razieh solgi

In body tissues, tumors generally have different speeds of sound (SOS) than normal tissues. In this respect, ultrasound computed tomography (UCT) can generate a cross-sectional SOS map as an innovative ultrasound imaging method. This technique can produce images with a resolution of millimeters and a high signal-to-noise ratio.  This study aimed to improve UCT image quality without increasing breast cancer screening and diagnosis time. In this analytical study, a ring-shaped UCT breast imaging system was simulated using the K-wave toolbox of MATLAB. The system has a 20 cm diameter and 256 ultrasonic piezoelectrics placed in the ring’s circumference. Different beamforming techniques imaged two designed phantoms (i.e., resolution and contrast), and the resolution and contrast to noise ratio (CNR) were calculated.  The results of resolution phantom imaging without any beamforming showed that only bars with the value of 0.125 and 0.167 lp/mm were distinguishable, and the 0.1 bars were not recognizable in the imaging. In addition, increasing the number of transmitters led to no noticeable change in resolution for 0.125 and 0.167 lp/mm bars. In all beamforming techniques for imaging the contrast phantom, the CNR parameter up to an object with a diameter of 8 mm increases with increasing diameter without any change.   The beamforming technique using three simultaneous transmitters improved the resolution by about 1 mm compared to the normal strategy. In addition to high-contrast images, beamforming with 9 simultaneous transmitters led to a preferable technique

This study aimed at evaluating the image quality characteristics of advanced noise-optimized and traditional virtual monochromatic images compared with conventional 120-kVp images from second-generation Dual-Source CT.

For spiral scans six syringes filled with diluted iodine contrast material (1, 2, 5, 10, 15, 20 mg I/ml) were inserted into the test phantom and scanned with a second-generation dual-source CT in both single-energy (120-kVp) and dual-energy modes. Images set contain conventional single-energy 120-kVp, and virtual monochromatic were reconstructed with energies ranging from 40 to 190-keV in 1-keV steps. An energy-domain noise reduction algorithm was applied and the mean CT number, image noise, and iodine CNR were calculated.

The iodine CT number of conventional 120-kVp images compared with monochromatic of 40-, 50-, 60- and 70-keV images showed increase. The improvement ratio of image noise on Advanced Virtual Monochromatic Images (AVMIs) compared with the Traditional Virtual Monochromatic Images (TVMIs) at energies of 40-, 50-, 60, 70-keV was 52.9%, 35.7%, 8.1%, 2.1%, respectively. At AVMIs from 75- to 190-keV, the image noise value was less than conventional 120-kVp images. CNR improvement ratio at 20 mg/ml of iodinated contrast material for TVMIs and AVMIs compared to 120-kVp CT images and AVMIs compared to TVMI was 18.3% and 56.3%, 32.1% respectively.

Both TVMIs (in energies ranging from 54 to 71-keV) and AVMIs (in energies ranging from 40 to 74-keV) represent improvement in the iodine contrast-to-noise ratio than conventional 120-kVp CT images for the same radiation dose. Also, AVMIs compared to TVMIs have been obtained considerable noise reduction and CNR improvement for low-energy virtual monochromatic images. In the present study, we show that virtual monochromatic image and its Advanced version (AVMI) may boost the dual-energy CT advantages by providing higher CNR images in the same exposure value compared to routinely acquired single-energy CT images.

Sound-speed images can be used for cancer detection and diagnosis. In soft tissues, tumors have generally different sound speeds than normal tissues. Improving ultrasound image quality and variety of imaged tissue properties should prove beneficial to breast cancer screening and diagnosis. The goal of this study is to compare the effect of five reconstruction filters on fan beam acquisition modes of ultrasound computed Tomography (UCT) and investigate the image quality parameters of the point spread function (PSF), modulate transform function (MTF) and spatial resolution for two different arrangements of ultrasonic array, ring-shaped and parallel shaped. These study results show that the spatial resolution affected by not only detector arrangement but also reconstruction filters

In clinical studies, it is difficult to determine the temperature distribution throughout both tumor and normal tissue during hyperthermia treatment, since temperatures are sampled at only a limited number of locations with conventional sensors. Simulation studies can help physicians understand better the effects of the treatment. In this study, three 2D tumor models are built in the COMSOL software environment based on the images of nano-particle distributions in sliced PC3, DU145 and LAPC4 tumors. The images are pre-processed in MATLAB before being imported into COMSOL. A uniform distribution model is added as a control group. Temperature distribution, maximum temperature, time to reach steady state, CEM43, iso-effective dose and heat flux at tumor-tissue boundary are analyzed to evaluate the effect of the nano particle distribution on hyperthermia treatment. The results indicate that a more concentrated nano-particle distribution is better in damaging diseased tissue than the uniform distribution under low heating power .A more uniform distribution is better than the concentrated distribution under high heating power. For concentrated nanoparticle distributions, the location where the nanoparticles are concentrated influences tissue damage: a more centered one has a better effect. Tumor tissue is more likely to be defective.