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Background: In patients with prostate cancer (PCa), imaging with gastrin-releasing peptide receptor (GRPR) ligands is an alternative to PSMA-targeted tracers, particularly if PSMA expression is low or absent. [99mTc]Tc-N4-BTG is a newly developed GRPR-directed probe for conventional scintigraphy and single photon emission computed tomography (SPECT) imaging. The current study aims to investigate the safety, biodistribution and dosimetry of [99mTc]Tc-N4-BTG in patients with biochemical recurrence (BCR) of PCa. Results: No adverse pharmacologic effects were observed. Injection of [99mTc]Tc-N4-BTG resulted in an effective dose of 0.0027 ± 0.0002 mSv/MBq. The urinary bladder was the critical organ with the highest mean absorbed dose of 0.028 ± 0.001 mGy/MBq, followed by the pancreas with 0.0043 ± 0.0015 mGy/MBq, osteogenic cells with 0.0039 ± 0.0005 mGy/MBq, the kidneys with 0.0034 ± 0.0003 mGy/MBq, and the liver with 0.0019 ± 0.0004 mGy/MBq, respectively. No focal tracer uptake suggestive of PCa recurrence could be revealed for any of the patients. Conclusion: [99mTc]Tc-N4-BTG appears to be a safe diagnostic agent. Compared to GRPR-targeted PET tracers, this 99mTc-labelled SPECT agent could contribute to a broader application and better availability of this novel approach. Further research to assess its clinical value is warranted. [ABSTRACT FROM AUTHOR]

Background: To date, studies on positron emission tomography (PET) with 18F‐fluorodeoxyglucose (FDG) in progressive supranuclear palsy (PSP) usually included PSP cohorts overrepresenting patients with Richardson's syndrome (PSP‐RS). Objectives: To evaluate FDG‐PET in a patient sample representing the broad phenotypic PSP spectrum typically encountered in routine clinical practice. Methods: This retrospective, multicenter study included 41 PSP patients, 21 (51%) with RS and 20 (49%) with non‐RS variants of PSP (vPSP), and 46 age‐matched healthy controls. Two state‐of‐the art methods for the interpretation of FDG‐PET were compared: visual analysis supported by voxel‐based statistical testing (five readers) and automatic covariance pattern analysis using a predefined PSP‐related pattern. Results: Sensitivity and specificity of the majority visual read for the detection of PSP in the whole cohort were 74% and 72%, respectively. The percentage of false‐negative cases was 10% in the PSP‐RS subsample and 43% in the vPSP subsample. Automatic covariance pattern analysis provided sensitivity and specificity of 93% and 83% in the whole cohort. The percentage of false‐negative cases was 0% in the PSP‐RS subsample and 15% in the vPSP subsample. Conclusions: Visual interpretation of FDG‐PET supported by voxel‐based testing provides good accuracy for the detection of PSP‐RS, but only fair sensitivity for vPSP. Automatic covariance pattern analysis outperforms visual interpretation in the detection of PSP‐RS, provides clinically useful sensitivity for vPSP, and reduces the rate of false‐positive findings. Thus, pattern expression analysis is clinically useful to complement visual reading and voxel‐based testing of FDG‐PET in suspected PSP. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Simple Summary: Despite novel targeted treatment options, small cell lung cancer (SCLC) still has a bad prognosis. However, as a relevant number of SCLC patients show a high expression of somatostatin receptors (SSTRs), SSTR-targeted radionuclide therapy (PRRT) may be a treatment option. Therefore, we investigated whether SSTR expression assessed in positron emission tomography (PET) has prognostic value. In patients with adequate PET uptake, PRRT was performed, and the outcome was investigated. We found that SSTR-targeted PET, although not a prognostic tool for outcome, is an important tool for treatment decision. In some patients, PRRT can be a promising treatment option as a second or third line treatment of SCLC. Background: Given the dismal prognosis of small cell lung cancer (SCLC), novel therapeutic targets are urgently needed. We aimed to evaluate whether SSTR expression, as assessed by positron emission tomography (PET), can be applied as a prognostic image biomarker and determined subjects eligible for peptide receptor radionuclide therapy (PRRT). Methods: A total of 67 patients (26 females; age, 41–80 years) with advanced SCLC underwent SSTR-directed PET/computed tomography (somatostatin receptor imaging, SRI). SRI-avid tumor burden was quantified by maximum standardized uptake values (SUVmax) and tumor-to-liver ratios (T/L) of the most intense SCLC lesion. Scan findings were correlated with progression-free (PFS) and overall survival (OS). In addition, subjects eligible for SSTR-directed radioligand therapy were identified, and treatment outcome and toxicity profile were recorded. Results: On a patient basis, 36/67 (53.7%) subjects presented with mainly SSTR-positive SCLC lesions (>50% lesions positive); in 10/67 patients (14.9%), all lesions were positive. The median SUVmax was found to be 8.5, while the median T/L was 1.12. SRI-uptake was not associated with PFS or OS, respectively (SUVmax vs. PFS, ρ = 0.13 with p = 0.30 and vs. OS, ρ = 0.00 with p = 0.97; T/L vs. PFS, ρ = 0.07 with p = 0.58 and vs. OS, ρ = −0.05 with p = 0.70). PRRT was performed in 14 patients. One patient succumbed to treatment-independent infectious complications immediately after PRRT. In the remaining 13 subjects, disease control was achieved in 5/13 (38.5%) with a single patient achieving a partial response (stable disease in the remainder). In the sub-group of responding patients, PFS and OS were 357 days and 480 days, respectively. Conclusions: SSTR expression as detected by SRI is not predictive of outcome in patients with advanced SCLC. However, it might serve as a therapeutic target in selected patients. [ABSTRACT FROM AUTHOR]

Purpose: Positron emission tomography (PET) with O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) is a well-established tool for non-invasive assessment of adult central nervous system (CNS) tumors. However, data on its diagnostic utility and impact on clinical management in children and adolescents are limited. Methods: Twenty-one children and young adults (13 males; mean age, 8.6 ± 5.2 years; range, 1–19 at initial diagnosis) with either newly diagnosed (n = 5) or pretreated (n = 16) CNS tumors were retrospectively analyzed. All patients had previously undergone neuro-oncological work-up including cranial magnetic resonance imaging. In all cases, [18F]FET-PET was indicated in a multidisciplinary team conference. The impact of PET imaging on clinical decision-making was assessed. Histopathology (n = 12) and/or clinical and imaging follow-up (n = 9) served as the standard of reference. Results: The addition of [18F]FET-PET to the available information had an impact on further patient management in 14 out of 21 subjects, with avoidance of invasive surgery or biopsy in four patients, biopsy guidance in four patients, change of further treatment in another five patients, and confirmation of diagnosis in one patient. Conclusion: [18F]FET-PET may provide important additional information for treatment guidance in pediatric and adolescent patients with CNS tumors. [ABSTRACT FROM AUTHOR]

A recent study published in the European Journal of Nuclear Medicine & Molecular Imaging discusses the use of prostate-specific membrane antigen (PSMA) targeting positron emission tomography (PET) imaging for prostate cancer staging. The study highlights the detection of intense PSMA expression in the uvula of a 74-year-old man with newly diagnosed high-risk prostate cancer. The researchers also mention the controversial discovery of "tubarial glands" in the nasopharynx, which were previously described in the nineteenth century. The study emphasizes the ability of PSMA-directed molecular imaging to detect salivary gland tissue within the human body. [Extracted from the article]