The RF Thermoseed-A Thermally Self-Regulating Implant for the Production of Brain Lesions

Burton, Charles V.; Hill, M. L.; Walker, A. Earl

doi:10.1109/tbme.1971.4502810

Cited by 71 publications

(14 citation statements)

References 6 publications

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“…Furthermore, there are no limitations of efficacy due to reflection and absorption phenomena, which can be encountered in deep regional hyperthermia using microwave or ultrasound techniques [20]. Thermally self-regulating ferromagnetic seeds have been developed for hyperthermia and investigated by several groups [21,22]. Deger et al [2] conducted a phase II-study using cobalt-palladium-thermoseeds, which were permanently implanted into the prostate.…”

Section: Discussionmentioning

confidence: 99%

Clinical hyperthermia of prostate cancer using magnetic nanoparticles: Presentation of a new interstitial technique

Johannsen

Gneveckow

Eckelt

et al. 2005

International Journal of Hyperthermia

709

479

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The aim of this pilot study was to evaluate whether the technique of magnetic fluid hyperthermia can be used for minimally invasive treatment of prostate cancer. This paper presents the first clinical application of interstitial hyperthermia using magnetic nanoparticles in locally recurrent prostate cancer. Treatment planning was carried out using computerized tomography (CT) of the prostate. Based on the individual anatomy of the prostate and the estimated specific absorption rate (SAR) of magnetic fluids in prostatic tissue, the number and position of magnetic fluid depots required for sufficient heat deposition was calculated while rectum and urethra were spared. Nanoparticle suspensions were injected transperineally into the prostate under transrectal ultrasound and flouroscopy guidance. Treatments were delivered in the first magnetic field applicator for use in humans, using an alternating current magnetic field with a frequency of 100 kHz and variable field strength (0-18 kA m À1). Invasive thermometry of the prostate was carried out in the first and last of six weekly hyperthermia sessions of 60 min duration. CT-scans of the prostate were repeated following the first and last hyperthermia treatment to document magnetic nanoparticle distribution and the position of the thermometry probes in the prostate. Nanoparticles were retained in the prostate during the treatment interval of 6 weeks. Using appropriate software (AMIRA), a non-invasive estimation of temperature values in the prostate, based on intra-tumoural distribution of magnetic nanoparticles, can be performed and correlated with invasively measured intra-prostatic temperatures. Using a specially designed cooling device, treatment was well tolerated without anaesthesia. In the first patient treated, maximum and minimum intraprostatic temperatures measured at a field strength of 4.0-5.0 kA m À1 were 48.5 C and 40.0 C during the 1st treatment and 42.5 C and 39.4 C during the 6th treatment, respectively. These first clinical experiences prompted us to initiate a phase I study to evaluate feasibility, toxicity and quality of life during hyperthermia using magnetic nanoparticles in patients with biopsy-proven local recurrence of prostate cancer following radiotherapy with curative intent. To the authors' knowledge, this

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Section: Discussionmentioning

confidence: 99%

Clinical hyperthermia of prostate cancer using magnetic nanoparticles: Presentation of a new interstitial technique

Johannsen

Gneveckow

Eckelt

et al. 2005

International Journal of Hyperthermia

709

479

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“…The Curie temperature is an important property for magnetic materials, as this indicates the temperature where the material will stop heating and reach steady state, even if the AC magnetic field is applied for a long period of time (81,82). Most large scale magnets will continue to heat upon application of an AC magnetic field to quite high temperatures.…”

Section: Magnetic Nanoparticle Selection and Designmentioning

confidence: 99%

Magnetothermally-responsive Nanomaterials: Combining Magnetic Nanostructures and Thermally-Sensitive Polymers for Triggered Drug Release

2008

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This paper reviews the design and development of magnetothermally-triggered drug delivery systems, whereby magnetic nanoparticles are combined with thermally-activated materials. By combining superparamagnetic nanoparticles with lower critical solution temperature (LCST) polymers, an alternating current (AC) magnetic field can be used to trigger localized heating in vivo, which in turn causes a phase change in the host polymer to allow diffusion and release of drugs. The use of magnetic nanoparticles for biomedical applications is reviewed, as well as the design of thermally-activated polymeric systems. Current research on externally-triggered delivery is highlighted, with a focus on the design and challenges in developing magnetothermally-activated systems.

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“…The idea of applying a magnetic induction heating device to brain using a ferromagnetic material was introduced by Burton et al [21] in 1971. They induced a coagulative lesion, not hyperthermia, in cat brain using Pd-Ni alloy.…”

Section: Al [31mentioning

confidence: 99%

Interstitial hyperthermia of malignant brain tumors by implant heating system: Clinical experience

et al. 1991

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An implant heating system using a ferromagnetic implant with low Curie temperature has been developed for treating human brain tumors. Safe and repeated hyperthermia was possible over periods averaging ten weeks in 23 out of 25 patients with malignant brain tumors without development of major side effects. Evaluation of the effects of this new treatment is still preliminary. Overall response rate was 34.8%. However, five of thirteen cases of malignant glioma and two of five cases of brain metastasis were responded well to interstitial hyperthermia given with or without irradiation. Pathological findings common to the treated tumors were circumscribed, ellipsoid shape of coagulation necrosis around the implant. Degeneration of tumor cells, hemorrhage, vascular stasis and thrombosis were found adjacent to the necrosis. In the future, a combination of interstitial hyperthermia with brachytherapy and chemotherapy may offer improved local control of brain tumor.

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The RF Thermoseed-A Thermally Self-Regulating Implant for the Production of Brain Lesions

Cited by 71 publications

References 6 publications

Clinical hyperthermia of prostate cancer using magnetic nanoparticles: Presentation of a new interstitial technique

Clinical hyperthermia of prostate cancer using magnetic nanoparticles: Presentation of a new interstitial technique

Magnetothermally-responsive Nanomaterials: Combining Magnetic Nanostructures and Thermally-Sensitive Polymers for Triggered Drug Release

Interstitial hyperthermia of malignant brain tumors by implant heating system: Clinical experience

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