Clinical evaluation and verification of the hyperthermia treatment planning system hyperplan

Gellermann, Johanna; Wust, Peter; Stalling, Detlev; Seebass, M.; Nadobny, Jacek; Beck, Rudolf; Hege, Hans-Christian; Deuflhard, Peter; Félix, R.

doi:10.1016/s0360-3016(00)00425-9

Cited by 98 publications

(71 citation statements)

References 25 publications

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“…24,25 This objective function was designed to drive the target (bladder content) temperatures above 43 C and to restrict normal tissue temperatures below 42 C. The free variables were the amplitudes (A 1 ; A 2 ; A 3 ; A 4 ) and phases (u 1 ; u 2 ; u 3 ; u 4 ) for the four antenna pairs of the applicator. Additional temperature constraints on the maximal allowable temperature in a specified tissue were also imposed: 44 C for all tissue, except 45 C for bladder.…”

Section: Iic Assessment Of Treatment Planning Utility In Nonmuscle mentioning

confidence: 99%

“…Sigma-HyperPlan is a commercial software product used for hyperthermia treatment planning [24][25][26] built on the modular platform Amira (Visage Image, Inc., San Diego, CA, USA), which includes algorithms for medical image processing, geometric modeling, and graphic display. The calculation engine in Sigma-Hyperplan uses finite element (FE) or finitedifference time-domain (FDTD) methods to solve Maxwell's equations on tetrahedral grids generated from segmented tissues on CT or MR image data.…”

Section: Iib Retrospective Treatment Planningmentioning

confidence: 99%

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Utility of treatment planning for thermochemotherapy treatment of nonmuscle invasive bladder carcinoma

et al. 2012

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Purpose: A recently completed Phase I clinical trial combined concurrent Mitomycin-C chemotherapy with deep regional heating using BSD-2000 Sigma-Ellipse applicator (BSD Corporation, Salt Lake City, UT, U.S.A.) for the treatment of nonmuscle invasive bladder cancer. This work presents a new treatment planning approach, and demonstrates potential impact of this approach on improvement of treatment quality. Methods: This study retrospectively analyzes a subset of five patients on the trial. For each treatment, expert operators selected "clinical-optimal" settings based on simple model calculation on the BSD-2000 control console. Computed tomography (CT) scans acquired prior to treatment were segmented to create finite element patient models for retrospective simulations with SigmaHyperPlan (Dr. Sennewald Medizintechnik GmbH, Munchen, Germany). Since Sigma-HyperPlan does not account for the convective nature of heat transfer within a fluid filled bladder, an effective thermal conductivity for bladder was introduced. This effective thermal conductivity value was determined by comparing simulation results with clinical measurements of bladder and rectum temperatures. Regions of predicted high temperature in normal tissues were compared with patient complaints during treatment. Treatment results using "computed-optimal" settings from the planning system were compared with clinical results using clinical-optimal settings to evaluate potential of treatment improvement by reducing hot spot volume. Results: For all five patients, retrospective treatment planning indicated improved matches between simulated and measured bladder temperatures with increasing effective thermal conductivity. The differences were mostly within 1.3 C when using an effective thermal conductivity value above 10 W/K/m. Changes in effective bladder thermal conductivity affected surrounding normal tissues within a distance of $1.5 cm from the bladder wall. Rectal temperature differences between simulation and measurement were large due to sensitivity to the sampling locations in rectum. The predicted bladder T90 correlated well with single-point bladder temperature measurement. Hot spot locations predicted by the simulation agreed qualitatively with patient complaints during treatment. Furthermore, comparison between the temperature distributions with clinical and computedoptimal settings demonstrated that the computed-optimal settings resulted in substantially reduced hot spot volumes. Conclusions: Determination of an effective thermal conductivity value for fluid filled bladder was essential for matching simulation and treatment temperatures. Prospectively planning patients using the effective thermal conductivity determined in this work can potentially improve treatment efficacy (compared to manual operator adjustments) by potentially lower discomfort from reduced hot spots in normal tissue.

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Section: Iic Assessment Of Treatment Planning Utility In Nonmuscle mentioning

confidence: 99%

Section: Iib Retrospective Treatment Planningmentioning

confidence: 99%

Utility of treatment planning for thermochemotherapy treatment of nonmuscle invasive bladder carcinoma

et al. 2012

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“…The side effects of AMF can include non-specific heating outside the target volume due to the magnetic induction of current density called eddy currents (EC) [30]. More problematic is the case of radiofrequencies [31], for which adverse excitation of neurons can be easily triggered by induced electric fields. Heat produced by EC, scaled as:…”

Section: Discussionmentioning

confidence: 99%

Local moderate magnetically induced hyperthermia using an implant formed in situ in a mouse tumor model

Renard

Buchegger

Petri‐Fink

et al. 2009

International Journal of Hyperthermia

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Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Methods: We evaluated heating and treatment efficacies by means of thermometry and survival studies in nude mice carrying subcutaneous human colocarcinomas. At day 1, we injected the formulation into the tumor. At day 2, a single 20-min hyperthermia treatment was delivered by 141-kHz magnetic induction using field strengths of 9 to 12 mT under thermometry.Results: SPIONs embedded in silica microbeads were effectively confined within the implant at the injection site. Heat-induced necro-apoptosis was assessed by histology on day 3. On average, 12 mT resulted in tumor temperature of 47.8 C, and over 70% tumor necrosis that correlated to the heat dose (AUC ¼ 282 CÁmin). In contrast, a 9-mT field strength induced tumoral temperature of 40 C (AUC ¼ 131 CÁmin) without morphologically identifiable necrosis. Survival after treatment with 10.5 or 12 mT fields was significantly improved compared to non-implanted and implanted controls. Median survival times were 27 and 37 days versus 12 and 21 days respectively. Conclusion: Five of eleven mice (45%) of the 12 mT group survived one year without any tumor recurrence, holding promise for tumor therapy using magnetically induced moderate hyperthermia through injectable implants.

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“…In an attempt to obtain reasonable values of these inputs, sophisticated treatment planning forms an important part of the clinical implementation of regional electromagnetic hyperthermia (21)(22)(23)(24)(25)(26)(27)(28). Typically, a large multislice computed tomography (CT) data set is acquired to visualize different anatomical structures within the patient.…”

Section: Introductionmentioning

confidence: 99%

MRI‐monitored electromagnetic heating using iterative feedback control and phase interference mapping

Behnia

Webb

2004

Concepts Magn Reson

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Noninvasive electromagnetic hyperthermia, used in combination with radiotherapy or chemotherapy, is a promising technique in the treatment of large, deep-lying tumours. One of the major difficulties in effective implementation, however, is that the spatial distribution of electric fields within the patient is strongly influenced by tissue morphology and dielectric properties, and is therefore difficult to model. Even when desired heating profiles are achieved experimentally, the specific absorption rate at the focus generally does not reach its theoretical maximum value since the E-fields are not completely coherent. In this article, a new method, phase interference mapping, is developed to address this latter problem and is demonstrated in phantoms. The complete process for optimizing spatial and temporal control of electromagnetic heating has three separate steps. The first involves phase calibration of the individual dipoles of a phased array applicator with a noninvasive E-field probe placed on the surface of the phantom. In the second step, an iterative feedback method is used to rapidly steer the thermal focus as close as possible to the desired location. Noninvasive mapping of the temperature and specific absorption rate is realized by magnetic resonance imaging. The final step in the process consists of phase interference mapping of the dipoles, to maximize E-field coherence. Temporal control of the temperature rise or specific absorption rate can then be performed.

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Clinical evaluation and verification of the hyperthermia treatment planning system hyperplan

Cited by 98 publications

References 25 publications

Utility of treatment planning for thermochemotherapy treatment of nonmuscle invasive bladder carcinoma

Utility of treatment planning for thermochemotherapy treatment of nonmuscle invasive bladder carcinoma

Local moderate magnetically induced hyperthermia using an implant formed in situ in a mouse tumor model

MRI‐monitored electromagnetic heating using iterative feedback control and phase interference mapping

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