Work

Low-Intensity Continuous Ultrasound vs. Traditional Ultrasound: A Systematic Review and Descriptive Analysis on Past and Future Gold Standards for Deep-Tissue Diathermy in Clinical Medicine

Year: 2026

Type: article

Abstract: Background/Objectives: The thermal effects of therapeutic ultrasound (US) have been utilized to promote musculoskeletal healing. However, the optimal combination of US parameters, while studied in the past, has yet to be updated with the advent of newer US modalities, including low-intensity continuous ultrasound (LICUS). The purpose of this study was to evaluate the effects of US frequency, intensity, and duration on changes in tissue temperature and to compare the thermal response between traditional US and LICUS. Methods: Following PRISMA guidelines, PubMed, Embase, and Web of Science were searched for in vivo human studies that reported temperature changes and used standard ultrasound parameters (1 or 3 MHz, 0.1–2.0 W/cm2, aqueous gel). US frequency, intensity, duration, effective radiating area (ERA), body region, and total energy delivered at three depths (1 cm, 3 cm, and 5 cm) were extracted. The outcome of interest was change in tissue temperature (i.e., ultrasonic diathermy). A mathematical model was used to interpolate missing data. Three-way ANOVA and t-tests were used to compare outcomes. Results: Nineteen studies (384 participants) were included. The weighted mean total energy delivered was 6698.5 ± 6767.4 J and was significantly correlated with tissue temperature change across all depths (r = 0.544, p < 0.001). At 1, 3, and 5 cm depths, significant interactions were observed between ultrasound intensity and frequency and between intensity and treatment duration (all p ≤ 0.05). Higher intensities generally produced greater temperature increases during shorter treatments (≤10 min), whereas longer treatment durations (≥60 min) at low intensity produced the greatest temperature increases overall. Frequency-dependent effects were also observed, with greater temperature increases at 3 MHz compared with 1 MHz at several intensity levels. LICUS delivered significantly more total energy than traditional 3 MHz US (13,854.4 ± 8129.6 vs. 3546.5 ± 2096.0 Joules, p < 0.001) and produced significantly greater tissue temperature increases at all depths (p < 0.001). Conclusions: Changes in tissue temperature are strongly correlated with the total US energy delivered. While frequency, intensity, and duration play a significant role in thermal energy, LICUS over sustained periods delivers significantly greater cumulative energy and, subsequently, greater tissue temperature change compared to traditional US.

Source: Medical Sciences

DOI: 10.3390/medsci14060631

Authors: Samuel Wang, Aaditya Jain, Jemy M. Delikat, Jude Delikat, Samuel Phillips, Stephanie Petterson

Institutions: Stamford Hospital, James A. Haley Veterans' Hospital

Language: English

Topic: Ultrasound and Hyperthermia Applications

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $1,689