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The aim of this study was to explore the influences of age‐matched control and/or age‐specific template on voxel‐wise analysis of brain 18F‐fluorodeoxyglucose positron emission tomography (18F‐FDG PET) data in pediatric epilepsy patients. We, retrospectively, included 538 pediatric (196 females; age range of 12 months to 18 years) and 35 adult subjects (18 females; age range of 20–50 years) without any cerebral pathology as pediatric and adult control group, respectively, as well as 109 pediatric patients with drug‐resistant epilepsy (38 females; age range of 13 months to 18 years) as epilepsy group. Statistical parametric mapping (SPM) analysis for 18F‐FDG PET data of each epilepsy patients was performed in four types of procedures, by using age‐matched controls with age‐specific template, age‐matched controls with adult template, adult controls with age‐specific template or adult controls with adult template. The numbers of brain regions affected by artifacts among these four types of SPM analysis procedures were further compared. Any template being adopted, the artifacts were significantly less in SPM analysis procedures using age‐matched controls than those using adult controls in each age range (p <.001 in each comparison), except in the age range of 15–18 (p >.05 in each comparison). No significant difference was found in artifacts, when compared procedures using the identical control group with different templates (p = 1.000 in each comparison). In conclusion, the age stratification for age‐matched control should be divided as many layers as possible for the SPM analysis of brain 18F‐FDG PET images, especially in pediatric patients ≤14‐year‐old, while age‐specific template is not mandatory. [ABSTRACT FROM AUTHOR]

Objective: Prostate-specific membrane antigen (PSMA)-PET/CT imaging has gained increasing clinical importance for the detection and staging of high-risk primary prostate cancer (PCa). However, it is unclear whether the routine practice of prostate biopsy obscures the image finding of PSMA-PET/CT. This study aimed to compare the tumor positivity rate of PSMA-PET/CT performed pre- (PSMA-PET/CTpre) and post-biopsy (PSMA-PET/CTpost) in high-risk PCa patients. Patients and methods: We matched 58 PSMA-PET/CTpost with 58 PSMA-PET/CTpre studies for primary detection of high-risk PCa according to clinical characteristics. Three subgroups of PSMA-PET/CTpost were defined by the intervals after biopsy (≤ 1 week, 1 ~ 2 weeks, and 2 ~ 5 weeks). Tumor positivity rates were determined, and SUVmax of primary tumors were compared separately for the two main groups and the related subgroups. Malignant prostate tissues from 20 of these patients were examined by immunohistochemical analysis of PSMA. In addition, the values of PSMA-PET/CTpre and PSMA-PET/CTpost in assessing seminal vesicle invasion (SVI) were evaluated in patients who underwent radical prostatectomy. Results: All the primary tumors were positive on PSMA-PET/CTpost and PSMA-PET/CTpre imaging, resulting in a patient-based positivity rates of 100% (58/58) in both groups. All examined IHC results (20/20) confirmed the high-level expression of PSMA. SUVmax of primary tumors did not differ between the two main groups (16.1, IQR 9.8–26.6 vs. 16.5, IQR 11.0–26.7, p > 0.05). Subgroup analysis of PSMA-PET/CTpost (≤ 1 week, 1 ~ 2 weeks, and 2 ~ 5 weeks) also showed no significant difference in tumor SUVmax (15.8, IQR 9.5–22.2; 17.8, IQR 9.8–29.2; and 15.4, IQR 10.1–30.3. p > 0.05). PSMA-PET/CTpost and PSMA-PET/CTpre exhibited similar value in SVI detection as well. Conclusions: The tumor positivity rate was consistently high for PSMA-PET/CT pre- and post-biopsy. A prior biopsy does not seem to affect the tumor positivity rate of PSMA-PET/CT in high-risk PCa. [ABSTRACT FROM AUTHOR]

Purposes: To explore the characteristics of PSMA PET/CT and FDG PET/CT images in prostatic ductal adenocarcinoma (DA) patients., Methods: We retrospectively enrolled prostatic DA patients with PET/CT scans at Tongji Hospital from 2018 to 2022. Patients with prostatic acinar adenocarcinoma (AA) and benign pathology (BP) were enrolled by 1:1 matching. Differences in the uptake of primary and metastatic foci on PET among the groups were analyzed., Results: A total of 42 patients were enrolled: 14 in each group. In primary foci, the mean PSMA uptake in the DA group was lower than that in the AA group (14.2 ± 9.6 vs. 27.1 ± 14.3, P = 0.009) and greater than that in the BP group (14.2 ± 9.6 vs. 4.7 ± 1.3, P = 0.003). The AUCs of the DA-AA ROC curve and DA-BP ROC curve were 0.781 and 0.872, respectively. The median PSMA uptake of metastatic lymph nodes in the DA group was lower than that in the AA group (5.6 vs. 14.2, P = 0.033), with no significant difference in metastatic bone lesions (9.5 vs 19.1, P = 0.485). No significant difference was found in the FDG uptake of primary and metastatic foci between the DA and AA groups (P > 0.05)., Conclusion: Prostatic DA has greater PSMA uptake than BP diseases, but lower uptake in both primary foci and metastatic lymph nodes than AA on PSMA PET/CT, aiding in the differential diagnosis of DA, AA and BP diseases. Clinicians should combine traditional imaging with PSMA PET/CT to avoid underestimating the clinical stage of DA patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Multiparametric magnetic resonance imaging (mpMRI) is a commonly used method to diagnose pelvic lymph node metastasis (PLNM) in prostate cancer (PCa) patients, but there are few comparative studies on mpMRI and 68 Ga-prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) in locally advanced PCa (LAPC) patients. Therefore, we designed a retrospective study to compare the diagnostic value of 68 Ga-PSMA PET/CT and mpMRI for PLNM of LAPC., Methods: A retrospective study was performed on 50 patients with LAPC who underwent radical prostatectomy (RP) in Tongji Hospital from 2021 to 2023. All patients underwent PET/CT and mpMRI examination, and were diagnosed as LAPC before surgery, followed by robot-assisted laparoscopic prostatectomy or laparoscopic RP and extended pelvic lymph node dissection (ePLND). Routine postoperative pathological examination was performed. According to the results, the sensitivity, specificity, positive predictive value, and negative predictive value of 68 Ga-PSMA PET/CT and mpMRI for the diagnosis of PLNM of LAPC were compared., Results: Among the 50 patients, the mean age was 65.5±10.3 years, the preoperative total serum prostate-specific antigen (PSA) was 30.7±12.3 ng/mL, and the Gleason score was 7 [7, 8]. The difference in diagnostic efficacy between 68 Ga-PSMA PET/CT and mpMRI in the preoperative diagnosis of PLNM of PCa was determined by postoperative pathological results. Based on the number of patients who developed PLNM, the sensitivity, specificity, positive predictive value, and negative predictive value of 68 Ga-PSMA PET/CT were as follows: 93.75%, 100.00%, 100.00%, 97.14%, and 68.75%, 97.06%, 91.67%, 86.84% for mpMRI, respectively. Based on the number of pelvic metastatic lymph nodes, the sensitivity, specificity, positive predictive value, and negative predictive value of 68 Ga-PSMA PET/CT were 95.24%, 100.00%, 100.00%, 99.48%, and 65.08%, 99.13%, 89.13%, 96.30% for mpMRI, respectively. It turned out that PET/CT was more sensitive than mpMRI in detecting PLNM of PCa, and the difference was statistically significant., Conclusions: 68 Ga-PSMA PET/CT is more sensitive than mpMRI in the detection of PLNM in patients with LAPC. It is a promising method in the diagnosis and preoperative assessment of PLNM in LAPC., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-24-15/coif). The authors have no conflicts of interest to declare., (2024 Translational Andrology and Urology. All rights reserved.)

Fibroblast activation protein (FAP) is highly expressed in many tumor types and constitutes a promising target for tumor-specific delivery of therapeutic radionuclides. [ 177 Lu]Lu-DOTAGA.(SA.FAPi) 2 is a novel radiopharmaceutical based on a novel bidentate inhibitor of FAP that is excreted more slowly than its monomeric counterparts. Still, the efficacy of radiotherapy is mitigated by cascades of DNA damage repair signaling in tumor cells including those via Poly(ADP-ribose) polymerase (PARP). We hereby aimed to evaluate the efficacy of [ 177 Lu]Lu-DOTAGA.(SA.FAPi) 2 in combination with a PARP inhibitor, Olaparib, in the 4T1 murine triple negative breast cancer (TNBC) model. The therapeutic efficacy was visualized using 18 F-FDG and [ 68 Ga]Ga-FAPI-04 positron emission imaging/computer tomography (PET/CT). Our results demonstrated that Olaparib suppressed BALB/3T3 fibroblasts in vitro and sensitized the efficacy of [ 177 Lu]Lu-DOTAGA.(SA.FAPi) 2 in mice bearing 4T1 tumors via enhancement of DNA damage. Treatment-associated toxicity was tolerable with only mild leukopenia. Therefore, the combination of [ 177 Lu]Lu-DOTAGA.(SA.FAPi) 2 and Olaparib is a feasible treatment against TNBC.

Recently, various immuno-PET tracers based on monoclonal antibodies (mAbs), engineered scaffold proteins, and peptides were developed to target either programmed cell death protein 1 (PD-1) or programmed cell death ligand 1 (PD-L1), showing promise in assessment of immune checkpoints. We sought to develop an immunotherapeutic agent based PET probe that enables real-time assessment of PD-L1 expression and evaluation of antibody drug biodistribution to select eligible candidates for anti-PD-1/PD-L1 immunotherapies. KN035, a 79.6 kDa size anti-PD-L1 domain antibody under analysis in clinical trials, was used to develop the immuno-PET probe, 89 Zr-Df-KN035. Immuno-PET studies were performed to monitor PD-L1 levels in nude mice bearing LN229 xenografts with positive expression for PD-L1, and to evaluate the whole-body biodistribution in healthy non-human primates (NHPs). LN229 xenografts were markedly visualized from 24 h after injection of 89 Zr-Df-KN035, with elevated accumulation persisting for up to 120 h. Tumor radioactivity was notably reduced in the presence of excess KN035. Mouse ex vivo biodistribution studies performed at 24 and 120 h revealed tumor-to-muscle ratios as high as 5.64 ± 0.65 and 7.70 ± 1.37, respectively. In the NHP model, PET imaging demonstrated low background. The liver and kidney showed moderate accumulation with the highest SUV mean value of 1.15 ± 0.15 and 2.13 ± 0.10 at 72 h, respectively. The spleen, lymph nodes, and salivary glands were also slightly visualized. In conclusion, 89 Zr-Df-KN035, a novel anti-PD-L1 domain antibody-based probe, shows the feasibility of noninvasive in vivo evaluation of PD-L1 expression. This work further provides a template for immunotherapeutic agent based imaging to evaluate human PD-L1 expression and to augment our understanding of therapeutic agent biodistribution, leading to better therapeutic strategies in the future.