10.6 Electromagnetic Modeling of Biological Tissue
261
Serum:
Fatty Lesion:
σ = 1.19
σ = 0.07
S/m
S/m
Coil
Fig. 10.8 Model of an Eddy-current coil scanned past a fatty lesion embedded in serum
-5e-07
0
5e-07
1e-06
1.5e-06
2e-06
2.5e-06
3e-06
-20 -15 -10 -5
0
5
10 15 20
Resistance (Ohms)
Probe Position (mm)
Response of Permeable Lesions at 1GHz
mu = 1.0
mu = 1.1
mu = 2.0
0
1e-06
2e-06
3e-06
4e-06
5e-06
6e-06
-20 -15 -10 -5
0
5
10 15 20
Reactance (Ohms)
Probe Position (mm)
Response of Permeable Lesions at 1GHz
mu = 1.0
mu = 1.1
mu = 2.0
Fig. 10.9 Response of lesions of varying magnetic permeability at 1 GHz. Left: resistance, right:
reactance
a nonpermeable lesion, with μ = 1.0, and two permeable lesions with μ = 1.1 and
μ = 2.0. The distinction is much clearer in the reactance.
10.6 Electromagnetic Modeling of Biological Tissue
In electromagnetic imaging, our goal is to directly determine the electromagnetic
state of the body, from which we infer its physiological state, which could even
include determining the change in temperature of tissue noninvasively. This is
done by inverting impedance measurements to infer the electromagnetic constitutive
properties of the body, from which other state variables can be determined.