MedWOW / Articles / medical equipment / High Intensity Focused Ultrasound

High Intensity Focused Ultrasound

18 March, 2012 | medical equipment, Ultrasound Scanners

Ultrasound -

High Intensity Focused Ultrasound (HIFU) is a newly designed non-invasive cancer treatment that has the ability to accurately destroy tumors , basically the HIFU operates by bringing numerous beams of ultrasound to a point within the tumor, this effectively destroys the tumor and the surrounding tissue remains unharmed.

This sound wave will pass through the tissue and in so doing parts are absorbed and converted into heat. Once the beam is correctly focused a tiny focus is achievable in deep tissue. Once the beam has reached a required temperature, coagulation of the tissue will take place, by focusing at numerous places a piece of deep tissue can be removed by this heat process.

With the acoustic intensities elevated there is a possibility that cavitation may occur- this cavitation is the formation of microbubbles that interact with the ultrasonic field. These bubbles will vibrate and maintain their growth pattern until they burst, during this process the temperatures within the bubble are extremely high the bursting causes jets and shock waves that have the capability to damage tissue. Due to the unforeseeable results, this cavitation procedure has nullified the clinical usage. Be that as it may, the procedure is being investigated to further heighten HIFU ablation as well as for various other uses.

As previously mentioned this process of HIFU is an exact microscopic medical procedure utilizing a direct ultrasound beam to heat and destroy tissue through the process of ablation. There should be no confusion with this procedure and the procedure of therapeutic ultrasound, which has the ability to bring on hyperthermia – as this heats much slower and ablation is possible with some hyperthermia treatments.

The main characteristic of HIFU procedures are that they are conducted via and image –guiding system, thus enabling all planning and aiming prior to the releasing of the energy and the ablation process. Magnetic Resonance-guided Focused Ultrasound is the term when a MRI is the guidance system that is used.

The ultrasonic beam is a non-ionizing energy flow and should not be confused with electromagnetic ionizing radiation such as X-ray radiation.

Ultrasound can be focused either by an acoustic lens, a curved type transducer or a phased array of many discrete small transducers. When the phased array system is used, electronically, by dynamically adjusting the electronic signals to the elements of a phased array, the beam can be steered to different locations, and aberrations in the ultrasound beam due to tissue structures can be corrected.

The actual tissue damage is as a result of the heated temperature as well as the time of the focusing thereon- the exposure is termed the “thermal Dosage”. By moving the focal point to several places a larger segment can be thermally ablated.

By using coagulation necrosis, the damaged tissue which is the focal point of the beams during HIFU, and with a temperature between 65 and 85 degrees, are destroyed. In most scenarios the use of any higher temperatures are avoided in order to not to allow the boiling of the liquids within the tissue. In theory the beams are meant to treat and predetermined and targeted portion of a tissue, there are however various hindrances that can occur namely cold spots and beam distortion. By moving the applicator on its robotic arm, the target is treated by numerous side by side beams as predetermined by the doctor performing the procedure. Exact ablation of the targeted area is achievable, and therefore this procedure is commonly called HIFU surgery, also known as “Non-invasive HIFU surgery”. Although general anesthesia in not required, it is regularly recommended, the treatment is also used in combination with chemotherapy or radiotherapy.

In so far as non-invasive medical technology the procedure HIFU ranks right up there, the ability to perform a microscopic ablation using an external applicator is without equal within the medical field. It is interesting to note that this is not a new idea, actually the use of ultrasound dates back to the early 20th century, and together with the continuous enhancements within the medical technology field, HIFU has become an essential element of modern medicine.

As there is no side affect to the successive usage of HIFU on a targeted area, therefore it is possible to redo the treatment in the event of the first procedure proving unsuccessful. HIFU, being a non-invasive procedure can treat a cancerous prostrate following radiation therapy or has the ability to apply partial treatment to an infected prostrate.