Page 164 - Bio Engineering Approaches to Cancer Diagnosis and Treatment

162 CHAPTER 7 Application of magnetic and electric fields for cancer therapy

Faraday’s law:
∂ B
∇ × E = − (7.4)
∇×E=−∂B∂t t ∂
Maxwell-Ampere equation:
1 ∂ E
∇ × B = µ j + (7.5)
2
∇×B=µ j+1C ∂E∂t 0 C ∂ t
2
0
Electric charge conservation:
∂ ρ
∇ j ⋅= − (7.6)
∇⋅j=−∂ρ∂t t ∂
ε µ 0 0 where ρ, E, B, j, ε , µ and C are electric charge density, electrical field, magnetic
0
0
field, electric current density, free space permittivity, vacuum magnetic permeability,
and speed of light, respectively.
Eqs. (7.2) and (7.5) as stated are suitable for the vacuum environment and are
rewritten for the material environment as follows, respectively [16]:
∇⋅D=ρ ∇⋅ D = ρ (7.7)
∂ D
∇ × H = + (7.8)
j
∇×H=j+∂D∂t t ∂
where H and P are the external magnetic field strength and the polarization, respec-
tively. The amount of electrical displacement (D) is calculated by [16]:
+
D=ε E+P D = ε 0 E P (7.9)
0
The relation between the magnetic induction and the external field in the Max-
well equations Eq. (7.5) is given by [16]:
B=µ (H+M) B = µ 0 ( H + M ) (7.10)
0
In the above equation, M is the magnetization (or the magnetic field induced in
the object), H is the external magnetic field strength, and B is the intensity of the field
produced by the interaction of the external field and the field produced in the object.

7.4 Electromagnetic fields application in drug delivery
Drug delivery is the method or process of administering a pharmaceutical compound
to achieve a therapeutic effect in humans or animals. Drug delivery system (DDS) is
systems based on interdisciplinary sciences such as polymer science, pharmaceutics,
bio-conjugated chemistry, and molecular biology. DDS transports pharmaceutical
compounds by nanocarriers to the desired location inside the human body in a safe
manner. The maximum efficiency and minimum side effect are achieved by using
nanocarriers and electromagnetic fields in DDSs. The delivery of drugs into human
body is designed based on several factors such as disease types, desired effect, and
the product availability [1].