Differentiated teaching modes of course of digital signal processing for undergraduates and postgraduates / 医疗卫生装备

Objective To analyze the difference of teaching modes of course of digital signal processing for the undergraduates and postgraduates.Methods The teaching modes were compared from the aspects of educational objective,teaching content, teaching method,examination mode and etc.Results Differentiated teaching modes contributed to the satisfactory education of the undergraduates and postgraduates. Conclusion The differentiated teaching modes for the undergraduates and postgraduates provide references for the high-level education in universities and colleges of science and technology. [Chinese Medical Equipment Journal,2018,39(5):87-89,102]

Accurately controlling resistivity of 3D printing materials for establishing human-head volume conductor model / 医疗卫生装备

Objective To propose a method for accurately controlling the resistivity of 3D printing materials to facilitate to establish a human-head volume conductor model.Methods Two kinds of ABS/CB composite conductive printing materials covering the resistivity ranges of parenchymal and skull were selected through resistivity measurement and analysis. The correlation between the proportions and resistivities of the two kinds of ABS/CB materials and the empirical formula on the correlation between the resistivity and proportion was obtained through exponential function fitting. Results The selected ABS/CB composite material behaved well in frequency stability and time stability,and the obtained empirical formula had high-correlation coefficient.Conclusion Accurate control of 3D printing model resistivity is realized,and it's facilitated to gain 3D printing material with the same resistivity as those of skull and parenchymal.

Novel human-head phantom with realistic skull anatomy and resistivity distribution / 医疗卫生装备

Objective To establish a human-head phantom with realistic skull anatomy and resistivity distribution in order to provide an accurate experimental platform for brain electrical impedance tomography(EIT).Methods Firstly a skull model with 3-layer structure was constructed with double-nozzle 3D printer,and every layer had its specific resistivity verified on the accuracy. Then brain parenchyma with its resistivity was modelled using 3D printer and cerebrospinal fluid and scalp were mimicked using NaCl solution;after the whole phantom was assembled,imaging test using EIT was performed.Results The skull model was similar to the realistic one in terms of anatomy and resistivity distribution;the EIT experiment on the new phantom showed similar results to simulation.Conclusion The proposed phantom has realistic skull anatomy,resistivity distribution and multi-layer anatomical structure, which reflects the features of skull resistivity and thus is suitable for experiments on brain EIT.

Method for synchronous measurement of multichannel electrode-scalp contact impedances in brain EIT / 医疗卫生装备

Objective To study a method for monitoring multichannel electrode-scalp contact impedances in electrical impedance tomography (EIT), and to provide support for exploring the impact of contact impedances on imaging and the suppression method.Methods A reference electrode was introduced for the system,placed on the back of the neck or the top of the head. In the spare time of boundary voltage signal acquisition phase, the method of two electrodes was adopted to measure the electrical impedance between each imaging electrode and reference electrode, which was used to analyze the characteristics of multichannel contact impedances.Based on the existing EIT hardware system,the module for monitoring multichannel contact impedance was implemented.Results The calibration board test showed that the measurement error of this method was less than 1‰,and the maximum relative fluctuation of the measurement result within 10 hours was less than 1‰. Preliminary human test indicated that this method had the ability to obtain two kinds of information about spatial consistency and temporal stability of 16-channel contact impedances. Conclusion This method has high accuracy and stability,so it meets the requirements of monitoring multichannel contact impedances in brain EIT.

Instructional mode of biomedical electronics based on constructivism / 医疗卫生装备

Objective To demonstrate the feasibility and necessity of constructivist pedagogy for teaching biomedical electronics so as to create a new instructional mode. Methods The new mode for teaching biomedical electronics was discussed from two aspects of teaching thought and practice with considerations on constructivist pedagogy connotation as well as the actualities of teaching resources and object. Results Instructional thoughts which boosted students' thinking ability,learning habits and confidence were developed.The instructional practice,which included integrated teaching units, problem-based discussion,task-driven experiment content,was also been achieved.Conclusion The reform of instructional mode gains high practical effect, and provides pedagogical implications to other specialized courses of biomedical engineering.

Simulation study of electrical impedance tomography based on approaching real finite-element model of brain / 医疗卫生装备

This paper is to build a finite element model of brain with a real brain shapeon which simulation studies of electrical impedance tomography EIT in the brain is based. A curve of a real brain shape is simulated with the curve-fitting methods and EIT in the brain is finished with finite-element methods and Equipotential Lines Back-Projection algorithm.The locationarea and amplitude of the change of the resistivity are reconstructed accurately. But the image quality has to be further improved.This paper provides a basis for clinical applications of EIT in brain.