Page 12 - Bio Engineering Approaches to Cancer Diagnosis and Treatment

1.8 Principles of heat and fluid flow 9

1.7 Bioengineering assisted cancer treatment using
nonbiological components

Applying heat to treat cancer has been started since 1700 BC by using a fired-drill to
treat breast cancer. Hyperthermia is based on the increasing the temperature of the
desired tissue till 41–47°C to selectively destruct tumor cells. The main idea behind
this technic is related to the low level of heat tolerance in tumor cells as compared
with normal cells. Cell damage during hyperthermia may related to the protein dena-
turation. There are several methods to induce heat to desired site such as ultrasound
waves, microwaves, radiofrequency and laser.
“Laser” is an acronym for the light amplification by the stimulated emission
of radiation which emits photons in a coherent beam. Using laser to apply heat to
tumorogenic region was firstly reported in 1965.
Laser may assist cancer treatment by several approaches including laser ablation,
surgery, photodynamic therapy (PDT), photothermal therapy (PTT), and triggering
an anticancer drug delivery. Laser ablation or photoablation is removing tumor cells
using laser beam with high intensity, usually pulse laser. Laser surgery performs
specific functions during surgery. PTT is a kind of cancer treatment using photother-
mal agents to selectively destroy cancer cells. Photothermal agents convert optical
energy into heat. PDT is another kind of treatment using photosensitizer to destroy
cancer cells. When light exposes to photosensitizers, it reacts with tissue oxygen and
produces toxic singlet oxygen.
Several kinds of laser have been used for cancer treatment included carbon diox-
ide (CO ) lasers, neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers, laser-
2
induced interstitial thermotherapy (LITT), and argon lasers [46].

1.8 Principles of heat and fluid flow
1.8.1 Fluid mechanics
Fluid mechanics are the branch of physics that studies the mechanics of fluids (liq-
uids, gases, and plasmas) and the forces on them. Fluid mechanics can be divided
into fluid statics or the study of fluids at rest; and fluid dynamics or the study of
the effect of forces on fluid motion. Fluid mechanics have a wide range of applica-
tions, including mechanical engineering, chemical engineering, geophysics, astro-
physics, and biology. Fluid mechanics, especially fluid dynamics, are an active field
of research with many problems that are partly or wholly unsolved. Commercial
code based on numerical methods is used to solve the problems of fluid mechanics.
The principles of these methods are developed by CFD. A modern discipline, called
computational fluid dynamics (CFD), is devoted to this approach to solve the afore-
mentioned problems.
The distinguished characteristic of fluids compare to solids is related to the
amount of deformation rate. Fluids show a continuous deformation when they get