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4. Experimental digital SQUID with integrated feedback circuit

Author

Fath, U., Hundhausen, R., Fregin, T., Gerigk, P., Eschner, W., Schindler, A., and Uhlmann, F.H.

Subjects
Superconducting quantum interference devices -- Research, Feedback (Electronics) -- Research, Integrated circuits -- Research, Business, Electronics, Electronics and electrical industries
Abstract

A digital superconducting quantum interference device (SQUID) with integrated feedback circuit was developed and tested. A latching comparator and a write gate were used to implement the basic architecture of a delta modulator analog-to-digital converter with coarse quantization. Design and experimental verification was conducted through numerical simulations. Models were also developed for estimating the feedback loop arrangement's noise and linearity.

Published
1997

7. Magnetic field sensors with digital feedback read-out

Author

Eschner, W., Fath, U., Hofer, G., Hundhausen, R., Kratz, H., Ludwig, W., Rothmund, W., and Wulker, M.

Subjects
Superconducting quantum interference devices -- Usage, Interferometers -- Innovations, Magnetic fields -- Measurement, Business, Electronics, Electronics and electrical industries
Abstract

The performance of several magnetic field sensors equipped with digital superconducting quantum interference device (SQUID) feedback read-out was evaluated. The interferometers, which were designed with different configurations, were taken in a magnetically shielded room for the experimental measurements. Results indicate that the digital read-out SQUID devices are less sensitive to the effects of resonance than a conventional direct current SQUID.

Published
1993

10. Direct comparison of spatially normalized PET and SPECT scans in Alzheimer's disease

Author

Herholz, K., Schopphoff, H., Schmidt, M., Mielke, R., Eschner, W., Scheidhauer, K., Schicha, H., Heiss, W. -D, and Klaus Ebmeier

Abstract

UNLABELLED: Hexamethylpropyleneamine oxime (HMPAO) SPECT and 18F-FDG PET depict similar aspects of perfusion and metabolic abnormalities in Alzheimer's disease (AD), but the correspondence between them is not known in detail. We therefore used statistical parametric mapping to detect and compare abnormal brain areas objectively and quantitatively. METHODS: Twenty-six patients with probable AD (mean age +/- SD, 66 +/- 9 y; mean Mini-Mental State Examination score, 22.5 +/- 4.2) and 6 nondemented healthy volunteers (mean age, 63 +/- 11 y) were studied with HMPAO SPECT and 18F-FDG PET. All images underwent the same processing steps, including 12-mm gaussian smoothing, spatial normalization, and z transformation with respect to normal average and SD. Thresholding of z maps was used to detect abnormal voxels. RESULTS: The overall correlation between PET and SPECT across the entire brain was significant but not close (average r = 0.43). The best correspondence was found in the temporoparietal and posterior cingulate association cortices. There, the number of abnormal voxels for PET correlated strongly with the number for SPECT (r = 0.90 at a z threshold of -2.25), but tracer uptake reductions were significantly more pronounced for PET than for SPECT. Discordant findings were most frequently seen in the temporobasal and orbitofrontal areas (PET low, SPECT high) and in the cerebellum, parahippocampal cortex, and midcingulate cortex (PET high, SPECT low). The correlation between dementia severity and the number of abnormal voxels was closer for PET than for SPECT. Separation of patients from healthy volunteers by counting the number of abnormal voxels was possible over a much wider range of z thresholds with PET than with SPECT. CONCLUSION: Correspondence between 18F-FDG PET and HMPAO SPECT is limited to the main finding of temporoparietal and posterior cingulate functional impairment in mild to moderate AD. The distinction between healthy volunteers and patients is less sensitive to threshold selection with PET than with SPECT, and findings in the frontal, temporobasal, and temporomesial cortices and in the cerebellum may differ between the 2 techniques.

Published
2016

13. FDG PET/CT: EANM procedure guidelines for tumour imaging: version 2.0

Author

Boellaard, R., Delgado-Bolton, R., Oyen, W.J.G., Giammarile, F., Tatsch, K., Eschner, W., Verzijlbergen, F.J., Barrington, S.F., Pike, L.C., Weber, W.A., Stroobants, S., Delbeke, D., Donohoe, K.J., Holbrook, S., Graham, M.M., Testanera, G., Hoekstra, O.S., Zijlstra, J., Visser, E., Hoekstra, C.J., Pruim, J., Willemsen, A., Arends, B., Kotzerke, J.o., ,rg, Bockisch, A., Beyer, T., Chiti, A., Krause, B.J., Boellaard, R., Delgado-Bolton, R., Oyen, W.J.G., Giammarile, F., Tatsch, K., Eschner, W., Verzijlbergen, F.J., Barrington, S.F., Pike, L.C., Weber, W.A., Stroobants, S., Delbeke, D., Donohoe, K.J., Holbrook, S., Graham, M.M., Testanera, G., Hoekstra, O.S., Zijlstra, J., Visser, E., Hoekstra, C.J., Pruim, J., Willemsen, A., Arends, B., Kotzerke, J.o., ,rg, Bockisch, A., Beyer, T., Chiti, A., and Krause, B.J.

Abstract

Item does not contain fulltext, The purpose of these guidelines is to assist physicians in recommending, performing, interpreting and reporting the results of FDG PET/CT for oncological imaging of adult patients. PET is a quantitative imaging technique and therefore requires a common quality control (QC)/quality assurance (QA) procedure to maintain the accuracy and precision of quantitation. Repeatability and reproducibility are two essential requirements for any quantitative measurement and/or imaging biomarker. Repeatability relates to the uncertainty in obtaining the same result in the same patient when he or she is examined more than once on the same system. However, imaging biomarkers should also have adequate reproducibility, i.e. the ability to yield the same result in the same patient when that patient would have been examined on different systems and at different imaging sites. Adequate repeatability and reproducibility are essential for the clinical management of patients and the use of FDG PET/CT within multicentre trials. A common standardized imaging procedure will help promote the appropriate use of FDG PET/CT imaging and increase the value of publications and, therefore, their contribution to evidence-based medicine. Moreover, consistency in numerical values between platforms and institutes that acquire the data will potentially enhance the role of semiquantitative and quantitative image interpretation. Precision and accuracy are additionally important as FDG PET/CT is used to evaluate tumour response as well as for diagnosis, prognosis and staging. Therefore both the previous and these new guidelines specifically aim to achieve standardized uptake value harmonization in multicentre settings.

Published
2015

24. 99mTc-MIBI SPECT in primary hyperparathyroidism

Author

Thoma, N., primary, Dietlein, M., primary, Moka, D., primary, Eschner, W., primary, Faust, M., primary, Schröder, W., primary, von Hülst-Schlabrendorff, M., primary, Ehses, W., primary, Schicha, H., primary, and Schmidt, M., additional

Published
2008
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43. Recombinant Human TSH Increases Uptake and Eff ective Half-life of Radioiodine in Thyroid Hormone Secreting Metastases of Follicular Thyroid Cancer.

Author

Schneider, C., Dietlein, M., Eschner, W., Schmidt, M., Kahraman, D., and Kobe, C.

Subjects
THYROID cancer treatment, THYROTROPIN, IODINE isotopes, THYROID hormones, SECRETION, METASTASIS, ESTRONE
Abstract

Follicular thyroid cancer with thyroid hormone secreting metastases is an extremely rare condition, with only a few cases reported world-wide. We here present the case of a 64-year-old female patient aff ected by follicular thyroid cancer with extensive thyroid hormone secreting metastases leading to TSH-suppression. We have also summarized the relevant diagnostic and therapeutic approaches and describe, for the fi rst time, the eff ects of rhTSH-application in this rare tumor entity. We have also summarized the relevant diagnostic and therapeutic approaches and describe, for the fi rst time, the eff ects of rhTSH-application in this rare tumor entity. In this patient, we found that rhTSH increased 131 I-uptake into the thyroid hormone secreting metastases and prolonged the eff ective half-life of 131 I. These eff ects of rhTSH should be considered when fi xed activities of 131 I are prescribed. [ABSTRACT FROM AUTHOR]

Published
2012
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46. The decay of the new isotopeYb and the search for the r-Process path toTa.

Author

Runte, E., Schmidt-Ott, W., Eschner, W., Rosner, I., Kirchner, R., Klepper, O., and Rykaczewski, K.

Abstract

IrradiatingW/Ta targets withW, the decay of the new isotopeYb was observed and its half-life determined to be 2.4(5) min. Based on the measured β-, γ- and X-ray data, the r-process production ofTa and the role of a possible isomerLu in this context are discussed. [ABSTRACT FROM AUTHOR]

Published
1987
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47. Measurement of the β-decay branch inLu toHf for Investigation of the r-process nucleosynthesis ofTa.

Author

Eschner, W., Schmidt-Ott, W., Gippert, K., Runte, E., Beer, H., Walter, G., Kirchner, R., Klepper, O., Roeckl, E., and Schardt, D.

Abstract

The β-decay branch ofLu toHf is measured by an integral method tracing the amount ofHf daughter activity, to be 0.46 (15)%. Samples ofLu are prepared by on-line mass separation ofXe-on-tungsten transfer reaction products. The amount of isobaricHf in the samples is strongly suppressed by the employed separator ion source; its directly produced fraction is derived from comparison withHf activity. The properties of lutetium and hafnium release from the ion source are separately determined. With this measurement r-process nucleosynthesis is estimated to account for at most 22% of the solarTa abundance. [ABSTRACT FROM AUTHOR]

Published
1984
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