11.6 Static Interaction Energy of Two Magnetic Moments
313
Tissue: σ=0.5
Lesion
Nonconducting, Permeable
S/m
Coil
Fig. 11.17 Model of an eddy-current probe scanned past a nonconducting, magnetically permeable lesion embedded in tissue of an averaged conductivity
-2.5e-09
-2e-09
-1.5e-09
-1e-09
-5e-10
0
5e-10
1e-09
1.5e-09
2e-09
2.5e-09
-20 -15 -10 -5
0
5
10 15 20
Resistance (Ohms)
Probe Position (mm)
Response of Permeable Lesions at 1.6GHz
mu = 2
mu = 10
mu = 100
-2e-09
-1.5e-09
-1e-09
-5e-10
0
5e-10
1e-09
1.5e-09
-20 -15 -10 -5
0
5
10 15 20
Reactance (Ohms)
Probe Position (mm)
Response of Permeable Lesions at 1.6GHz
mu = 2
mu = 10
mu = 100
Fig. 11.18 Response of probe to a lesion whose permeability (at 1.6 GHz) is μ = 2, 10, and 100
+1.299
S
(1)
y S
(3)
x + S
(1)
x S
(3)
y − S
(2)
y S
(3)
x − S
(2)
x S
(3)
y
−2.25
S
(1)
y S
(3)
y + S
(2)
y S
(3)
y
,
(11.38)
where the units of H dd in (11.38) are in GHz. This matrix operator is added to that
in (11.27) to get the overall spin-Hamiltonian for Zeeman + Exchange + Dipolar
effects.