Valdezahmad1726

The computed HU values were compared against experimentally measured values obtained by scanning batches of GNPs of various sizes and concentrations using a GE LightSpeed 4 Big Bore CT scanner at 80 kVp and 140 kVp energies, as well as the kV CBCT capability of a Varian Novalis Tx linear accelerator. HU analysis was carried out using Velocity Medical Solutions clinical CT image analysis software. The MCNP calculated HU values matched the measured values to within ± 5%. Image contrast enhancement analysis showed a total increase in HU of up to 223. The sample having the highest gold mass percentage tested showed the greatest increase in HU number compared to water.The simulation of proton Spread-Out Bragg Peaks (SOBPs) was implemented using the Geant4-based TOPAS Monte Carlo software. Dynamic proton energy switching was implemented using TOPAS time features, while beam weights were calculated using an empirical power law formalism with Bragg peaks spaced by 0.5 mm. To find power parameters yielding flat SOBPs we sampled power parameters for maximum kinetic energies of 50 MeV to 250 MeV and SOBP widths of 15% to 40% of the depth of the distal SOBP end. Simulations were run in a 50 cm cubic water phantom using a uniform squared proton beam. Depth dose was scored along the central axis in a binned cylinder with 1 cm diameter in 2.5 mm increments. Power parameters yielding a flat SOBPs were found to vary with, both energy and SOBP width and differed significantly from previously reported values based on simulations with MCNPX.A gradient coil with integrated second and third order shims has been designed and constructed for use inside an actively shielded 310 mm horizontal bore 9.4 T small animal MRI. An extension of the boundary element method, to minimise the power deposited in conducting surfaces, was used to design the gradients, and a boundary element method with a constraint on mutual inductance was used to design the shims. The gradient coil allows for improved imaging performance and was optimized for an imaging region appropriate for marmoset imaging studies. Efficiencies of 1.5 mT m-1 A-1 were achieved in a 15 cm wide bore while maintaining gradient uniformity ≤5% over the 8 cm region of interest. Two new cooling methods were implemented which allowed the gradient coil to operate at 100 A RMS, 25 % of max current with a temperature rise below 30 C.

Due to use of ionization radiation in the computed tomography (CT), optimal parameters should be used to reduce the risk of incidence of secondary cancers in patients who are constantly exposed to x-rays. To reduce the dose delivered to patients in each scan, CT technologists can change the image acquisition parameters. However, this reduces image quality. The present study aimed to optimize and reduce radiation dose in a CT of the paranasal sinuses while minimizing deterioration of image quality.

In this study patients were divided in two groups Group A was scanned axially and coronally using default parameters, while Group B was scanned axially and coronally using new parameters. Common CT dose descriptors including weighted computed tomography dose index (CTDIw), volumetric CTDI (CTDIvol), dose length product (DLP), effective dose (ED) and image noise were measured for each group. The patients' organ doses were estimated using the ImPACT CT patient Dosimetry Calculator. The tube voltage, tube current, rgency CT of the paranasal sinuses.Some diseases could be treated by Tanshinone IIA (TA), which is an isolated component from the Chinese medicinal herb Tanshen (Salvia miltiorrhiza). However, the poor water solubility and low oral bioavailability of TA limited its clinical application. In this paper, TA was encapsulated by water - soluble chitosan/poly - γ - glutamic acid (WCS-γ-PGA) to improve its dissolution and oral bioavailability. The in vitro dissolution and in vivo metabolism of the encapsulated composite in rats were employed to evaluate the efficiency of the improvement. FTIR spectroscopy was applied to confirm the validity of encapsulation for TA by WCS-γ-PGA. The study's results showed that the optimal ratio of TA to drug carrier (WCS + γ-PGA) was 15.5 in weight with a reaction time of 1 h at room temperature for the encapsulation. The proper concentrations for WCS and TA in preparing the encapsulated composite using γ-PGA 0.125 mg ml-1 were 6 mg ml-1 and 1 mg ml-1, respectively; The encapsulation efficiency and drug loading efficiency of WCS-γ-PGA-TA composite were (93.99 ± 2.20)% and (10.73 ± 0.75)%, respectively. The cumulative release of TA from the WCS-γ-PGA-TA encapsulated composite reached to 81% within 60 min, which was 5.56 times of that of the original TA in vitro dissolution. The peak concentration Cmax of TA from the encapsulated composite in rat blood as measured by an ultracentrifugation test of an intra - gastric administration was 4.43 times that of the original TA concentration, and the area under the drug-time curve AUC (0-t) and AUC (0-∞) (p less then 0.01) of the WCS-γ-PGA-TA encapsulated composite were 4.56 and 4.20 times that of the original TA, respectively. It indicated that the encapsulation of TA with WCS-γ-PGA improved its solubility and bioavailability significantly.The use of intra-operative imaging system as an intervention solution to provide more accurate localization of complicated structures has become a necessity during the neurosurgery. However, due to the limitations of conventional imaging systems, high-quality real-time intra-operative imaging remains as a challenging problem. learn more Meanwhile, photoacoustic imaging has appeared so promising to provide images of crucial structures such as blood vessels and microvasculature of tumors. To achieve high-quality photoacoustic images of vessels regarding the artifacts caused by the incomplete data, we proposed an approach based on the combination of time-reversal (TR) and deep learning methods. The proposed method applies a TR method in the first layer of the network which is followed by the convolutional neural network with weights adjusted to a set of simulated training data for the other layers to estimate artifact-free photoacoustic images. It was evaluated using a generated synthetic database of vessels. The mean of signal to noise ratio (SNR), peak SNR, structural similarity index, and edge preservation index for the test data were reached 14.