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Ultrasound Physics
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
Ultrasound has an exceptional safety profile compared to other imaging modalities and is safe enough for use during pregnancy. However, interactions of sound waves with tissue, through thermal and non-thermal mechanisms, do have the potential to lead to biological effects if not used prudently. In therapeutic applications, such as ablation of tissue using HIFU, ultrasound power output is several orders of magnitude higher than diagnostic levels. At present, HIFU is still under evaluation and is only available at specialist centres. This section is limited to the safety of diagnostic rather than therapeutic ultrasound applications.
Combination Approaches: Using Fillers With Toxins and Energy-Based Devices
Published in Neil S. Sadick, Illustrated Manual of Injectable Fillers, 2020
MFU-V is an energy-based modality that directs ultrasound waves to precisely identified points in the dermis, subcutaneous tissues, and myofascial planes in order to generate distinct thermal coagulation points (TCPs). TCP temperatures reach between 60 and 70 °C, creating microcoagulation zones at three depths: 4.5, 3.0, and 1.5 mm. This technology utilizes a therapeutic ultrasound image prior to and during treatment in order to confirm the apposition of the transducer to the epidermis and to accurately visualize the depth of treatment target (36,37). Immediate tissue contraction with treatment occurs, corresponding to the destruction of intramolecular hydrogen bonds, while delayed neocollagenesis can be seen as early as 3 months following treatment and continues for up to 6 months. MFU-V (Ultherapy®; Ulthera Inc., Mesa, AZ/Merz Pharmaceuticals GmbH, AZ) has a brow lift, submental neck lift, and improvement in chest wrinkle indication (5).
Medical Imaging Informatics
Published in Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam, Introduction to Computational Health Informatics, 2019
Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam
Ultrasound signal loses its intensity during propagation due to scattering, absorption, attenuation and reflection. Part of the lost energy is converted into heat, raising the tissue-temperature. Physical therapists use ultrasound machines to improve the healing of muscle-injuries by improving the circulation in the affected area. Heating from ultrasound is also used in noninvasive cancer therapy, e.g., therapeutic ultrasound. Furthermore, in radiation therapy, a malignant mass, if heated to 43°C, can be treated effectively with a much lower dose.
The effect of ultrasound or phonophoresis as an adjuvant treatment for non-specific neck pain: systematic review of randomised controlled trials
Published in Disability and Rehabilitation, 2022
Kinley Dorji, Nadine Graham, Luciana Macedo, Janelle Gravesande, Charles H. Goldsmith, Geoffrey Gelley, Maureen Rice, Patricia Solomon
Therapeutic ultrasound is a common therapeutic modality often used in conjunction with exercise or manual therapy to treat various musculoskeletal conditions, including neck pain. Ultrasound is defined as a “sound wave or pressure wave with a frequency above the limit of the human hearing (16 to 20 kHz)” [9, p 410]. Therapeutic ultrasound used in rehabilitation treatments utilises frequencies within 1–3 MHz with intensities of 0.1–2.0 W/cm2 [9]. Ultrasound at 1 MHz can penetrate deep into the tissues from 2 to 4 cm, while ultrasound at 3 MHz has been demonstrated to penetrate 1–2 cm [10]. The two theories explaining the biophysiological effect of ultrasound include thermal and non-thermal effect theory [11]. However, it is difficult to separate the therapeutic effects caused by ultrasound into thermal and non-thermal as these coexist as the application of ultrasound on tissues continually produces mechanical and thermal effects. Thermal effects are generally used to manage pain, muscle spasm, and improve connective tissue disorders in sub-acute and chronic conditions [9,12]. Non-thermal effects are typically used in acute conditions to manage pain, reduce oedema and to stimulate tissue repair [12]. Overall, the thermal and non-thermal effects promote healing of the tissues and control pain which would theoretically result in reduced pain and improved function and disability during both acute and chronic stages
Low intensity ultrasound targeted microbubble destruction assists MSCs delivery and improves neural function in brain ischaemic rats
Published in Journal of Drug Targeting, 2020
Hai Cui, Qiong Zhu, Qinli Xie, Zheng Liu, Yunhua Gao, Ying He, Xi Tan, Yali Xu
In recent studies, the focussed therapeutic ultrasound has been widely used under the guidance of magnetic resonance imaging (MRI), in order to prompt the targeted delivery of antibodies, genes and stem cells into the brain [10–13,20]. The present results and another study [9] revealed that LI-UTMD could open the BBB and assist in the targeted delivery of stem cells into the brain, which might be another option on drugs or stem cell delivery. It is known that the diagnostic ultrasound system is a commercialised apparatus, which is applicable and feasible in clinical practice, and the standardised parameters, such as frequency, MI and PRP, allow researchers to easily repeat the experiments. The limitation for this method is the little control over the sonication volume and exposure conditions due to the unfocused ultrasound beam, while focussed devices could control the focal delivery of ultrasound energy and exposure based on bubble oscillations. Therefore, the present approach has both advantages and disadvantages, when compared to a high-intensity therapeutic ultrasound apparatus. Hence, further studies are needed to investigate and compare the reliability, safety and efficacy of BBB opening and stem cell delivery via these two approaches in experimental studies, even in clinical use.
A randomized, controlled multicenter study evaluating focused ultrasound treatment for fat reduction in the flanks
Published in Journal of Cosmetic and Laser Therapy, 2019
Michael H Gold, W. Patrick Coleman, William Coleman, Robert Weiss
Novel treatment techniques and technologies that can noninvasively address the excess and unwanted subcutaneous fat deposits have become very popular in the aesthetic field, with each modality having a varying efficacy, efficiency, and safety. Ultrasound has become a cornerstone modality in medicine and is widely used for diagnostic, as well as therapeutic applications. Therapeutic ultrasound is known to induce a vast range of biological effects at very different acoustic parameters. While low levels of ultrasound can produce beneficial but reversible cellular effects, higher levels (such as high-intensity focused ultrasound) can cause instantaneous cell necrosis. Most therapeutic ultrasound-based devices use heating to achieve a desired effect. In contrast, pulsed, focused ultrasound technology achieves its intended effect of adipocyte destruction in a non-thermal fashion. The non-thermal focused ultrasound technology results in the destruction of adipocytes via cavitation or mechanical acoustic effect, while controlling the temperature elevation (less than 0.5°C increase) in the targeted tissues. Therefore, typical side effects associated with thermal-based devices such as pain, dysesthesia, bruising, swelling, and downtime are not commonly associated with focused ultrasound treatment.