Page 168 - Bio Engineering Approaches to Cancer Diagnosis and Treatment

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

FIGURE 7.5 The internal induction field of nanocarrier in terms of the intensity of the
external magnetic field.

By combining Eqs. (7.14)–(7.18), the magnetic force applied to a nanocarriers is
obtained from:
1    3χ H  1  
F = µ ∀ M ∇  H coth   −   (7.19)

m
2 0 MNP s    M s  3χ H  
F→m=12µ ∀MNPMs∇Hcoth3χHMs−13χHMs    M s   
0
/
3χH/Ms<2.5 For the nonintense magnetic field (3χ HM < 2.5), Eq. (7.19) simplify into a use-
s
ful and accurate equation as follow:
1 χ
2
F = µ ∀ ∇ H ( )
+
F→m=12µ ∀MNPχ1+0.33χ∇H 2 m 2 0 MNP 1 0.33χ (7.20)
0
7.5 Hyperthermia
Hyperthermia therapy is one of the new types of treating cancer tissue. Hyperther-
mia is usually utilized in combination with other therapies such as chemotherapy or
radiotherapy. In hyperthermia therapy, the cancerous tissue alone or the tissue and its
surrounding are exposed to high temperature, as high as 44°C, which is higher than
deep heating of the cancerous tissue, also called diathermy [23]. In this method by
increasing the temperature of the cancerous tissue up to 44°C the living cancerous
cells that are very sensitive to high temperature, get damaged before reproduction.
Temperature higher than 45°C may completely damage the healthy and the cancer-
ous tissue. Therefore, the healthy cell temperature during the hyperthermia treatment
should stay less than 41°C [24].