Improving locoregional hyperthermia delivery using the 3-D controlled AMC-8 phased array hyperthermia system: A preclinical study

Crezee, J.; Haaren, P. M. A. van; Westendorp, R.; Greef, Martijn de; Kok, H. Petra; Wiersma, J.; Stam, Gerard van; Sijbrands, Jan; Vörding, P. Zum Vörde Sive; Dijk, J.D.P. van; Hulshof, Maarten C.C.M.; Bel, Arjan

doi:10.3109/02656730903213374

Cited by 302 publications

(80 citation statements)

References 51 publications

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“…30 s per setting) the T90, T50 and T10 became 41.4 C, 42.8 C and 43.9 C. For this example, the gain of using alternating antenna settings is limited because heating with a single setting is already very effective with a T50 of 42. 6 C, but in general such an advanced optimisation can help to improve tumour coverage and reduce treatment limiting hot spots.…”

Section: Locoregional Heatingmentioning

confidence: 99%

“…In this example, a pancreatic cancer patient is treated with locoregional hyperthermia delivered by the 70 MHz AMC-8 waveguide system that can be used as a single-ring or a double-ring system [6]. For this patient a single ring of four antennas was used.…”

Section: Locoregional Heatingmentioning

confidence: 99%

“…For example, locoregional hyperthermia using phased array systems with one or more rings of antennas surrounding the patient is applied to deep-seated tumours [6][7][8], whereas superficial hyperthermia is applied to tumours up to 4 cm depth from the skin [9][10][11][12][13]. Intraluminal or intracavitary heating can be applied when the tumour is accessible through an existing lumen or cavity [14,15].…”

Section: Introductionmentioning

confidence: 99%

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Planning, optimisation and evaluation of hyperthermia treatments

Kok

Kotte

Crezee

2017

International Journal of Hyperthermia

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Background: Hyperthermia treatment planning using dedicated simulations of power and temperature distributions is very useful to assist in hyperthermia applications. This paper describes an advanced treatment planning software package for a wide variety of applications. Methods: The in-house developed Cþþ software package Plan2Heat runs on a Linux operating system. Modules are available to perform electric field and temperature calculations for many heating techniques. The package also contains optimisation routines, post-treatment evaluation tools and a sophisticated thermal model enabling to account for 3D vasculature based on an angiogram or generated artificially using a vessel generation algorithm. The use of the software is illustrated by a simulation of a locoregional hyperthermia treatment for a pancreatic cancer patient and a spherical tumour model heated by interstitial hyperthermia, with detailed 3D vasculature included. Results: The module-based set-up makes the software flexible and easy to use. The first example demonstrates that treatment planning can help to focus the heating to the tumour. After optimisation, the simulated absorbed power in the tumour increased with 50%. The second example demonstrates the impact of accurately modelling discrete vasculature. Blood at body core temperature entering the heated volume causes relatively cold tracks in the heated volume, where the temperature remains below 40 C. Conclusions: A flexible software package for hyperthermia treatment planning has been developed, which can be very useful in many hyperthermia applications. The object-oriented structure of the source code allows relatively easy extension of the software package with additional tools when necessary for future applications.

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Section: Locoregional Heatingmentioning

confidence: 99%

Section: Locoregional Heatingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Planning, optimisation and evaluation of hyperthermia treatments

Kok

Kotte

Crezee

2017

International Journal of Hyperthermia

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“…They utilize the constructive wave interference from a set of antennas at the tumor site [5][6][7][8]. The parameters that determine the system's ability to focus are the phases and amplitudes of the excitation of antennas in the phased array.…”

Section: Introductionmentioning

confidence: 99%

A Computational Study Using Time Reversal Focusing for Hyperthermia Treatment Planning

Takook¹,

Trefná²,

Zeng³

et al. 2017

PIER B

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Abstract-In hyperthermia treatment planning (HTP) the goal is to find the amplitudes and phases of antennas in the applicator to efficiently heat the tumor. To do this prior information regarding tumor characteristics such as the size, position and geometry, in addition to an exact model of the hyperthermia applicator is needed. Based on this information, the optimal frequency of operation can be determined. In this paper the optimum frequency for hyperthermia treatment based on the tumor and applicator characteristics, using time reversal as the focusing technique, is studied. As prior information, we consider tumor size and position, the number of the antennas in the applicator and the frequency characteristics. The obtained optimal frequency range is found using hyperthermia quality indicator values calculated from simulations. We also determine the optimum position of the virtual source in the initial step of the time reversal method to increase the quality of the treatment.

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“…[10][11][12] These devices may be designed for extracorporeal placement, intracavitary or endoluminal deployment, or interstitial or percutaneous insertion. [13][14][15] Typically, these treatments involve heating tumor targets for 30-60 min duration. For maximum clinical benefit, uniform temperature profiles are desired within target volumes, with minimum temperature greater than 40…”

Section: Introductionmentioning

confidence: 99%

Model‐based feasibility assessment and evaluation of prostate hyperthermia with a commercial MR‐guided endorectal HIFU ablation array

et al. 2014

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Purpose: Feasibility of targeted and volumetric hyperthermia (40-45• C) delivery to the prostate with a commercial MR-guided endorectal ultrasound phased array system, designed specifically for thermal ablation and approved for ablation trials (ExAblate 2100, Insightec Ltd.), was assessed through computer simulations and tissue-equivalent phantom experiments with the intention of fast clinical translation for targeted hyperthermia in conjunction with radiotherapy and chemotherapy. Methods: The simulations included a 3D finite element method based biothermal model, and acoustic field calculations for the ExAblate ERUS phased array (2.3 MHz, 2.3 × 4.0 cm 2 , ∼1000 channels) using the rectangular radiator method. Array beamforming strategies were investigated to deliver protracted, continuous-wave hyperthermia to focal prostate cancer targets identified from representative patient cases. Constraints on power densities, sonication durations and switching speeds imposed by ExAblate hardware and software were incorporated in the models. Preliminary experiments included beamformed sonications in tissue mimicking phantoms under MR temperature monitoring at 3 T (GE Discovery MR750W). Results: Acoustic intensities considered during simulation were limited to ensure mild hyperthermia (T max < 45• C) and fail-safe operation of the ExAblate array (spatial and time averaged acoustic intensity I SATA < 3.4 W/cm 2 ). Tissue volumes with therapeutic temperature levels (T > 41 • C) were estimated. Numerical simulations indicated that T > 41• C was calculated in 13-23 cm 3 volumes for sonications with planar or diverging beam patterns at 0.9-1.2 W/cm 2 , in 4.5-5.8 cm 3 volumes for simultaneous multipoint focus beam patterns at ∼0.7 W/cm 2 , and in ∼6.0 cm 3 for curvilinear (cylindrical) beam patterns at 0.75 W/cm 2 . Focused heating patterns may be practical for treating focal disease in a single posterior quadrant of the prostate and diffused heating patterns may be useful for heating quadrants, hemigland volumes or even bilateral targets. Treatable volumes may be limited by pubic bone heating. Therapeutic temperatures were estimated for a range of physiological parameters, sonication duty cycles and rectal cooling. Hyperthermia specific phasing patterns were implemented on the ExAblate prostate array and continuous-wave sonications (∼0.88 W/cm 2 , 15 min) were performed in tissue-mimicking material with real-time MR-based temperature imaging (PRFS imaging at 3.0 T). Shapes of heating patterns observed during experiments were consistent with simulations. Conclusions: The ExAblate 2100, designed specifically for thermal ablation, can be controlled for delivering continuous hyperthermia in prostate while working within operational constraints.

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Improving locoregional hyperthermia delivery using the 3-D controlled AMC-8 phased array hyperthermia system: A preclinical study

Abstract: The AMC-8 system is capable of 3-D SAR control and its SAR distribution is more favourable than for the 2-D AMC-4 system. This result promises improvement in clinical tumour temperatures.

Cited by 302 publications

References 51 publications

Planning, optimisation and evaluation of hyperthermia treatments

Planning, optimisation and evaluation of hyperthermia treatments

A Computational Study Using Time Reversal Focusing for Hyperthermia Treatment Planning

Model‐based feasibility assessment and evaluation of prostate hyperthermia with a commercial MR‐guided endorectal HIFU ablation array

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