumors. This technique is performed using the induction of electromagnetic waves in the ferromagnetic cores implanted at the solid tumor. Objective: This study aims at determining the conditions of the optimal thermal distribution in the different frequencies before performing the in vitro cellular study. Material and Methods: In this experimental study, the i-Cu alloy (70.4-29.6; wt%) was prepared and characterized and then the parameters, affecting the amount of induction heating in the ferromagnetic core, were investigated. Self-regulating cores in 1, 3, 6, and 9 arrangements in the water phantom with a volume of 2 cm3 were used as a replacement for solid tumor. Results: Inductively Coupled Plasma (ICP) analysis and Energy Dispersive X-ray Spectroscopy (EDS) show the uniformity of the alloy after 4 times remeling by vacuum arc remelting furnace. The Vibrating Sample Magnetometer (VSM) shows that the Curie temperature (TC) of the ferromagnetic core is less than 50 °C. Temperature profile with a frequency of 100-400 kHz for 30 min, was extracted by infrared imaging camera, indicating the increase temperature in the range of 42 °C to 46 °C. Conclusion: The optimum conditions with used hyperthermia system are supplied in the frequency of 100 kHz, 200 kHz and 400 kHz with 6, 3 and 1 seeds, respectively. It is also possible to induce a temperature up to 50 °C by increasing the number of seeds at a constant frequency and power, or by increasing the applied frequency at a constant number of seeds. [ABSTRACT FROM AUTHOR]

Purpose: With improvements in positron emission tomography/magnetic resonance imaging (PET/MRI) over the last decade, there is a need to investigate the projected annihilation (shine‐through) artifact and resolution impact for different PET radiopharmaceuticals, magnetic field (MF) strengths, and tissues. Methods: The GATE Monte Carlo (MC) simulation was used to simulate the annihilation distribution of positrons in different tissues and MFs. The positron distribution was studied in magnetic field (MF) intensities up to 15 T for 11C, 13N, 15O, 18F, 68Ga, and 82Rb. Moreover, the image quality in terms of the occurrence of projected annihilation artifacts was investigated using the 4D anthropomorphic digital extended cardiac‐torso (XCAT) phantom. Results: Positron ranges were restricted across the directions perpendicular to the MF, but no change along the direction of the MF was detected. The projected annihilation artifacts were observed with the presence of MF in the sagittal and coronal view of PET images prepared from the XCAT phantom. The intensity of artifact was constant in MFs higher than 3 T. The significant effect of the MF on resolution improvement was observed in soft tissue for 68Ga in 7 T and 82Rb in 3 and 7 T, while higher MFs have no impact on resolution. The improvement of resolution in the lung tissue was observed for the medium‐ and high‐energy radionuclides in 7 T MF. Conclusion: The MF can create the projected annihilation artifact in the boundary of air cavities and other tissues for medium‐ and high‐energy radionuclides especially for 68Ga in clinical studies. In addition, the strength of the MFs more than 3 T was ineffective on the intensity of the projected annihilation artifact. In a clinical PET/MR scanner, MF has remarkable spatial resolution improvement in lung tissue, especially for medium‐ and high‐energy radionuclides, and negligible effect in bone and soft tissue for most radionuclides. [ABSTRACT FROM AUTHOR]

Objectives: The present study aims to assess the impact of acquisition time, different iterative reconstruction protocols as well as image context (including contrast levels and background activities) on the measured spatial resolution in PET images.Methods: Discovery 690 PET/CT scanner was used to quantify spatial resolutions in terms of full width half maximum (FWHM) as derived (i) directly from capillary tubes embedded in air and (ii) indirectly from 10 mm-diameter sphere of the NEMA phantom. Different signal-to-background ratios (SBRs), background activity levels and acquisition times were applied. The emission data were reconstructed using iterative reconstruction protocols. Various combinations of iterations and subsets (it × sub) were evaluated.Results: For capillary tubes, improved FWHM values were obtained for higher it × sub, with improved performance for PSF algorithms relative to non-PSF algorithms. For the NEMA phantom, by increasing acquisition times from 1 to 5 min, intrinsic FWHM for reconstructions with it × sub 32 (54) was improved by 15.3% (13.2%), 15.1% (13.8%), 14.5% (12.8%) and 13.7% (12.7%) for OSEM, OSEM + PSF, OSEM + TOF and OSEM + PSF + TOF, respectively. Furthermore, for all reconstruction protocols, the FWHM improved with more impact for higher it × sub.Conclusion: Our results indicate that PET spatial resolution is greatly affected by SBR, background activity and the choice of the reconstruction protocols. [ABSTRACT FROM AUTHOR]

The purpose of this study is to measure the concentration of gold nanoparticles (AuNPs) attached to folic acid through cysteamin as the linker (FA-Cys-AuNPs) and AuNPs in KB human nasopharyngeal cancer cells using dual-energy CT (DECT). In this study, nanoparticles with a size of ~15 nm were synthesized and characterised using UV-Vis, TEM, FTIR and ICP-OES analyses. The non-toxicity of nanoparticles was confirmed by MTT assay under various concentrations (40-100 µg/ml) and incubation times (6, 12 and 24 h). To develop an algorithm for revealing different concentrations of AuNPs in cells, a corresponding physical phantom filled with 0.5 ml vials containing FA-Cys-AuNPs was used. The CT scan was performed at two energy levels (80 and 140 kVp). One feature of DECT is material decomposition, which allows separation and identification of different elements. The values obtained from the DECT algorithm were compared with values quantitatively measured by ICP-OES. Cells were also incubated with AuNPs and FA-Cys-AuNPs at different concentrations and incubation times. Subsequently, by increasing the incubation time in the presence of FA-Cys-AuNPs, in comparison with AuNPs, DECT pixels were increased. Thus, FA-Cys-AuNPs could be a suitable candidate for targeted contrast agent in DECT molecular imaging of nasopharyngeal cancer cells. [ABSTRACT FROM AUTHOR]

The purpose of this study is to measure the concentration of gold nanoparticles (AuNPs) attached to folic acid through cysteamin as the linker (FA‐Cys‐AuNPs) and AuNPs in KB human nasopharyngeal cancer cells using dual‐energy CT (DECT). In this study, nanoparticles with a size of ∼15 nm were synthesized and characterised using UV‐Vis, TEM, FTIR and ICP‐OES analyses. The non‐toxicity of nanoparticles was confirmed by MTT assay under various concentrations (40– 100 µg/ml) and incubation times (6, 12 and 24 h). To develop an algorithm for revealing different concentrations of AuNPs in cells, a corresponding physical phantom filled with 0.5 ml vials containing FA‐Cys‐AuNPs was used. The CT scan was performed at two energy levels (80 and 140 kVp). One feature of DECT is material decomposition, which allows separation and identification of different elements. The values obtained from the DECT algorithm were compared with values quantitatively measured by ICP‐OES. Cells were also incubated with AuNPs and FA‐Cys‐AuNPs at different concentrations and incubation times. Subsequently, by increasing the incubation time in the presence of FA‐Cys‐AuNPs, in comparison with AuNPs, DECT pixels were increased. Thus, FA‐Cys‐AuNPs could be a suitable candidate for targeted contrast agent in DECT molecular imaging of nasopharyngeal cancer cells. [ABSTRACT FROM AUTHOR]

Purpose: Xtrim‐PET is a newly designed Silicon Photomultipliers (SiPMs)‐based prototype PET scanner dedicated for small laboratory animal imaging. We present the performance evaluation of the Xtrim‐PET scanner following NEMA NU‐4 2008 standards to help optimizing scanning protocols which can be achieved through standard and reliable system performance characterization. Methods: The performance assessment was conducted according to the National Electrical Manufacturers Association (NEMA) NU‐4 2008 standards in terms of spatial resolution, sensitivity, counting rate performance, scatter fraction and image quality. The in vivo imaging capability of the scanner is also showcased through scanning a normal mouse injected with 18F‐FDG. Furthermore, the performance characteristics of the developed scanner are compared with commercially available systems and current prototypes. Results: The volumetric spatial resolution at 5 mm radial offset from the central axis of the scanner is 6.81 µl, whereas a peak absolute sensitivity of 2.99% was achieved using a 250–650 keV energy window and a 10 ns timing window. The peak noise‐equivalent count rate (NECR) using a mouse‐like phantom is 113.18 kcps at 0.34 KBq/cc with 12.5% scatter fraction, whereas the NECR peaked at 82.76 kcps for an activity concentration level of 0.048 KBq/cc with a scatter fraction of 25.8% for rat‐like phantom. An excellent uniformity (3.8%) was obtained using NEMA image quality phantom. Recovery coefficients of 90%, 86%, 68%, 40% and 12% were calculated for rod diameters of 5, 4, 3, 2 and 1 mm, respectively. Spill‐over ratios for air‐filled and water‐filled chambers were 35% and 25% without applying any correction for attenuation and Compton scattering effects. Conclusion: Our findings revealed that beyond compactness, lightweight, easy installation and good energy resolution, the Xtrim‐PET prototype presents a reasonable performance making it suitable for preclinical molecular imaging‐based research. [ABSTRACT FROM AUTHOR]

Introduction: The position estimation in gamma detection system will have constant misplacements which can be corrected in the calibration procedure. In the pixelated crystal uniformly irradiation of detector will produce irregular shape due to position estimation errors. This image is called flood field image and is used to calibrate the position estimation. In this work we present a novel approach to automatically calibrate pixelated crystal array position estimation. Methods: In the flood image of a pixelated crystal array the local peaks represent the estimation of position for the gamma photons that interacted in a single crystal pixel. First, the method detects 2-D peak locations automatically in the case of blurred pixel responses in the presence of noise and disturbance of the image. The algorithm consists of a filtering step for smoothing the image followed by two rounds of local peak detection. After localizing image peaks, the correction routine will map the image locations to the crystal pixels using the thin-plate spline interpolation method. Results: The algorithm is tested for two flood images obtained from developed detector with different irregularity levels. By configuring constant parameters according to the detector configuration the method detected all crystal pixels in the image and map them correctly. The method further has been tested for10 identical blocks and the result showed automatic peak detection routine for all the blocks. Conclusion: An automatic peak detection is presented to work instead of time consuming manual calibration routines. The method shows robust performance in the presence of image noise. [ABSTRACT FROM AUTHOR]

The authors describe an electrochemical method for aptamer-based determination of insulin at femtomolar concentrations. The surface of a screen printed electrode was modified with ordered mesoporous carbon that was chemically modified with 1,3,6,8-pyrenetetrasulfonate (TPS). The amino-terminated aptamer was then covalently linked to TPS via reactive sulfonyl chloride groups. Subsequently, the redox probe Methylene Blue (MB) was interacted into the aptamer. The MB-modified binds to insulin and this results in the release of MB and a decreased signal as obtained by differential pulse voltammetry, best at a working voltage of -0.3 V (versus silver pseudo-reference electrode). Insulin can be quantified by this method in the 1.0 fM to 10.0 pM concentration range, with a 0.18 fM limit of detection (at 3σ/slope). The assay was applied to the determination of insulin in spiked human serum samples. The method is highly sensitive, selective, stable, and has a wide analytical range. [ABSTRACT FROM AUTHOR]

Introduction: There is a strong need for developing clinical technologies and instruments for prompt tissue assessment in a variety of oncological applications as smart methods. Elastic scattering spectroscopy (ESS) is a real-time, noninvasive, point-measurement, optical diagnostic technique for malignancy detection through changes at cellular and subcellular levels, especially important in early diagnosis of invasive skin cancer, melanoma. In fact, this preliminary study was conducted to provide a classification method for analyzing the ESS spectra. Elastic scattering spectra related to the normal skin and melanoma lesions, which were already confirmed pathologically, were provided as input from an ESS database. Materials and Methods: A program was developed in MATLAB based on singular value decomposition and K-means algorithm for classification. Results: Accuracy and sensitivity of the proposed classifying method for normal and melanoma spectra were 87.5% and 80%, respectively. Conclusion: This method can be helpful for classification of melanoma and normal spectra. However, a large body of data and modifications are required to achieve better sensitivity for clinical applications. [ABSTRACT FROM AUTHOR]

Objective (s): Various iterative reconstruction algorithms in nuclear medicine have been introduced in the last three decades. For each new imaging system, it is wise to select appropriate image reconstruction algorithms and evaluate their performance. In this study, three approaches of image reconstruction were developed for a novel desktop open-gantry SPECT system, PERSPECT, to assess their performance in terms of the quality of the resultant reconstructed images. Methods: In the present work, a proposed image reconstruction algorithm for the PERSPECT, referred to as quasi-simultaneous multiplicative algebraic reconstruction technique (qSMART), together with two popular image reconstruction methods, maximum-likelihood expectation-maximization (MLEM) and ordered-subsets EM (OSEM), were implemented and compared. Analytic and Monte Carlo simulations were applied for data acquisition of various phantoms including a micro-Derenzo phantom. All acquired data were reconstructed by the three algorithms using different number of iterations (1-40). A thorough set of figures-of-merit was utilized to quantitatively compare the generated images. Results: OSEM depicted reconstructed images of higher (or matching) quality in comparison to qSMART. MLEM also reached nearly similar quality as OSEM but at higher number of iterations. The graph of data discrepancy revealed that the ranking of the three approaches in terms of convergence speed is as qSMART, OSEM, and MLEM. Furthermore, bias-versus-noise curves indicated that optimal bias-noise results were achieved using OSEM. Conclusion: The results showed that although qSMART can be applied for image reconstruction if being halted in the early iterations (up to 5), the best achievable quality of images is obtained using the OSEM. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the biodistribution of polyethylene glycol (PEG) coated superparamagnetic iron oxide nanoparticles radiolabeled with Ga in normal mice after intravenous administration of this probe. Three mice were sacrificed at specific time intervals. The biodistribution data revealed high uptake by liver and spleen (60.62 and 12.65 %ID/g at 120 min post injection for liver and spleen, respectively). The clearance of other organs was fast. These results suggest that Ga-PEG-SPIONs has magnificent capabilities for applying in (PET-MRI) as a theranostic agent for detection of liver and spleen malignancies. [ABSTRACT FROM AUTHOR]

Nowadays molecular imaging plays a vital role in achieving a successful targeted and personalized treatment. Hence, the approach of combining two or more medical imaging modalities was developed. The objective of this review is to systematically compare recent dual contrast agents in Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI) and in some cases Single photon emission computed tomography (SPECT)/MRI in terms of some their characteristics, such as tumor uptake, and reticuloendothelial system uptake (especially liver) and their relaxivity rates for early detection of primary cancer tumor. To the best of our knowledge, this is the first systematic and integrated overview of this field. Two reviewers individually directed the systematic review search using PubMed, MEDLINE and Google Scholar. Two other reviewers directed quality assessment, using the criteria checklist from the CAMARADES (Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies) tool, and differences were resolved by consensus. After reviewing all 49 studies, we concluded that a size range of 20-200 nm can be used for molecular imaging, although it is better to try to achieve as small a size as it is possible. Also, small nanoparticles with a hydrophilic coating and positive charge are suitable as a T2 contrast agent. According to our selected data, the most successful dual probes in terms of high targeting were with an average size of 40 nm, PEGylated using peptides as a biomarker and radiolabeled with copper 64 and gallium 68. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose: Given increasing efforts in biomedical research utilizing molecular imaging methods, development of dedicated high-performance small-animal SPECT systems has been growing rapidly in the last decade. In the present work, we propose and assess an alternative concept for SPECT imaging enabling desktop open-gantry imaging of small animals. Methods: The system, PERSPECT, consists of an imaging desk, with a set of tilted detector and pinhole collimator placed beneath it. The object to be imaged is simply placed on the desk. Monte Carlo (MC) and analytical simulations were utilized to accurately model and evaluate the proposed concept and design. Furthermore, a dedicated image reconstruction algorithm, finite-aperture-based circular projections (FABCP), was developed and validated for the system, enabling more accurate modeling of the system and higher quality reconstructed images. Image quality was quantified as a function of different tilt angles in the acquisition and number of iterations in the reconstruction algorithm. Furthermore, more complex phantoms including Derenzo, Defrise, and mouse whole body were simulated and studied. Results: The sensitivity of the PERSPECT was 207 cps/MBq. It was quantitatively demonstrated that for a tilt angle of 30°, comparable image qualities were obtained in terms of normalized squared error, contrast, uniformity, noise, and spatial resolution measurements, the latter at ~0.6 mm. Furthermore, quantitative analyses demonstrated that 3 iterations of FABCP image reconstruction (16 subsets/iteration) led to optimally reconstructed images. Conclusions: The PERSPECT, using a novel imaging protocol, can achieve comparable image quality performance in comparison with a conventional pinhole SPECT with the same configuration. The dedicated FABCP algorithm, which was developed for reconstruction of data from the PERSPECT system, can produce high quality images for small-animal imaging via accurate modeling of the system as incorporated in the forward- and back-projection steps. Meanwhile, the developed MC model and the analytical simulator of the system can be applied for further studies on development and evaluation of the system. [ABSTRACT FROM AUTHOR]

Fluorescence molecular tomography (FMT) is a rapidly growing imaging method that facilitates the recovery of small fluorescent targets within biological tissue. The major challenge facing the FMT reconstruction method is the ill-posed nature of the inverse problem. In order to overcome this problem, the acquisition of large FMT datasets and the utilization of a fast FMT reconstruction algorithm with sparsity regularization have been suggested recently. Therefore, the use of a joint L1/total-variation (TV) regularization as a means of solving the ill-posed FMT inverse problem is proposed. A comparative quantified analysis of regularization methods based on L1-norm and TV are performed using simulated datasets, and the results show that the fast composite splitting algorithm regularization method can ensure the accuracy and robustness of the FMT reconstruction. The feasibility of the proposed method is evaluated in an in vivo scenario for the subcutaneous implantation of a fluorescent-dye-filled capillary tube in a mouse, and also using hybrid FMT and x-ray computed tomography data. The results show that the proposed regularization overcomes the difficulties created by the ill-posed inverse problem. [ABSTRACT FROM AUTHOR]

The application of rod‐shaped gold nanoparticles as probes and carriers in biological systems have recently attracted great interest. UV–vis spectroscopy, circular dichroism, Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy were used to study optical and structural properties of rod‐shaped gold nanoparticles when interacting with DNA oligomers in phosphate sodium salt buffer. The morphological transformation process of rod‐shaped gold nanoparticles resulting from the interaction with single‐stranded DNA (ssDNA) showed the role of hexadecyltrimethylammonium bromide (CTAB) in nanostructures as the main interacting agent. The obtained results confirmed that the CTAB coat of rod‐shaped gold nanoparticles have powerful positive charges for conjugations with surface negative charges of phosphate groups on ssDNA oligomers. The CTAB also inhibit the formation of covalent sulphide bonds between the gold core of rod‐shaped nanoparticles and alkanethiol oligonucleotides. The authors found that when the nanorods were exposed to ssDNA oligonucleotides, the gold nanorods changed their shapes and sizes, and exposed some microscopic malformations which could be used in the development of colorimetric assays of nucleic acids. [ABSTRACT FROM AUTHOR]

The artificial neural networks (ANNs) were used to provide a model for investigating the relationships of the electrospinning parameters with the diameter of polyethylene oxide (PEO) nanofibers from acid acetic aqueous solution. The effects of four parameters including PEO concentration, acetic acid concentration, applied voltage, and temperature of the electrospinning media on the nanofibers mean diameter were investigated. To train, test, and valid the model, three datasets of the input variables with random values were prepared and the mean diameters obtained were taken as the output for the network. The datasets were analyzed by ANNs software and the correlation coefficient, R-squared ( R2), between the predicted values of the nanofibers mean diameter and actual amount were obtained. The results demonstrate the capability of the ANNs model for predicting the nanofibers diameter. The 3-D plots generated from the model show complex and nonlinear relationships between the parameters and nanofibers diameter. From the model, increasing the PEO concentration above a critical point leads to a sharp increase in the nanofibers mean diameter. The effects of applied voltage and temperature are mainly dependent on the PEO concentration. The acetic acid concentration, in general shows a direct relation with the nanofibers mean diameter. The plots also show that to produce nanofibers with the lowest diameter, both the PEO concentration and AcOH concentration should be at lowest values regardless the applied voltage and temperature. In contrast, highest nanofibers diameters are obtained when the PEO concentration and AcOH concentration are at their high values. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Introduction: Reliable quantification in positron emission tomography (PET) requires accurate attenuation correction of emission data, which in turn entails accurate determination of the attenuation map (µ-map) of the object under study. One of the main steps involved in CT-based attenuation correction (CTAC) is energy-mapping, or the conversion of linear attenuation coefficients (µ) calculated at the effective CT energy to those corresponding to 511 keV.Materials and Methods: The aim of this study is to compare different energy-mapping techniques including scaling, segmentation, the hybrid method, the bilinear calibration curve technique and the dual-energy approach to generate the µ-maps required for attenuation correction. In addition, our newly proposed method involving a quadratic polynomial calibration curve was also assessed. The µ-maps generated for both phantom and clinical studies were assessed qualitatively and quantitatively. A cylindrical polyethylene phantom containing different concentrations of K(2)HPO(4) in water was scanned and the µ-maps calculated from the corresponding CT images using the above-referenced energy-mapping methods. The CT images of five whole-body data sets acquired on a GE Discovery LS PET/CT scanner were employed to generate µ-maps using different energy-mapping approaches that were compared with the µ-maps generated at 511 keV using (68)Ge/(68)Ga rod sources. In another experiment, the evaluation was performed on PET images of a clinical study corrected for attenuation using µ-maps generated using the above described methods. The evaluation was performed for three different tissue types, namely, soft tissue, lung, and bone.Results and Discussion: All energy-mapping methods yielded almost similar results for soft tissues. The mean relative differences between scaling, segmentation, hybrid, bilinear, and quadratic polynomial calibration curve methods and the transmission scan serving as reference were 6.60%, 6.56%, 6.60%, 5.96%, and 7.36%, respectively. However, the scaling method produced the largest difference (16%) for bone tissues. For lung tissues, the segmentation method produced the largest difference (14.9%). The results for reconstructed PET images followed a similar trend. For soft tissues, all energy-mapping methods yield results in nearly the same range. However, in bone tissues, the scaling method resulted in considerable bias in the µ-maps and the reconstructed PET images. The segmentation method also produced noticeable bias especially in regions with variable densities such as the lung, since a single µ is assigned to the lungs. Apart from the aforementioned case, despite small differences in the generated µ-maps, the use of different energy-mapping methods does not affect, to a visible or measurable extent, the reconstructed PET images. [ABSTRACT FROM AUTHOR]

cysteamine (CysAm) nanostructure was generated to act as an intermediate layer between gold electrode and carbon nanotubes. A bare gold electrode was placed in a solution of CysAm to create a self-assembled monolayer on its surface. The modified electrode was then incubated with a solution of multi-walled carbon nanotubes. Cyclic voltammetry and atomic force microscopy were used to characterize the modified electrode. The results indicated that the number of functionalized MWCNTs on the surface of the electrodes increased by enhancing incubation time. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Oral contrast is usually administered in most X-ray computed tomography (CT) examinations of the abdomen and the pelvis as it allows more accurate identification of the bowel and facilitates the interpretation of abdominal and pelvic CT studies. However, the misclassification of contrast medium with high-density bone in CT-based attenuation correction (CTAC) is known to generate artifacts in the attenuation map ( μmap), thus resulting in overcorrection for attenuation of positron emission tomography (PET) images. In this study, we developed an automated algorithm for segmentation and classification of regions containing oral contrast medium to correct for artifacts in CT-attenuation-corrected PET images using the segmented contrast correction (SCC) algorithm. The proposed algorithm consists of two steps: first, high CT number object segmentation using combined region- and boundary-based segmentation and second, object classification to bone and contrast agent using a knowledge-based nonlinear fuzzy classifier. Thereafter, the CT numbers of pixels belonging to the region classified as contrast medium are substituted with their equivalent effective bone CT numbers using the SCC algorithm. The generated CT images are then down-sampled followed by Gaussian smoothing to match the resolution of PET images. A piecewise calibration curve was then used to convert CT pixel values to linear attenuation coefficients at 511 keV. The visual assessment of segmented regions performed by an experienced radiologist confirmed the accuracy of the segmentation and classification algorithms for delineation of contrast-enhanced regions in clinical CT images. The quantitative analysis of generated μmaps of 21 clinical CT colonoscopy datasets showed an overestimation ranging between 24.4% and 37.3% in the 3D-classified regions depending on their volume and the concentration of contrast medium. Two PET/CT studies known to be problematic demonstrated the applicability of the technique in clinical setting. More importantly, correction of oral contrast artifacts improved the readability and interpretation of the PET scan and showed substantial decrease of the SUV (104.3%) after correction. An automated segmentation algorithm for classification of irregular shapes of regions containing contrast medium was developed for wider applicability of the SCC algorithm for correction of oral contrast artifacts during the CTAC procedure. The algorithm is being refined and further validated in clinical setting. [ABSTRACT FROM AUTHOR]

To purify the mammalian cell membrane porphyrin binding proteins (PBP), an original affinity chromatographic technique is proposed. The method is based on the application of an agarose attached fullerene-porphyrin ligand connected to a polysaccharide gel matrix through the epoxy-cyclohexyl residue interface. A selective PBP-stationary phase coupling has been managed in a single column chromatographic run leading to a complete purification of the 17.6 kDa monomer protein from the rat myocardium mitochondria membranes. A synchronous pH and ionic strength linear gradients were used to separate this protein with a high specific affinity to the porphyrin K related structures from all non-specific sorption retained membrane proteins. [ABSTRACT FROM AUTHOR]

This is a first case ever reported on the fullerene-based low toxic nanocationite particles (porphyrin adducts of cyclohexl fullerene-C60) designed for targeted delivery of the paramagnetic magnesium stable isotope to the heart muscle providing a sharp clinical effect close to about 80% recovery of the tissue hypoxia symptoms in less than 24 h after a single injection (0.03–0.1 LD50). A whole principle of this therapy is novel: 25Mg2+-magnetic isotope effect selectively stimulates the ATP over-production in the oxygen-depleted cell due to 25Mg2+ released by nanoparticles. Being membranotropic cationites, these "smart nanoparticles" release the over-activating paramagnetic cations only in response to the metabolic acidic shift. The resulting positive changes in the heart cell energy metabolism may help to prevent and/or treat the local myocardial hypoxic disorders and, hence, to protect the heart muscle from a serious damage in a vast variety of the hypoxia-caused clinical situations including both Doxorubicin and 1-methylnicotineamide cardiotoxic side effects. Both pharmacokinetics and pharmacodynamics of the drug proposed makes it suitable for safe and efficient administration in either single or multi-injection (acute or chronic) therapeutic schemes. [ABSTRACT FROM AUTHOR]

The advent of dual-modality PET/CT imaging has revolutionized the practice of clinical oncology, cardiology and neurology by improving lesions localization and the possibility of accurate quantitative analysis. In addition, the use of CT images for CT-based attenuation correction (CTAC) allows to decrease the overall scanning time and to create a noise-free attenuation map (μmap). The near simultaneous data acquisition in a fixed combination of a PET and a CT scanner in a hybrid PET/CT imaging system with a common patent table minimizes spatial and temporal mismatches between the modalities by elimination the need to move the patient in between exams. As PET/CT technology becomes more widely available, studies are beginning to appear in the literature that document the use of PET/CT in a variety of different cancers, including lung, thyroid, ovarian, lymphoma, and unknown primary cancers, and for general oncology, cardiology and neurology applications. Specific applications of PET/CT, such as those for radiation therapy planning, are also being explored. The purpose of this review paper is to introduce the principles of PET/CT imaging systems and describe the sources of error and artifact in CT-based attenuation correction algorithm. This paper also focuses on recent developments and future trends in hybrid imaging and their areas of application. It should be noted that due to limited space, the references contained herein are for illustrative purposes and are not inclusive; no implication that those chosen are better than others not mentioned is intended. [ABSTRACT FROM AUTHOR]

In this work, a correlation function based on linograms and sinograms of the projection data was introduced, implemented and evaluated in order to estimate and compensate for the patient motion. Parabolic fitting of the peak of the correlation function was utilized to improve in the motion-estimation task. In dynamic planar imaging, the method checked for motion via its separate frames similar to the SPECT work; on the other hand, in static planar imaging, the data acquisition protocol was first exchanged from static to the dynamic modality, followed by application of the motion-correction scheme, and a final combination via summation of the motion-compensated frames. The method was successfully evaluated in many cases. Our tests showed that in SPECT imaging, the time of motion starting in a specific projection and the duration of motion are very important in the motion detection process. Measuring relative error showed that the error in the images with presence of motion along the axis of patient bed was 21.1%, being reduced to 1.4% while the 24.4% error along the perpendicular axis to the patient bed was reduced to 1.5% with the inclusion of our motion correction scheme. Experimental results in planar imaging also demonstrated the ability of this method to reduce error in the maximum count from 40.7% to 9.7%, wherein intended sudden motion was introduced in static planar acquisition. Similarly, the error produced by gradual simulated motion was reduced from 37% to 1.6%. This method was clinically examined in the bone scan (static planar data) of an old man for an Osteomyelitis study, as well as in a kidney washout study (dynamic planar data) for a child. As a result, the motion artifacts shown in the images were reduced considerably. [ABSTRACT FROM AUTHOR]

Abstract: Background and aim: Cholestatic animals display abnormal hypothalamic responses to pyrogenic stimuli and decreased febrile response to lipopolysaccharide. The present study was undertaken to determine if obstructive cholestasis was associated with abnormal thermoregulation under thermoneutral conditions. Methods: Male Sprague–Dawley rats weighing 200–250g were randomly divided into 21 groups. Three sets of seven groups were unoperated control, sham-operated and bile duct-ligated rats. The groups of unoperated control, sham-operated and bile duct-ligated rats were treated with daily administration of isotonic saline solution, N(ω)-nitro-l-arginine methyl ester (l-NAME) (3, 10, or 20mg/kg), naltrexone (10 or 20mg/kg) or aminoguanidine (150mg/kg). Body temperatures were measured before and 1, 3, 5 and 7 days after the surgery. Results: Bile duct-ligated rats had lower body temperature than sham-operated animals at 3 (P <0.001) and 5 (P <0.01) days after surgery. l-NAME, a non-selective inhibitor of nitric oxide synthase (NOS) (10, 20mg/kg, i.p.) or aminoguanidine, a selective iNOS inhibitor (150mg/kg, i.p.), completely reversed this hypothermia (P >0.05). Naltrexone, a non-selective opioid antagonist (20mg/kg, i.p.), also completely corrected this hypothermia (P >0.05). There was a drop in temperature in the first day after the surgery in sham and BDL groups compared to unoperated controls, which was significant in some groups demonstrating the effect of surgery and anesthetic drugs on the body temperature. Conclusions: Cholestatic rats show impaired thermoregulation suggesting the involvement of nitrergic and opioidergic systems. [Copyright &y& Elsevier]

The development of novel nanoparticles for diagnostic and therapeutic applications has been one of the most crucial challenges in cancer theranostics for the last decades. Herein, we functionalized iron oxide nanoparticles (IONPs) with the fourth generation (G4) of poly amidoamine (PAMAM) dendrimers (G4@IONPs) for magnetic hyperthermia treatment of breast cancer in Bagg albino strain C (BALB/c)mice. The survival of breast cancer cells significantly decreased after incubation with G4@IONPs and exposure to an alternating magnetic field (AMF) due to apoptosis and elevation of Bax (Bcl-2 associated X)/Bcl-2(B-cell lymphoma 2) ratio. After intratumoral injection of G4@IONPs, tumor-bearing BALB/c mice were exposed to AMF for 20 min; this procedure was repeated three times every other day. After the last treatment, tumor size was measured every three days. Histopathological and Immunohistochemical studies were performed on the liver, lung, and tumor tissues in treated and control mice. The results did not show any metastatic cells in the liver and lung tissues in the treatment group, while the control mice tissues contained metastatic breast cancer cells. Furthermore, the findings of the present study showed that magnetic hyperthermia treatment inhibited tumor growth by increasing cancer cell apoptosis, as well as reducing the tumor angiogenesis. [ABSTRACT FROM AUTHOR]

Background: Recently, some studies have focused on dendrimer nanopolymers as a magnetic resonance imaging (MRI) contrast agent or a vehicle for gene and drug delivery. Considering the suitable properties of these materials, they are appropriate candidates for coating iron-oxide nanoparticles which are applied in magnetic hyperthermia. To the best of our knowledge, the novelty of this study is the investigation of fourth-generation dendrimer-coated iron-oxide nanoparticles (G4@IONPs) in magnetic hyperthermia and MRI.Methods: IONPs were synthesized via co-precipitation and coated with the fourth generation (G4) of polyamidoamine dendrimer. The cytotoxicity of G4@IONPs with different concentrations was assessed in a human breast cancer cell line (MCF7) and human fibroblast cell line (HDF1). Hemolysis and stability of G4@IONPs were investigated, and in addition, the interaction of these particles with MCF7 cells was assessed by Prussian blue staining. Heat generation and specific absorption rate (SAR) were calculated from measurement and simulation results at 200 and 300 kHz. MCF7 and HDF1 cells were incubated with G4@IONPs for 2 h and then put into the magnetic coil for 120 min. Relaxometry experiments were performed with different concentrations of G4@IONPs with T1- and T2-weighted MR images.Results: The TEM results showed that G4@IONPs were 10 ± 4 nm. The in vitro toxicity assessments showed that synthesized nanoparticles had low toxicity. The viability of MCF7 cells incubated with G4@IONPs decreased significantly after magnetic hyperthermia. In addition, MR imaging revealed that G4@IONPs improved transverse relaxivity (r2) significantly.Conclusions: Our results encouraged the future application of G4@IONPs in magnetic hyperthermia and MR imaging. [ABSTRACT FROM AUTHOR]