Purpose In 2014, we published the qPET method to quantify fluorodeoxyglucose positron emission tomography (FDG‐PET) responses. Analysis of the distribution of the quantified signals suggested that a clearly abnormal FDG‐PET response corresponds to a visual Deauville score (vDS) of 5 and high qPET values ≥ 2. Evaluation in long‐term outcome data is still pending. Therefore, we analyzed progression‐free survival (PFS) by early FDG‐PET response in a subset of the GPOH‐HD2002 trial for pediatric Hodgkin lymphoma (PHL). Patients/Methods Pairwise FDG‐PET scans for initial staging and early response assessment after two cycles of chemotherapy were available in 93 PHL patients. vDS and qPET measurement were performed and related to PFS. Results Patients with a qPET value ≥ 2.0 or vDS of 5 had 5‐year PFS rates of 44%, respectively 50%. Those with qPET values < 2.0 or vDS 1 to 4 had 5‐year PFS rates of 90%, respectively 80%. The positive predictive value of FDG‐PET response assessment increased from 18% (9%; 33%) using a qPET threshold of 0.95 (vDS ≤ 3) to 30% (13%; 54%) for a qPET threshold of 1.3 (vDS ≤ 4) and to 56% (23%; 85%) when the qPET threshold was ≥ 2.0 (vDS 5). The negative predictive values remained stable at ≥92% (CI: 82%; 98%). Conclusion Only strongly enhanced residual FDG uptake in early response PET (vDS 5 or qPET ≥ 2, respectively) seems to be markedly prognostic in PHL when treatment according to the GPOH‐HD‐2002 protocol is given.

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The paper presents a simulation of the transient temperature distribution in the human body caused by induced eddy currents during magnetic resonance imaging (MRI). In a first simulation the validity of the used heat conduction equation was proven using a simple example of a cool-down-process of a sphere. Thereafter the heating of a phantom model with an implanted electrode placed in a MRI-System (active body coil) was examined. The resulting increase in temperature was compared with existing measurements. Finally the implications of the heating of the tissue are discussed based on the observed experimental and numerical results.

Patients having a heart pacemaker are not allowed to go to MR tomography (MRT). One of the most dangerous effects is the heating of the tissue around the electrode caused by the coupling to the RF field of the MR system. Experiments have been carried out using tanks filled with saline water and large heating has sometimes been observed. Other experiments e.g. with electrodes in the brain did not show any heating at all. In this work numerical studies have been carried out to understand the different results. In conclusion it is suggested that MRT could be possible if the "normal" geometry of the wires of a heart pacemaker is ensured and an open MR system is used.

The measurement of the dielectric properties of biological tissue is of increasing scientific relevance. Models for the comprehension of the dielectric properties at various frequencies have been successfully set up. However, students often have problems in understanding the effects taking place on cellular level which lead to the observed dispersion. A numerical model of a biological tissue brick composed of single cells (micron-dimensions) between two plate electrodes is presented in this study. An electrical current in a range of 1 Hz to 3 GHz was applied to the electrodes and hence to the tissue model. Using an equivalent series circuit of a resistor and a capacitor it is possible to calculate the effective equivalent dielectric properties of the whole tissue model. The results show an increasing conductivity and decreasing permittivity with increasing frequency. This corresponds to experimental results obtained with different biological tissues.