Publikationen

The current standard-of-care salvage therapy in relapsed/refractory classic Hodgkin lymphoma (cHL) includes consolidation high-dose chemotherapy (HDCT)/autologous stem cell transplant (aSCT).

This joint practice guideline/procedure standard was collaboratively developed by the European Association of Nuclear Medicine (EANM), the Society of Nuclear Medicine and Molecular Imaging (SNMMI), the European Association of Neuro-Oncology (EANO), and the PET task force of the Response Assessment in Neurooncology Working Group (PET/RANO). Brain metastases are the most common malignant central nervous system (CNS) tumors. PET imaging with radiolabeled amino acids and to lesser extent [F]FDG has gained considerable importance in the assessment of brain metastases, especially for the differential diagnosis between recurrent metastases and treatment-related changes which remains a limitation using conventional MRI. The aim of this guideline is to assist nuclear medicine physicians in recommending, performing, interpreting and reporting the results of brain PET imaging in patients with brain metastases. This practice guideline will define procedure standards for the application of PET imaging in patients with brain metastases in routine practice and clinical trials and will help to harmonize data acquisition and interpretation across centers.

Positron emission tomography/computed tomography (PET/CT) using prostate-specific membrane antigen (PSMA)-radioligands is currently suggested by several clinical guidelines for the assessment of prostate cancer (PCa) in various clinical settings. However, PSMA will also be overexpressed in different cancers, which should be considered on the PSMA PET/CT reading in patients with concomitant neoplastic diseases. We report a case of 82-year-old male presented with prostate and history of oesophageal cancer and B-cell chronic lymphocytic leukemia (B-CLL). Both Ga-PSMA-11 and 2-(3-(1-carboxy-5-((6-(18f)fluoro-pyridine-3-carbonyl)-amino)-pentyl)-ureido)-pentanedioic acid (F-DCFPyL) PET/CT, which were performed for prostate cancer staging and re-staging in about 1 year interval, showed focal uptake in the primary prostate tumor as well as an intense focal lesion in L2, suggestive of bone metastasis. F-FDG PET/CT scans performed before and after PSMA PET/CT examinations showed no abnormal uptake related to oesophageal and/or B-CLL. This pattern could present an oligometastatic PCa disease, which might change the treatment plan of the patient to radiation of the bone metastasis. However, bone biopsy of the detected lesion on L2 revealed infiltrates of B-CLL. The role of Ga- and F-labeled PSMA PET/CT in prostate cancer is evolving and has been demonstrated to have high sensitivity, but may present limited specificity in patients with coexisting cancer(s), which should be considered in PSMA PET/CT reading.

Preoperative localization of hyperfunctioning parathyroid glands in primary hyperparathyroidism is essential for successful parathyroid surgery, particularly in patients with previous negative imaging or reoperations.

Poly (ADP-ribose) polymerase (PARP) enzymes are crucial for the repair of DNA single-strand breaks and have become key therapeutic targets in homologous recombination-deficient cancers, including prostate cancer. To enable non-invasive monitoring of PARP-1 expression, several PARP-1-targeting positron emission tomography (PET) tracers have been developed. Here, we aimed to preclinically investigate [carbonyl-C]DPQ as an alternative PARP-1 PET tracer as it features a strongly distinct chemotype compared to the frontrunners [F]FluorThanatrace and [F]PARPi.

Cardiac involvement in amyloid light chain (AL) amyloidosis significantly influences prognosis, necessitating timely diagnosis and meticulous risk stratification.

Several exploratory studies have demonstrated the feasibility of cholecystokinin-2 receptor (CCK2R) targeting in patients with medullary thyroid carcinoma (MTC) and other neuroendocrine tumors (NETs). We report the results of a prospective phase I/IIA pilot study (clinicaltrials.gov NCT06155994) conducted at our center with the Ga-labeled peptide analog DOTA-DGlu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1-Nal-Phe-NH (Ga-DOTA-MGS5). Six patients with advanced MTC and 6 patients with gastroenteropancreatic and bronchopulmonary NETs confirmed by previous PET/CT imaging with other PET tracers received a single dose of 180 MBq of Ga-DOTA-MGS5. The first 6 patients enrolled in the study were included in the dosimetry evaluation, and safety was assessed in all 12 patients. PET/CT imaging was performed at different time points after injection to perform dosimetric calculations and to determine the optimal imaging time window. In addition, blood and urine samples were collected for pharmacokinetic assessments. The administration of Ga-DOTA-MGS5 was well tolerated, with minor adverse drug reactions occurring only in 3 patients. Ga-DOTA-MGS5 was cleared rapidly from the blood, with less than 21% of the injected activity present in blood 215 ± 10 min after injection. Tracer elimination occurred mainly through the kidneys, with a cumulative urinary excretion greater than 40% 3 h after injection. A high percentage of intact radiopeptide was confirmed in plasma. The highest absorbed dose was found for the urinary bladder wall, the stomach wall, and the kidneys, with an effective dose of 0.023 ± 0.007 mSv/MBq. The time points of 1 and 2 h after injection proved to be optimal for PET/CT imaging. In the 6 patients included in the dosimetry evaluation, local metastasis was confirmed in 2 patients with advanced MTC, whereas only 1 of 4 patients with gastroenteropancreatic NETs was positive in Ga-DOTA-MGS5 PET/CT. Besides confirming the safety of administration, within the phase I part of the prospective clinical trial, an acceptable effective whole-body dose, an overall favorable biodistribution, and the feasibility of cholecystokinin-2 receptor imaging could be shown for Ga-DOTA-MGS5.

Despite the potential of dosimetry in optimizing personalized radiopharmaceutical therapy (RPT), its limited clinical implementation impedes the development of simplified protocols for routine adoption. However, simplifications may introduce errors in dosimetry, prompting questions about their impact on clinical practice.

: Dual-modality probes, combining positron emission tomography (PET) with fluorescence imaging (FI) capabilities in a single molecule, are of high relevance for the accurate staging and guided resection of tumours. We herein present a pair of candidates targeting the cholecystokinin-2 receptor (CCK2R), namely [Ga]Ga-CyTMG and [Ga]Ga-CyFMG. In these probes, the SulfoCy5.5 fluorophore and two units of a CCK2R-binding motif are coupled to the chelator acting as a core scaffold, triazacyclononane-phosphinic acid (TRAP), and Fusarinine C (FSC), respectively. Using this approach, we investigated the influence of these chelators on the final properties. : The synthetic strategy to both precursors was based on the stoichiometric conjugation of the components via click chemistry. The characterization in vitro included the evaluation of the CCK2R affinity and internalization in A431-CCK2R cells. Ex vivo biodistribution as well as PET and FI studies were performed in xenografted mice. : Ga labelling was accomplished with high radiochemical yield and purity for both precursors. A CCK2R affinity in the subnanomolar range of the conjugates and a receptor-specific uptake of the radioligands in cells were observed. In A431-CCK2R/A431-mock xenografted mice, the investigated compounds showed specific accumulation in the tumours and reduced off-target uptake compared to a previously developed compound. Higher accumulation and prolonged retention in the kidneys were observed for [Ga]Ga-CyTMG when compared to [Ga]Ga-CyFMG. Despite the promising targeting properties observed, further probe optimization is required to achieve enhanced imaging contrast at early timepoints. Additionally, the results indicate a distinct influence of the chelators in terms of renal accumulation and retention.

The phase-3 INDIGO trial demonstrated that the isocitrate dehydrogenase () inhibitor vorasidenib significantly prolonged progression-free survival and delayed intervention in patients with CNS WHO grade 2 gliomas. However, conventional MRI showed limited response, with only 11% of patients having objective responses. Studies suggest that serial PET imaging with radiolabeled amino acids, such as -(2-[ F]-fluoroethyl)-L-tyrosine (FET) PET, may provide earlier and more informative assessments of treatment response than MRI. In an initial experience with FET PET, 3 out of 5 patients showed metabolic response to vorasidenib. This highlights FET PET's potential to guide decision-making, though further trials are needed to confirm outcome benefits.