**1. Introduction**

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Hyperthermia is part of thermal medicine, in which increasing body or tissue temperature used for the treatment of diseases. It can be traced back to the earliest practice of medicine. Cultures from around the world can point to ancient uses of hot therapy for specific medical applications. As mentioned in the foregoing books, cauterization is the first application of hyperthermia in medicine. Cauterization can be done by heat, or by chemicals such as caustics. Al-Zahrawi - an ancient Arabic scientist- generally preferred the former for the use of cauterization in treatment of diseases (1). Depending on the nature of the disease, the patient's temperament and the weather condition, different kinds of metals such as bronze, iron and gold could be used. The important considerations in the procedure include the shape of the cautery, the site of cauterization and the number of exposures. Many of the cauteries were taken from the Greeks, but Al-Zahrawi takes an independent line while describing cauterization for hare-lip, entropion, pulmonary disease, pre-anal fistula, dislocation of femur, back pain, headache, ptosis, perianal fistulae, humeral dislocation, sciatica and face swellings (fig 1).

Modern research in thermal medicine aims to understand molecular, cellular and physiological effects of temperature manipulation and the "stress" response, as well as to develop effective and safe equipment for clinical application and temperature monitoring. As a result, today there are a growing number of clinical applications of thermal therapy that benefit patients with a variety of diseases. Remarkable progress in engineering, radiology and physics over the past decades has led to the implementation of clinical trials that are revealing the true potential of hyperthermia for the treatment of different disease. Hyperthermia ablation (e.g. by radiofrequency electric current, microwaves, laser, or ultrasound), whereby localized heating destroys tissue is now used worldwide for tumors treatment and many other important medical applications. In most circumstances thermal ablation is used under guidance of different radiological modalities such as ultrasound (US), computed tomography (CT) or magnetic resonance imaging (MRI). Thermal ablation is a

© 2013 Donkol and Al Nammi, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Hyperthermia and Radiology 147

Both are minimally invasive techniques that treat lesions by applying intense heat through a small probe inserted directly into the tumor. Hyperthermia can be either superficial, produced by a microwave generator, or regional, produced by a radiofrequency applicator with multiple antennas, which emanate a deep focalized heating, saving the skin, or interstitial heating. In all these systems the radiations are non-ionizing, in which the energy presents a heterogeneous distribution inside the tissues, depending on their thermal characteristics and on blood perfusion. Radiofrequency ablation (RFA) involves percutaneous or intra-operative insertion of an electrode into a lesion under ultrasonic or CT guidance. Radiofrequency energy is emitted through the electrode and generates heat,

**3. Rational of tissue necrosis (ablation) in hyperthermia medicine** 

The main actions of hyperthermia in the neoplastic tissues are the following:

**4. Common clinical application of hyperthermia therapy:** 

Modern research in thermal medicine aims to understand molecular, cellular and physiological effects of temperature manipulation and the "stress" response, as well as to develop effective and safe equipment for clinical application and temperature monitoring. Multiple facets of tumor growth and the tumor microenvironment, including vascular perfusion, heat shock protein expression, endothelial/stromal cells, hypoxia, immune cells, pro-inflammatory cytokines, are impacted by heat and these effects may underlie remarkable successes being obtained in a surge of clinical trials throughout the world. Thermal ablation whereby tissue is destroyed by localized heating or freezing, is now used worldwide for treatment of many benign and malignant tumors and several other important

Greater heat sensitivity of neoplastic tissues to hyperthermia, due to its chronic

 Lethal effect of temperature of 42-43 °C on tumor cells, depending on the application time; Temporary growth stabilization of tumor cells after a moderate hyperthermia (39-41

 Prolonged action of temperature, due to lower thermal dissipation, caused by a chronic ischemia inside the tumor, as a result of its reduced vessel regulation mechanisms; Alterations in the neoplastic cell cycle, which lead to the blocking of mitosis, due to a

Marked action on the core of the tumor, less sensitive to radiation because of ischemia,

Today there are a growing number of clinical applications of thermal therapy that benefit patients with a variety of diseases. Several studies have been published reporting efficacy of

leading to coagulative necrosis of the tissue.

medical applications (2-4).

°C);

ischemia, hypoxia and acid pH;

disruption in the S phase;

action in favor of apoptosis mechanisms.

RFA in treatment of many different clinical conditions.

hypoxia and low pH;

**Figure 1.** Technique of Cauterization by fire for a patient with neck swelling (1)

minimally invasive procedure that significantly reduces risks and speeds recovery. So, it provides an excellent safe alternative to major surgery. The primary advantage of percutaneous radiofrequency thermal ablation is a reduction in the need for post-operative hospitalization and a reduced duration of convalescence. In this chapter, we will review the recent application of hyperthermia medicine in treatment of different disease under the guidance of different radiological modalities. In this chapter, we will provide a clearer picture of the intimate relation between hyperthermia, radiology and medical imaging. We will discuss the multiple facets of tumor growth and the tumor microenvironment that can be impacted by heat during hyperthermia medicine. We will emphasize the approved clinical application of hyperthermia in management of growing number of patients with a variety of diseases. We also discuss other experimental and investigational trial studies that can be used effectively in the future for management of other clinical conditions. Also we will emphasize the adjuvant role of thermal therapy in combination with radiotherapy and chemotherapy in management of cancer. Finally, we will elaborate the exciting new generation of clinical trials of heat-activated drug delivery.
