@article{AertsEberleinHolmetal.2021, author = {Aerts, An and Eberlein, Uta and Holm, S{\"o}ren and Hustinx, Roland and Konijnenberg, Mark and Strigari, Lidia and van Leeuwen, Fijs W. B. and Glatting, Gerhard and Lassmann, Michael}, title = {EANM position paper on the role of radiobiology in nuclear medicine}, series = {European Journal of Nuclear Medicine and Molecular Imaging}, volume = {48}, journal = {European Journal of Nuclear Medicine and Molecular Imaging}, number = {11}, doi = {10.1007/s00259-021-05345-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265595}, pages = {3365-3377}, year = {2021}, abstract = {With an increasing variety of radiopharmaceuticals for diagnostic or therapeutic nuclear medicine as valuable diagnostic or treatment option, radiobiology plays an important role in supporting optimizations. This comprises particularly safety and efficacy of radionuclide therapies, specifically tailored to each patient. As absorbed dose rates and absorbed dose distributions in space and time are very different between external irradiation and systemic radionuclide exposure, distinct radiation-induced biological responses are expected in nuclear medicine, which need to be explored. This calls for a dedicated nuclear medicine radiobiology. Radiobiology findings and absorbed dose measurements will enable an improved estimation and prediction of efficacy and adverse effects. Moreover, a better understanding on the fundamental biological mechanisms underlying tumor and normal tissue responses will help to identify predictive and prognostic biomarkers as well as biomarkers for treatment follow-up. In addition, radiobiology can form the basis for the development of radiosensitizing strategies and radioprotectant agents. Thus, EANM believes that, beyond in vitro and preclinical evaluations, radiobiology will bring important added value to clinical studies and to clinical teams. Therefore, EANM strongly supports active collaboration between radiochemists, radiopharmacists, radiobiologists, medical physicists, and physicians to foster research toward precision nuclear medicine.}, language = {en} } @phdthesis{Andermann2007, author = {Andermann, Paul}, title = {Evaluierung der Intra- und Interobserver-Variabilit{\"a}t bei der 2D-Ultraschall-Schilddr{\"u}senvolumetrie an einem Schilddr{\"u}senphantom - Vergleich zu 3D-Ultraschall-Referenzmessungen an gesunden Probanden}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-23434}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2007}, abstract = {Mehrere Autoren haben schon die Intra- und Interobserver-Variabilit{\"a}t bei der Bestimmung des Schilddr{\"u}senvolumens und knotiger Herdbefunde mit Hilfe des zweidimensionalen (2D) Ultraschalls evaluiert. Dar{\"u}ber hinaus wurde {\"u}ber Interobserver-Korrelationen f{\"u}r Schilddr{\"u}senvolumenmessungen berichtet. Es gibt jedoch keine prospektive verblindete Studie, die die Intra- bzw. Interobserver-Variabilit{\"a}t bei der Volumenbestimmung der gesamten Schilddr{\"u}se an gesunden Probanden bzw. einzelner Knoten unterschiedlicher Echogenit{\"a}t an einem Phantom untersucht hat. Die Ergebnisse der Einzelstudien sollen hier vorgestellt und - soweit m{\"o}glich - miteinander verglichen werden. Im Rahmen einer quantitativen Studie mit dem hier pr{\"a}sentierten Schilddr{\"u}senphantom soll die Intra- und Interobserver-Variabilit{\"a}t bei der 2D-Ultraschallvolumetrie einzelner Knoten unterschiedlicher Gr{\"o}ße und Echogenit{\"a}t und der Schilddr{\"u}senlappen evaluiert werden. Da Schilddr{\"u}senknoten wegen des geringeren Volumens und ihrer oft unscharfen Randkontur schwieriger zu entdecken und auszumessen sind als die Gesamtschilddr{\"u}se, soll untersucht werden, welche Gr{\"o}ßenordnungen des Messfehlers auftreten und in welcher Relation sie zueinander stehen. Außerdem soll der methodenimmanente Fehler quantifiziert und detektierbare Volumen{\"a}nderungen erfassbar gemacht werden. Bisher war in der Schilddr{\"u}sensonographie kein geeignetes Phantom verf{\"u}gbar, das kommerziell erh{\"a}ltlich ist und mit dem qualitativ unterschiedliche intrathyreoidale Herdbefunde untersucht werden k{\"o}nnen. Die vorliegende Studie an gesunden Probanden hatte das prim{\"a}re Ziel, die Frage nach der Quantifizierbarkeit von Unsicherheitsfaktoren in der Schilddr{\"u}senvolumetrie durch den konventionellen 2D-Ultraschall im Vergleich zu 3D-Referenzvolumina bei gesunden Erwachsenen m{\"o}glichst exakt zu beantworten und die Untersucherabh{\"a}ngigkeit der Methode zu demonstrieren. Damit soll die Genauigkeit (Richtigkeit und Pr{\"a}zision) der sonographischen Schilddr{\"u}sendiagnostik mathematisch erfasst und eine bessere Bewertungsgrundlage f{\"u}r die Frage nach der Reproduzierbarkeit von Ultraschall-Volumenbestimmungen der Schilddr{\"u}se und ihrer pathologischen Ver{\"a}nderungen geschaffen werden. Hierf{\"u}r wurden m{\"o}glichst aussagekr{\"a}ftige statistische Parameter wie die Intra- und Interobserver-Variabilit{\"a}t, der systematische und zuf{\"a}llige Fehler, der reine Fehler der Messmethode, minimale, sicher detektierbare Volumen{\"a}nderungen und im Rahmen einer multivariaten Reliabilit{\"a}tsanalyse die Reliabilit{\"a}tskoeffizienten untersucht. Ein weiteres Ziel dieser Studie bestand darin, die Reliabilit{\"a}t der in der klinischen Routine benutzten Ellipsoidformel zur Berechnung des Schilddr{\"u}senvolumens zu {\"u}berpr{\"u}fen.}, language = {de} } @article{AngheloiuHaenscheidWenetal.2012, author = {Angheloiu, George O. and H{\"a}nscheid, Heribert and Wen, Xiaoyan and Capponi, Vincent and Anderson, William D. and Kellum, John A.}, title = {Experimental first-pass method for testing and comparing sorbent polymers used in the clearance of iodine contrast materials}, series = {Blood Purification}, volume = {34}, journal = {Blood Purification}, number = {1}, issn = {0253-5068}, doi = {10.1159/000339816}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199118}, pages = {34-39}, year = {2012}, abstract = {Background: Sorbents have been shown to adsorb iodinated radiocontrast media. Objective: In this study we describe a simple method to compare various sorbents in terms of capacity to adsorb radiocontrast media. Methods: Iodixanol solution was injected into columns filled with three types of sorbent at filtration velocities of increasing magnitude. Two variables of interest - contrast removal rate and matched iodine retention (MIR) - were calculated to measure the adsorption efficiency and the mass of contrast iodine adsorbed versus sorbent used, respectively. Results: The highest contrast removal and MIR for Porapak Q, CST 401 and Amberlite XAD4 were 41, 38 and 16\% (p = 0.22 and 0.0005 for comparisons between Porapak Q-CST 401 and CST 401-Amberlite XAD4) and 0.060, 0.055 and 0.024, respectively (p = 0.18 and 0.0008). Extrapolation to a clinical scenario may suggest that removal of 8 ml iodixanol could be achieved by masses of sorbents of 43, 47 and 107 g, respectively. Conclusion: In this study we set a benchmark for comparing the radiocontrast-adsorbing efficiency of polymer sorbents during first-pass experiments, using a readily available methodology.}, language = {en} } @article{AsterRomanosWalitzaetal.2022, author = {Aster, Hans-Christoph and Romanos, Marcel and Walitza, Susanne and Gerlach, Manfred and M{\"u}hlberger, Andreas and Rizzo, Albert and Andreatta, Marta and Hasenauer, Natalie and Hartrampf, Philipp E. and Nerlich, Kai and Reiners, Christoph and Lorenz, Reinhard and Buck, Andreas K. and Deserno, Lorenz}, title = {Responsivity of the striatal dopamine system to methylphenidate — A within-subject I-123-β-CIT-SPECT study in male children and adolescents with attention-deficit/hyperactivity disorder}, series = {Frontiers in Psychiatry}, volume = {13}, journal = {Frontiers in Psychiatry}, issn = {1664-0640}, doi = {10.3389/fpsyt.2022.804730}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270862}, year = {2022}, abstract = {Background: Methylphenidate (MPH) is the first-line pharmacological treatment of attention-deficit/hyperactivity disorder (ADHD). MPH binds to the dopamine (DA) transporter (DAT), which has high density in the striatum. Assessments of the striatal dopamine transporter by single positron emission computed tomography (SPECT) in childhood and adolescent patients are rare but can provide insight on how the effects of MPH affect DAT availability. The aim of our within-subject study was to investigate the effect of MPH on DAT availability and how responsivity to MPH in DAT availability is linked to clinical symptoms and cognitive functioning. Methods Thirteen adolescent male patients (9-16 years) with a diagnosis of ADHD according to the DSM-IV and long-term stimulant medication (for at least 6 months) with MPH were assessed twice within 7 days using SPECT after application of I-123-β-CIT to examine DAT binding potential (DAT BP). SPECT measures took place in an on- and off-MPH status balanced for order across participants. A virtual reality continuous performance test was performed at each time point. Further clinical symptoms were assessed for baseline off-MPH. Results On-MPH status was associated with a highly significant change (-29.9\%) of striatal DAT BP as compared to off-MPH (t = -4.12, p = 0.002). A more pronounced change in striatal DAT BP was associated with higher off-MPH attentional and externalizing symptom ratings (Pearson r = 0.68, p = 0.01). Striatal DAT BP off-MPH, but not on-MPH, was associated with higher symptom ratings (Pearson r = 0.56, p = 0.04). Conclusion Our findings corroborate previous reports from mainly adult samples that MPH changes striatal DAT BP availability and suggest higher off-MPH DAT BP, likely reflecting low baseline DA levels, as a marker of symptom severity.}, language = {en} } @article{BaurSchedelbeckPulzeretal.2015, author = {Baur, Johannes and Schedelbeck, Ulla and Pulzer, Alina and Bluemel, Christina and Wild, Vanessa and Fassnacht, Martin and Steger, U.}, title = {A case report of a solitary pancreatic metastasis of an adrenocortical carcinoma}, series = {BMC Surgery}, volume = {15}, journal = {BMC Surgery}, number = {93}, doi = {10.1186/s12893-015-0076-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126130}, year = {2015}, abstract = {Background Solitary metastases to the pancreas are rare. Therefore the value of resection in curative intention remains unclear. In the literature there are several promising reports about resection of solitary metastasis to the pancreas mainly of renal origin. Case presentation Here we report for the first time on the surgical therapy of a 1.5 cm solitary pancreatic metastasis of an adrenocortical carcinoma. The metastasis occurred almost 6 years after resection of the primary tumor. A partial pancreatoduodenectomy was performed and postoperatively adjuvant mitotane treatment was initiated. During the follow-up of 3 years after surgery no evidence of tumor recurrence occurred. Conclusion Resection of pancreatic tumors should be considered, even if the mass is suspicious for metastatic disease including recurrence of adrenocortical cancer.}, language = {en} } @phdthesis{Becker2010, author = {Becker, Kilian}, title = {Entwicklung eines 3D-Ganzk{\"o}rper-Ultraschalls an Kleintieren f{\"u}r morphologische Bildgebung, Volumetrie und Bildfusion mit PET}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-55916}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {Einleitung: Ultraschall wird seit mehr als 50 Jahren in der Medizin eingesetzt und ist mittlerweile ein unverzichtbares diagnostisches Verfahren, es erlaubt eine nicht-invasive Darstellung der Morphologie und Funktion von Organen in Echtzeit. In der Kleintierbildgebung dominieren bisher zur morphologischen Bildgebung Computertomographie (CT) und Magnetresonanztomographie (MRT). Daher wurde in der vorliegenden Arbeit die Idee entwickelt, die morphologischen Informationen des 3D-Ultraschalls (3D-US) f{\"u}r Untersuchungen an Kleintieren zu verwenden, außerdem sollten Methoden zur multimodalen Bildgebung und Bildfusion von 3D-US und Kleintier-Positronenemissionstomographie (PET) entwickelt werden. Der Vorteil des Ultraschalls gegen{\"u}ber dem Kleintier-CT liegt in der fehlenden Strahlenbelastung und der guten Verf{\"u}gbarkeit, was besonders f{\"u}r Verlaufsstudien von Interesse ist. Methoden und Ergebnisse: Zur Bildoptimierung wurde ein Fadenphantom entwickelt, welches aufgrund der feinen Strukturen die qualitative als auch quantitative Bestimmung der Aufl{\"o}sung erm{\"o}glicht. Die Vorarbeiten am Fadenphantom konnten exzellent die Probleme des 3D-Ultraschalls mit der achsenabh{\"a}ngigen Aufl{\"o}sung zeigen und erm{\"o}glichten eine schnelle Beurteilung der Bildqualit{\"a}t. Hier bestehen Einsatzm{\"o}glichkeiten in der Bewertung verschiedener Ultraschallger{\"a}te bez{\"u}glich der Tauglichkeit f{\"u}r 3D-Datenaquisition. Zur reproduzierbaren Lagerung von M{\"a}usen wurde eine Schallkopff{\"u}hrung ein sowohl f{\"u}r 3D-US als auch Kleintier-PET kompatibler Tierhalter entwickelt. Die Maus lag zur Untersuchung im angew{\"a}rmten Wasserbad auf dem Tierhalter fixiert, mit Inhalationsan{\"a}sthesie und Sauerstoff {\"u}ber eine Atemmaske versorgt. Der Zeitaufwand f{\"u}r eine 3D-US-Untersuchung betrug f{\"u}r die Akquisition etwa eine Minute. Die generierten Ultraschalldatens{\"a}tze waren von guter Qualit{\"a}t, Strukturen wie Leber, Nieren, Blase, Wirbels{\"a}ule und Lunge konnten selbst bei kleinen M{\"a}usen von unter 20 Gramm K{\"o}rpergewicht gut dargestellt werden. Zur Validierung des 3D-Ultraschalls wurde das Volumen verschiedener Organe und Tumore bestimmt und mit dem Goldstandard verglichen. Um die Koregistrierung mit der Kleintier-PET zu erm{\"o}glichen, wurden auf dem Tierhalter drei „fiducial markers" angebracht, die Position und Orientierung eindeutig definieren. Die Kleintier-PET-Untersuchungen wurden nach standardisierten Protokollen durchgef{\"u}hrt. Die anschließende Bildfusion erfolgte mittels der frei verf{\"u}gbaren Software "Amide". Diskussion: Mit dem in dieser Arbeit beschriebenen Verfahren ist eine standardisierte Gewinnung von 3D-US-Datens{\"a}tzen an Kleintieren m{\"o}glich; zus{\"a}tzlich konnte die Machbarkeit der Bildfusion mit PET-Datens{\"a}tzen gezeigt werden. Der Einsatz des 3D-Ultraschalls in longitudinalen Studien, zum Beispiel zur Beurteilung der Tumorprogression, ist vorstellbar. Die Zuverl{\"a}ssigkeit der volumetrischen Berechnungen ist f{\"u}r gr{\"o}ßere Organvolumina gut, bei kleineren Volumina besteht noch Optimierungsbedarf. Weitere Verbesserungen k{\"o}nnten durch den Einsatz von speziellen Schallk{\"o}pfen und h{\"o}heren Schallfrequenzen erzielt werden.}, subject = {Ultraschalldiagnostik}, language = {de} } @article{BeykanDamEberleinetal.2016, author = {Beykan, Seval and Dam, Jan S. and Eberlein, Uta and Kaufmann, Jens and Kj{\ae}rgaard, Benedict and J{\o}dal, Lars and Bouterfa, Hakim and Bejot, Romain and Lassmann, Michael and Jensen, Svend Borup}, title = {\(^{177}\)Lu-OPS201 targeting somatostatin receptors: in vivo biodistribution and dosimetry in a pig model}, series = {EJNMMI Research}, volume = {6}, journal = {EJNMMI Research}, number = {50}, doi = {10.1186/s13550-016-0204-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146888}, year = {2016}, abstract = {Background \(^{177}\)Lu is used in peptide receptor radionuclide therapies for the treatment of neuroendocrine tumors. Based on the recent literature, SST2 antagonists are superior to agonists in tumor uptake. The compound OPS201 is the novel somatostatin antagonist showing the highest SST2 affinity. The aim of this study was to measure the in vivo biodistribution and dosimetry of \(^{177}\)Lu-OPS201 in five anesthetized Danish Landrace pigs as an appropriate substitute for humans to quantitatively assess the absorbed doses for future clinical applications. Results \(^{177}\)Lu-OPS201 was obtained with a specific activity ranging from 10 to 17 MBq/μg. Prior to administration, the radiochemical purity was measured as s > 99.7 \% in all cases. After injection, fast clearance of the compound from the blood stream was observed. Less than 5 \% of the injected activity was presented in blood 10 min after injection. A series of SPECT/CT and whole-body scans conducted until 10 days after intravenous injection showed uptake mostly in the liver, spine, and kidneys. There was no visible uptake in the spleen. Blood samples were taken to determine the time-activity curve in the blood. Time-activity curves and time-integrated activity coefficients were calculated for the organs showing visible uptake. Based on these data, the absorbed organ dose coefficients for a 70-kg patient were calculated with OLINDA/EXM. For humans after an injection of 5 GBq \(^{177}\)Lu-OPS201, the highest predicted absorbed doses are obtained for the kidneys (13.7 Gy), the osteogenic cells (3.9 Gy), the urinary bladder wall (1.8 Gy), and the liver (1.0 Gy). No metabolites of 177Lu-OPS201 were found by radio HPLC analysis. None of the absorbed doses calculated will exceed organ toxicity levels. Conclusions The \(^{177}\)Lu-OPS201 was well tolerated and caused no abnormal physiological or behavioral signs. In vivo distributions and absorbed doses of pigs are comparable to those observed in other publications. According to the biodistribution data in pigs, presented in this work, the expected radiation exposure in humans will be within the acceptable range.}, language = {en} } @article{BeykanFaniJensenetal.2019, author = {Beykan, Seval and Fani, Melpomeni and Jensen, Svend Borup and Nicolas, Guillaume and Wild, Damian and Kaufmann, Jens and Lassmann, Michael}, title = {In vivo biokinetics of \(^{177}\)Lu-OPS201 in Mice and Pigs as a Model for Predicting Human Dosimetry}, series = {Contrast Media \& Molecular Imaging}, volume = {2019}, journal = {Contrast Media \& Molecular Imaging}, doi = {10.1155/2019/6438196}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177382}, pages = {6438196}, year = {2019}, abstract = {Introduction. \(^{177}\)Lu-OPS201 is a high-affinity somatostatin receptor subtype 2 antagonist for PRRT in patients with neuroendocrine tumors. The aim is to find the optimal scaling for dosimetry and to compare the biokinetics of \(^{177}\)Lu-OPS201 in animals and humans. Methods. Data on biokinetics of \(^{177}\)Lu-OPS201 were analyzed in athymic nude Foxn1\(^{nu}\) mice (28 F, weight: 26 ± 1 g), Danish Landrace pigs (3 F-1 M, weight: 28 ± 2 kg), and patients (3 F-1 M, weight: 61 ± 17 kg) with administered activities of 0.19-0.27 MBq (mice), 97-113 MBq (pigs), and 850-1086 MBq (patients). After euthanizing mice (up to 168 h), the organ-specific activity contents (including blood) were measured. Multiple planar and SPECT/CT scans were performed until 250 h (pigs) and 72 h (patients) to quantify the uptake in the kidneys and liver. Blood samples were taken up to 23 h (patients) and 300 h (pigs). In pigs and patients, kidney protection was applied. Time-dependent uptake data sets were created for each species and organ/tissue. Biexponential fits were applied to compare the biokinetics in the kidneys, liver, and blood of each species. The time-integrated activity coefficients (TIACs) were calculated by using NUKFIT. To determine the optimal scaling, several methods (relative mass scaling, time scaling, combined mass and time scaling, and allometric scaling) were compared. Results. A fast blood clearance of the compound was observed in the first phase (<56 h) for all species. In comparison with patients, pigs showed higher liver retention. Based on the direct comparison of the TIACs, an underestimation in mice (liver and kidneys) and an overestimation in pigs' kidneys compared to the patient data (kidney TIAC: mice = 1.4 h, pigs = 7.7 h, and patients = 5.8 h; liver TIAC: mice = 0.7 h, pigs = 4.1 h, and patients = 5.3 h) were observed. Most similar TIACs were obtained by applying time scaling (mice) and combined scaling (pigs) (kidney TIAC: mice = 3.9 h, pigs = 4.8 h, and patients = 5.8 h; liver TIAC: mice = 0.9 h, pigs = 4.7 h, and patients = 5.3 h). Conclusion. If the organ mass ratios between the species are high, the combined mass and time scaling method is optimal to minimize the interspecies differences. The analysis of the fit functions and the TIACs shows that pigs are better mimicking human biokinetics.}, language = {en} } @phdthesis{Blasl2004, author = {Blasl, Christiana}, title = {Chromatografischer Nachweis endogen radioiodierter Verbindungen im Urin von Patienten mit differenziertem Schilddr{\"u}senkarzinom nach Iod-131-Ganzk{\"o}rperszintigrafie}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12726}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {Der Follow-UP von Patienten mit differenziertem Schilddr{\"u}senkarzinom (DTC) wird konventionell mit I-131-Ganzk{\"o}rperzintigrafie (GKS) und Bestimmung des Serumthyreoglobulins (hTg) durchgef{\"u}hrt. Wegen der Inzidenz von 15\%-20\% diskordanter Resultate entwickelte Bianchi et al. (J Nucl Med 1993; 34: 2032-2037) die Serumchromatografie von endogen radioiodiertem Triiodthyronin (L-T3) und Thyroxin (L-T4) bei Patienten mit DTC nach oraler Applikation von I-131. Da im Rahmen des Iodstoffwechsels auch radioiodierte Verbindungen im Urin erscheinen, versuchten wir eine Urinchromatografiemethode zu entwickeln, basierend auf der Annahme, dass ein pathologischer I-131-Uptake, wenngleich zu niedrig um im GKS erkannt zu werden, gleichwohl {\"u}ber endogen iodierte Schilddr{\"u}senprodukte im Urin nachgewiesen werden kann. In der Urinchromatografie konnten die Ergebnisse der Serumchromatografie nicht erreicht werden.}, language = {de} } @article{BluemelLinkeHerrmannetal.2016, author = {Bluemel, Christina and Linke, Fraenze and Herrmann, Ken and Simunovic, Iva and Eiber, Matthias and Kestler, Christian and Buck, Andreas K. and Schirbel, Andreas and Bley, Thorsten A. and Wester, Hans-Juergen and Vergho, Daniel and Becker, Axel}, title = {Impact of \(^{68}\)Ga-PSMA PET/CT on salvage radiotherapy planning in patients with prostate cancer and persisting PSA values or biochemical relapse after prostatectomy}, series = {EJNMMI Research}, volume = {6}, journal = {EJNMMI Research}, number = {78}, doi = {10.1186/s13550-016-0233-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147798}, year = {2016}, abstract = {Background Salvage radiotherapy (SRT) is clinically established in prostate cancer (PC) patients with PSA persistence or biochemical relapse (BCR) after prior radical surgery. PET/CT imaging prior to SRT may be performed to localize disease recurrence. The recently introduced \(^{68}\)Ga-PSMA outperforms other PET tracers for detection of recurrence and is therefore expected also to impact radiation planning. Forty-five patients with PSA persistence (16 pts) or BCR (29 pts) after prior prostatectomy, scheduled to undergo SRT of the prostate bed, underwent \(^{68}\)Ga-PSMA PET/CT. The median PSA level was 0.67 ng/ml. The impact of \(^{68}\)Ga-PSMA PET/CT on the treatment decision was assessed. Patients with oligometastatic (≤5 lesions) PC underwent radiotherapy (RT), with the extent of the RT area and dose escalation being based on PET positivity. Results Suspicious lesions were detected in 24/45 (53.3 \%) patients. In 62.5 \% of patients, lesions were only detected by 68Ga-PSMA PET. Treatment was changed in 19/45 (42.2 \%) patients, e.g., extending SRT to metastases (9/19), administering dose escalation in patients with morphological local recurrence (6/19), or replacing SRT by systemic therapy (2/19). 38/45 (84.4 \%) followed the treatment recommendation, with data on clinical follow-up being available in 21 patients treated with SRT. All but one showed biochemical response (mean PSA decline 78 ± 19 \%) within a mean follow-up of 8.12 ± 5.23 months. Conclusions \(^{68}\)Ga-PSMA PET/CT impacts treatment planning in more than 40 \% of patients scheduled to undergo SRT. Future prospective studies are needed to confirm this significant therapeutic impact on patients prior to SRT.}, language = {en} }