Laboratory investigations of rapid tissue heating by focused ultrasonic beams

Haar, Gail Reinette ter; Clarke, Robert L.; Vaughan, Michael; Rivens, Ian; Chen, L.; Loverock, P.H.; Hill, Christopher

doi:10.1016/0041-624x(92)90047-p

Cited by 4 publications

(2 citation statements)

References 6 publications

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“…These results resemble those reported by other research teams (Vallancien et al 1991, ter Haar et al 1992, Darzi et al 1993, Watkin et al 1996. The mechanisms behind tissue destruction are elevated temperature and cavitation.…”

Section: Discussionsupporting

confidence: 94%

“…HIFU thermotherapy is a subject investigated by several research groups (Corry et al 1984, Hynynen et al 1989, 1996a, Vallancien et al 1991, 1992, Hynynen 1992, ter Haar et al 1992, Darzi et al 1993, Buchanan and Hynynen 1994, Watkin et al 1996. However, HIFU is not yet an established routine treatment method, due to many factors which limit this therapeutic procedure.…”

Section: Introductionmentioning

confidence: 98%

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Thermotherapy: feasibility study using a single focussed ultrasound transducer

Barkman

Almquist²,

Kirkhorn³

et al. 1999

International Journal of Hyperthermia

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Feasibility studies on tissue lesioning using high intensity focussed ultrasound (HIFU) thermotherapy were carried out. A single strongly focussed transducer was used. The transducer has a diameter of 50 mm, a centre resonance frequency of 1 MHz and a focal distance of 50mm. Experiments were carried out both in vitro on pig muscle samples and in vivo on a pig (exposures on the thigh and on the liver). Different types of burst pulse signals were used, the best results were obtained with 1-2 s burst pulses, with a repetition period of 10s. The risk for skin damage increases for longer burst pulses. Lesions at the focus were obtained both in the experiments in vitro as well as in vivo. The size and the shape of the lesions in vivo resemble those obtained in vitro. The results of the experiments show that tissue lesions can be obtained at deep locations (4.5 cm in the tissue) with the transducer. The lesions were well discriminated from the surrounding tissue and were ellipsoid- or drop-shaped. The lesion size can be controlled by the choice of time parameters of the burst pulse signal, power and treatment time. Temperatures of about 80 degrees C were measured in the tissue at the ultrasound focus in vitro. These results show that elevated temperatures can be induced rapidly at the focus, thus reducing the effect of heat dissipation through blood perfusion.

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Section: Discussionsupporting

confidence: 94%