The development of PdNi thermoseeds for interstitial hyperthermia

Meijer, J. G.; Wieringen, N. Van; Koedooder, C.; Nieuwenhuys, G. J.; Dijk, J.D.P. van

doi:10.1118/1.597527

Cited by 24 publications

(14 citation statements)

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“…Basic research mainly focused on heat generation by different materials (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33), thermoseed processing methods (34,35), heating coil designs (36,37), improving uniform temperature distribution (38)(39)(40)(41)(42)(43)(44)(45)(46)(47), and the in vivo effects on animals (12,21,25,28,30,32,33,36,38,41,(48)(49)(50)(51). Clinical research mainly focused on intracranial tumors (52,53), prostate cancer (54)(55)(56)57), and some other tumors …”

Section: Discussionmentioning

confidence: 99%

Feasibility study of high-temperature thermoseed inductive hyperthermia in melanoma treatment

Xia

Li²,

Zhao³

et al. 2011

Oncol Rep

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Abstract. Current treatment modalities for melanoma do not offer satisfactory efficacy. We have developed a new, minimally invasive hyperthermia technology based on radio-frequency hyperthermia. Herein, we investigated the feasibility of using a nickel-copper thermoseed for inductive hyperthermia at a relatively high temperature (46-55˚C). In vitro, the thermoseed showed good thermal effects and effective killing of B16/F10 melanoma cells. Temperatures of 53.1±0.5˚C were achieved for a single thermoseed and 56.5±0.5˚C for two in parallel (spacing 5 mm). No B16/F10 melanoma cells survived with heating time longer than 20 min in the parallel thermoseed group. Magnetic fields or thermoseeds alone did not affect the survival rate of B16/F10 cells (P>0.05). In vivo, B16/F10 melanoma cells were subcutaneously injected into the right axilla of C57BL/6 mice. After the tumors grew to ~11-13 mm, two thermoseeds (spacing 5 mm) were implanted into the tumors and the mice were subjected to an alternating magnetic field (100-250 kHz, 15 kA/m) to induce hyperthermia. The temperature at the center of the tumor reached 46˚C at 5 min and plateaued at 50˚C. Thermoseed treatment produced large necrotic areas, inhibited tumor growth in 60% (6 of 10) of animals and prolonged survival time (P<0.05). Thus, with further optimization and testing, high-temperature thermoseed inductive hyperthermia may have therapeutic potential for melanoma.

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Section: Discussionmentioning

confidence: 99%

Feasibility study of high-temperature thermoseed inductive hyperthermia in melanoma treatment

Xia

Li²,

Zhao³

et al. 2011

Oncol Rep

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“…The improvement of the Curie gradient towards an ideal step-like transition would further increase the temperature control of thermoseeds significantly. However, the Curie gradient has been optimized in earlier studies (Chen et al 1988, Meijer et al 1995, Van Wieringen et al 1996. It was also found to be limited by the asymptote for the heat production which is a result of magnetic saturation (Van Wieringen et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Dose uniformity of ferromagnetic seed implants in tissue with discrete vasculature: a numerical study on the impact of seed characteristics and implantation techniques

Wieringen¹,

Kotte²,

Leeuwen³

et al. 1998

Phys. Med. Biol.

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The results from simulations with a new three-dimensional treatment planning system for interstitial hyperthermia with ferromagnetic seeds are presented in this study. The thermal model incorporates discrete vessel structures as well as a heat sink and enhanced thermal conductivity. Both the discrete vessels and the ferroseeds are described parametrically in separate calculation spaces. This parametric description has the advantage of an arbitrary orientation of the structures within the tissue grid, easy manipulation of the structures and independence from the resolution of the tissue voxels (tissue calculation space). The power absorption of the self-regulating seeds is according to empirical data. The thermal effects of an unlimited number of thin layers surrounding the seed (coatings, catheters) can be modelled. The initial calculations have been performed for an array of 12 identical ferromagnetic seeds in a tissue volume with a computer generated artificial vessel network spanning four vessel generations in both the arterial and venous tree. The heterogeneously distributed large isolated vessels impair the temperature distribution significantly, indicating the limited accuracy of continuum models. Simulations with different types of ferromagnetic seeds have confirmed that the efforts of previous studies to optimize the self-regulating temperature control and the implantation techniques of the ferroseeds will improve the homogeneity of the temperature distribution in the target volume. Multifilament seeds implanted in brachytherapy needles and tubular seeds appear to be the most favourable configurations. The division of long seeds into shorter segments with the appropriate Curie temperature will further improve the homogeneity of the temperature distribution without increasing the average temperature in the volume of interest. Given the proper thermal tissue data, the model presented in this study will prove to be a useful tool in making choices for the implant geometry, seed spacing and Curie temperature.

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“…We note that the size of our seeds in the present study is substantially smaller than seeds used in ferromagnetic induction heating experiments published previously. 6,7,15,16,30,31 A slight difference between temperature measured at the phantom surface (IR camera) and in the middle of implantation plane (FO thermometer) in Fig. 9 is due to ambient air cooling of the phantom surface.…”

Section: F Preliminary Induction Heating Experimentsmentioning

confidence: 97%

Practical considerations for maximizing heat production in a novel thermobrachytherapy seed prototype

et al. 2014

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Purpose: A combination of hyperthermia and radiation in the treatment of cancer has been proven to provide better tumor control than radiation administered as a monomodality, without an increase in complications or serious toxicities. Moreover, concurrent administration of hyperthermia and radiation displays synergistic enhancement, resulting in greater tumor cell killing than hyperthermia and radiation delivered separately. The authors have designed a new thermobrachytherapy (TB) seed, which serves as a source of both radiation and heat for concurrent brachytherapy and hyperthermia treatments when implanted in solid tumors. This innovative seed, similar in size and geometry to conventional seeds, will have self-regulating thermal properties. Methods:The new seed's geometry is based on the standard BEST Model 2301 125 I seed, resulting in very similar dosimetric properties. The TB seed generates heat when placed in an oscillating magnetic field via induction heating of a ferromagnetic Ni-Cu alloy core that replaces the tungsten radiographic marker of the standard Model 2301. The alloy composition is selected to undergo a Curie transition near 50• C, drastically decreasing power production at higher temperatures and providing for temperature self-regulation. Here, the authors present experimental studies of the magnetic properties of Ni-Cu alloy material, the visibility of TB seeds in radiographic imaging, and the ability of seed prototypes to uniformly heat tissue to a desirable temperature. Moreover, analyses are presented of magnetic shielding and thermal expansion of the TB seed, as well as matching of radiation dose to temperature distributions for a short interseed distance in a given treatment volume. Results: Annealing the Ni-Cu alloy has a significant effect on its magnetization properties, increasing the sharpness of the Curie transition. The TB seed preserves the radiographic properties of the BEST 2301 seed in both plain x rays and CT images, and a preliminary experiment demonstrates thermal self-regulation and adequate heating of a tissue-mimicking phantom by seed prototypes. The effect of self-shielding of the seed against the external magnetic field is small, and only minor thermal stress is induced in heating of the seeds from room temperature to well above the seed operating temperature. With proper selection of magnetic field parameters, the thermal dose distribution of an arrangement of TB and hyperthermia-only seeds may be made to match with its radiation dose distribution. Conclusions:The presented analyses address several practical considerations for manufacturing of the proposed TB seeds and identify critical issues for the prototype implementation. The authors' preliminary experiments demonstrate close agreement with the modeling results, confirming the feasibility of combining sources of heat and radiation into a single thermobrachytherapy seed.

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The development of PdNi thermoseeds for interstitial hyperthermia

Cited by 24 publications

References 0 publications

Feasibility study of high-temperature thermoseed inductive hyperthermia in melanoma treatment

Feasibility study of high-temperature thermoseed inductive hyperthermia in melanoma treatment

Dose uniformity of ferromagnetic seed implants in tissue with discrete vasculature: a numerical study on the impact of seed characteristics and implantation techniques

Practical considerations for maximizing heat production in a novel thermobrachytherapy seed prototype

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