title: Temperature changes caused by the difference in the distance between the ultrasound transducer and bone during 1 mhz and 3 mhz continuous ultrasound: a phantom study.
abstract: [Purpose] This study aimed to use a thermograph to observe temperature changes caused by different distances between an ultrasound transducer and bone during 1 MHz and 3 MHz continuous ultrasound emission on a phantom. [Materials and Methods] We observed the distribution of temperature elevations on a phantom consisting of pig ribs and tissue-mimicking material. One megahertz and 3 MHz ultrasound were delivered at 2.0 W/cm(2) for 5 minutes. To record the temperature changes on the phantom, we took a screenshot of the thermograph with a digital camera every 20 seconds. [Results] With 1 MHz ultrasound at the distances of 2 and 3 cm, the temperature elevation near the bone was higher than that near the transducer. However, with 3 MHz ultrasound, the temperature elevation was higher near the transducer rather than near the bone. At this point, we consider that there is a possibility of heat injury to internal organs in spite of there being no elevation of skin temperature. [Conclusion] When performing ultrasonic therapy, not only should the frequency be taken into consideration, but also the influence of the absorption coefficient and the reflection of the tissue. We visually confirmed the thermal ultrasound effect by thermography. Special attention to the temperature elevation of the internal organs is necessary to avoid injuries.
authors: Course of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Japan ; Department of Rehabilitation and Physical Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan.
authors: Akihiko
authors: A
authors: Ohwatashi
authors: Department of Rehabilitation and Physical Medicine, Hokkaido University Hospital, Japan.
authors: Satoshi
authors: S
authors: Ikeda
authors: Department of Rehabilitation and Physical Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan.
authors: Katsuhiro
authors: K
authors: Harada
authors: Department of Rehabilitation and Physical Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan.
authors: Yurie
authors: Y
authors: Kamikawa
authors: Department of Rehabilitation and Physical Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan.
authors: Akira
authors: A
authors: Yoshida
authors: Course of Occupational Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Japan.
authors: Kazuhiro
authors: K
authors: Inoue
authors: Course of Occupational Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Japan.
authors: Nobuhiko
authors: N
authors: Yanagida
authors: Course of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Japan.
authors: Kiyohiro
authors: K
authors: Fukudome
authors: Course of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Japan.
authors: Ryoji
authors: R
authors: Kiyama
authors: Course of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Japan.
authors: Tadasu
authors: T
authors: Ohshige
authors: Course of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Japan.
authors: Tetsuo
authors: T
authors: Maeda
keywords: Thermal effect; Thermography; Ultrasound
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