hifu

Development of this therapy significantly broadened the range of treatment options for patients suffering from uterine fibroids. HIFU treatment for uterine fibroids was approved by the Food and Drug Administration (FDA) in October 2004.[3] This is a non-invasive treatment option for patients suffering from symptomatic fibroids. Most patients benefit from HIFU and symptomatic relief is sustained for two plus years. Up to 16-20% of patient will require an additional treatment.[4]

Currently available FDA approved uterine fibroids treatment devices are GE Insightec ExAblate 2000 and ExAblate 2100. Additionally, Philips Sonalleve MR-HIFU and Haifu models JC and JC200 have CE approval.

Functional Neuro Surgery

Transcranial Magnetic Resonance-guided Focused Ultrasound Surgery (tcMRgFUS) is a promising new technology for the non-invasive treatment of various brain disorders such as Essential Tremor, Neuropathic Pain and Parkinson’s Disease. With preclinical and clinical precedents set for the safety, efficacy, and reproducibility of MRgFUS for treating uterine fibroids, painful bone metastases, adenomyosis, breast tumors, and a host of other conditions, tcMRgFUS for cranial disorders could become a groundbreaking and potentially disruptive technology in the field of neurosurgery.

Neurological disorders such as Essential Tremor, Neuropathic Pain and Parkinson’s Disease, affect millions of people worldwide and may cause significant loss of functionality, suffering, and medication dependency, negatively affecting the quality of life of patients and their caretakers. For patients who do not respond to drug treatments, procedures include deep brain stimulation, radiofrequency ablation, radio surgery which are either invasive or involve ionizing radiation. These are associated with recognized risks: either high doses of ionizing radiation or high risk of complications and side effects. tcMRgFUS can potentially offer a non-invasive alternative to these treatments with minimal side effects.

Clinical trials are currently being conducted in Switzerland, and the University of Virginia with ExAblate Neuro tcMRgFUS system by InSightec.[5] Preliminary results demonstrate the ability to effectively ablate targets deep in the brain with high precision.[6]

Prostate cancer

The earliest widespread use of HIFU ablation was as a treatment for prostate cancer. This treatment is administered through a trans-rectal probe and relies on heat developed by focusing ultrasound waves into the prostate to kill the tumor. Promising results approaching those of surgery have been reported in large series of prostate cancer patients. These treatments are performed under ultrasound imaging guidance, which allows for treatment planning and some minimal indication of the energy deposition. HIFU may also be used to ablate the entire prostate gland using a transrectal probe. This is an outpatient procedure that usually lasts 1–3 hours. Results show that it greatly reduces some of the side effects common with other treatments for prostate cancer.

During HIFU, the entire prostate is ablated, including the prostatic urethra. The urethra has regenerative ability because it is derived from a different type of tissue (bladder squamous-type epithelium) rather than prostatic tissue (glandular, fibrotic and muscular). While the urethra is an important anatomical structure, the sphincter and bladder neck are more important to maintaining the urinary function. During HIFU the sphincter and bladder neck are identified and avoided.[7]

Available devices for prostate cancer treatment

Ablatherm Robotic HIFU

Developed in 1989 in France with Inserm (French National Institute of Medical Research), Edouard Herriot Hospital in Lyon and EDAP TMS (Nasdaq : EDAP), Ablatherm HIFU was the first prostate cancer HIFU device to receive CE marking in 2000. The first "Ablathermy" treatments on men were performed in 1993 and as of January, 2010, more than 21,000 treatments have been performed worldwide.

Sonablate 500

Developed in the early 1990s for the treatment of benign prostate hyperplasia (BPH) in the US by Misonix (Nasdaq: MSON), Sonablate was then modified to treat prostate cancer at the end of the 1990s. Sonablate 500 received CE marking in 2001. As of January 2010, a total of more than 9,000 treatments have been performed for benign prostate hyperplasia and over 7,000 prostate cancer treatments.[citation needed]

During Sonablate HIFU, the physician obtains real-time ultrasound images of the prostate and surrounding areas. From these images, a customized plan for delivering the ultrasound energy is created. The Sonablate software allows the physician to precisely define the treatment zones in order to destroy the entire gland.

Sonablate HIFU is minimally invasive, performed on an outpatient basis and typically lasts 2–4 hours, depending on the size of the prostate. There is no surgery or radiation involved. Patients wear a catheter post-procedure but are able to resume normal activities almost immediately. The Sonablate is the only HIFU device for prostate cancer that does not require an advance surgical procedure (known as a TURP) in order to achieve effective results when treating enlarged prostate glands. Sonablate HIFU can treat large prostates up to 40 grams.

The Sonablate incorporates three-dimensional imaging to provide better visuals of the prostate, especially any irregularities, and allow the physician to create the most effective treatment plan possible. The newest technological enhancement to the Sonablate is tissue change monitoring (TCM) software, which gives real-time feedback to the physician, thus confirming if sufficient energy has been delivered to completely ablate the tissue.

HIFU-2001 (SUMO)

HIFU-2001 has CFDA (China Food and Drug Administration) approval, and has been used clinically since 2001. Currently, more than 180 HIFU treatment centers are active in China, Hong Kong and Korea. This method of HIFU does not require the use of anesthesia.

Other cancers

Further information: Hyperthermia therapy
HIFU has been successfully applied in treatment of cancer to destroy solid tumors of the bone, brain, breast, liver, pancreas, rectum, kidney, testes, prostate.[8][9] At this stage, cancer treatments are still in the investigatory phases as there is a need to find more about their effectiveness.

HIFU has been found to offer palliative care. CE approval has been given for palliative treatment of bone metastasis.[10] Experimentally, a palliative effect was found in cases of advanced pancreatic cancer.[11]

HIFU may be used to create high temperatures not necessarily to treat the cancer alone, but in conjunction with targeted delivery of cancer drugs. For example, HIFU and other devices may be used to activate temperature-sensitive liposomes, filled with cancer drug "cargo" to release the drug in high concentrations only at the tumor site(s) only where triggered to do so by the hyperthermia device (See Hyperthermia therapy). This novel approach is resulting in drug concentrations 10 times or more than traditional chemo with a fraction of the side effects since the drug is not released system-wide.

In addition, several thousand patients with different types of tumors have been treated in China with HIFU using ultrasound image-guided devices built by several different companies.

Delivering drugs to brain

In current research, HIFU is being used to temporarily open the blood–brain barrier, allowing absorption of drugs into the brain. It is most effective when used in combination with a calcium channel blocker like verapamil.

Treatment of atrial fibrillation

HIFU has been used to treat the most common heart arrhythmia, atrial fibrillation (AF). A minimally invasive catheter based system designed to ablate heart tissue responsible for propagating AF has been approved for use in Europe and is undergoing an FDA approved phase III pivotal efficacy trial in the United States.

HideDiscoveries during use

Currently, the only proven imaging method to accurately quantify the heating produced during HIFU in vivo is Magnetic Resonance Imaging (MRI). MRI also has superior soft tissue contrast and can image in any orientation, making it the state of the art for guiding HIFU treatments. But MRI can't operate in real-time with HIFU, with the current state of the art being one image acquisition approximately every six seconds using a full scan of k-space. Researchers are working to reduce this image acquisition time through some of the speed enhancements common in other areas of MRI, including pulse sequences to scan a reduced k-space, constrained reconstruction, and model-based filtering using data from the bioheat equation.

The University of Minnesota produced a dual-mode ultrasound transducer that offers time resolution measured in milliseconds and offers closed-loop, real-time, intensity modulation based on continuous monitoring of tissue response to the HIFU beam. This method offers improved resolution over MRI.

Clinically, MRI-guided HIFU treatments have been tested for uterine fibroids, breast fibroadenomas, breast cancer, bone metastases, and liver tumors. The largest number of patients treated with MRI-guided HIFU have been with uterine fibroids.

USgFUS treatments have been approved with CE for wider range of benign and malignant tumors due to its higher power, precision and realtime monitoring system. The largest number of patients are uterine fibroids.

Ultrasound-guided HIFU treatments have been approved in Europe and Asia. MRI-guided treatments of uterine fibroids have been approved in Europe and Asia, and were granted FDA approval in the US in 2004.[3]

Focal HIFU treatment

With the latest improvements in biopsy techniques enabling to better locate cancer, focal HIFU treatment (i.e. partial HIFU ablation) is now starting to be investigated to further reduce the side effects of cancer treatment.

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