18 research outputs found
Regional deep hyperthermia: quantitative evaluation of predicted and direct measured temperature distributions in patients with high-risk extremity soft-tissue sarcoma
Background: Temperature distributions resulting from hyperthermia treatment of patients with high-risk soft-tissue sarcoma (STS) were quantitatively evaluated and globally compared with thermal simulations performed by a treatment planning system. The aim was to test whether the treatment planning system was able to predict correct temperature distributions.
Methods: Five patients underwent computed tomography (CT) fluoroscopy-guided placement of tumor catheters used for the interstitial temperature measurements. For the simulations, five 3 D patient models were reconstructed by segmenting the patient CT datasets into different tissues. The measured and simulated data were evaluated by calculating the temperature change (ΔT), T90, T50, T20, Tmean, Tmin and Tmax, as well as the 90th percentile thermal dose (CEM43T90). In order to measure the agreement between both methods quantitatively, the Bland–Altman analysis was applied.
Results: The absolute difference between measured and simulated temperatures were found to be 2°, 6°, 1°, 4°, 5° and 4 °C on average for Tmin, Tmax, T90, T50, T20 and Tmean, respectively. Furthermore, the thermal simulations exhibited relatively higher thermal dose compared to those that were measured. Finally, the results of the Bland–Altman analysis showed that the mean difference between both methods was above 2 °C which is considered to be clinically unacceptable.
Conclusion: Given the current practical limitations on resolution of calculation grid, tissue properties, and perfusion information, the software SigmaHyperPlan™ is incapable to produce thermal simulations with sufficient correlation to typically heterogeneous tissue temperatures to be useful for clinical treatment planning
Scattering of a two-soliton molecule by Gaussian potential barriers and wells
Two anti-phase bright solitons in a dipolar Bose-Einstein condensate can form
stable bound states, known as soliton molecules. In this paper we study the scattering of a twosoliton
molecule by external potential, using the simplest and analytically tractable Gaussian
potential barriers and wells, in one spatial dimension. Theoretical model is based on the
variational approximation for the nonlocal Gross-Pitaevskii equation (GPE). At sufficiently
low velocity of the incident molecule we observe quantum reflection from the potential well.
Predictions of the mathematical model are compared with numerical simulations of the GPE,
and good qualitative agreement between them is demonstrated
Quantitative, Multi-institutional Evaluation of MR Thermometry Accuracy for Deep-Pelvic MR-Hyperthermia Systems Operating in Multi-vendor MR-systems Using a New Anthropomorphic Phantom
Clinical outcome of hyperthermia depends on the achieved target temperature, therefore
target conformal heating is essential. Currently, invasive temperature probe measurements are the
gold standard for temperature monitoring, however, they only provide limited sparse data. In contrast,
magnetic resonance thermometry (MRT) provides unique capabilities to non-invasively measure
the 3D-temperature. This study investigates MRT accuracy for MR-hyperthermia hybrid systems
located at five European institutions while heating a centric or eccentric target in anthropomorphic
phantoms with pelvic and spine structures. Scatter plots, root mean square error (RMSE) and
Bland–Altman analysis were used to quantify accuracy of MRT compared to high resistance thermistor
probe measurements. For all institutions, a linear relation between MRT and thermistor probes
measurements was found with R
2
(mean ± standard deviation) of 0.97 ± 0.03 and 0.97 ± 0.02,
respectively for centric and eccentric heating targets. The RMSE was found to be 0.52 ± 0.31 ◦C and
0.30 ± 0.20 ◦C, respectively. The Bland-Altman evaluation showed a mean difference of 0.46 ± 0.20 ◦C
and 0.13 ± 0.08 ◦C, respectively. This first multi-institutional evaluation of MR-hyperthermia hybrid
systems indicates comparable device performance and good agreement between MRT and thermistor
probes measurements. This forms the basis to standardize treatments in multi-institution studies of
MR-guided hyperthermia and to elucidate thermal dose-effect relations
A multi-institution study: comparison of the heating patterns of five different MR-guided deep hyperthermia systems using an anthropomorphic phantom
Introduction
Within the hyperthermia community, consensus exists that clinical outcome of the treatment radiotherapy and/or chemotherapy plus hyperthermia (i.e. elevating tumor temperature to 40 − 44 °C) is related to the applied thermal dose; hence, treatment quality is crucial for the success of prospective multi-institution clinical trials. Currently, applicator quality assurance (QA) measurements are implemented independently at each institution using basic cylindrical phantoms. A multi-institution comparison of heating quality using magnetic resonance thermometry (MRT) and anatomical representative anthropomorphic phantoms provides a unique opportunity to obtain novel QA insights to f
Inducing intravesical hyperthermia of the ex-vivo porcine bladder wall: radiofrequency-induction versus recirculation using a custom-made device.
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Regional deep hyperthermia: quantitative evaluation of predicted and direct measured temperature distributions in patients with high-risk extremity soft-tissue sarcoma
Inducing intravesical hyperthermia of the ex-vivo porcine bladder wall: radiofrequency-induction versus recirculation using a custom-made device
Quantitative, Multi-institutional Evaluation of MR Thermometry Accuracy for Deep-Pelvic MR-Hyperthermia Systems Operating in Multi-vendor MR-systems Using a New Anthropomorphic Phantom
FGF21 suppresses alcohol consumption through an amygdalo-striatal circuit
Excessive alcohol consumption is a major health and social issue in our society. Pharmacologic administration of the endocrine hormone fibroblast growth factor 21 (FGF21) suppresses alcohol consumption through actions in the brain in rodents, and genome wide association studies have identified single nucleotide polymorphisms in genes involved with FGF21 signaling as being associated with increased alcohol consumption in humans. However, the neural circuit(s) through which FGF21 signals to suppress alcohol consumption are unknown, as are its effects on alcohol consumption in higher organisms. Here, we demonstrate that administration of an FGF21 analogue to alcohol-preferring non-human primates reduces alcohol intake by 50%. Further, we reveal that FGF21 suppresses alcohol consumption through a projection-specific sub-population of KLB-expressing neurons in the basolateral amygdala. Our results illustrate how FGF21 suppresses alcohol consumption through a specific population of neurons in the brain and demonstrate its therapeutic potential in non-human primate models of excessive alcohol consumption