MRgHIFU at the Interventional Centre

Magnetic Resonance guided High Intensity Focused Ultrasounds (MRgHIFU) has recently been installed at the Interventional Centre – Rikshospitalet by Philips Healthcare [1]. This is one of the few systems available in the world for completely non-invasive (without any inonizing radiation involved) treatment of Uterine Fibroids [Figure 1]. Patients treatment is about to be started in a few weeks.
MRgHIFU [2,3] may be a disruptive technology in the future by its total non-invasiveness compared to surgery or even radiation therapy where unwanted ionising radiation dose deposits always is an issue. Thus, target tissues (fibroids and tumours) can be destroyed without any device insertion in the body. Figure 1: Shematic view of MR guided HIFU treatment of Uterine Fibroid (Courtesy: Philips Healthcare, The Netherlands). Klick image for larger view.

The installed HIFU device at Rikshospitalet [Figure 2] uses an array of 256 ultrasounds transducers to produce a continuous focused beam with 10000-15000 stronger power than imaging ultrasounds [Figure 3]. The ultrasound focus point is continuously moved to ensure a volumetric heating of target tissues [4]. Patient sonication is controlled in real-time by MRI temperature monitoring [5] to ensure that only target tissue is heated and neither excessive heating nor cavitation is produced [Figure 4, Figure 5].

First eligible patients will hopefully be treated at the Interventional Centre from November/December this year [6].
Other application of MRgHIFU are being investigated worldwide [7] for tumour ablation in breast , liver, prostate etc. A very novel application of MRgHIFU is the development of targeted drug delivery [8] where encapsulated drug is selectively released in a specific target zone using only HIFU to destroy the capsule structure.

The Interventional Centre at Rikshospitalet is starting intensive research work using this novel technique. Researchers and medical staff from the Interventional Centre and many other departments at Oslo University Hospital are involved together in a truly multidisciplinary environment. Collaboration agreement between Rikshospitalet and Philips Healthcare is also established.

References

[1] http://www.apptech.philips.com/healthcare/projects/high_intensity_focused_ultrasound.html

[2] Cline HE, Schenck JF, Hynynen K, et al. MR-guided focused ultrasound surgery. J Comput Assist Tomogr 1992;16(6):956–65.

[3] Jolesz FA, Hynynen K, et al. MR Imaging–Controlled Focused Ultrasound Ablation: A Noninvasive Image-Guided Surgery. Magn Reson Imaging Clin N Am 2005;13 :545–560.

[4] Mougenot C, Salomir R, Palussie`re J, Grenier N, Moonen CTW. Automatic spatial and temporal temperature control for MR-guided focused ultrasound using fast 3D MR thermometry and multispiral trajectory of the focal point. Magn Reson Med 2004;52:1005–1015.

[5] Arora D, Minor MA, Skliar M, Roemer RB. Control of thermal therapies with moving power deposition field. Phys Med Biol 2006;51:1201–1219.

[6] Volumetric MRgHIFU with real-time feedback submission for FDA approval by Philips Healthcare in progress.

[7] Grenier N, Quesson B, de Senneville BD, Trillaud H, Couillaud F, Moonen C. Molecular MR imaging and MR-guided ultrasound therapies in cancer. JBR-BTR. 2009;92(1):8-12 (Review)

[8] Dromi S, Frenkel V et al. Pulsed-high intensity focused ultrasound and low temperature-sensitive liposomes for enhanced targeted drug delivery and antitumor effect. Clin Cancer Res. 2007;13(9):2722-7