PSMA RLT employing 177Lu by use of [177Lu]Lu-PSMA-617 has been demonstrated to be effective and well-tolerated, maintaining or even improving quality of life. Other radionuclides such as 161Tb are currently under investigation concerning clinical feasibility and therapeutic efficacy. However, patient-centered evaluations of well-being and adverse events are scarce. This study evaluates the impact of [161Tb]Tb-PSMA-617 RLT on health-related quality of life (HRQoL) across multiple scales, including adverse events. Analysis included 20 advanced, heavily pre-treated mCRPC patients enrolled in the REALITY registry (NCT04833517) who received [161Tb]Tb-PSMA-617 RLT (median two cycles; mean activity per cycle: 6.1 ± 1.2 GBq) after prior conventional PSMA RLT. HRQoL, covering physical, emotional, cognitive, and social functioning, was assessed using EORTC QLQ-C30. Hematotoxicities, liver and kidney function impairments, as well as xerostomia were evaluated according to CTCAE v5.0. For statistical analysis, the Wilcoxon matched-pairs signed-rank test was employed, with a significance threshold set at p < 0.05. Analysis of QLQ-C30 demonstrated that patient-reported well-being was largely maintained. Increased tiredness reached statistical significance (p = 0.036). Global health (p = 0.581) and overall quality of life (p > 0.999) remained stable throughout therapy. Most CTCAE ratings were mild or moderate. Worsening under therapy was limited: One anemia case progressed from CTCAE °2 to °4, and another from °2 to °3. Regarding renal function, two cases progressed from °2 to °3. No cases of xerostomia higher than °2 were observed. [161Tb]Tb-PSMA-617 RLT represents a well-tolerated and safe treatment option for advanced mCRPC, with patient-reported quality of life maintained over time, with only rare higher-grade hematological and renal toxicities.

BACKGROUND:Papillary thyroid carcinoma (PTC) with a BRAFV600E mutation is linked to more aggressive tumor characteristics, as well as a higher likelihood of recurrence and disease-specific mortality. This study aimed to investigate the association between BRAFV600E mutation status in patients with recurrent PTC post radioiodine (RAI) therapy and its relationship with clinicopathological characteristics and [18F]FDG-uptake patterns on PET/CT. METHODS:The multi-step selection process resulted in a final cohort of 38 patients out of 851 patients with thyroid carcinoma. The final cohort had confirmed papillary thyroid carcinoma, underwent thyroidectomy with subsequent RAI treatment, documented BRAFV600E status and elevated thyroglobulin (Tg) levels, and a [18F]FDG-PET/CT scan post-biopsy. Collected clinicopathological data encompassed among others tumor size and number of metastases. Furthermore, the lesions' SUVmax, peak, mean, MTV, and TLG were assessed, and associated with the respective BRAF-Status and the clinicopathological data. RESULTS:The statistical analyses showed a significant association between SUVmax, SUVpeak, SUVmean, and BRAFV600E mutation status, with P=0.009, P=0.0088, P=0.0092, respectively. There was also an independent correlation between tumor size and SUVmax. No significant difference in tumor size was observed between the BRAF+ and BRAF- groups. There was no significant association between TLG, MTV, Tg levels with SUVs. CONCLUSIONS:The BRAFV600E mutation and larger tumor size are linked to increased maximum, mean, and peak FDG uptake values on [18F]FDG-PET/CT in patients with recurrent PTC. These findings improve understanding of mutation-associated metabolic behavior in recurrent PTC; however, they do not support changes in clinical management or risk stratification based solely on FDG PET/CT metrics or BRAFV600E status. Further research should investigate the potential of [18F]FDG-PET/CT metrics as biomarkers for guiding individualized treatment strategies in BRAFV600E-positive PTC.

Evaluating efficacy and safety of individualized [177Lu]Lu‑PSMA‑617 radioligand therapy in heavily pretreated post-taxane patients with metastatic castration‑resistant prostate cancer (mCRPC), and to present a comparison with outcomes of non-individualized regimens. Per‑cycle activities of [177Lu]Lu-PSMA-617 were individualized by normalizing to body surface area and adjusting for renal clearance, hematopoietic function, and tumor burden and progression parameters. 227 post-taxane mCRPC patients with intense PSMA expression on PET/CT were enrolled in the prospective registry (REALITY; NCT04833517) and retrospectively analyzed. PSA progression-free survival (PSA-PFS) and overall survival (OS) according to Kaplan-Meier analysis, Cox proportional‑hazards models with backward elimination for identification of outcome predictors, safety assessment according to CTCAE v5.0. Median administered activity was 7.1 GBq per cycle (range 2.7–11.6 GBq) and cumulative activity 22.3 GBq (range 2.7–77.8 GBq), while patients received a median of 3 cycles within a 6-week interval. After a median follow‑up of 15.9 months (95

Background: Despite its high diagnostic accuracy, conventional prostate-specific membrane antigen (PSMA) targeting positron emission tomography/computed tomography (PET/CT) fails to localize disease in a non-negligible proportion of patients with biochemical recurrence (BCR). Preliminary studies in small patient cohorts suggest that [ 89 Zr]Zr-PSMA-617 PET/CT may improve localization of BCR, presumably due to its longer physical half-life, in patients with previously failed localization efforts. This study seeks to validate reported preliminary detection rates in a markedly larger cohort and to identify predictive biomarkers for positive findings on [ 89 Zr]Zr-PSMA-617 PET/CT in patients with prior negative conventional PSMA PET/CT. Results: Among 70 patients with prior negative conventional PSMA PET/CT, 52 demonstrated tumor suspicious lesions on subsequent [ 89 Zr]Zr-PSMA-617 imaging, resulting in a detection rate of 74.3%. A total of 76 lesions were detected, predominantly in lymph nodes (46.1%) and local recurrence sites (40.8%), with fewer osseous (9.2%) and visceral (4.0%) metastases. Scan positivity was significantly higher in patients with higher prostate-specific antigen levels (PSA > 0.2 ng/mL, p = 0.002) and lower PSA doubling times (PSA dt < 4 months, p = 0.041). Conclusion: In the largest cohort to date investigating PET/CT with long-lived PSMA tracers, [ 89 Zr]Zr-PSMA-617 PET/CT demonstrated a high detection rate for biochemical recurrence in patients with negative findings on conventional PSMA PET/CT, achieving a sensitivity of 74.3%. PSA level and PSA doubling time represent predictive biomarkers for lesion detection on [ 89 Zr]Zr-PSMA-617 PET/CT. Pending forthcoming prospective studies validating its apparently exceptional clinical potential, [ 89 Zr]Zr-PSMA-617 PET/CT may serve as a useful complementary imaging approach, enabling and facilitating individualized and targeted therapeutic approaches including curative salvage treatment in non-advanced prostate cancer disease.

PSMA PET/CT using PSMA ligands labeled with the long-lived radionuclide zirconium-89 represents a promising novel imaging approach for prostate cancer. Preliminary evidence indicates that [89Zr]Zr-PSMA PET/CT may enhance the detection of tumor lesions in patients with biochemical recurrence (BCR). This study aims to evaluate the positivity rate and feasibility of [89Zr]Zr-PSMA imaging in patients with very low PSA levels (≤ 0.2 ng/mL). Sixty-five patients with BCR and PSA levels ≤ 0.2 ng/mL undergoing [89Zr]Zr-PSMA PET/CT were analyzed. The mean PSA level at imaging was 0.14 ± 0.04 ng/mL. PET/CT was performed using a mean injected activity of 129.0 ± 19.3 MBq and an uptake time of 48 h. Positivity rates and potential predictors of scan positivity, including PSA level, PSA doubling time, and initial Gleason score, were evaluated. [89Zr]Zr-PSMA PET/CT achieved a high overall positivity rate of 72.3

INTRODUCTION:To enhance the effectiveness of radioligand therapy (RLT), new prostate-specific membrane antigen (PSMA) targeting radiopharmaceuticals utilizing alternative radionuclides are under active investigation. One promising alternative to the established 177 Lu is the use of 161 Tb. A key advantage of 161 Tb is its emission of a higher proportion of low-energy conversion and Auger electrons, which may contribute to enhanced therapeutic effectiveness. This study provides a first exploratory evaluation of the efficacy and safety of [ 161 Tb]Tb-PSMA-617 in patients with progression after [ 177 Lu]Lu-PSMA-617, aiming to generate early clinical insights. METHODS:The study included 15 patients with mCRPC, who were enrolled in the "prospective registry to assess outcome and toxicity of targeted radionuclide therapy in patients with mCRPC in clinical routine" (REALITY Study; NCT04833517). All patients had received conventional PSMA RLT using [ 177 Lu]Lu-PSMA-617, which resulted in initial biochemical response (PSA decline ≥50%), followed by a biochemical relapse, prompting the re-initiation of PSMA RLT using [ 161 Tb]Tb-PSMA-617. Patients received a median of 3 (range: 2-7) cycles with mean administered activity of 5.4 ± 1.1 GBq and mean cumulative activity of 19.2 ± 6.4 GBq [ 161 Tb]Tb-PSMA-617. Treatment response was assessed both biochemically by serum PSA levels and through molecular imaging by total lesion PSMA (TLP) on [ 68 Ga]Ga-PSMA-11 PET/CT scans. Adverse events were assessed at baseline and follow-up using the "Common Terminology Criteria for Adverse Events" (Version 5.0). RESULTS:[ 161 Tb]Tb-PSMA-617 RLT showed response rates of 66.7% (10/15 patients) based on biochemical assessment and 86.7% (13/15 patients) based on molecular imaging assessment. Beginning with the initiation of [ 161 Tb]Tb-PSMA-617 RLT, the median progression-free survival (PFS) was 6.4 months, and the median overall survival (OS) was 15.5 months. In total, 6 CTCAE grade deteriorations from grade 2 to grade 3 or from grade 3 to grade 4 were observed. No discontinuation of PSMA RLT due to adverse events was reported. CONCLUSIONS:[ 161 Tb]Tb-PSMA-617 RLT emerges as a promising treatment option, demonstrating encouraging response rates, preliminary clinical outcomes, and a favorable safety profile as second-line RLT in progressing patients who previously benefited from [ 177 Lu]Lu-PSMA-617 RLT.

Terbium-161 (161Tb) has emerged as a promising radionuclide for radioligand therapy (RLT) due to its emission of Auger and conversion electrons, which may support therapeutic efficacy through increased local energy deposition. Despite growing research efforts aimed at the clinical potential of 161Tb, dosimetric data, particularly for tumor lesions, remain scarce. To address this gap, we assessed tumor and organ dosimetry in mCRPC patients treated with [161Tb]Tb-PSMA-617. The study involved n = 15 patients with metastasized castration-resistant prostate cancer (mCRPC) participating in a registry (NCT04833517) and receiving [161Tb]Tb-PSMA-617. All patients received a median of 2 (range: 1–3) cycles with mean administered activity of 6.0 ± 1.3 GBq and mean cumulative activity of 12.3 ± 4.6 GBq [161Tb]Tb-PSMA-617. Hybrid dosimetry of organs at risk, including the salivary glands, the kidneys, the liver, and tumor lesions was performed analyzing whole-body planar and SPECT/CT images. Absorbed doses were estimated using OLINDA/EXM for 161Tb. Tumor-to-organ ratios (TR) of mean tumor-absorbed doses over relevant organs at risk were calculated. Mean absorbed dose to kidneys, parotid glands, submandibular glands and liver was 0.70 ± 0.41 Gy/GBq, 0.40 ± 0.20 Gy/GBq, 0.36 ± 0.14 Gy/GBq and 0.13 ± 0.08 Gy/GBq, respectively. Tumor kinetics in 43 lesions demonstrated stable activity over time (mean half-life of all lesions: 44.07 h ± 15.88 h) delivering a mean overall absorbed tumor dose of 5.95 ± 3.60 Gy/GBq, the resulting TR over kidney and parotid gland were 10.55 ± 8.32 and 16.15 ± 11.85, respectively. [161Tb]Tb-PSMA-617 delivers high tumor-absorbed doses with tolerable doses to relevant organs at risk, translating into favorable tumor-to-normal-organ ratios. Dosimetry results confirm 161Tb as a promising radionuclide for PSMA-targeted radioligand therapy in mCRPC.

Background the aim of this study is to investigate the safety profile and efficacy of single-dose docetaxel augmented targeted radionuclide therapy (TRT) in the form of prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) using Lutetium-177 (177Lu) in patients who have progressed on PSMA-617 RLT. A retrospective analysis was conducted on 10 mCRPC patients (median age: 68 years; range: 51-74 years) who were progressing on prior RLT. The patients received one cycle of treatment involving 50 mg/m & sup2; of docetaxel combined with [Lu]Lu-PSMA-617. Efficacy was assessed via biochemical (PSA, PCWG3) and molecular imaging endpoints (TLP/MTV via [68Ga]Ga-PSMA-11 PET/CT). PSA-progression-free survival (PSA-PFS) and overall survival (OS) were analyzed using Kaplan-Meier statistics. Toxicity was graded by CICAE v5.0. Results After single-dose docetaxel augmented ["Lu]Lu-PSMA-617 RLT, 60% of the patients showed a disease stabilization for 4-8 weeks based on PSA (10% partial remission and 50% stable disease). Based on the molecular imaging-based response assessment, 62.5% of the patients showed a disease stabilization (25% parietal response and 37.5% stable disease). The median PSA-PFS and OS thereafter were 4.4 months (95%CI: 1.3-7.6 months) and 7.2 months (95%CI: 2.9-11.5 months), respectively. The augmentation therapy was well-tolerated without any serious acute adverse events. During the first 4-8 weeks thereafter 3 patients exhibited transient grade 3 anemia and one patient a transient grade 2 nephrotoxicity. Conclusions This pilot experience demonstrates that single-dose docetaxel application to [17"Lullu-PSMA-617 radioligand therapy is feasible and may present an option for late-stage heavily pretreated mCRPC progressing on PSMA-617 RLT. Formal study of this combination is warranted.

The aim of this study was to evaluate the dosimetry for [177Lu]Lu-PSMA-617 in advanced non-prostate cancer (non-PCa) patients with previous intense radiotracer uptake of the tumor lesions on PET/CT using [68Ga]Ga-PSMA-11. Dosimetry data of 5 patients with non-prostate cancer (non-PCa group) were assessed and compared; Non-PCa tumors were breast cancer (BC), renal cell carcinoma (RCC), hepatocellular carcinoma (HCC) and anaplastic astrocytoma (AA). Five patients with metastatic castration-resistant prostate cancer (PCa group) were used as control-group. All patients were given [177Lu]Lu-PSMA-617 after proven sufficient PSMA uptake of tumor lesions by [68Ga]Ga-PSMA-11 PET/CT. Post-therapeutic dosimetry with serial whole-body scans (24, 48 and 72–120 h post-injection) included calculation of effective half-life and absorbed doses for tumor and non-tumor lesions and comparison between non-PCa and PCa patients. The mean effective half-life in tumor lesions was significantly shorter in non-PCa compared to PCa patients (27.1 ± 13.1 h vs. 74.9 ± 23.1 h, respectively, p < 0.001). Likewise, the mean absorbed dose per injected activity was significantly lower in tumor lesions of non-PCa compared to PCa (0.49 ± 0.40 Gy/GBq vs. 3.51 ± 2.20 Gy/GBq, respectively, p < 0.001). No significant differences for the source organ absorbed dose or effective half-life were observed between both groups. In non-prostate malignancy with impressive diagnostic PSMA-mediated tumor uptake, i.e. high tracer uptake at early time points in [68Ga]Ga-PSMA-11 PET/CT, [177Lu]Lu-PSMA-617 delivers a low tumor-absorbed dose due to a short effective half-life, therefore this therapy does not appear to be a potential antitumor option.

Abstract Background the aim of this study is to investigate the safety profile and efficacy of single-dose docetaxel augmented targeted radionuclide therapy (TRT) in the form of prostate-specific membrane antigen (PSMA)- targeted radioligand therapy (RLT) using Lutetium-177 (177Lu) in patients who have progressed on PSMA-617 RLT. A retrospective analysis was conducted on 10 mCRPC patients (median age: 68 years; range: 51–74 years) who were progressing on prior RLT. The patients received one cycle of treatment involving 50 mg/m² of docetaxel combined with [177Lu]Lu-PSMA-617. Efficacy was assessed via biochemical (PSA, PCWG3) and molecular imaging endpoints (TLP/MTV via [68Ga]Ga-PSMA-11 PET/CT). PSA-progression-free survival (PSA-PFS) and overall survival (OS) were analyzed using Kaplan–Meier statistics. Toxicity was graded by CTCAE v5.0. Results After single-dose docetaxel augmented [177Lu]Lu-PSMA-617 RLT, 60% of the patients showed a disease stabilization for 4–8 weeks based on PSA (10% partial remission and 50% stable disease). Based on the molecular imaging-based response assessment, 62.5% of the patients showed a disease stabilization (25% parietal response and 37.5% stable disease). The median PSA-PFS and OS thereafter were 4.4 months (95%CI: 1.3–7.6 months) and 7.2 months (95%CI: 2.9–11.5 months), respectively. The augmentation therapy was well-tolerated without any serious acute adverse events. During the first 4–8 weeks thereafter 3 patients exhibited transient grade 3 anemia and one patient a transient grade 2 nephrotoxicity. Conclusions This pilot experience demonstrates that single-dose docetaxel application to [177Lu]Lu-PSMA-617 radioligand therapy is feasible and may present an option for late-stage heavily pretreated mCRPC progressing on PSMA-617 RLT. Formal study of this combination is warranted.

Large language models (LLMs) are increasingly explored for clinical use. However, the extent to which such models can reliably support physicians in reporting, staging, and the assessment of classification remains an active area of research. This study aimed to evaluate and compare multiple LLMs for automated PROMISE V2 classification for prostate cancer. A total of 126 unambiguous German-language PSMA PET/CT text reports were retrospectively analyzed, with reference standards established by expert consensus based on image interpretation and the original report text. Five LLMs (GPT-5.4, DeepSeek-V3.2, Claude Sonnet 4.6, Gemini 3 Flash and Grok 4) were assessed using two English-language prompting strategies of varying complexity. Agreement with the reference standard served as the primary endpoint. Performance varied in the short-prompt setting (36.5-79.4%) but improved consistently with the long prompt (74.6-86.5%), with Gemini 3 Flash achieving the highest agreement. Across PROMISE V2 subcategories, agreement rates were high (miT: 81.0-92.1%, miN: 92.9-96.0%, miM: 92.9-95.2%), despite inter-model differences. In conclusion, contemporary LLMs demonstrate promising performance in deriving PROMISE V2 scores from unambiguous original report texts, particularly when guided by detailed prompts.

The increasing use of artificial intelligence (AI) chatbots for patient education raises questions about their accuracy, readability, and conciseness in delivering medical information. This study evaluates the performance of ChatGPT 4o and DeepSeek V3 in answering common patient inquiries about Peptide Receptor Radionuclide Therapy (PRRT). Twelve frequently asked patient questions regarding PRRT were submitted to both chatbots. The responses were assessed by nine professionals using a blinded survey, scoring accuracy, conciseness, and readability on a five-point scale. Statistical analyses included the Mann-Whitney U test for nonparametric data and the Chi-square test for medically incorrect responses. A total of 324 individual assessments were conducted. No significant differences were found in accuracy between ChatGPT 4o (mean 4.43) and DeepSeek V3 (mean 4.56; P = 0.0909) or in readability between ChatGPT 4o (mean 4.38) and DeepSeek V3 (mean 4.25; P = 0.1236). However, ChatGPT 4o provided significantly more concise responses (mean 4.55) compared to DeepSeek V3 (mean 4.24; P = 0.0013). Medically incorrect information defined as accuracy ≤ 3 was present in 7-8% of chatbot responses, with no significant difference between the two models (P = 0.8005). Both AI chatbots demonstrated strong performance in providing medical information on PRRT, with ChatGPT 4o excelling in conciseness. However, the presence of medical inaccuracies highlights the need for physician oversight when using AI chatbots for patient education. Future research should explore methods to enhance AI reliability and personalization in clinical communication.

BACKGROUND:This study aims to further strengthen the evidence of tumor sink effect (TSE) and to confirm this phenomenon in patients undergoing 225Ac/177Lu-PSMA tandem radioligand therapy. METHODS:The study included a total of N.=31 mCRPC patients who undergone two cycles of [177Lu]Lu-PSMA-617 RLT, with at least one cycle being augmented by [225Ac]Ac-PSMA-617. For pre- and post-therapeutic [68Ga]Ga-PSMA-11 PET/CT scans the standardized uptake value (SUVmean) of the liver, kidneys, parotid glands, and spleen as well as the total lesion PSMA (TLP) were assessed and compared. RESULTS:The mean TLP value decreased by 31.32% after two cycles of PSMA-RLT. Overall, significant increases in SUVmean were noted in the spleen (P=0.002) and liver (P=0.009). Especially, responders exhibited significant SUVmean increases in the spleen (P<0.001, baseline mean: 5.35 vs. follow-up mean: 7.28), liver (P=0.001, 4.21 vs. 5.00), and kidney (P=0.003, 17.30 vs. 20.43). Correlation analysis revealed significant relationships between change in TLP and change in SUVmean in the parotid gland (r=0.408, P=0.023) and spleen (r=0.410, P=0.022). The strength of TSE varied with tumor size, with an increase in tumor burden leading to a stronger TSE. CONCLUSIONS:This analysis demonstrates the presence of the TSE in mCRPC patients undergoing the innovative 225Ac/177Lu-PSMA tandem radioligand therapy concept. TSE may hold significant clinical implications and may play a role towards more individualized RLT.

An increase of PSMA expression under androgen receptor signaling inhibitors (ARSi) measured on PSMA PET was reported: However, results were inconsistently reproduced clinically and the frequency and timing of the PSMA expression modulation by ARSi remains unknown. In this multicenter retrospective study, we aimed at assessing in patients with CRPC the influence of ARSi early after initiation (≤ 30 days) on PSMA expression at the whole-body (WB) level by using WB PSMA PET quantitative parameters. (m)CRPC patients from 5 international sites who underwent a PSMA PET prior to (PET1) and early (< 30 days) after (PET2) ARSi initiation were included. WB-PSMA PET quantitative parameters (PSMA-positive WB-tumor volume (TV), WB-SUVmax, WB-SUVmean) and PSA changes between PET1 and PET2 (PSA1/PSA2) were evaluated. Changes of WB-TV / WB-SUVmax/mean between PET1 and PET2 were considered significant if ≥ 30

PURPOSE:With increasing life expectancy, the number of older patients with metastatic castration-resistant prostate cancer (mCRPC) continues to rise, but this group is currently underrepresented in clinical trials. This study aims to assess the efficacy and safety of prostate-specific membrane antigen (PSMA) targeted radioligand therapy (RLT) in patients over 85 years old with mCRPC. MATERIALS AND METHODS:A retrospective analysis was conducted on 21 mCRPC patients aged 85 years or older receiving PSMA-RLT (range: 85-96 y). The median number of treatment cycles was 4 (range: 1-13 cycles), with a mean cumulative administered activity of 26.9±17.3 GBq (range: 8.0-87.2  GBq) of [ 177 Lu]Lu-PSMA-617. Adverse events, including anemia, thrombocytopenia, leukopenia, renal impairment, fatigue, and xerostomia were classified according to CTCAE version 5.0. RESULTS:The mean best PSA response across the cohort was -37.6±73.3%, with 62% (13 of 21 patients) showing partial remission. Median progression-free survival and overall survival were 4.6 and 14.7 months, respectively. Severe adverse events were rare, occurring in 2 patients: 1 case of grade 3 anemia and 1 of grade 3 thrombocytopenia. CONCLUSIONS:The results demonstrate that PSMA-RLT is an effective and well-tolerated treatment for mCRPC patients over 85 years, with clinical outcomes and safety comparable to those observed in studies involving younger populations. This highlights its potential as a valuable therapeutic option for this aging patient group.

The heterogeneous expression of somatostatin receptors in gastroenteropancreatic neuroendocrine tumors (GEP-NET) leads to significant intra-individual variability in tracer uptake during pre-therapeutic [68Ga]Ga-DOTATOC PET/CT for patients receiving peptide receptor radionuclide therapy (PRRT). This study aims to evaluate the lesion-based relationship between receptor-mediated tracer uptake and the functional response to PRRT. A retrospective analysis was conducted on 32 patients with metastatic GEP-NET (12 pancreatic and 20 non-pancreatic), all treated with [177Lu]Lu-octreotate (4 cycles, with a mean of 7.9 GBq per cycle). [68Ga]Ga-DOTATOC PET/CT was performed at baseline and 3 months after the final PRRT cycle. Tumor uptake was quantified using the standardized uptake value (SUV). For each patient, 2 to 3 well-delineated tumor lesions were selected as target lesions. SUVmax, SUVmean (automated segmentation with a 50% SUVmax threshold), and corresponding tumor-to-liver ratios (SUVmaxT/L and SUVmeanT/L) were calculated. Functional tumor response was assessed based on the relative change in metabolic tumor volume (%ΔTVPET). The correlation between baseline SUV parameters and lesion-based functional response was analyzed using Spearman's rank correlation. A total of 71 lesions were included in the analysis. The mean baseline SUVmax and SUVmean were 28.1 ± 15.9 and 13.6 ± 5.1, respectively. Three months after PRRT completion, the mean %ΔTVPET was 39.6 ± 52.1%. Baseline SUVmax and SUVmean demonstrated a poor correlation with lesion-based response (p = 0.706 and p = 0.071, respectively). In contrast, SUVmaxT/L and SUVmeanT/L were significantly correlated with lesion-based response (SUVmeanT/L: p = 0.011, r = 0.412; SUVmaxT/L: p = 0.004, r = 0.434). Among patient characteristics-including primary tumor origin, baseline tumor volume, and metastatic sites-only pancreatic origin was significantly associated with functional tumor volume reduction (ΔTVPET%: 56.8 ± 39.8 in pancreatic vs. 28.4 ± 50.1 in non-pancreatic NET; p = 0.020). The lesion-based molecular response to PRRT correlates with pretreatment somatostatin receptor PET uptake, particularly when expressed as tumor-to-liver SUV ratios (SUVmaxT/L and SUVmeanT/L).

A 72-year-old man underwent 18F-DCFPyL PSMA PET/CT imaging for the localization of biochemical recurrence (BCR) of prostate cancer. The scan revealed no definite findings, with only a vague uptake of uncertain significance in the bladder neck region. An additional PET/CT scan using a 64Cu-labeled trimeric PSMA ligand demonstrated astonishing distinct uptake in the former prostate bed, unequivocally confirming the presence of a small local recurrence and allowing for targeted local therapy. This intriguing case highlights the potential of PET/CT using 64Cu-labeled trimeric PSMA ligands, especially when conventional PSMA PET/CT scans yield ambiguous results.

The Auger emitter 161Tb is an increasingly discussed radionuclide for targeted radionuclide therapy. The aim of this study was to assess the feasibility of scintigraphic imaging with 161Tb in terms of image quality and quantitative capabilities by phantom measurements and to evaluate the suitability of this radionuclide for clinical use. Phantom measurements were conducted using a standardized NEMA IEC body phantom filled with activity concentrations ranging from 2.5 GBq to 100 MBq. Both visual and quantitative analyses were performed, including assessment of the image calibration factor (CF), as well as the recovery coefficient (RC) and the contrast-to-noise ratio (CNR) of the individual spheres. The results observed in this study demonstrate that quantitative SPECT/CT imaging with 161Tb is feasible over a wide range of activity making this radionuclide suitable for clinical applications. Acquiring a total of at least 5 million photopeak counts enables visual detectability of lesions of diameter lower than 20 mm and quantitative calibration for dosimetry purposes.

We present an 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) scan of a 27 y/o patient with long-standing significant B symptoms, diffuse bone pain, increased inflammation parameters, and polydipsia revealing multiple FDG-avid osteolytic lesions of the axial skeleton including a vertebra plana of T7 and paraosseous soft tissue lesions. A CT-guided biopsy confirmed the diagnosis of Langerhans cell histiocytosis (LCH). This case highlights the importance of considering LCH in young patients with vertebral collapse and underscores the role of PET/CT imaging in establishing an accurate diagnosis.

Aim of this study was to analyze the safety of prostate-specific membrane antigen radioligand therapy (PSMA-RLT) in patients with metastatic castration-resistant prostate cancer (mCRPC) with preexisting mild to moderate leukopenia (CTCAE ≥ 1). Thirty-seven mCRPC patients with preexisting leukopenia (leukocyte count < 3.8 × 109/L) were included in this study. Patients received a median of 3 cycles of [177Lu]Lu-PSMA-617 (range 1–9). No significant difference in leukocyte counts was observed between baseline and follow-up after each PSMA-RLT cycle: first cycle (3.0 ± 0.5 at baseline vs. 3.4 ± 1.4 at follow up [in × 109/L], p = 0.0921), second cycle (3.1 ± 0.4 vs. 3.8 ± 1.7, p = 0. 0.0509), and third cycle (3.1 ± 0.4 vs. 3.2 ± 2.0, p = 0.2929), respectively. Similarly, baseline and end of treatment values, irrespective of the number of administered cycles, did not reveal a significant difference (3.0 ± 0.5 vs. 3.5 ± 1.4, p = 0.0684). After the end of therapy, irrespective of the number of administered cycles, 27