Theoretical study of convergent ultrasound hyperthermia for treating bone tumors

Lu, Bing-Yuh; Yang, Rong‐Sen; Lin, Win-Li; Cheng, Kit‐Yan; Chen, Ming-Fong; Kuo, Te‐Son

doi:10.1016/s1350-4533(00)00031-x

Cited by 12 publications

(7 citation statements)

References 30 publications

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“…In recent years, there have been several other theoretical and experimental studies concerned specifically with temperature elevations at soft tissue-bone interfaces induced by focused ultrasound beams during thermal therapy (e.g. Fujii et al (1999), Hynynen and DeYoung (1988), Lin et al (2000), Lu et al (2000), Smith et al (2001), Wu and Du (1990)). Although our findings are in general agreement with these studies, it must be emphasized that we employed a static planar radiator.…”

Section: Further Discussion and Conclusionmentioning

confidence: 99%

Thermal contribution of compact bone to intervening tissue-like media exposed to planar ultrasound

Moros¹,

Novák²,

Straube³

et al. 2004

Phys. Med. Biol.

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The presence of bone in the ultrasound beam path raises concerns, both in diagnostic and therapeutic applications, because significant temperature elevations may be induced at nearby soft tissue-bone interfaces due the facts that ultrasound is (i) highly absorbed in bone and (ii) reflected at soft tissue-bone interfaces in various degrees depending on angle of incidence. Consequently, in ultrasonic thermal therapy, the presence of bone in the ultrasound beam path is considered a major disadvantage and it is usually avoided. However, based on clinical experience and previous theoretical studies, we hypothesized that the presence of bone in superficial unfocused ultrasound hyperthermia can actually be exploited to induce more uniform and enhanced (with respect to the no-bone situation) temperature distributions in superficial target volumes. In particular, we hypothesize that the presence of underlying bone in superficial target volume enhances temperature elevation not only by additional direct power deposition from acoustic reflection, but also from thermal diffusion from the underlying bone. Here we report laboratory results that corroborate previous computational studies and strengthen the above-stated hypothesis. Three different temperature measurement techniques, namely, thermometric (using fibre-optic temperature probes), thermographic (using an infrared camera) and magnetic resonance imaging (using proton resonance frequency shifts), were used in high-power short-exposure, and in low-power extended-exposure, experiments using a 19 mm diameter planar transducer operating at 1.0 and 3.3 MHz (frequencies of clinical relevance). The measurements were performed on three technique-specific phantoms (with and without bone inclusions) and experimental set-ups that resembled possible superficial ultrasound hyperthermia clinical situations. Results from all three techniques were in general agreement and clearly showed that significantly higher heating rates (greater than fourfold) were induced in soft tissue-like phantom materials adjacent (within approximately 5 mm) to a bovine bone as compared to similar experiments without bone inclusions. For low-power long-exposure experiments, where thermal conduction effects are significant, the thermal impact of bone reached at distances > 10 mm from the bone surface (upstream of the bone). Therefore, we hypothesize that underlying bone exposed to planar ultrasound hyperthermia creates a high-temperature thermal boundary at depth that compensates for beam attenuation, thus producing more uniform temperature distribution in the intervening tissue layers. With appropriate technology, this finding may lead to improved thermal doses in superficial treatment sites such as the chest wall and the head/neck.

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Section: Further Discussion and Conclusionmentioning

confidence: 99%

Thermal contribution of compact bone to intervening tissue-like media exposed to planar ultrasound

Moros¹,

Novák²,

Straube³

et al. 2004

Phys. Med. Biol.

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“…In the targeted region, the destruction of endothelium cells of microvessels and thrombosis was readily detected, suggesting that high intensity focused ultrasound could potentially prevent hematogenous dissemination of the tumor cells [71]. The treatable diameters of bone tumors increase with the absorption ratio of bone marrow to tumor, acoustic window of surface skin, and diameter of bone, but decrease with muscle depth and specific absorption rate ratio of the bone tumor to the surface skin, bone marrow, and bone [72].…”

Section: Resultsmentioning

confidence: 99%

“…The optimal driving frequency depends on tumor depth, ultrasound absorption of bone marrow, and bone diameter, but was independent of the acoustic window area and specific absorption rate ratio of the bone [72]. In a study, 96 patients with bone tumors have been successfully treated with high intensity focused ultrasound; there were patients with primary bone tumors and bone metastases [73][74].…”

Section: Resultsmentioning

confidence: 99%

Modern Palliative Treatments for Metastatic Bone Disease

Mavrogenis

Angelini

Vottis

et al. 2016

The Clinical Journal of Pain

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Currently, modern treatments are available for the palliative management of patients with metastatic bone disease. These include modern radiation therapy, chemotherapy, embolization, electrochemotherapy, radiofrequency ablation, and high-intensity focused ultrasound. As such it is of interest for all physicians with no experience with these developments to make palliative procedures safer and more reliable.

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“…Intriguingly, HIFU has the potential to induce osteonecrosis non-invasively by thermally inducing osteocyte damage and vascular thrombosis. This combination may closely mimic clinical osteonecrosis, characterized by ischemia and a lack of a reparative response [ 137 ]. Hyperthermia induces osteonecrosis, and the vascular insult results in ischemia and a lack of reparative response.…”

Section: Discussionmentioning

confidence: 99%