Publications by authors named "Lilli Geworski"

38 Publications

Prenatal radiation exposure in diagnostic and interventional radiology.

Rofo 2020 Dec 16. Epub 2020 Dec 16.

Clinic for Radiooncology and Radiotherapy; Department Medical Radiological Physics, Hospital Carl-Thiem-Klinikum Cottbus gGmbH, Cottbus, Germany.

Background:  The exposure of a pregnant woman to X-rays is an event that can cause uncertainty for all concerned. This review provides guidance on how to assess such a situation and how to determine the dose to the unborn child. In general, the use of X-rays in pregnant women in radiology should be avoided. If possible, alternatives should be used, or examinations postponed to a time after the pregnancy. This review gives a summary of the procedure for determining the radiation exposure of a pregnant woman.

Method:  Based on the previous report of 2002 and the literature on prenatal radiation exposure published thereafter, the DGMP/DRG report on the procedure for the assessment of prenatal radiation exposure was adapted to the current state of science and technology.

Results:  Typically, only relatively low radiation exposures of less than 20 mSv occur for the unborn child in X-ray diagnostics in the vast majority of cases. At these dose level the additional risk of damage to the embryo or fetus caused by the radiation is low and therefore only a rough conservative estimate using tabulated values are made. Only in a few types of examination (CT and interventional radiology) higher doses values might occur in the uterus. Instead of dose estimates (step 1 in the two-step model) in these cases the calculation of dose (step 2) are required and further action by the physician may be necessary.

Conclusions:  During the assessment, it is useful to initially use simple conservative estimation procedures to quickly determine whether a case falls into this large group less than 20 mSv, where there is a very low risk to the unborn child. If this is the case, the pregnant woman should be informed immediately by the doctor who performed the examination/treatment. This avoids a psychological burden on the patient. The DGMP/DRG report suggests a relatively simple, clearly structured procedure with advantages for all parties involved (physician, medical physics experts, MTRA and patient).

Key Points:   · The DGMP/DRG report on prenatal radiation exposure describes the procedure for calculating radiation exposures and the associated risks for the unborn child.. · Using the two-step model, only a simple assessment based on the first step is necessary for most prenatal radiation exposures.. · With the given tables it is possible to estimate individual risks for the unborn child taking into account the radiation exposure.. · Only in the rare case that the first estimate results in a uterine dose larger 20 mSv a more accurate calculation is necessary..

Citation Format: · Fiebich M, Block A, Borowski M et al. Prenatal radiation exposure in diagnostic and interventional radiology. Fortschr Röntgenstr 2020; DOI: 10.1055/a-1313-7527.
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http://dx.doi.org/10.1055/a-1313-7527DOI Listing
December 2020

Assessment of the radiation exposure of relatives and caregivers of patients treated with Ra-223 - Results of a German multicenter study.

Z Med Phys 2021 Feb 10;31(1):58-64. Epub 2020 Dec 10.

Department for Radiation Protection and Medical Physics, Hannover Medical School, Hannover, Germany.

A multicenter study was conducted to assess the radiation exposure of relatives and caregivers of patients suffering from castration resistant prostate cancer with bone metastases and treated with Ra-223 dichloride in an outpatient setting. As Ra-223 and most of its progeny emit alpha particles, especially the internal exposure of persons in the patient's vicinity had to be evaluated.

Methods: The external radiation was measured in distances of 1 m and 2 m. Wipe-tests were taken in the patients' homes to identify significant contaminations and evaluated by liquid scintillation counting. Samples of saliva and sweat were taken and measured using gamma spectrometry.

Results: The external exposure from the patients measured 10-20min post injection (p. i.) was<0.080μSv/h in median in 1 m distance (range: below decision threshold (
Conclusions: The potential exposure of relatives by external irradiation and incorporation of Ra-223 excreted by the patient with saliva or sweat is estimated to be well below 1 mSv. No objections are seen regarding outpatient treatment.
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http://dx.doi.org/10.1016/j.zemedi.2020.09.002DOI Listing
February 2021

Combined Brain-Perfusion SPECT and EEG Measurements Suggest Distinct Strategies for Speech Comprehension in CI Users With Higher and Lower Performance.

Front Neurosci 2020 11;14:787. Epub 2020 Aug 11.

Department of Nuclear Medicine, Hannover Medical School, Hanover, Germany.

Cochlear implantation constitutes a successful therapy of inner ear deafness, with the majority of patients showing good outcomes. There is, however, still some unexplained variability in outcomes with a number of cochlear-implant (CI) users, showing major limitations in speech comprehension. The current study used a multimodal diagnostic approach combining single-photon emission computed tomography (SPECT) and electroencephalography (EEG) to examine the mechanisms underlying speech processing in postlingually deafened CI users ( = 21). In one session, the participants performed a speech discrimination task, during which a 96-channel EEG was recorded and the perfusions marker Tc-HMPAO was injected intravenously. The SPECT scan was acquired 1.5 h after injection to measure the cortical activity during the speech task. The second session included a SPECT scan after injection without stimulation at rest. Analysis of EEG and SPECT data showed N400 and P600 event-related potentials (ERPs) particularly evoked by semantic violations in the sentences, and enhanced perfusion in a temporo-frontal network during task compared to rest, involving the auditory cortex bilaterally and Broca's area. Moreover, higher performance in testing for word recognition and verbal intelligence strongly correlated to the activation in this network during the speech task. However, comparing CI users with lower and higher speech intelligibility [median split with cutoff + 7.6 dB signal-to-noise ratio (SNR) in the Göttinger sentence test] revealed for CI users with higher performance additional activations of parietal and occipital regions and for those with lower performance stronger activation of superior frontal areas. Furthermore, SPECT activity was tightly coupled with EEG and cognitive abilities, as indicated by correlations between (1) cortical activation and the amplitudes in EEG, N400 (temporal and occipital areas)/P600 (parietal and occipital areas) and (2) between cortical activation in left-sided temporal and bilateral occipital/parietal areas and working memory capacity. These results suggest the recruitment of a temporo-frontal network in CI users during speech processing and a close connection between ERP effects and cortical activation in CI users. The observed differences in speech-evoked cortical activation patterns for CI users with higher and lower speech intelligibility suggest distinct processing strategies during speech rehabilitation with CI.
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http://dx.doi.org/10.3389/fnins.2020.00787DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7431776PMC
August 2020

Interim PET Evaluation in Diffuse Large B-Cell Lymphoma Using Published Recommendations: Comparison of the Deauville 5-Point Scale and the ΔSUV Method.

J Nucl Med 2021 Jan 8;62(1):37-42. Epub 2020 May 8.

Klinik für Hämatologie, Universitätsklinikum, Essen, Germany.

The value of interim F-FDG PET/CT (iPET)-guided treatment decisions in patients with diffuse large B-cell lymphoma (DLBCL) has been the subject of much debate. This investigation focuses on a comparison of the Deauville score and the change-in-SUV (ΔSUV) approach-2 methods to assess early metabolic response to standard chemotherapy in DLBCL. Of 609 DLBCL patients participating in the PET-Guided Therapy of Aggressive Non-Hodgkin Lymphomas trial, iPET scans of 596 patients originally evaluated using the ΔSUV method were available for post hoc assessment of the Deauville score. A commonly used definition of an unfavorable iPET result according to the Deauville score is an uptake greater than that of the liver, whereas an unfavorable iPET scan with regard to the ΔSUV approach is characterized as a relative reduction of the SUV between baseline and iPET staging of less than or equal to 66%. We investigated the 2 methods' correlation and concordance by Spearman rank correlation coefficient and the agreement in classification, respectively. We further used Kaplan-Meier curves and Cox regression to assess differences in survival between patient subgroups defined by the prespecified cutoffs. Time-dependent receiver-operating-characteristic curve analysis provided information on the methods' respective discrimination performance. Deauville score and ΔSUV approach differed in their iPET-based prognosis. The ΔSUV approach outperformed the Deauville score in terms of discrimination performance-most likely because of a high number of false-positive decisions by the Deauville score. Cutoff-independent discrimination performance remained low for both methods, but cutoff-related analyses showed promising results. Both favored the ΔSUV approach, for example, for the segregation by iPET response, where the event-free survival hazard ratio was 3.14 (95% confidence interval, 2.22-4.46) for ΔSUV and 1.70 (95% confidence interval, 1.29-2.24) for the Deauville score. When considering treatment intensification, the currently used Deauville score cutoff of an uptake above that of the liver seems to be inappropriate and associated with potential harm for DLBCL patients. The ΔSUV criterion of a relative reduction in SUV of less than or equal to 66% should be considered as an alternative.
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http://dx.doi.org/10.2967/jnumed.120.244145DOI Listing
January 2021

Reliable quantification of F-GE-180 PET neuroinflammation studies using an individually scaled population-based input function or late tissue-to-blood ratio.

Eur J Nucl Med Mol Imaging 2020 11 23;47(12):2887-2900. Epub 2020 Apr 23.

Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany.

Purpose: Tracer kinetic modeling of tissue time activity curves and the individual input function based on arterial blood sampling and metabolite correction is the gold standard for quantitative characterization of microglia activation by PET with the translocator protein (TSPO) ligand F-GE-180. This study tested simplified methods for quantification of F-GE-180 PET.

Methods: Dynamic F-GE-180 PET with arterial blood sampling and metabolite correction was performed in five healthy volunteers and 20 liver-transplanted patients. Population-based input function templates were generated by averaging individual input functions normalized to the total area under the input function using a leave-one-out approach. Individual population-based input functions were obtained by scaling the input function template with the individual parent activity concentration of F-GE-180 in arterial plasma in a blood sample drawn at 27.5 min or by the individual administered tracer activity, respectively. The total F-GE-180 distribution volume (V) was estimated in 12 regions-of-interest (ROIs) by the invasive Logan plot using the measured or the population-based input functions. Late ROI-to-whole-blood and ROI-to-cerebellum ratio were also computed.

Results: Correlation with the reference V (with individually measured input function) was very high for V with the population-based input function scaled with the blood sample and for the ROI-to-whole-blood ratio (Pearson correlation coefficient = 0.989 ± 0.006 and 0.970 ± 0.005). The correlation was only moderate for V with the population-based input function scaled with tracer activity dose and for the ROI-to-cerebellum ratio (0.653 ± 0.074 and 0.384 ± 0.177). Reference V, population-based V with scaling by the blood sample, and ROI-to-whole-blood ratio were sensitive to the TSPO gene polymorphism. Population-based V with scaling to the administered tracer activity and the ROI-to-cerebellum ratio failed to detect a polymorphism effect.

Conclusion: These results support the use of a population-based input function scaled with a single blood sample or the ROI-to-whole-blood ratio at a late time point for simplified quantitative analysis of F-GE-180 PET.
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http://dx.doi.org/10.1007/s00259-020-04810-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7651670PMC
November 2020

Measurement of Rn-219 with Alphaguard radon monitors.

Appl Radiat Isot 2019 Sep 1;151:310-316. Epub 2019 Apr 1.

Medizinische Hochschule Hannover, Stabsstelle Strahlenschutz und Abteilung Medizinische Physik - OE 0020, Carl-Neuberg-Str. 1, D-30625, Hannover, Germany.

The alpha-emitting radionuclide Ra-223 is used in nuclear medicine in form of the commercially available radiopharmaceutical "Xofigo". The direct progeny of Ra-223 is Rn-219, a noble gas with a half-life of approx. four seconds, that might be exhaled by patients treated with Ra-223. For assessing the exhalation of Rn-219, a radon monitor calibrated for this isotope is necessary. This work investigates on the response of the commercially available Alphaguard radon monitor to Rn-219 and proposes for the first time a factor for the calculation of the Rn-219-concentration in the instrument's measurement chamber from the instrument reading suitable for estimating patients exhalations.
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http://dx.doi.org/10.1016/j.apradiso.2019.03.041DOI Listing
September 2019

Visualization of the auditory pathway in rats with 18F-FDG PET activation studies based on different auditory stimuli and reference conditions including cochlea ablation.

PLoS One 2018 2;13(10):e0205044. Epub 2018 Oct 2.

Cluster of Excellence Hearing4all, Hannover Medical School, Hannover, Germany.

Activation studies with positron emission tomography (PET) in auditory implant users explained some of the mechanisms underlying the variability of achieved speech comprehension. Since future developments of auditory implants will include studies in rodents, we aimed to inversely translate functional PET imaging to rats. In normal hearing rats, activity in auditory and non-auditory regions was studied using 18F-fluorodeoxyglucose (18F-FDG) PET with 3 different acoustic conditions: sound attenuated laboratory background, continuous white noise and rippled noise. Additionally, bilateral cochlea ablated animals were scanned. 3D image data were transferred into a stereotaxic standard space and evaluated using volume of interest (VOI) analyses and statistical parametric mapping (SPM). In normal hearing rats alongside the auditory pathway consistent activations of the nucleus cochlearis (NC), olivary complex (OC) and inferior colliculus (IC) were seen comparing stimuli with background. In this respect, no increased activation could be detected in the auditory cortex (AC), which even showed deactivation with white noise stimulation. Nevertheless, higher activity in the AC in normal hearing rats was observed for all 3 auditory conditions against the cochlea ablated status. Vice versa, in ablated status activity in the olfactory nucleus (ON) was higher compared to all auditory conditions in normal hearing rats. Our results indicate that activations can be demonstrated in normal hearing animals based on 18F-FDG PET in nuclei along the central auditory pathway with different types of noise stimuli. However, in the AC missing activation with respect to the background advises the need for more rigorous background noise attenuation for non-invasive reference conditions. Finally, our data suggest cross-modal activation of the olfactory system following cochlea ablation-underlining, that 18F-FDG PET appears to be well suited to study plasticity in rat models for cochlear implantation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0205044PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6168174PMC
March 2019

Imaging of chemokine receptor CXCR4 expression in culprit and nonculprit coronary atherosclerotic plaque using motion-corrected [Ga]pentixafor PET/CT.

Eur J Nucl Med Mol Imaging 2018 10 3;45(11):1934-1944. Epub 2018 Jul 3.

Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.

Purpose: The chemokine receptor CXCR4 is a promising target for molecular imaging of CXCR4 cell types, e.g. inflammatory cells, in cardiovascular diseases. We speculated that a specific CXCR4 ligand, [Ga]pentixafor, along with novel techniques for motion correction, would facilitate the in vivo characterization of CXCR4 expression in small culprit and nonculprit coronary atherosclerotic lesions after acute myocardial infarction by motion-corrected targeted PET/CT.

Methods: CXCR4 expression was analysed ex vivo in separately obtained arterial wall specimens. [Ga]Pentixafor PET/CT was performed in 37 patients after stent-based reperfusion for a first acute ST-segment elevation myocardial infarction. List-mode PET data were reconstructed to five different datasets using cardiac and/or respiratory gating. Guided by CT for localization, the PET signals of culprit and various groups of nonculprit coronary lesions were analysed and compared.

Results: Ex vivo, CXCR4 was upregulated in atherosclerotic lesions, and mainly colocalized with CD68 inflammatory cells. In vivo, elevated CXCR4 expression was detected in culprit and nonculprit lesions, and the strongest CXCR4 PET signal (median SUV 1.96; interquartile range, IQR, 1.55-2.31) was observed in culprit coronary artery lesions. Stented nonculprit lesions (median SUV 1.45, IQR 1.23-1.88; P = 0.048) and hot spots in naive remote coronary segments (median SUV 1.34, IQR 1.23-1.74; P = 0.0005) showed significantly lower levels of CXCR4 expression. Dual cardiac/respiratory gating provided the strongest CXCR4 PET signal and the highest lesion detectability.

Conclusion: We demonstrated the basic feasibility of motion-corrected targeted PET/CT imaging of CXCR4 expression in coronary artery lesions, which was triggered by vessel wall inflammation but also by stent-induced injury. This novel methodology may serve as a platform for future diagnostic and therapeutic clinical studies targeting the biology of coronary atherosclerotic plaque.
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http://dx.doi.org/10.1007/s00259-018-4076-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132552PMC
October 2018

Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL): A Multicenter, Randomized Phase III Trial.

J Clin Oncol 2018 07 11;36(20):2024-2034. Epub 2018 May 11.

Ulrich Dührsen, Stefan Müller, Jan Dürig, Johannes Matschke, Christine Schmitz, Thorsten Pöppel, Andreas Bockisch, and Andreas Hüttmann, Universitätsklinikum Essen; Claudia Ose, Marcus Brinkmann, Karl-Heinz Jöckel, André Scherag, and Jan Rekowski, Universität Duisburg-Essen, Essen; Bernd Hertenstein and Henrike Thomssen, Klinikum Bremen Mitte; Christiane Franzius, Zentrum für moderne Diagnostik, Bremen; Jörg Kotzerke and Frank Kroschinsky, Universitätsklinikum Carl Gustav Carus; Gabriele Prange-Krex, Onkologische Gemeinschaftspraxis, Dresden; Rolf Mesters, Wolfgang E. Berdel, and Matthias Weckesser, Universitätsklinikum Münster, Münster; Dorothea Kofahl-Krause, Frank M. Bengel, and Lilli Geworski, Medizinische Hochschule Hannover, Hannover; Paul La Rosée, Martin Freesmeyer, and André Scherag, Universitätsklinikum Jena, Jena; Andreas Hertel and Heinz-Gert Höffkes, Klinikum Fulda, Fulda; Dirk Behringer, Augusta-Kranken-Anstalt, Bochum; Stefan Wilop and Thomas Krohn, Universitätsklinikum Aachen, Aachen; Jens Holzinger and Martin Griesshammer, Johannes Wesling Klinikum, Minden; Aristoteles Giagounidis, Helios St Johannes Klinik, Duisburg; Aruna Raghavachar, Helios Universitätsklinikum, Wuppertal; Georg Maschmeyer and Ingo Brink, Klinikum Ernst von Bergmann, Potsdam; Helga Bernhard, Klinikum Darmstadt, Darmstadt; Uwe Haberkorn, Universitätsklinikum Heidelberg, Heidelberg; Tobias Gaska, Brüderkrankenhaus St Josef, Paderborn; Lars Kurch, Universitätsklinikum Leipzig, Leipzig; Wolfram Klapper, Universitätsklinikum Schleswig-Holstein, Kiel; Dieter Hoelzer, Onkologikum, Frankfurt/Main, Germany; and Daniëlle M.E. van Assema, Vrije Universiteit Medical Center, Amsterdam, the Netherlands.

Purpose Interim positron emission tomography (PET) using the tracer, [F]fluorodeoxyglucose, may predict outcomes in patients with aggressive non-Hodgkin lymphomas. We assessed whether PET can guide therapy in patients who are treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Patients and Methods Newly diagnosed patients received two cycles of CHOP-plus rituximab (R-CHOP) in CD20-positive lymphomas-followed by a PET scan that was evaluated using the ΔSUV method. PET-positive patients were randomly assigned to receive six additional cycles of R-CHOP or six blocks of an intensive Burkitt's lymphoma protocol. PET-negative patients with CD20-positive lymphomas were randomly assigned or allocated to receive four additional cycles of R-CHOP or the same treatment with two additional doses rituximab. The primary end point was event-free survival time as assessed by log-rank test. Results Interim PET was positive in 108 (12.5%) and negative in 754 (87.5%) of 862 patients treated, with statistically significant differences in event-free survival and overall survival. Among PET-positive patients, 52 were randomly assigned to R-CHOP and 56 to the Burkitt protocol, with 2-year event-free survival rates of 42.0% (95% CI, 28.2% to 55.2%) and 31.6% (95% CI, 19.3% to 44.6%), respectively (hazard ratio, 1.501 [95% CI, 0.896 to 2.514]; P = .1229). The Burkitt protocol produced significantly more toxicity. Of 754 PET-negative patients, 255 underwent random assignment (129 to R-CHOP and 126 to R-CHOP with additional rituximab). Event-free survival rates were 76.4% (95% CI, 68.0% to 82.8%) and 73.5% (95% CI, 64.8% to 80.4%), respectively (hazard ratio, 1.048 [95% CI, 0.684 to 1.606]; P = .8305). Outcome prediction by PET was independent of the International Prognostic Index. Results in diffuse large B-cell lymphoma were similar to those in the total group. Conclusion Interim PET predicted survival in patients with aggressive lymphomas treated with R-CHOP. PET-based treatment intensification did not improve outcome.
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http://dx.doi.org/10.1200/JCO.2017.76.8093DOI Listing
July 2018

Feasibility of O-water PET studies of auditory system activation during general anesthesia in children.

EJNMMI Res 2018 Feb 5;8(1):11. Epub 2018 Feb 5.

Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.

Background: O-Water positron emission tomography (PET) enables functional imaging of the auditory system during stimulation via a promontory electrode or cochlear implant, which is not possible using functional magnetic resonance imaging (fMRI). Although PET has been introduced in this context decades ago, its feasibility when performed during general anesthesia has not yet been explored. However, due to a shift to earlier (and bilateral) auditory implantation, the need to study children during general anesthesia appeared, since they are not able to cooperate during scanning. Therefore, we evaluated retrospectively results of individual SPM (statistical parametric mapping) analysis of O-water PET in 17 children studied during general anesthesia and compared them to those in 9 adults studied while awake. Specifically, the influence of scan duration, smoothing filter kernel employed during preprocessing, and cut-off value used for statistical inferences were evaluated. Frequencies, peak heights, and extents of activations in auditory and extra-auditory brain regions (AR and eAR) were registered.

Results: It was possible to demonstrate activations in auditory brain regions during general anesthesia; however, the frequency and markedness of positive findings were dependent on some of the abovementioned influence factors. Scan duration (60 vs. 90 s) had no significant influence on peak height of auditory cortex activations. To achieve a similar frequency and extent of AR activations during general anesthesia compared to waking state, a lower cut-off for statistical inferences (p < 0.05 or p < 0.01 vs. p < 0.001) had to be applied. However, this lower cut-off was frequently associated with unexpected, "artificial" activations in eAR. These activations in eAR could be slightly reduced by the use of a stronger smoothing filter kernel during preprocessing of the data (e.g., [30 mm]).

Conclusions: Our data indicate that it is feasible to detect auditory cortex activations in O-water PET during general anesthesia. Combined with the improved signal to noise ratios of modern PET scanners, this suggests reasonable prospects for further evaluation of the method for clinical use in auditory implant users. Adapted parameters for data analysis seem to be helpful to improve the proportion of signals in AR versus eAR.
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http://dx.doi.org/10.1186/s13550-018-0362-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5799087PMC
February 2018

EANM guideline for radionuclide therapy with radium-223 of metastatic castration-resistant prostate cancer.

Eur J Nucl Med Mol Imaging 2018 05 12;45(5):824-845. Epub 2017 Dec 12.

Institute of Nuclear Medicine and Endocrinology, Kepler University Hospital, Krankenhausstrasse 9, 4020, Linz, Austria.

Radium Ra-223 dichloride (radium-223, Xofigo®) is a targeted alpha therapy approved for the treatment of castration-resistant prostate cancer (CRPC) with symptomatic bone metastases and no known visceral metastatic disease. Radium-223 is the first targeted alpha therapy in this indication providing a new treatment option, with evidence of a significant survival benefit, both in overall survival and in the time to the first symptomatic skeletal-related event. The skeleton is the most common metastatic site in patients with advanced prostate cancer. Bone metastases are a clinically significant cause of morbidity and mortality, often resulting in bone pain, pathologic fracture, or spinal cord compression necessitating treatment. Radium-223 is selectively accumulated in the bone, specifically in areas of high bone turnover, by forming complexes with the mineral hydroxyapatite (the inorganic matrix of the bone). The alpha radiation generated during the radioactive decay of radium-223 produces a palliative anti-tumour effect on the bone metastases. The purpose of this guideline is to assist nuclear medicine specialists in evaluating patients who might be candidates for treatment using radium-223, planning and performing this treatment, understanding and evaluating its consequences, and improving patient management during therapy and follow-up.
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http://dx.doi.org/10.1007/s00259-017-3900-4DOI Listing
May 2018

Expert System for Bone Scan Interpretation Improves Progression Assessment in Bone Metastatic Prostate Cancer.

Adv Ther 2017 04 7;34(4):986-994. Epub 2017 Mar 7.

Department of Urology and Urologic Oncology, Hannover Medical School, Hannover, Germany.

Introduction: The bone scan index (BSI) was introduced as a quantitative tool for tumor involvement in bone of patients with metastatic prostate cancer (mPCa). The computer-aided diagnosis device for BSI analysis EXINIbone seems to represent technical progress for the quantitative assessment of bone involvement. But it is not yet clear if the automated BSI (aBSI) could contribute to improved evaluation of progression in patients under antiandrogens or chemotherapy in contrast to the visual interpretation and/or conventional biomarkers such as the prostate-specific antigen (PSA).

Methods: In 49 mPCa patients, bone scans were performed initially and during different therapy courses. Scans were evaluated visually and by the artificial-neural-network-based expert system EXINIbone. Progression of metastatic bone involvement was defined according to the Prostate Cancer Clinical Trials Working Group 2 (PCWG2) criteria in the visual interpretation. The computer-assisted interpretation was based on different cutoff values in relative changes of the aBSI. Additionally, assessments according to bone scanning were compared to changes in the PSA value as a potential surrogate for treatment response.

Results: Using a sensitive cutoff value (5% or 10%) for the relative aBSI increase led to significantly increased progression determination compared to the visual interpretation of bone scans (49% and 43% vs. 27%, p < 0.001). In 63% of the cases PSA and BSI changes matched, whereas in 18% progression was only indicated by the aBSI. A relative cutoff of 5% for the aBSI decrease could reclassify 47 serial scan pairs which were visually interpreted as stable into 22 progressive and 25 remissive scans.

Conclusion: Distinct thresholds of the relative aBSI could help to better assess disease progression in mPCa patients. Manual corrections of the BSI values are not required in most cases. The aBSI could serve as a useful additional parameter for therapy monitoring in mPCa patients in the future.
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http://dx.doi.org/10.1007/s12325-017-0505-zDOI Listing
April 2017

Multiple Time-Point 68Ga-PSMA I&T PET/CT for Characterization of Primary Prostate Cancer: Value of Early Dynamic and Delayed Imaging.

Clin Nucl Med 2017 Jun;42(6):e286-e293

From the Departments of *Nuclear Medicine, †Medical Physics and Radiation Protection, ‡Urology and Urological Oncology, and §Radiation and Special Oncology, Hannover Medical School, Hannover; and ∥Department of Pharmaceutical Radiochemistry, Technical University Munich, Munich, Germany.

Purpose: The aims of this study were to gain mechanistic insights into prostate cancer biology using dynamic imaging and to evaluate the usefulness of multiple time-point Ga-prostate-specific membrane antigen (PSMA) I&T PET/CT for the assessment of primary prostate cancer before prostatectomy.

Methods: Twenty patients with prostate cancer underwent Ga-PSMA I&T PET/CT before prostatectomy. The PET protocol consisted of early dynamic pelvic imaging, followed by static scans at 60 and 180 minutes postinjection (p.i.). SUVs, time-activity curves, quantitative analysis based on a 2-tissue compartment model, Patlak analysis, histopathology, and Gleason grading were compared between prostate cancer and benign prostate gland.

Results: Primary tumors were identified on both early dynamic and delayed imaging in 95% of patients. Tracer uptake was significantly higher in prostate cancer compared with benign prostate tissue at any time point (P ≤ 0.0003) and increased over time. Consequently, the tumor-to-nontumor ratio within the prostate gland improved over time (2.8 at 10 minutes vs 17.1 at 180 minutes p.i.). Tracer uptake at both 60 and 180 minutes p.i. was significantly higher in patients with higher Gleason scores (P < 0.01). The influx rate (Ki) was higher in prostate cancer than in reference prostate gland (0.055 [r = 0.998] vs 0.017 [r = 0.996]).

Conclusions: Primary prostate cancer is readily identified on early dynamic and static delayed Ga-PSMA ligand PET images. The tumor-to-nontumor ratio in the prostate gland improves over time, supporting a role of delayed imaging for optimal visualization of prostate cancer.
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http://dx.doi.org/10.1097/RLU.0000000000001589DOI Listing
June 2017

Simultaneous dual-isotope solid-state detector SPECT for improved tracking of white blood cells in suspected endocarditis.

Eur Heart J 2017 02;38(6):436-443

Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany.

Aims: High-energy resolution and sensitivity of novel cadmium-zinc-telluride (CZT) detector equipped SPECT systems facilitate simultaneous imaging of multiple isotopes and may enhance the detection of molecular/cellular signals. This may refine the detection of endocarditis. This study was designed to determine the feasibility and diagnostic accuracy of simultaneous imaging of inflammation with 111In-labeled white blood cells (WBCs) and myocardial perfusion with 99mTc-sestamibi, for localization of WBCs relative to the valve plane in suspected endocarditis.

Methods And Results: A dedicated cardiac CZT camera (Discovery 530c, GE Healthcare) was employed. Anthropomorphic thorax phantom studies were followed by clinical studies in 34 patients with suspected infection of native valves (n = 12) or implants (n = 22). Simultaneous 111In-WBC/99mTc perfusion imaging was performed, and compared with standard 111In-WBC planar scintigraphy and SPECT-CT. Phantom studies ruled out significant radioisotope crosstalk. Downscatter on 99mTc images was not observed for 111In activity as high as 2.5*99mTc activity. In patients, image quality was superior for CZT imaging vs. conventional SPECT-CT and planar scintigraphy (P < 0.01). Cadmium-zinc-telluride dual isotope imaging improved reader confidence for detection of inflammatory foci. Diagnostic accuracy based on surgery or Duke Criteria during follow-up was highest for CZT imaging (P < 0.001).

Conclusion: Novel CZT SPECT technology improves the accuracy of molecular/cellular cardiac imaging. Simultaneous multi-isotope imaging with 111In and 99mTc is feasible and aids in the workup of suspected endocarditis.
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http://dx.doi.org/10.1093/eurheartj/ehw231DOI Listing
February 2017

Effect of Deep Brain Stimulation on Regional Cerebral Blood Flow in Patients with Medically Refractory Tourette Syndrome.

Front Psychiatry 2016 5;7:118. Epub 2016 Jul 5.

Department of Nuclear Medicine, Hannover Medical School , Hannover , Germany.

In this study, alterations in brain perfusion have been investigated in patients with Tourette syndrome (TS) compared with control subjects. In addition, we investigated the effects of deep brain stimulation (DBS) in both globus pallidus internus (GPi) and centromedian-parafascicular/ventralis oralis internus nuclei of the thalamus (CM/Voi) and sham (SHAM) stimulation on cerebral blood flow. In a prospective controlled, randomized, double-blind setting, five severely affected adult patients with TS with predominant motor or vocal tics (mean total tic score on the Yale Global Tic Severity Scale: 39) underwent serial brain perfusion single photon emission computed tomography with (99m)Tc-ECD. Results were compared with data from six age-matched control subjects. All patients were investigated at four different time points: once before DBS implantation (preOP) and three times postoperatively. Postoperative scans were performed in a randomized order, each after 3 months of either GPi, CM/Voi, or SHAM stimulation. At each investigation, patients were injected at rest while awake, but scanned during anesthesia. This procedure ensured that neither anesthesia nor movement artifacts influenced our results. Control subjects were investigated only once at baseline (without DBS or anesthesia). At baseline, cerebral blood flow was significantly reduced in patients with TS (preOP) compared with controls in the central region, frontal, and parietal lobe, specifically in Brodmann areas 1, 4-9, 30, 31, and 40. Significantly increased perfusion was found in the cerebellum. When comparing SHAM stimulation to preOP condition, we found significantly decreased perfusion in basal ganglia and thalamus, but increased perfusion in different parts of the frontal cortex. Compared with SHAM condition both GPi and thalamic stimulation resulted in a significant decrease in cerebral blood flow in basal ganglia and cerebellum, while perfusion in the frontal cortex was significantly increased. Our results provide substantial evidence that, in TS, brain perfusion is altered in the frontal cortex and the cerebellum and that these changes can be reversed by both GPi and CM/Voi DBS.
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http://dx.doi.org/10.3389/fpsyt.2016.00118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4932098PMC
July 2016

[Disposal of radioactive contaminated waste from Ga-68-PET - calculation of a clearance level for Ge-68].

Z Med Phys 2017 Mar 16;27(1):49-55. Epub 2016 Jul 16.

Medizinische Hochschule Hannover, Stabsstelle Strahlenschutz und Abteilung Medizinische Physik - OE 0020, Carl-Neuberg-Str. 1, D-30625 Hannover, Deutschland.

Ga-68-labeled radiotracers, particularly used for the detection of neuroendocrine tumors by means of Ga-68-DOTA-TATE or -DOTA-TOC or for the diagnosis of prostate cancer by means of Ga-68-labeled antigens (Ga 68-PSMA), become increasingly important. In addition to the high sensitivity and specificity of these radiopharmaceuticals, the short-lived radionuclide Ga-68 offers almost ideal nuclear characteristics for use in PET. Ga-68 is obtained from a germanium-gallium-generator system, so that the availability of Ga-68-labeled radiotracers is independent of an on-site-cyclotron regardless of the short half-life of Ga-68 of about 68minutes. Regarding the disposal of the radioactively contaminated waste from the preparation of the radiopharmaceutical, the eluted Ga-68 has to be considered to be additionally contaminated with its parent nuclide Ge-68. Due to this production-related impurity in combination with the short half-life of Ga-68, the radioactive waste has to be considered to be contaminated with Ge-68 and Ga-68 in radioactive equilibrium (hereafter referred to as Ge-68+). As there are no clearance levels for Ge-68+ given in the German Radiation Protection Ordinance, this work presents a method to calculate the missing value basing on a recommendation of the German Radiation Protection Commission in combination with simple geometric models of practical radiation protection. Regarding the relevant exposure scenarios, a limit value for the unrestricted clearance of Ge-68+ of 0.4 Bq/g was determined.
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http://dx.doi.org/10.1016/j.zemedi.2016.06.004DOI Listing
March 2017

[Therapy of bone metastases with radium-223. German guidelines].

Nuklearmedizin 2016 Sep 15;55(5):177-86. Epub 2016 Jul 15.

Dr. Thorsten Pöppel, Universitätsklinikum Essen, Klinik für Nuklearmedizin, Hufelandstr. 55, 45122 Essen,

This document describes the guideline for therapy of bone metastases with radium-223 ((223)Ra) published by the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften in Germany (AWMF) under the auspices of the Deutsche Gesellschaft für Nuklearmedizin (DGN), Östereichische Gesellschaft für Nuklearmedizin (OGN), and Schweizerische Gesellschaft für Nuklearmedizin (SGNM). This guidance is based on an interdisciplinary consensus. These recommendations are a prerequisite for the quality management in the treatment of patients with bone metastases from prostate cancer using (223)Ra. They are aimed at guiding nuclear medicine specialists in selecting candidates to receive therapy and to deliver the treatment in a safe and effective manner. The document contains background information and definitions. It covers the rationale, indications and contraindications for therapy with (223)Ra. Essential topics are the requirements for institutions performing the therapy, which patient data have to be available prior to performance of therapy, and how treatment has to be carried out technically and organisationally. Moreover, essential elements of follow-up and aftercare are specified. As a matter of principle, the treatment inclusive aftercare has to be realised in close cooperation with the involved medical disciplines.
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http://dx.doi.org/10.3413/Nukmed-2016050001DOI Listing
September 2016

[Constancy check of system linearity for dose calibrators. Effect of molybdenum impurities at high start activities of 99mTc].

Nuklearmedizin 2016 Aug 15;55(4):172-5. Epub 2016 Apr 15.

Christian Schütze, Stabsstelle Strahlenschutz und Abteilung Medizinische Physik, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Tel. 05 11/532-30 83, Fax -26 76,

Unlabelled: Dose calibrators are one of the most important and most frequently used instruments for the determination of activities in nuclear medicine. For guaranteeing a constant quality of the dose calibrators' measurements, constancy checks including the examination of the system linearity have to be performed regularly, usually measured using 99mTc. The 99mTc eluate extracted from a 99Mo/99mTc generator is contaminated with molybdenum. Not accounting for the molybdenum impurity might lead to an exceed of the tolerance limit of 5% deviation to the reference value for this constancy check. The reason for this effect is the contamination of the 99mTc eluate with 99Mo, whose impact depends on both the amount of the impurity and on the total measurement time (high start activities).

Result: In this work, the influence of the molybdenum impurity on the results of the constancy check of the system linearity was investigated and maximum start activities for certain impurities were determined providing that the deviation to the reference values is below 5%.

Conclusion: Provided that certain boundary conditions are observed, a correction of the results with respect to the molybdenum contamination is not necessary.
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http://dx.doi.org/10.3413/Nukmed-0779-15-11DOI Listing
August 2016

Dose rate constants for the quantity H(3) for frequently used radionuclides in nuclear medicine.

Z Med Phys 2016 Dec 17;26(4):304-310. Epub 2015 Dec 17.

Department for Radiation Protection and Medical Physics, Medical School Hannover.

According to recent studies, the human eye lens is more sensitive to ionising radiation than previously assumed. Therefore, the dose limit for personnel occupationally exposed to ionising radiation will be lowered from currently 150 mSv to 20 mSv per year. Currently, no data base for a reliable estimation of the dose to the lens of the eye is available for nuclear medicine. Furthermore, the dose is usually not monitored. The aim of this work was to determine dose rate constants for the quantity H(3), which is supposed to estimate the dose to the lens of the eye. For this, H(3)-dosemeters were fixed to an Alderson Phantom at different positions. The dosemeters were exposed to radiation from nuclides typically used in nuclear medicine in their geometries analog to their application in nuclear medicine, e.g. syringe or vial. The results show that the handling of high-energy beta (i.e. electron or positron) emitters may lead to a relevant dose to the lens of the eye. For low-energy beta emitters and gamma emitters, an exceeding of the lowered dose limit seems to be unlikely.
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http://dx.doi.org/10.1016/j.zemedi.2015.11.003DOI Listing
December 2016

Impact of radiation protection means on the dose to the lens of the eye while handling radionuclides in nuclear medicine.

Z Med Phys 2016 Dec 2;26(4):298-303. Epub 2015 Sep 2.

Department for Radiation Protection and Medical Physics, Medical School Hannover, Carl-Neuberg-Str. 1, 30625 Hannover.

The human eye lens appears to be more radiosensitive than previously assumed. The reduction of the limit for the dose to the lens of the eye to 20 mSv per year has been passed in the current Euratom Directives (2013). Therefore, in this work the impact of laboratory glasses and X-ray protective goggles was investigated and reciprocal attenuation factors (i.e. transmission factors) for different nuclides (Tc-99m, I-131, Y-90, F-18 and Ga-68) were determined. The radionuclides in typical geometry (syringe, applicator) were positioned at a distance of 50 cm to the eyes of four Alderson-Head-Phantoms. Different dosemeters measuring H(3) respective H(0.07) were fixed to the eyes of the phantoms, either behind the glasses or without any protection means, respectively. The mean reciprocal attenuation factors were determined to be between unity for F-18 and I-131 using laboratory glasses (no attenuation effect) and < 0.01 for Y-90 using X-ray protective goggles. All other results were between these extremes. It has been shown, that prospective doses to the lens of the eye can be reduced significantly by using appropriate radiation protection means, especially for those dose-relevant beta radiation emitting nuclides such as Y-90.
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http://dx.doi.org/10.1016/j.zemedi.2015.07.002DOI Listing
December 2016

Positron Emission Tomography Imaging Reveals Auditory and Frontal Cortical Regions Involved with Speech Perception and Loudness Adaptation.

PLoS One 2015 5;10(6):e0128743. Epub 2015 Jun 5.

Departments of Biomedical Engineering and Otolaryngology-Head & Neck Surgery, University of Minnesota, Minneapolis, Minnesota, United States of America.

Considerable progress has been made in the treatment of hearing loss with auditory implants. However, there are still many implanted patients that experience hearing deficiencies, such as limited speech understanding or vanishing perception with continuous stimulation (i.e., abnormal loudness adaptation). The present study aims to identify specific patterns of cerebral cortex activity involved with such deficiencies. We performed O-15-water positron emission tomography (PET) in patients implanted with electrodes within the cochlea, brainstem, or midbrain to investigate the pattern of cortical activation in response to speech or continuous multi-tone stimuli directly inputted into the implant processor that then delivered electrical patterns through those electrodes. Statistical parametric mapping was performed on a single subject basis. Better speech understanding was correlated with a larger extent of bilateral auditory cortex activation. In contrast to speech, the continuous multi-tone stimulus elicited mainly unilateral auditory cortical activity in which greater loudness adaptation corresponded to weaker activation and even deactivation. Interestingly, greater loudness adaptation was correlated with stronger activity within the ventral prefrontal cortex, which could be up-regulated to suppress the irrelevant or aberrant signals into the auditory cortex. The ability to detect these specific cortical patterns and differences across patients and stimuli demonstrates the potential for using PET to diagnose auditory function or dysfunction in implant patients, which in turn could guide the development of appropriate stimulation strategies for improving hearing rehabilitation. Beyond hearing restoration, our study also reveals a potential role of the frontal cortex in suppressing irrelevant or aberrant activity within the auditory cortex, and thus may be relevant for understanding and treating tinnitus.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0128743PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4457827PMC
February 2016

Anti-leucine rich glioma inactivated 1 protein and anti-N-methyl-D-aspartate receptor encephalitis show distinct patterns of brain glucose metabolism in 18F-fluoro-2-deoxy-d-glucose positron emission tomography.

BMC Neurol 2014 Jun 20;14:136. Epub 2014 Jun 20.

Department of Neurology, Hannover Medical School, Carl-Neuberg-Str, 1, 30625 Hannover, Germany.

Background: Pathogenic autoantibodies targeting the recently identified leucine rich glioma inactivated 1 protein and the subunit 1 of the N-methyl-D-aspartate receptor induce autoimmune encephalitis. A comparison of brain metabolic patterns in 18F-fluoro-2-deoxy-d-glucose positron emission tomography of anti-leucine rich glioma inactivated 1 protein and anti-N-methyl-D-aspartate receptor encephalitis patients has not been performed yet and shall be helpful in differentiating these two most common forms of autoimmune encephalitis.

Methods: The brain 18F-fluoro-2-deoxy-d-glucose uptake from whole-body positron emission tomography of six anti-N-methyl-D-aspartate receptor encephalitis patients and four patients with anti-leucine rich glioma inactivated 1 protein encephalitis admitted to Hannover Medical School between 2008 and 2012 was retrospectively analyzed and compared to matched controls.

Results: Group analysis of anti-N-methyl-D-aspartate encephalitis patients demonstrated regionally limited hypermetabolism in frontotemporal areas contrasting an extensive hypometabolism in parietal lobes, whereas the anti-leucine rich glioma inactivated 1 protein syndrome was characterized by hypermetabolism in cerebellar, basal ganglia, occipital and precentral areas and minor frontomesial hypometabolism.

Conclusions: This retrospective 18F-fluoro-2-deoxy-d-glucose positron emission tomography study provides novel evidence for distinct brain metabolic patterns in patients with anti-leucine rich glioma inactivated 1 protein and anti-N-methyl-D-aspartate receptor encephalitis.
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http://dx.doi.org/10.1186/1471-2377-14-136DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4076767PMC
June 2014

[Conservative calibration of a clearance monitor system for waste material from nuclear medicine].

Z Med Phys 2014 Sep 18;24(3):252-60. Epub 2014 Feb 18.

Medizinische Hochschule Hannover, Stabsstelle Strahlenschutz und Abteilung Medizinische Physik - OE 0020, Carl-Neuberg-Str. 1, D-30625 Hannover.

Clearance monitor systems are used for gross gamma measurements of waste potentially contaminated with radioactivity. These measurements are to make sure that legal requirements, e.g. clearance criteria according to the german radiation protection ordinance, are met. This means that measurement results may overestimate, but must not underestimate the true values. This paper describes a pragmatic way using a calibrated Cs-137 point source to generate a conservative calibration for the clearance monitor system used in the Medizinische Hochschule Hannover (MHH). The most important nuclides used in nuclear medicine are considered. The measurement result reliably overestimates the true value of the activity present in the waste. The calibration is compliant with the demands for conservativity and traceability to national standards.
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http://dx.doi.org/10.1016/j.zemedi.2014.01.001DOI Listing
September 2014

Calibration test of PET scanners in a multi-centre clinical trial on breast cancer therapy monitoring using 18F-FLT.

PLoS One 2013 13;8(3):e58152. Epub 2013 Mar 13.

Department of Nuclear Medicine, Academic Hospital, Angers, France.

Unlabelled: A multi-centre trial using PET requires the analysis of images acquired on different systems We designed a multi-centre trial to estimate the value of 18F-FLT-PET to predict response to neoadjuvant chemotherapy in patients with newly diagnosed breast cancer. A calibration check of each PET-CT and of its peripheral devices was performed to evaluate the reliability of the results.

Material And Methods: 11 centres were investigated. Dose calibrators were assessed by repeated measurements of a 68Ge certified source. The differences between the clocks associated with the dose calibrators and inherent to the PET systems were registered. The calibration of PET-CT was assessed with an homogeneous cylindrical phantom by comparing the activities per unit of volume calculated from the dose calibrator measurements with that measured on 15 Regions of Interest (ROIs) drawn on 15 consecutive slices of reconstructed filtered back-projection (FBP) images. Both repeatability of activity concentration based upon the 15 ROIs (ANOVA-test) and its accuracy were evaluated.

Results: There was no significant difference for dose calibrator measurements (median of difference -0.04%; min = -4.65%; max = +5.63%). Mismatches between the clocks were less than 2 min in all sites and thus did not require any correction, regarding the half life of 18F. For all the PET systems, ANOVA revealed no significant difference between the activity concentrations estimated from the 15 ROIs (median of difference -0.69%; min = -9.97%; max = +9.60%).

Conclusion: No major difference between the 11 centres with respect to calibration and cross-calibration was observed. The reliability of our 18F-FLT multi-centre clinical trial was therefore confirmed from the physical point of view. This type of procedure may be useful for any clinical trial involving different PET systems.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0058152PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3596383PMC
September 2013

[Radioembolization with (90)Y-labeled microspheres: post-therapeutic therapy validation with Bremsstrahlung-SPECT].

Z Med Phys 2011 Dec 29;21(4):274-80. Epub 2011 Jun 29.

Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R, Otto-von-Guericke-Universität, Deutschland.

During the last years angiographic Selective Internal Radiotherapy (SIRT) with (90)Y-labelled microspheres has become a common technique for the local-ablative treatment of cancer patients. SIRT is a palliative therapy concept for the treatment of liver malignancies. As a result of (90)Y-decay as β(-)-emitter without a concomitant gamma radiation, Bremsstrahlung imaging is needed to validate the distribution achieved by radioembolisation. This article demonstrates the method of imaging through phantom measurement and shows the advantages of post-therapeutic tomography by means of a patient study. Approaches for further optimization of Bremsstrahlung imaging are discussed.
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http://dx.doi.org/10.1016/j.zemedi.2011.05.002DOI Listing
December 2011

[External radiation exposure and effective half-life in Lu-177-Dota-Tate therapy].

Z Med Phys 2011 Dec 29;21(4):266-73. Epub 2011 Jun 29.

Stabsstelle Strahlenschutz und Medizinische Physik, Medizinische Hochschule Hannover, Deutschland.

The aim of the study was to estimate the external radiation exposure emitted by the patient to his surroundings after discharge. Being in compliance with legal requirements is especially important when doing multiple therapies. To estimate the effective half-life to be used quite realistically, the individual effective half-lives for 41 patients with 52 therapies were calculated. From the resulting histogram the maximum value was determined to be 100 h. Substituting the physical half-life by this maximum effective half-life results in dose estimates, which are lower but still conservative. In addition, the analysis of dose related parameters for patients who underwent multiple therapies demonstrates that the parameters estimated for the first therapy cannot be transferred to the subsequent ones.
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http://dx.doi.org/10.1016/j.zemedi.2011.05.001DOI Listing
December 2011

Validating PET scanner calibration for multicenter trials.

J Nucl Med 2010 Jun 19;51(6):997-8. Epub 2010 May 19.

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http://dx.doi.org/10.2967/jnumed.109.069989DOI Listing
June 2010

[Quality control in PET/CT systems: experiences and requirements].

Z Med Phys 2010 25;20(1):46-50. Epub 2009 Nov 25.

Stabsstelle Strahlenschutz und Medizinische Physik, Medizinische Hochschule Hannover, Hannover.

Today, in most cases PET examinations are performed using PET/CT hybrid systems. While acceptance testing and routine control of the basic modalities PET and CT, respectively, are described by appropriate regulations, corresponding instructions with regard to the interface connecting both are still missing. This interface includes the adjustment of gantries and patient bed to each other as well as the energy scaling of attenuation coefficients from CT energy to 511 keV. Measurements checking the mechanical adjustment (determination of off-set parameters) are performed following manufacturer's recommendation, with a typical frequency twice a year. On a Biograph 16 (Siemens, Inc.), these measurements were systematically extended to a weekly frequency over an observation period of 10 months, supplemented by measurements with additional load to the patient bed (up to 135 kg), and different vertical bed positions. The results show, that for the construction tested additional off-set measurements for routine control extending well beyond manufacturer's recommendation are not necessary. The energy scaling of attenuation coefficients is depending on methodological aspects and software implementation, and therefore is not part of routine control. On the contrary, the development of appropriate methods for acceptance testing to assess and to determine the mechanical adjustment in all its degrees of freedom as well as the accuracy of attenuation corrected emission data is urgently needed.
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http://dx.doi.org/10.1016/j.zemedi.2009.10.009DOI Listing
June 2010

Potential impact of (68)Ga-DOTATOC PET/CT on stereotactic radiotherapy planning of meningiomas.

Eur J Nucl Med Mol Imaging 2010 Feb 18;37(2):310-8. Epub 2009 Sep 18.

Department for Nuclear Medicine, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.

Purpose: Since meningiomas show a high expression of somatostatin receptor subtype 2, PET with (68)Ga-DOTATOC was proposed as an additional imaging modality beside CT and MRI for planning radiotherapy. We investigated the input of (68)Ga-DOTATOC-PET/CT on the definition of the "gross tumour volume" (GTV) in meningiomas, in order to assess the potential value of this method.

Methods: Prior to radiotherapy, 42 patients with meningiomas (26 f, 16 m, mean age 55) underwent MRI and (68)Ga-DOTATOC-PET/CT examinations.

History: operated n = 24, radiotherapy n = 1, operation and radiotherapy n = 8, no treatment n = 9. PET/CT and MRI data were co-registered using a BrainLAB workstation. For comparison, the GTV was defined first under consideration of CT and MRI data, then using PET data.

Results: 3/42 patients were excluded from the analysis (two with negative PET results, one with an extensive tumour, not precisely delineable by MRI or PET/CT). The average GTV(CT/MRI) was 22(+/-19)cm(3); GTV(PET) was 23(+/-20)cm(3). Additional GTV, obtained as a result of PET was 9(+/-10)cm(3) and was observed in patients with osseous infiltration. In some pre-treated patients there were intratumoural areas (as identified in CT/MRI) without SR-expression (7(+/-11)cm(3)). Common GTV as obtained by both CT/MRI and PET was 15(+/-14)cm(3). The mean bi-directional difference between the GTV(CT/MRI) and GTV(PET) accounted to 16(+/-15)cm(3) (93%, p < 0.001). In a subgroup of seven patients with multiple meningiomas, PET showed a total of 19 lesions; nine of them were not recognizable by CT or MRI.

Conclusion: (68)Ga-DOTATOC-PET enables delineation of SR-positive meningiomas and delivers additional information to both CT and MRI regarding the planning of stereotactic radiotherapy. The acquisition on a PET/CT scanner helps to estimate the relation of PET findings to anatomical structures and is especially useful for detection of osseous infiltration. (68)Ga-DOTATOC-PET also allows detection of additional lesions in patients with multiple meningiomas.
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http://dx.doi.org/10.1007/s00259-009-1270-2DOI Listing
February 2010

Increased serotonin transporter availability in the brainstem of migraineurs.

J Neurol 2007 Jun 12;254(6):789-96. Epub 2007 Mar 12.

Dept. of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.

For decades, serotonin has been speculated to play a major role in migraine pathophysiology. The central serotonergic system is located in the raphe nuclei and the adjacent reticular formation in the brainstem. Recently, radioligands targeting the brain serotonin transport protein (SERT) have been developed. We used the highly specific SERT-radioligand (123)I-ADAM [2-((2-((dimethylamino) methyl)phenyl)thio)-5-iodophenylamine] to test the hypothesis of the mesopontine serotonergic system being involved in the pathophysiology of migraine. Nineteen migraine patients and 10 healthy, age- and sex-matched controls were enrolled. The neuroimaging study was performed interictally during the pain-free interval. Single Photon Emission Computed Tomography (SPECT)-images were coregistered with MRI-scans. Region of interest (ROI)-analysis revealed a highly significant increase of (123)I-ADAM uptake in the mesopontine brainstem of migraineurs (p < 0.001). In contrast, (123)IADAM uptake in the thalamus did not differ significantly between migraineurs and controls. Our study demonstrates for the first time a significant increase of brainstem SERT-availability in migraineurs, suggesting a dysregulation of the brainstem serotonergic system. It remains to be elucidated whether the altered SERT-availability is causally related to migraine pathophysiology or whether it reflects secondary pathophysiological mechanisms.
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http://dx.doi.org/10.1007/s00415-006-0444-0DOI Listing
June 2007