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

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 RFA in treatment of many different clinical conditions.

Several studies have been published reporting successful use of radiofrequency ablation in the following conditions: as an alternative to surgical resection for debulking of primary and metastatic malignant neoplasms, removal of primary or metastatic malignant neoplasms, treatment of distant metastases of medullary thyroid carcinoma, treatment of metastatic gastrointestinal stromal tumors (GIST) with limited progression, treatment of osteoid osteoma, as a less invasive alternative to surgical resection of the tumor ,treatment of soft tissue sarcoma of the trunk or extremities in symptomatic persons with disseminated metastases and many other condition.

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prevent recurrence a wide resection margin may be required. This results in many complications such as hematoma, infection, and fracture. In addition, surgical treatment may require a long period of hospitalization, a period during which the patient cannot bear weight on the affected limb resulting in delayed resumption of physical activity [7]. The optimal method of treatment for osteoid osteoma would involve minimization of bone removal with avoidance of grafting and fixation while ensuring complete destruction of the tumor nidus in a single session. During the past two decades, many attempts have been made to minimize bone removal to decrease the risk of postoperative complications. Percutaneous resection utilizing CT guidance to guide trephines and drills has been described. However, the complication rates are as high as 24% and include fractures, muscular haematomas, paraesthesia, skin burns, transient paresis, and osteomyelitis [8]. Radiofrequency ablation has proved to be an effective method for the treatment of many malignant and benign tumors. RF ablation for the treatment of osteoid osteoma was first described in a four-patient series in 1992 [9]. Since the promising results of Rosenthal et al in the management of osteoid osteoma with RF ablation a large number of studies evaluating RF ablation of osteoid osteoma have been reported in the peer-reviewed medical literature. Most of these studies found very high technical success rates (100%) and good primary success rates with a single session of ablation ranging from 76% to 100% (fig 2 and fig 3). Today, percutaneous CT-guided RF ablation is an effective and safe minimally invasive procedure for the treatment of osteoid osteoma in all ages. It has high technical and clinical

**Figure 2.** Technique of RFA of osteoid osteoma in a 12-year-boy with chronic right hip pain. a Radiograph of the pelvis shows an ill-defined area of dense sclerosis in the medial aspect of the proximal femoral shaft (arrow). b Bone scan shows active uptake at the site of the dense sclerosis consistent with the diagnosis of osteoid osteoma. c CT scan shows the nidus located deep to the cortex and surrounded by dense new bone. The radiopaque markers on the skin surface are for planning the skin entry point. d Axial 1-mm CT slice shows the correct position of the tip of the RF electrode within

the centre of the nidus. e Follow-up CT after 15 months shows sclerosis within the nidus (12)

success rates (10-12)

There is growing research and experimental and investigational studies interest in the use of hyperthermia for treatment of many other clinical conditions. But these studies need to improve its clinical outcomes to be implemented in the practical life. Examples of these studies include; curative treatment of primary or metastatic malignant neoplasms (e.g., breast cancer, kidney cancer including renal angiomyolipoma, lung cancer, and pancreatic cancer) in persons who are able to tolerate surgical resection, treatment of malignant bile duct obstruction due to insufficient evidence in the peer-reviewed literature. Treatment of Barrett's esophagus, treatment of hepatic tumors, treatment of benign prostatic hypertrophy (transurethral needle ablation or TUNA) ,cardiac catheter thermal ablation is now standard of care for a variety of cardiac arrhythmia types (irregular heart beat rhythm) ,endometrial ablation is clinically used to treat endometrial bleeding ,intravascular heating can eliminate varicose veins with laser or radiofrequency current, laser and other thermal methods treat excessive subcutaneous fat, which can contribute to obesity and metabolic disorders including diabetes. Hyperthermia can also be used to activate cytotoxic effects of chemotherapy within tumors, thereby sparing normal tissue, when the drugs are encapsulated in thermally sensitive nanoparticles. As a result of these and other clinical applications, combined with a rapidly expanding research base, interest in thermal medicine is rapidly growing, attracting the attention of laboratory and clinical researchers, physicians, engineers, physicists and biotechnologists
