Der Stellenwert der PET mit radioaktiv markierten Aminosäuren in der neuroonkologischen Diagnostik ist in vielen Studien validiert. Die Methode kann auch bei pädiatrischen Patienten zur Früherkennung von Rezidiv-/Resttumoren und vor allem zur Differenzierung eines vitalen Tumors von therapiebedingten Veränderungen eingesetzt werden. lm Rahmen einer prospektiven, multizentrischen Studie (FET PET 2010) soll die Genauigkeit der FET-PET in der Nachsorge von kindlichen Hirntumoren im Vergleich zum gegenwärtigen diagnostischen „Goldstandard“ MRT vergleichen werden.

Objective: To assess the diagnostic efficacy data from clinical trial Kupsch et al, 2012 (data not previously published) conducted using DaTSCAN™/INS; ([123I]Ioflupane Injection).

SummaryPurpose: To evaluate the calibration of an adaptive thresholding algorithm (contrastoriented algorithm) for FDG PET-based delineation of tumour volumes in eleven centres with respect to scanner types and image data processing by phantom measurements. Methods: A cylindrical phantom with spheres of different diameters was filled with FDG realizing different signal-to-background ratios and scanned using 5 Siemens Biograph PET/CT scanners, 5 Philips Gemini PET/CT scanners, and one Siemens ECAT-ART PET scanner. All scans were analysed by the contrast-oriented algorithm implemented in two different software packages. For each site, the threshold SUVs of all spheres best matching the known sphere volumes were determined. Calibration parameters a and b were calculated for each combination of scanner and image-analysis software package. In addition, “scanner-typespecific” calibration curves were determined from all values obtained for each combination of scanner type and software package. Both kinds of calibration curves were used for volume delineation of the spheres. Results: Only minor differences in calibration parameters were observed for scanners of the same type (Δa ≤ 4%, Δb ≤ 14%) provided that identical imaging protocols were used whereas significant differences were found comparing calibration parameters of the ART scanner with those of scanners of different type (Δa ≤ 60%, Δb ≤ 54%). After calibration, for all scanners investigated the calculated SUV thresholds for auto-contouring did not differ significantly (all p > 0.58). The resulting sphere volumes deviated by less than –7% to +8% from the true values. Conclusion: After multi-centre calibration the use of the contrast-oriented algorithm for FDG PET-based delineation of tumour volumes in the different centres using different scanner types and specific imaging protocols is feasible.

Wir beschreiben das Studienprotokoll einer prospektiven, multizentrischen Studie zum Stellenwert der 18F-FET-PET in der Nachsorge von Hirntumoren im Kindes- und Jugendalter. Das Hauptziel dieser Studie ist die Evaluierung der Wertigkeit der 18F-FET-PET im Vergleich zur MRT zum Resttumor-/Rezidivnachweis nach einer „first line“-Therapie bei Kindern und Jugendlichen mit ZNS-Tumoren. Insgesamt 160 pädiatrische Patienten sollen eingeschlossen werden. Die Gesamtdauer der Studie wird 3 Jahre betragen.

Background:Dopaminergic availability is known to linearly decline in Parkinson's disease (PD). In contrast, temporal characteristics of serotonergic markers like the serotonin transporter (SERT) in relation to clinical staging of PD and dopaminergic cell loss are less clear. This study investigated SERT availability using [123I]-ADAM and single-photon emission tomography (SPECT) in drug-naive, de novo patients, i.e., in a PD stage where dopaminergic decline starts to lead to the occurence of the characteristic motor symptoms.Methods:Nine de novo patients with PD and 9 age-matched healthy controls were studied. Measurements were repeated after 3 months of levodopa treatment in patients with PD, and dopaminergic transporter (DAT) binding was examined at baseline using [123I]-FP-CIT SPECT.Results:No alterations of SERT availability were found between groups, and neither correlation between SERT and DAT nor effects of levodopa treatment on SERT was found in patients with PD.Conclusions:These preliminary findings indicate that midbrain SERT is preserved in unmedicated patients at this early stage of PD, supporting the view that serotonergic decline temporally follows dopaminergic cell loss.

In nuclear medicine therapy the treatment of tumours by radiation exposure from internally deposited labelled antibodies or labelled peptides is currently an active field of investigation. To permit the efficient delivery of high amounts of radiation dose to tumours while limiting the radiation dose to critical organs dosimetry calculations have to be performed. These are relying on scintigraphic data being input to the well known MIRD formalism. This paper focuses on the methods and the difficulties associated with the scintigraphic determination of organ kinetics. The physical properties of the well-known scintigraphic imaging modalities, PET, SPECT and planar scintigraphy, are discussed thereby taking into account the properties of the appropriate radionuclides currently being available for therapy and dosimetry. Several arguments are given and disputed for the limited clinical use of PET and SPECT in dosimetry and the ongoing preference of planar whole-body imaging as the method of choice. The quantitative restrictions still inherent to this method are also discussed in detail. Procedural recommendations are proposed covering all processes related to data acquisition, data correction and data analysis which finally lead to reliable estimations of organ dose.