A software tool for fabricating phantoms mimicking human tissues with designated dielectric properties and frequency.

Objectives: Dielectric materials play a crucial role in assessing and refining the measurement performance of dielectric properties for specific tasks. The availability of viable and standardized dielectric materials could greatly enhance medical applications related to dielectric properties. However, obtaining reliable phantoms with designated dielectric properties across a specified frequency range remains challenging.

A Reliable Approach for Fabricating Tissue-Mimicking Phantoms with Designated Dielectric Properties from 16 MHz to 3 GHz.

Tissue-mimicking dielectric phantoms are widely used to mimic the relative permittivity and conductivity of human tissues in various medical applications. The artificial material combinations determine the characterization of dialectic phantoms. However, a method that reliably determined the composition of artificial materials with designed values of dielectric properties and frequency is still lacking.

Effects of radiofrequency channel numbers on B mapping using the Bloch-Siegert shift method.

Purpose: This paper aims to investigate the impact of the channel numbers on the performance of B mapping, by using the Bloch-Siegert shift (BSS) method. B mapping plays a crucial role in various brain imaging protocols.

Theory And Methods: We simulated the radiofrequency field of the human head model in six groups of multi-channel receive coil with a range of different channel numbers.

Sensitivity investigation of open-ended coaxial probe in skin cancer detection.

Open-ended coaxial probe method is one of the most common modalities in measuring dielectric properties (DPs) of biological tissues. Due to the significant differences between the tumors and normal tissues in DPs, the technique can be used to detect skin cancer in the early stage. Although various studies have been reported, systematic assessment is in urgent need to advance it to clinical applications, for its parameters interactions and detecting limitations remained unclear.

Effect of radiofrequency inhomogeneity on water-content based electrical properties tomography and its correction by flip angle maps.

Water-content based electrical properties tomography (wEPT) can retrieve electrical properties (EPs) from water-content maps. B field information is not involved in the traditional magnetic resonance electrical properties tomography approach. wEPT can be performed through conventional MR scanning, such as T-weighted spin-echo imaging, which provides convenient access to multiple clinical applications.

Statistical analysis of the accuracy of water content-based electrical properties tomography.

Water content-based electrical properties tomography (wEPT) can retrieve electrical properties (EPs) from water content maps, thereby eliminating the need for B field measurement in the traditional magnetic resonance electrical properties tomography method. The wEPT is performed by conventional MR scanning, such as T -weighted spin-echo imaging, and thus can be directly applied to clinical settings. However, the random noise propagation involved in wEPT causes inaccuracy in EP mapping.

Channel-combination method for phase-based |B| mapping techniques.

Purpose: The aim of this study was to propose a channel combination method for |B| mapping methods using phase difference to reconstruct |B| map.

Theory And Methods: Phase-based |B| mapping methods commonly consider the phase difference of two scans to measure |B|. Multiple receiver coils acquire a number of images and the phase difference at each channel is theoretically the same in the absence of noise.

Obtaining source current density related to irregularly structured electromagnetic target field inside human body using hybrid inverse/FDTD method.

Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed.

[Research of the influences on the electromagnetic fields by the pelvic tissues in the design of the radio frequency coils].

In the present study, the effect of the electromagnetic field, induced by radio frequency (RF) coils and coupled with the pelvic tissues, was calculated with the method of finite difference time domain (FDTD). Using the established electromagnetic model of human pelvis region, the simulation was implemented. The imaging uniformity was quantitatively calculated and scaled with the values of the percentage image uniformity (PIU).

Combined processes of two-stage Fenton-biological anaerobic filter-biological aerated filter for advanced treatment of landfill leachate.

There are numerous non-biodegradable organic materials in the mature landfill leachate. To meet the new discharge standard of China, additional advanced treatment is needed for the effluent from the biological treatment processes of leachate. In this study, a combined process including two stages of "Fenton-biological anaerobic filter (BANF)-biological aerated filter (BAF)" was evaluated to address the advanced treatment need.

Inverse design of an organ-oriented RF coil for open, vertical-field, MR-guided, focused ultrasound surgery.

The advantages of open, vertical-field, magnetic resonance-guided, focused ultrasound surgery (MRgFUS) are attractive. The inverse technique using the bi-boundary conditions is proposed to design a uterine-oriented intraoperative RF coil with an ultrasound aperture for the MRgFUS system. In the current proposed scheme, the desired magnetic field of the RF coil was set to completely overlap the target organ.

Development of a calibration phantom set for MRI temperature imaging system quality assurance.

Rationale And Objectives: Magnetic resonance imaging (MRI) temperature imaging systems need to be routinely calibrated to guarantee accurate temperature results and qualified MRI. No independent physical temperature calibration phantom (TCP) set is currently available. An economical TCP set was developed to routinely ensure the quality of MRI temperature imaging system.

Numerical optimization of a three-channel radiofrequency coil for open, vertical-field, MR-guided, focused ultrasound surgery using the hybrid method of moment/finite difference time domain method.

The numerical optimization of a three-channel radiofrequency (RF) coil with a physical aperture for the open, vertical-field, MR-guided, focused ultrasound surgery (MRgFUS) system using the hybrid method of moment (MoM)/finite difference time domain (FDTD) method is reported. The numerical simulation of the current density distribution on an RF coil with a complicated irregular structure was performed using MoM. The electromagnetic field simulation containing the full coil-tissue interactions within the region of interest was accomplished using the FDTD method.

[Decoupling of multi-channel RF coil and its application in the intraoperative MRI].

The coupling from different elements of the multi-channel coil leads to the splitting of the resonance frequency and deviation from the Lamor frequency. Decoupling between different elements is the key technology in the design of the radiofrequency (RF) coil. The electrical decoupling circuits should vary with different arrangements of the elements.

Evaluation of four cell lines for assay of infectious adenoviruses in water samples.

Human viral contamination in drinking and recreational waters poses health risks. The application of PCR-based molecular technology has advanced our knowledge of the occurrence and prevalence of human viruses in water; however, it has provided no information on viral viability and infectivity. Four human cell lines were compared for their sensitivity to different serotypes of human adenoviruses using the TCID50 test.