High intensity focused ultrasound (HIFU) is a promising technology for a variety of therapeutic applications. This concept initiated in 1942 by Lynn Zwemer [1]. HIFU has long been known as a minimal invasive or non-invasive procedure that destroys tissue through ablation. However, it is only in recent years that clinical applications are becoming feasible, with the development of high power ultrasound transducers compatible with the MRI scanner which is used to monitor these non-invasive HIFU applications. New technologies, combined with more sophisticated treatment methods and monitoring methods allow non-invasive procedures in many areas such as the brain, eye, breast, kidney, liver, pancreas, thyroid, uterine fibroids and pancreas. Meanwhile, new investigations are underway for treading cardiac arithmia, strokes, palliative pain treatment of bone metastases and brain disorders such as Parkinson's disease, essential tremor, and neuropathic pain. These optimistic investigations have encouraged physicians and provided them new valuable tools for medical research.

Ultrasound imaging technology has many applications for the medical field and for the public. Thanks to ultrasound imaging, parents can meet their precious child even before the baby is born. In clinical applications, ultrasound is inexpensive, portable and reveals the structure and movement of organs in real time, allowing physicians to monitor the growth and physical development of a fetus. Because there is no ionizing radiation exposure to the patient, it is a very safe technology. In addition to diagnostic applications, ultrasound has been used for therapeutic treatment. High intensity focused ultrasound (HIFU) has been widely used to treat different types of tumors, including those of prostate, liver, breast, kidney, bone and pancreas because of its non-invasive and precise approach for tissue ablation. The basic concept of using HIFU is to focus continuous ultrasound at the focal point and a temperature increase beyond a certain point creates a lesion without damaging the surrounding tissue. For successful HIFU operation, it is important to have a reliable method for guidance and monitoring of the treatment such as ultrasound imaging. Most ultrasound image-guided HIFU systems need separate imaging and HIFU transducers, and require a cooling system due to properties of piezoelectric transducers such as narrow fractional bandwidth and self-heating. As an alternative, capacitive micromachined ultrasonic transducers (CMUTs) have a distinctive advantage over piezoelectric transducers in respect to self-heating and a wide fractional bandwidth. Thus, CMUTs are especially beneficial in dual-mode operations where a single transducer is used for both imaging and therapy. By taking advantage of this CMUT technology, I developed a compact dual-mode ultrasound system that can perform both ultrasound imaging and HIFU with a single 2-D CMUT array. A dual-mode ultrasound probe is equipped with a dual-mode application-specific integrated circuit (ASIC) and a 2-D 32x32-element CMUT array. The dual-mode ASIC consists of pulsers, transmit beamforming circuitry, and low-noise amplifiers for imaging mode and high voltage (HV) switches for HIFU mode. By turning HV switches on and off, the system can alternately operate imaging mode and HIFU mode on demand. A 2-D 32x32-element CMUT array was fabricated to have a center frequency of 5 MHz in immersion. Both ASIC and CMUT array were flip-chip bonded to a custom-designed flexible printed circuit board (flex PCB). After polydimethylsiloxane (PDMS) encapsulation, the acoustic performance of the probe was evaluated. I successfully demonstrated the imaging mode of the dual-mode probe using nylon wire phantom. Using HIFU mode, I measured 7.4 MPa peak-to-peak pressure at 8 mm focal depth. To get higher pressure for the ablation, high AC and DC voltage were used, and CMUT arrays got shorted due to the insulator breakdown. With this probe, obtaining high pressure levels needed for tissue ablation was problematic with CMUTs due to device failure at high voltages. Therefore, I re-optimized a CMUT design that can produce higher output pressure without breakdown or device failure. With CMUT simulation software, the design parameters of CMUT element were optimized with a gap height of 0.13 um and a top plate thickness of 1 um. After it was fabricated and integrated, the dual-mode probe was tested again in an acoustic setup. Compared with previous results, the device shows improved performance without device failure. The focused pressure at F-1 (8 mm) was measured to 16 MPa peak-to-peak. More importantly, most of the device can produce high pressure levels reliably without device failure. Using HIFU simulation software, the specification for HIFU ablation was explored if the dual-mode probe can ablate the tissue. It shows that even with 10 MPa peak-to-peak the dual-mode probe can create the lesion. An ablation test was successfully performed on HIFU phantom gel and ex-vivo tissue using HIFU mode of the dual-mode probe. Another important evaluation as a HIFU probe was the heating of the device. While CMUT array has very low self-heating, because of the power dissipation on HV switches of dual-mode ASIC, the ASIC was heated during HIFU mode. To reduce the heating of dual-mode ASIC, the copper heat sink rod, the chiller, and the water circulation heat sink were added to the system and it significantly reduced the heating. With the thermal management system, the probe was thermally stable around the body temperature during HIFU mode and imaging mode. Lastly, I successfully demonstrated ultrasound image-guided HIFU on HIFU phantom gel with guide wires by switching between imaging mode and HIFU mode using dual-mode ultrasound system. Our studies established a dual-mode HIFU system that will improve the non invasive ablation of tissue. This work of the dual mode system certainly shows the possibility of the new treatment application that was impossible to achieve using the conventional image-guided HIFU system.

Principles and Applications of Therapeutic Ultrasound in Healthcare introduces concepts, principles, construction, and applications of therapeutic ultrasound: from bench to bedside. A comprehensive examination of the industry and medical application of ultrasound therapy, this book highlights working principles, research progress, and system

Minimally invasive surgical techniques are moving into the mainstream of urological practice. Even less invasive techniques, some of which can involve no use of the knife whatsoever, are rapidly being developed and implemented for treating urological cancer. Interventional Techniques in Uro-oncology is the first text to cover these techniques in total and provides a comprehensive review of the state-of-the-art minimally invasive interventions. This well-illustrated reference provides the basic science behind each technique before explaining when and how best to perform them. It examines their use in different clinical settings, the advantages and disadvantages of each technique in the management of specific tumor types, and their suitability for different patients. Future techniques are discussed including the potential of nanotechnology in the delivery of urologic healthcare. Each chapter is easy to navigate with key points and references. Interventional Techniques in Uro-oncology is an essential reference for training and practicing oncologists, urologists and radiologists as well as the general physician with a keen interest in cancer care. Its approachable style will also inform non-experts on what is available and whether a particular intervention is suitable for their patient in the clinic.

This book provides the latest recommendations for ultrasound examination of the entire urogenital system, particularly in the male. The coverage encompasses the role of ultrasound in imaging of disorders of the kidneys, urinary tract, prostate, seminal vesicles, bladder, testes, and penis, including male infertility disorders. In addition, detailed consideration is given to intraoperative and interventional ultrasound and recently developed ultrasound techniques. Each chapter defines the purpose of and indications for ultrasound, identifies its benefits and limitations, specifies the technological standards for devices, outlines performance of the investigation, establishes the expected accuracy for differential diagnosis, and indicates the reporting method. Most of the recommendations are based on review of the literature, on previous recommendations, and on the opinions of the experts of the Imaging Working Group of the Italian Society of Urology (SIU) and the Italian Society of Ultrasound in Urology, Andrology, and Nephrology (SIEUN). The book will be of value for all physicians involved in the first-line evaluation of diseases of the renal/urinary system and male genital disorders.

Image-Guided Cancer Therapy: A Multidisciplinary Approach provides clinicians with in-depth coverage of the growing, dynamic field of interventional oncology. Combining the knowledge of expert editors and authors into one powerhouse reference, this book looks at tumor ablation, HIFU, embolic therapies, emerging technologies, and radiation therapy throughout the body (liver, bone, breast, gynecologic and prostate cancers, to name just a few) , and includes discussion of different imaging modalities. In the words of Peter Mueller, MD, author of the book’s Foreword: “... The senior authors are all world renowned experts in interventional oncology, which is another example of the high quality authorship and experience that is brought to this book. The later chapters discuss therapies that are simply not covered in any other source. Everyone who is doing or wants to do ablation therapies and interventional oncology will face a time when they will be asked to use their expertise in less used and less investigated areas. There is nowhere else where the reader can get information on the prostate, breast, and gynecologic areas, and especially pediatrics....This book is an outstanding contribution to the literature and will become a ‘must read’ for all physicians who are interested in Interventional Oncology.”

There is an enormous sense of excitement in the communities of cancer research and cancer care as we move into the middle third of the ?rst decade of the 21st century. For the ?rst time,there is a true sense of c- ?dence that the tools provided by the human genome project will enable cancer researchers to crack the code of genomic abnormalities that allow tumor cells to live within the body and provide highly speci?c, virtually non-toxic therapies for the eradication,or at least ?rm control of human cancers. There is also good reason to hope that these same lines of inquiry will yield better tests for screening, early detection, and prev- tion of progression beyond curability. While these developments provide a legitimate basis for much op- mism, many patients will continue to develop cancers and suffer from their debilitating effects, even as research moves ahead. For these in- viduals, it is imperative that the cancer ?eld make the best possible use of the tools available to provide present day cancer patients with the best chances for cure, effective palliation, or, at the very least, relief from symptoms caused by acute intercurrent complications of cancer. A modality that has emerged as a very useful approach to at least some of these goals is tumor ablation by the use of physical or physiochemical approaches.