Watson S, Williams R J, Griffiths H, Gough W, Morris A
School of Electronics, University of Glamorgan, Pontypridd CF37 1DL, UK.
Physiol Meas. 2003 May;24(2):555-64. doi: 10.1088/0967-3334/24/2/365.
In magnetic induction tomography (MIT) the in-quadrature component, and hence the phase, of the received signal contains information about the conductivity of the tissue. The quality of imaging will depend on the precision with which phase can be measured. Preliminary studies suggest that a precision of 10 m degrees may be required for a practical biomedical MIT system operating at 10 MHz. This paper describes the results of measurements carried out with a 16-channel, downconverting, 10 MHz, MIT system utilizing two types of data extraction techniques: direct-phase measurement and measurement of the in-phase and in-quadrature components of the signal with a vector voltmeter. The basic precision provided by each technique was 50 m degrees, with thermal drift representing the major limiting factor. Preliminary measurements of average conductivity and permittivity for a human thigh in vivo are given.
在磁感应断层成像（MIT）中，接收信号的正交分量以及相位包含有关组织电导率的信息。成像质量将取决于相位测量的精度。初步研究表明，对于工作在10 MHz的实用生物医学MIT系统，可能需要10毫度的精度。本文描述了使用16通道、下变频、10 MHz的MIT系统进行测量的结果，该系统采用了两种数据提取技术：直接相位测量和用矢量电压表测量信号的同相和正交分量。每种技术提供的基本精度为50毫度，热漂移是主要限制因素。给出了人体大腿体内平均电导率和电容率的初步测量结果。
