Image-Guided High-Intensity Focused Ultrasound, A Novel Application for Interventional Nuclear Medicine?

Abstract

Image-guided high-intensity focused ultrasound (HIFU) has been increasingly used in medicine over the past few decades, and several systems for such have become commercially available. HIFU has passed regulatory approval for the ablation of various solid tumors, the treatment of neurological diseases, and the palliative management of bone metastases around the world. The mechanical and thermal effects of focused ultrasound provide a possibility for histotripsy, support radiation therapy, and targeted drug delivery. The integration of imaging modalities into HIFU systems allows for precise temperature monitoring and accurate treatment planning, increasing the safety and efficiency of treatment. Preclinical and clinical results have demonstrated the potential of image-guided HIFU to reduce adverse effects and increase the quality of life postoperatively. Interventional nuclear image-guided HIFU is an attractive noninvasive option for the future.

A contrastive study on the clinical efficacy and safety of laparoscopic myomectomy and high intensity focused ultrasound in the treatment of uterine fibroidsn the treatment of uterine fibroids

“…In the past two decades, HIFU has been widely applied in the treatment of uterine fibroids [10]. HIFU is a non-invasive technique guided by magnetic resonance imaging (MRI) or ultrasound, which can achieve myoma ablation without damaging adjacent structures [11]. Numerous previous studies have confirmed the efficacy and safety of HIFU, with rapid symptom relief, short recovery time and reduced risk of complications [12][13][14][15].…”

Methods for MRI-guided treatment of painful bone metastases with Focused Ultrasound

“…The reference phase map was calculated by averaging 3 pre-heating phase maps. A correction for phase drift was applied [7,24]: drift was estimated from the average phase value in an ROI of 67 voxels in an unheated region in the gel of the phantom from the PRFS scans. The phase error due to drift was subtracted to correct the temperature change maps.…”

“…US imaging is cheap, portable, compatible with patient implants and its frame rate favourable for imaging moving organs [25]. MR imaging has excellent soft tissue differentiation, provides spatial guidance in the targeted area independently from the acoustic absorption and reflection of tissues (inside the skull, for example) and is able to monitor temperature intraprocedurally using temperature-dependent proton resonance frequency shift, T 1 temperature mapping, or diffusion temperature mapping [7].…”

“…Although it is possible to generate focused heat through microwaves or radiofrequencies, long waves cannot be focused as precisely as shorter waves, and their penetration depth is limited. The use of short waves as therapeutic ultrasound with High-Intensity Focused Ultrasound (HIFU) provides adequate tissue penetration, ranging from 1 to 20 cm, non-invasively, allowing the creation of localized heated areas [7]. This thesis covers the work carried out to improve MR-guided High-Intensity Focused Ultrasound (MR-HIFU) therapies, specifically in the context of palliative treatment of painful bone metastases.…”

“…A possible image-based indicator is the measurement of temperature and thermal dose [5], that can both be derived from MR temperature maps. Such maps are typically measured by means of Proton Resonance Frequency Shift (PRFS) MR thermometry [7,8] and the thermal dose can be calculated from time series of temperature maps [9,10]. However, PRFS thermometry is limited by the lack of temperature information in cortical bone and fat, and by its sensitivity to motion [11,12].…”