PURPOSE: To test the feasibility of noninvasive magnetic resonance (MR) imaging–guided focused ultrasound surgery (FUS) of benign fibroadenomas in the breast. MATERIALS AND METHODS: Eleven fibroadenomas in nine patients under local anesthesia were treated with MR imaging-guided FUS. Based on a T2-weighted definition of target volumes, sequential sonications were delivered to treat the entire target. Temperature-sensitive phase-difference–based MR imaging was performed during each sonication to monitor focus localization and tissue temperature changes. After the procedure, T2-weighted and contrast material–enhanced T1-weighted MR imaging were performed to evaluate immediate and long-term effects. RESULTS: Thermal imaging sequences were improved over the treatment period, with 82% (279 of 342) of the hot spots visible in the last seven treatments. The MR imager was used to measure temperature elevation (12.8°–49.9°C) from these treatments. Eight of the 11 lesions treated demonstrated complete or partial lac...

MR imaging-guided focused ultrasound surgery of fibroadenomas in the breast: a feasibility study.

High intensity focused ultrasound (HIFU) is gaining rapid clinical acceptance as a treatment modality enabling non-invasive tissue heating and ablation for numerous applications. HIFU treatments are usually carried out in a single session, often as a day case procedure, with the patient either fully conscious, lightly sedated or under light general anaesthesia. A major advantage of HIFU over other thermal ablation techniques is that there is no necessity for the transcutaneous insertion of probes into the target tissue. The high powered focused beams employed are generated from sources placed either outside the body (for treatment of tumours of the liver, kidney, breast, uterus, pancreas and bone) or in the rectum (for treatment of the prostate), and are designed to enable rapid heating of a target tissue volume, while leaving tissue in the ultrasound propagation path relatively unaffected. Given the wide-ranging applicability of HIFU, numerous extra-corporeal, transrectal and interstitial devices have been designed to optimise application-specific treatment delivery. Their principle of operation is described here, alongside an overview of the physical mechanisms governing HIFU propagation and HIFU-induced heating. Present methods of characterising HIFU fields and of quantifying HIFU exposure and its associated effects are also addressed.

https://www.tandfonline.com/doi/pdf/10.1080/02656730601186138

High intensity focused ultrasound: physical principles and devices.

For 50 years, high intensity focused ultrasound (HIFU) has been a subject of interest for medical research. HIFU causes selective tissue necrosis in a very well defined volume, at a variable distance from the transducer, through heating or cavitation. Over the past decade, the use of HIFU has been investigated in many clinical settings. This literature review aims to summarize recent advances made in the field. A Medline-based literature search (1965-2002) was conducted using the keywords "HIFU" and "high intensity focused ultrasound". Additional literature was obtained from original papers and published meeting abstracts. The most abundant clinical trial data comes from studies investigating its use in the treatment of prostatic disease, although early research looked at applications in neurosurgery. More recently horizons have been broadened, and the potential of HIFU as a non-invasive surgical tool has been demonstrated in many settings including the treatment of tumours of the liver, kidney, breast, bone, uterus and pancreas, as well as conduction defects in the heart, for surgical haemostasis, and the relief of chronic pain of malignant origin. Further clinical evaluation will follow, but recent technological development suggests that HIFU is likely to play a significant role in future surgical practice.

High intensity focused ultrasound: surgery of the future?

For 50 years, high intensity focused ultrasound (HIFU) has been a subject of interest for medical research. HIFU causes selective tissue necrosis in a very well defined volume, at a variable distance from the transducer, through heating or cavitation. Over the past decade, the use of HIFU has been investigated in many clinical settings. This literature review aims to summarize recent advances made in the field. A Medline-based literature search (1965-2002) was conducted using the keywords ''HIFU'' and ''high intensity focused ultrasound''. Additional literature was obtained from original papers and published meeting abstracts. The most abundant clinical trial data comes from studies investigating its use in the treatment of prostatic disease, although early research looked at applications in neurosurgery. More recently horizons have been broadened, and the potential of HIFU as a non-invasive surgical tool has been demonstrated in many settings including the treatment of tumours of the liver, kidney, breast, bone, uterus and pancreas, as well as conduction defects in the heart, for surgical haemostasis, and the relief of chronic pain of malignant origin. Further clinical evaluation will follow, but recent technological development suggests that HIFU is likely to play a significant role in future surgical practice. The quest continues for a reliable and minimally-invasive alternative to open surgery. The endoscopic revolution is well underway and there is much research activity in other fields such as laser, radiofrequency, cryo-, thermo- and brachy-therapies. Lithotripsy is now an established treat- ment for stone disease, but currently, the only non-invasive modalities in mainstream use for cancer treatment are chemotherapy and radiotherapy, both of which carry significant side-effect profiles. High intensity focused ultrasound (HIFU) has the potential to provide the clinician with another truly non- invasive, targeted treatment option. Its scope is not, however, limited to the direct treatment of cancers. It may also be used in a palliative setting for relief of chronic pain of malignant origin, for haemostasis, or even for the treatment of cardiac conduction or congenital anomalies.

Review article High intensity focused ultrasound: surgery of the future?

The feasibility and safety of magnetic resonance (MR) imaging-guided focused ultrasound surgery for uterine leiomyomas is reported. Sequential sonications were delivered to nine targets. Temperature-sensitive phase-difference MR imaging monitored the location of the focus and measured tissue temperature elevations, ensuring therapeutic dose. MR images and hysterectomy specimens were evaluated. Six leiomyomas received full therapeutic doses, and 98.5% of the sonications were visualized. MR thermometry was successful in all sonications and cases. Focal necrotic lesions were seen in all cases at MR, and five were pathologically confirmed. MR imaging-guided focused ultrasound causes thermocoagulation and necrosis in uterine leiomyomas and is feasible and safe, without serious consequences.

MR imaging-guided focused ultrasound surgery of uterine leiomyomas: a feasibility study.

Transrectal high-intensity focused ultrasound (HIFU) was recently established as a highly effective means of inducing contact and irradiation-free intraprostatic coagulative necrosis. This technique, therefore, appears potentially useful for treating localized prostate cancer (PC). To evaluate this issue, a total of 29 human prostates with localized cancer was subjected to HIFU treatment in vivo before radical retropubic prostatectomy. HIFU therapy was performed with the use of HIFU transducers with focal lengths of 3.0 cm (n = 3), 3.5 cm (n = 19), and 4.0 cm (n = 7), and the site intensity was varied from 1260 to 2000 W/cm2. The extent of intraprostatic necrosis was determined by planimetrical analysis of whole mount prostatic sections. Transrectal HIFU consistently induced sharply delineated intraprostatic coagulative necrosis within the target area, whereas alterations of perioprostatic structures were never observed. The cross-sectional area of necrosis increased from 1.1 +/- 0.7 cm2 (SD; n = 3; 3.0-cm focal length; 1428 W/cm2) to 1.2 +/- 0.7 cm2 (n = 2; 3.5-cm focal length; 1428 W/cm2), 1.8 +/- 0.17 cm2 (n = 8; 3.5-cm focal length; 1680 W/cm2), 2.8 +/- 0.32 cm2 (n = 9; 3.5-cm focal length; 2000 W/cm2) and 3.8 +/- 0.4 cm2 (n = 7; 4.0 cm focal length; 1260 W/cm2). HIFU beam transmission and the therapeutic effect were comparable in benign and malignant prostatic tissue. Interstitial thermometry (n = 6) revealed maximum intraprostatic temperatures in the focal zone up to 98.6 degrees C. Outside the focal zone and on the rectal wall, no significant temperature rises were noted. Subsequently, HIFU was applied to unilateral histologically proven T2a/T2b PC (n = 10) in an attempt to destroy all cancer before radical retropubic prostatectomy. PC was always correctly targeted. In 7 individuals, PC was partially (mean, 53%; range, 38-77%) destroyed; in the remaining 3 cases the entire tumor was ablated. Although these histological data permit no definitive conclusion on the clinical efficacy of this approach, transrectal HIFU seems to be an attractive novel minimally invasive treatment option for localized PC.

https://cancerres.aacrjournals.org/content/canres/55/15/3346.full.pdf

Markus Pedevilla

Papers

Effect of high-intensity focused ultrasound on human prostate cancer in vivo.

Transcutaneous High-Intensity Focused Ultrasound and Irradiation: An Organ-Preserving Treatment of Cancer in a Solitary Testis