To refine the optimal PRIMARY score thresholds across different PSA ranges, enhancing diagnostic accuracy for clinically significant prostate cancer (csPCa). The study retrospectively analyzed 373 patients who underwent PSMA PET/CT scans for suspected csPCa between June 2021 and December 2023. The diagnostic efficacy of PRIMARY score was independently assessed using 68Ga-PSMA PET/CT. Receiver-operating characteristic curve analysis was used to estimate the diagnostic performance. The diagnostic efficacy of the PRIMARY score with different thresholds in different PSA ranges was also calculated and compared. The PRIMARY score maintains high diagnostic accuracy either in group of PSA ≤ 20 ng/mL or PSA > 20 ng/mL, with an AUC exceeding 0.8 at appropriate thresholds. Notably, in patients with PSA > 20 ng/mL, a PRIMARY score threshold of 4 demonstrated enhanced diagnostic accuracy compared to a threshold of 3, significantly improving specificity from 70.6% to 91.2% while maintaining high sensitivity (from 99.2% to 98.4%). Consequently, 91.2% (31/34) patients could avoid unnecessary biopsies, at the expense of missing 1.6% (2/125) of csPCa cases. Across different PSA ranges, the PRIMARY score based on 68Ga-PSMA PET/CT imaging is useful in the diagnosis of csPCa. A threshold of 3 for PSA ≤ 20 ng/mL and a threshold of 4 for 20 ng/mL < PSA ≤ 50 ng/mL respectively demonstrated favorable diagnostic performance.

Head and neck cancer (HNC) patients frequently develop post-radiation maxillary sinusitis. This study investigated how different radiation therapy (RT) modalities, photon, proton, and mixed photon/proton RT, affect maxillary sinus inflammation, using 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT). Seventy-seven HNC patients treated with RT (30 with photon, 20 with proton, and 27 with mixed photon/proton RT) underwent FDG-PET/CT imaging before and 3 months after treatment. Demographic information, tumor location, chemotherapy details, radiation dose (cGy), and post-radiation sinusitis ratings (scale 0-2) were collected. The mean standardized uptake value (SUVmean) of the maxillary sinus was measured by a radiologist with two years of experience using manually delineated regions of interest. Parametric paired t-tests were used to compare pre- and post-treatment SUVmeans for each RT modality. Pre-minus-post-treatment changes in SUVmean (ΔSUVmean) between RT modalities were compared using independent t-tests. Correlation between radiation dose and ΔSUVmean and correlation between ΔSUVmean and clinical sinusitis scores were assessed using Pearson correlation analysis. Photon RT was associated with a statistically significant increase in maxillary sinus SUVmean post-treatment (+14.32%, P = 0.0324), while proton RT and mixed photon/proton RT did not result in significant changes (-3.39%, P = 0.6549 and -5.33%, P = 0.4541, respectively). A significant difference was found between photon and mixed photon/proton RT (P = 0.0444), whereas the difference between photon and proton RT approached significance (P = 0.0790). Clinical inflammation ratings were highest for photon therapy (average 0.97), followed by mixed therapy (0.78), then proton therapy (0.65), though these differences were not statistically significant. Our findings demonstrate that photon RT leads to significant increases in maxillary sinus SUVmean as measured by FDG-PET/CT, while proton and mixed photon/proton RT do not show statistically significant changes. These preliminary results suggest that proton-based radiation modalities may be associated with reduced maxillary sinus inflammatory activity compared to photon RT alone, though larger studies with longer follow-up are needed to establish clinical significance and patient outcomes.

Neuroendocrine tumors (NETs) can affect several organ systems and present a variety of clinical symptoms, which are difficult to diagnose by conventional methods. Somatostatin receptor (SSTR) is a group of specific receptors expressed on the well-differentiated NET cell membrane. [68Ga]-labeled somatostatin analogues (SSAs) PET/CT, endogenous ligands targeting SSTR, is widely used in currently clinical NETs diagnosis. The dual-tracer strategy ([68Ga]Ga-SSAs + [18F]FDG) allows for a more detailed evaluation of tumor metabolism and receptor expression. The NETPET score, integrating [68Ga]Ga-SSAs PET/CT and [18F]FDG PET/CT results, enhances the accuracy of predicting treatment response and prognosis. In addition, novel isotopes ([18F]/[64Cu]) labeled SSAs and SSTR antagonists outperformed [68Ga]-SSAs in lesion detection, tumor uptake, and tumor-to-background ratio. Due to undifferentiated or dedifferentiated NETs, SSTR may not be expressed. [68Ga]Ga-Pentixafor and [18F]-FDG PET/CT are applicable for SSTR-negative NET diagnosis. [18F]-MFBG and [18F]-DOPA have a higher sensitivity for identifying non-metastatic pheochromocytoma and paraganglioma (PPGL) than other radiotracers. This review addressed NET diagnosis with conventional imaging techniques, the clinical application of novel radiotracers, and the merits and limitations of the various radiotracers.

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.

Gallium-68 labeled fibroblast activation protein inhibitor ([68Ga]Ga-FAPI-04) can be visualized just 15 min post-injection. However, the appearance of imaging at 15 and 60 min remains unclear. This study aimed to explore the relationship between quantitative values in [68Ga]Ga-FAPI-04 PET, specifically at 15 and 60 minutes post-injection, in patients with various tumor. We enrolled 30 patients with cancer who underwent [68Ga]Ga-FAPI-04 PET/CT scan between January 2021 and February 2025 at our institute. Image acquisition was performed using a PET/CT scanner at 15 min and 60 min after [68Ga]Ga-FAPI-04 injection. The maximum, mean and peak standardized uptake value (SUVmax, SUVmean and SUVpeak), tumor-to-liver ratio (TLR), and uptake tumor volume (UTV) were measured in the region of interest of the target lesion, liver SUVmean (SUVliver) was also measured. Correlation coefficients of the between-image variables were evaluated by Spearman's rank correlation test. Agreement between the variables was evaluated by Bland-Altman plots with 95% limits of agreement. The SUVmax, SUVmean, SUVpeak and UTV in tumors of all examinations were decreased from 15 min to 60 min. The SUVmax, SUVmean, SUVpeak, TLR, and UTV at 15 min and 60 min were highly correlated (rs = 0.945, 0.949, 0.959, 0.943, and 0.958; P < 0.001). The 95% limits of agreement ranged from -27.8 to 29.1 with a mean of 0.7 and -24.1 to 29.5 with a mean of 2.7 for SUVmax and SUVmean, respectively. Other PET metrics demonstrated that all limits are above ± 30% between 15 min and 60 min. We observed a high correlation between the quantitative values at 15 min and 60 min. Meanwhile, 15 min and 60 min [68Ga]Ga-FAPI-04 PET SUVmax and SUVmean have clinically acceptable reproducibility, and 15 min scan is feasible for all patients, but SUVpeak, TLR and UTV should not be used interchangeably.

The purpose of this study is to evaluate the PSMA PET imaging parameters in association with outcomes among patients with oligorecurrent prostate cancer. This retrospective single-center study included 101 patients (median age 71; interquartile range 65-75) with biochemically recurrent prostate cancer who underwent PSMA PET between May 2021 and May 2022, revealing 5 or fewer sites of metastases (oligometastatic disease). Multiple variables including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), and molecular tumor volume (MTV) were measured and analyzed on a per-patient basis, along with total MTV and molecular tumor burden (MTB). Multivariable Cox proportional-hazards regression models were used to identify factors associated with progression-free survival (PFS). PSMA PET revealed a total of 216 lesions across all patients, of which 134 (62.0%) involved the lymph nodes and 56 (25.9%) involved the bone. A total of 61 (60.4%) patients received combined metastasis-directed and hormone therapy, and 40 (39.6%) received hormone therapy only. The median subsequent follow-up from PSMA PET detection of oligorecurrent disease was 18.2 months (IQR 10.3-25.0). MTV on PSMA PET was associated with worse PFS (hazard ratio: 1.05, 95% CI 1.00-1.11; P = 0.04). Molecular tumor volume on PSMA PET is associated with worse clinical outcomes in patients with oligorecurrent prostate cancer.

Glomerular filtration rates (GFR's) are used to guide patient management. GFR's are based on radioactivity measurements of blood samples sampled at different times. We compared GFR computations from blood collected at 6 times to those collected at 2 timepoints. Thirty-seven GFR studies were performed on 25 patients. After intravenous administration of I-125 sodium iothalamate, 6 plasma samples were obtained at 5 min, 10 min, 15 min, 3 hr, 3.5 hr and 4 hr after injection, then counted in a well counter. Two different GFR calculation tools were applied to each set of 6 plasma counts (Methods 1 and 2), and a 2-sample algorithm (Method 3) computed GFR using only 3 hr and 4 hr data. Linear correlation between Method 1 and 2 GFR's was stronger than for Method 3 versus Methods 1 and 2 (r = 1.00 versus r = .91, P < .0001). Bland-Altman limits of agreement were larger (P < .0001) for Method 3 versus Methods 1 and 2 (-39.5 to +22.0 ml/min/1.73 m2) than for Method 1 versus 2 (-7.6 to +4.5 ml/min/1.73 m2). Method 3 overestimated lower GFR's and underestimated higher GFR's. Methods 1 and 2 agreed exactly in identifying 3 cases of GFR < 74 ml/min/1.73 m2 (κ = 1.00), while Method 3 detected only 1 of the three (κ = .48). To avoid underdiagnosing low GFR's, larger GFR sample sizes are preferable to smaller sample sizes.

Trop2 is overexpressed in various tumors and serves as a key biomarker. Targeted immunoPET ligands, mainly developed from Trop2 monoclonal antibodies and nanobodies, provide the landscape of heterogeneous expression of Trop2 in tumors, which has great potential in improving accuracy of cancer diagnosis and staging, as well as decision-making in therapy.

Phosphodiesterase 4B (PDE4B) is an enzyme that hydrolyzes cyclic adenosine monophosphate (cAMP), a critical signaling molecule involved in various cellular processes. Dysregulated PDE4B activity has been implicated in psychiatric diseases like depression and schizophrenia. In this report, a PDE4B-targeted PET tracer, [18F]PF-06445974, was synthesized using an automated synthesis module. [18F]PF-06445974 demonstrated high brain specificity, robust uptake, and excellent stability. In vivo metabolic studies confirmed that its radioactive metabolites did not cross the blood-brain barrier, and no abnormal bone uptake was observed in PET imaging. Furthermore, PET studies and quantitative autoradiography revealed significantly increased expression of PDE4B in the hippocampus and cortex of depression model rats compared to normal controls. The findings highlight the potential of in vivo PDE4B PET imaging as a valuable tool for monitoring PDE4B changes in depression, providing insights into its pathophysiological processes and paving the way for clinical translational research in this domain.

The metabotropic glutamate receptor 3 (mGluR3) is a G-protein-coupled receptor (GPCR) involved in modulating glutamatergic neurotransmission and maintaining neural homeostasis. By inhibiting adenylyl cyclase activity, mGluR3 negatively modulates the activity of adenylyl cyclase via Gi/o protein coupling, reducing cyclic AMP (cAMP) levels and modulating downstream signaling pathways. Dysfunction of mGluR3 is associated with a range of neurological and psychiatric disorders, including depression, autism, cognitive impairment, bipolar affective disorder, schizophrenia, and neurodegenerative diseases. Despite its therapeutic relevance, no selective mGluR3 positron emission tomography (PET) radioligand is currently available to image this target in vivo. In this study, we report the radiosynthesis and preclinical evaluation of [18F]VU6010572 - a novel PET tracer based on a therapeutical drug candidate. VU6010572 exhibits potent binding affinity (IC50 = 39.9 nM) and exceptional selectivity (>100-fold over other mGluR subtypes). Radiolabeling with fluorine-18 yielded [18F]VU6010572 with high radiochemical yield (48%, decay-corrected) and molar activity (59 GBq/µmol). While in vitro autoradiography demonstrated heterogeneous brain distribution, dynamic PET imaging in rodents revealed reasonable brain uptake in vivo yet modest binding specificity and rapid brain washout. While these findings support the potential of [18F]VU6010572 as a lead structure, further medicinal chemistry optimization is warranted to enhance the metabolic and pharmacokinetic properties.