Dual-head PET can simply and flexibilly adjust its architecture to fit the size of the imaging object, making it great potential for simultaneous multi-modality molecular imaging. In this paper, we proposed conceptally dual-modality imaging system of distance-adjustable dual-head PET and Cerenkov luminescence imaging (CLI), and implemented a CLI guided selective-reconstruction method. In the selective-reconstruction, we reconstructed the information inside a predefined region of interest using a fine voxel, whereas reconstructed other regions using a coarse voxel. We used CLI data as a priori information to outline the predefined region of interest. Simultaneously, for reducing the computaion burden, an attenuation map with a coarse voxel size was used for the attenuation correction. We demonstrated the feasibility and effectiveness of our proposed method with Monte Carlo based simulations by reconstructing phantom consisted of two hot rods. Experiment results show that an most improved efficiency over 70 times speedup with an MSE of 5.2235.
Objective
To investigate the risk factors and preventive measures of deep venous thrombosis (DVT) in lower limbs after hip arthroplasty.
Methods
78 patients undertaking hip replacement at our hospital from June, 2014 to June, 2016 were collected and were divided into a thrombosis group and a no thrombosis group according to the presence of postoperative lower extremity DVT. The gender, age, coronary heart disease, hypertension, obesity, body mass index, operation time, time in bed over 7 days, etc. affect DVT in lower limbs were compared between these two groups. Single and multiple factors logistic regression analysis were used to analyze the risk factors of lower extremity DVT after hip replacement.
Results
Univariate analysis showed that there statistical differences in over 60 years old, hypertension, operation time, time in bed over 7 days, etc. between these two groups (all P<0.05). Multivariate logistic regression analysis showed that over 60 years old, hypertension, and time in bed over 7 days were important risk factors for DVT in lower limbs after hip replacement.
Conclusions
Over 60 years old, hypertension, and time in bed over 7 days are important risk factors for DVT in lower limbs after hip replacement. Preventive measures should be taken early to prevent the occurrence of DVT.
Key words:
Hip replacement; Deep venous thrombosis; Risk factors; Countermeasures
Abstract This paper presents a data-driven calibration method for tri-axial magnetic sensors that eliminates the need to solve the sensor error model parameters. Calibration was achieved solely through the input and output of the sensor in a known magnetic field. Using both simulation and experimental data, this study employed a Multi-layer Perceptron (MLP) algorithm as the data-driven calibration model. In static and dynamic calibration experiments conducted in a laboratory setting, the calibration performance of MLP was compared with that of traditional calibration algorithms. The experimental results demonstrate that in a static experiment under a 90 μT magnetic field, the sensor error after calibration using the data-driven method was reduced by 30.37% compared to the traditional method. In the dynamic experiments, the proposed method reduced the errors by 71.57% compared with the traditional method. The method proposed in this paper offers a new approach for improving the calibration accuracy and effective measurement range of tri-axial magnetic sensors and holds potential application value for other types of tri-axial sensors.
Lipid droplets (LDs) and lysosomes are crucial for maintaining intracellular homeostasis. But single fluorescent probes (SFPs) capable of simultaneous and discriminative visualizing of two organelles above and their interaction in living cells are still challenging due to the lack of rational design strategies. To break this bottleneck, herein, we develop a reliable strategy based on a pH-sensitive intramolecular spirocyclization. As a proof of concept, an SFP CMHCH, which possesses a switchable hemicyanine/spiro-oxazine moiety induced by pH, has been designed and synthesized. In acidic environments, the ring-open form CMHCH exhibits red-shift emission and low logP value, whereas the ring-closed form CMHC displays blue-shift emission and high logP value in neutral or basic environments. Thus, the distinct different hydrophilicity/hydrophobicity and absorption/emission properties of these two forms enable targeting LDs and lysosomes simultaneously and discriminatingly. Very importantly, the dynamic process of lipophagy can be directly monitored with CMHCH. The success of CMHCH indicated that the spirocyclization strategy is efficient for constructing SFPs to LDs and lysosomes.
Photodynamic therapy (PDT) continues to evolve into a mature clinical treatment of a variety of cancer types as well as age-related macular degeneration of the eye. However, there are still aspects of PDT that need to be improved in order for greater clinical acceptance. While a number of new PDT photo-sensitizers, sometimes referred to as second- or third- generation therapeutic agents, are currently under clinical investigation, the direct treatment through the skin of subcutaneous tumors deeper than 5 mm remains problematic. Currently approved PDT porphyrin photo-sensitizers, as well as several modified porphyrins (e.g. chlorins, bacteriochlorins, etc.) that are under clinical investigation can be activated at 630-730 nm, but none above 800 nm. It would be highly desirable if new PDT paradigms could be developed that would allow photo-activation deep in the tissue transparency window in the Near-infrared (NIR) above 800 nm to reduce scattering and absorption phenomena that reduce deep tissue PDT efficacy. Rasiris and MPA Technologies have developed new porphyrins that have greatly enhanced two-photon absorption ( P A ) cross-sections and can be activated deep in the NIR (ca. 780-850 nm). These porphyrins can be incorporated into a therapeutic triad that also employs an small molecule targeting agent that directs the triad to over-expressed tumor receptor sites, and a NIR onephoton imaging agent that allows tracking the delivery of the triad to the tumor site, as well as clearance of excess triad from healthy tissue prior to the start of PDT treatment. We are currently using these new triads in efficacy studies with a breast cancer cell line that has been transfected with luciferase genes that allow implanted tumor growth and post- PDT treatment efficacy studies in SCID mouse models by following the rise and decay of the bioluminescence signal. We have also designed highly absorbing and scattering collagen breast cancer phantoms in which we have demonstrated dramatic cell kill to a depth of at least 4 cm. We have also demonstrated that at the wavelength and laser fluences used in the treatment of implanted tumors in the mouse mammary fat pads, there is little, if any, damage to the skin or internal mouse organs. In addition, we have also demonstrated that the implanted tumors can be treated to a depth of more than 1 cm by direct radiation through the dorsal side of the mouse.
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