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Purpose: We aimed to investigate the potential of [68Ga]Ga-FAPI-04 PET/CT as an alternative diagnostic and theranostic tool in well-differentiated NETs refractory to [177Lu]Lu-DOTATATE therapy. Methods: Patients who received at least two cycles of [177Lu]Lu-DOTATATE therapy for metastatic NETs and progressed under treatment were included. All patients had performed [68Ga]Ga-DOTATATE and [68Ga]Ga-FAPI-04 PET/CT within 3 weeks. The number of PET-positive lesions related to NETs and tumor sites was documented. Mann-Whitney U and chi-square tests were used to compare SUVmax levels of tracers and the number of detected metastases. Results: Twelve patients (7 male, 5 female) who met the eligibility criteria were included in the study. Ten patients had grade 1–2 NET of various origins, and two had paraganglioma and pheochromocytoma. One hundred ninety-eight of 230 lesions (86%) were SSTR positive with a median SUVmax of 16.6 (2.2–76.5), and 88 of 230 lesions (38.2%) were [68Ga]Ga-FAPI-04 positive with a median SUVmax of 5.1 (2.3–21). Median SUVmax level and detected number of tumors were significantly higher in [68Ga]Ga-DOTATATE PET/CT (p=<0.001). [68Ga]Ga-FAPI-04 PET/CT was completely (n:2) or almost completely (n:3) negative in 5 (42%) patients. Two (17%) patients had flip-flop SSTR/FAPI uptake in tumors. In four patients (33%), tumor uptake or the number of PET-positive lesions was inferior in [68Ga]Ga-FAPI-04 PET/CT. In only one patient (8%), tumor uptakes were higher in [68Ga]Ga-FAPI-04 PET/CT. Low-dose [177Lu]Lu-FAPI-46 dosimetry was performed on the FAPI-dominant patient; absorbed radiation doses per GBq were 1.26 Gy, 0.36 Gy, 0.32 Gy, and 0.2 Gy for kidneys, liver, spleen, and total body, respectively. The mean absorbed dose per GBq was 0.33 Gy for liver mass and 0.41 Gy for metastatic lymph nodes. Conclusion: Our preliminary results demonstrated that [68Ga]Ga-FAPI-04 PET/CT mainly failed in well-differentiated NETs refractory to [177Lu]Lu-DOTATATE therapy and had a limited role as an alternative diagnostic or theranostic agent. Further investigations with a larger patient population are required to determine the impact of [68Ga]Ga-FAPI-04 PET/CT on NETs. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to investigate the role of [68 Ga]Ga-FAPI-04 PET/CT and uptake patterns of primary and metastatic lesions in patients with renal cell carcinoma (RCC). Methods: Twenty patients with a suspicious lesion considered primary renal malignancy or a history of RCC were included in our study. Two patients were excluded from further analyses due to other confirmed malignancies. Six patients were newly diagnosed, while the indication of 12 patients was restaging. All patients underwent [68 Ga]Ga-FAPI-04 and [18F]F-FDG PET/CT. SUVmax and tumor-to-background ratio (TBR) of primary (n = 7) and local recurrent lesions (n = 6) and lymph node (n = 26), lung (n = 32), bone (n = 5), and other metastases (n = 14) were compared between the two tracers. Results: We detected 90 lesions in 18 patients with varying FAPI and FDG uptake values on both PET/CT. The median TBR of FAPI-PET/CT of all lesions was higher than TBR of FDG-PET/CT with statistically significance (5.6 vs. 2.1, p < 0.001). In primary and recurrent lesions, the median SUVmax, TBR, and tumor volume on FAPI-PET/CT were higher than FDG-PET/CT. The median SUVmax of lung lesions on FAPI-PET/CT was statistical significantly higher than FDG-SUVmax (3.8 vs. 1.8, p = 0.02). The median of FAPI-SUVmax on primary lesions was lower in the early stage based on TNM compared to the advanced stage. FAPI-SUVmax in 49% of all lesions were SUVmax ≥ 6, and 13% were SUVmax ≥ 10. In patient-based analyses, seven patients (39%) had at least one lesion with FAPI-SUVmax ≥ 10; 12 patients (67%) had at least one lesion with FAPI-SUVmax ≥ 6. Conclusion: This study showed the potential utility of [68 Ga]Ga-FAPI-04 PET/CT showing promising results in RCC. We have presumed that FAPI-PET/CT may be performed for complementary imaging modality providing prognosis and possibility of theranostic application in selected patients. [ABSTRACT FROM AUTHOR]

Purpose: This study investigates the prognostic value of 68Ga-Pentixafor PET/CT using PET-derived quantitative in multiple myeloma (MM) patients with suspected recurrence in comparison to 18F-FDG PET/CT and clinical data. Methods: Twenty-four MM patients with suspicion for relapse who underwent 68Ga-Pentixafor and 18F-FDG PET/CT were retrospectively evaluated. Total bone marrow glycolysis for 18F-FDG (TBMFDG) and total bone marrow uptake for 68Ga-Pentixafor PET/CT (TBMCXCR4) were calculated using whole-body metabolic tumor burden obtained by dedicated software (MIM 7.0.6). The patients were followed for 19–24 months, and the association of PET-derived quantitative data with overall survival (OS) was analyzed. Results: 68Ga-Pentixafor PET/CT was positive in 17 patients, of which 13 were also positive on 18F-FDG PET/CT, whereas 7 patients were negative on both scans. The positive rate of 68Ga-Pentixafor and 18F-FDG PET/CT on a patient-based approach was 70.8% and 54.1%, respectively. 68Ga-Pentixafor positivity was significantly associated with OS (p = 0.009), and 18F-FDG positivity was at the margin of statistical significance (p = 0.056). TBMCXCR4 and TBMFDG were negatively correlated with OS (r = −0.457, p = 0.025 and r = −0.617, p = 0.001, respectively). The OS was negatively correlated with beta-2-microglobulin levels (r = −0.511, p = 0.01) and CRAB score (r = −0.592, p = 0.002) as an indicator of the end-organ disease, which confirmed these results. Serum beta-2-microglobulin levels and CRAB score were also correlated with TBMCXCR4 (r = 0.442, p = 0.039 and r = 0.573, p = 0.003, respectively) and TBMFDG (r = 0.543, p = 0.009 and r = -0.424, p = 0.003, respectively). Conclusion: 68Ga-Pentixafor PET/CT positivity is a negative prognostic factor in the survival outcome of MM patients. Complementary 68Ga-Pentixafor PET/CT has the potential to overcome 18F-FDG PET/CT limitations and helps a more precise risk stratification. [ABSTRACT FROM AUTHOR]

Demonstration of in vivo estrogen receptor status with 16 - [18F]fluoro-17ß-oestradiol (FES) PET/CT in a rare case of benign metastasizing leiomyoma This case demonstrates the in vivo expression of ER status of BML lung lesions with [ SP 18 sp F]FES PET/CT, which can be an indicator of hormonal status and guide the therapy management of BML. [ SP 18 sp F]FDG PET/CT (a) was performed to exclude malignancy; however, no significant [ SP 18 sp F]FDG uptake in lung nodules (b) and no [ SP 18 sp F]FDG-avid primary tumor were detected. [Extracted from the article]

Background and Aim: Gallium-68 (68Ga)-Prostate Membrane Specific Antigen Positron Emission Tomography/Computed Tomography (68Ga-PSMA PET/CT) is an emerging diagnostic modality which is gaining importance in individualized prostate cancer (PCa) management era. This study aimed to investigate the diagnostic accuracy of 68Ga-PSMA PET/CT on primary LN staging before radical prostatectomy (RP) in intermediate and high risk PCa.Materials and Methods: The retrospectively documented 49 patients with intermediate and high risk non-metastatic PCa who had 68Ga-PSMA PET/CT before RP were enrolled into this study. The histopathology of dissected LNs was used as reference standard to evaluate the accuracy of 68Ga-PSMA PET/CT on primary LN staging, both in per-patient (n = 49) and in per-node (n = 454) analyses. The diagnostic accuracy was investigated using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), and by area under the curve (AUC) provided using receiver operating curve (ROC) analysis.Results: Median age was 64 (48-79) years and, median and mean PSA values were 10 (1.31-138) ng/ml and 16.2 (±19.8) ng/ml, respectively. 22 (44.9%) and 27 (55.1%) of patients had intermediate and high risk PCa, respectively. A total of 5 (10.2%) patients had histopathologically proven LN metastasis and 3 (60%) of them was detected in 68Ga-PSMA PET/CT. In per patient analysis, the sensitivity, specifity, PPV and NPV of 68Ga-PSMA PET/CT on primary LN staging were 0.60, 0.96, 0.60 and 0.96, respectively. Among overall 454 LNs, 16 (3.5 %) of them were reported as metastatic in histopathology and, 13 (2.9%) of these metastatic LNs were detected in 68Ga-PSMA PET/CT. In per-node analysis, the sensitivity, specificity, PPV and NPV of 68Ga-PSMA PET/CT on primary LN staging were 0.82, 0.99, 0.87 and 0.99, respectively. The ROC analyses found AUCs for primary LN staging as 0.777 (95%CI:0.508-1.0) in per patient analysis and, as 0.904 (95%CI:0.790 - 1.0) in per node analysis, respectively.Conclusion: The use of 68Ga-PSMA PET/CT has promising diagnostic accuracy on primary LN staging before RP in intermediate and high risk PCa. However, the efforts should be taken to increase sensitivity of 68Ga-PSMA PET/CT in individualized treatment era. [ABSTRACT FROM AUTHOR]

Introduction: This study aims to assess 68 Ga-Trivehexin PET/CT for detecting hyperfunctioning parathyroid tissue in comparison to [ 99m Tc]Tc-MIBI scintigraphy-SPECT/CT (MIBI scan) in patients with primary hyperparathyroidism (PHPT)., Methods: The cohort comprised 13 patients diagnosed with PHPT based on biochemical analyses, including serum calcium, phosphorus, and parathyroid hormone (PTH) levels. Each participant underwent cervical ultrasonography, MIBI scan, and 68 Ga-Trivehexin PET/CT imaging. Complementary 4D-CT and [ 18 F]fluorocholine PET/CT were conducted in 7 patients. Ten lesions of 7 patients underwent PTH wash-out (WO) procedure. 68 Ga-Trivehexin PET/CT findings were compared with other modalities and PTH-WO results., Results: Ten patients had sporadic PHPT, while 3 were diagnosed with MEN-1 syndrome-associated PHPT. One patient did not have any identifiable parathyroid lesion across the imaging modalities. On a patient-based analysis, MIBI scan and 68 Ga-Trivehexin PET/CT identified parathyroid lesions in 10 and 11 patients, respectively. However, 68 Ga-Trivehexin PET/CT detected 7 additional parathyroid lesions that were negative on the MIBI scan. Consequently, 17 lesions were identified and confirmed as hyperfunctioning parathyroid tissue through imaging, PTH-WO, or a combination of both modalities. In lesion-based evaluation, 68 Ga-Trivehexin identified 16 lesions compared to 10 by MIBI scan, resulting in a detection rate of 94.1% and 58.8%, respectively. Notably, in three patients who underwent [ 18 F]fluorocholine PET/CT, no lesions were detected; yet 68 Ga-Trivehexin PET/CT successfully identified parathyroid lesions in two of these patients., Conclusion: Our study provides the first evidence that 68 Ga-Trivehexin PET/CT can effectively identify hyperfunctioning parathyroid tissue with a high detection rate warranting further investigations to comprehensively explore its potential in PHPT management., (© 2024. The Author(s).)

Purpose: The aim of this study was to evaluate the potential role of [ 18 F]FDG positron emission tomography/computed tomography (PET/CT) in the characterization of thymic epithelial tumors (TETs). Materials and Methods: A total of 73 patients who underwent preoperative [ 18 F]FDG PET/CT were included in this study. Visual total score (VTS), maximum standard uptake values (SUV max ), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and heterogeneity index (HI) parameters were analyzed to investigate the prediction of histopathologic grade and advanced stage. Results: The cohort included 26 patients with low-grade thymoma (LGT), 36 patients with high-grade thymoma (HGT), and 11 patients with thymic carcinoma (TC). Ninety-one percent of TC had VTS >2, whereas 31% of LGT and 75% of HGT had VTS >2. SUV max , MTV, and TLG were statistically significantly higher in the TC group than in both thymoma and HGT. Using the cutoff value of 7.25 for SUV max , TC was differentiated from thymomas with 91% sensitivity and 74% specificity. TC had significantly lower HI values than thymomas. HI parameters showed good diagnostic ability to differentiate TC from thymoma and TC from HGT. SUV max , MTV, and TLG were significantly higher in advanced-stage disease than in early-stage disease. Conclusions: Visual and quantitative parameters can reliably predict both advanced disease and the grade of primary tumor in TETs. Therefore, as a promising metabolic imaging method, [ 18 F]FDG PET/CT makes important contributions to preoperative evaluation in routine clinical practice.

Purpose: This study evaluated the effect of an increase in the time interval between hepatic intra-arterial injection of 99m Tc-macroaggregated albumin (MAA) and hepatic artery perfusion scintigraphy (HAPS) on the lung shunt fraction (LSF) and perfused volume (PV) calculations in the treatment planning of selective internal radiation therapy (SIRT). Methods: The authors enrolled 51 HAPS sessions from 40 patients diagnosed with primary or metastatic liver malignancy. All patients underwent scan at the first and fourth hour after hepatic arterial injection of 99m Tc-MAA. Based on single-photon emission computed tomography images, LSF values were measured from each patient's first and fourth hour images. PV1 and PV4 were also calculated based on three-dimensional images using 5% and 10% cutoff threshold values and compared with each other. Results: The authors found that the median of LSF4 was statistically significantly higher than LSF1 (3.05 vs. 4.14, p  ≤ 0.01). There was no statistically significant difference between PV1 and PV4 on the 10% ( p  = 0.72) thresholds. Conclusions: LSF values can be overestimated in case of delayed HAPS, potentially leading to treatment cancellation due to incorrectly high results in patients who could benefit from SIRT. Threshold-based PV values do not significantly change over time; nevertheless, keeping the short interval time would be safer.

Abstract: We present isolated bilateral adrenal metastases successfully treated with 177 Lu-PSMA in a 66-year-old man diagnosed with castration-resistant prostate cancer. The patient had progression under chemotherapy as depicted by 68 Ga-PSMA PET/CT showing intense bilateral PSMA uptake in the adrenal masses, and metastasis-directed therapies were considered as the first option for improving survival because the patient was oligometastatic. However, surgery and radiotherapy were not justifiable options due to the high risk of definitive adrenal insufficiency; therefore, the patient received 4 cycles of 177 Lu-PSMA treatment. 68 Ga-PSMA PET/CT showed near-complete response in bilateral adrenal metastases, and no sign of adrenal insufficiency was observed during follow-up., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)