SUVmax Of Lesions Research Articles

Diagnostic Ability of Quantitative Parameters of Whole-Body Bone SPECT/CT Using a Full-Ring 360° Cadmium-Zinc-Telluride Camera for Detecting Bone Metastasis in Patients with Prostate Cancer

Background/Objectives: This study aimed to assess the diagnostic capability of quantitative parameters from whole-body bone single-photon emission computed tomography/computed tomography (SPECT/CT) in detecting bone metastases in prostate cancer patients; Methods: We retrospectively analyzed 82 prostate cancer patients who underwent staging bone scintigraphy with a full-ring 360° Cadmium-Zinc-Telluride (CZT) SPECT/CT system. From the SPECT/CT images, we measured the maximum (SUVmax) and mean (SUVmean) standardized uptake values at six normal bone sites (skull, humerus, thoracic spine, lumbar spine, iliac bone, and femur), and the SUVmax for both metastatic and benign bone lesions. Ratios of lesion SUVmax-to-maximum and mean uptake values at the skull, humerus, and femur were computed for each lesion; Results: SUVmax and SUVmean at the skull and femur exhibited significantly lower variance compared to those at the thoracic spine, lumbar spine, and iliac bone, and revealed no significant differences between patients with and without bone metastasis. In receiver operating characteristic curve analysis for detecting bone metastasis among 482 metastatic lesions, 132 benign bone lesions, and 477 normal bone sites, the lesion-to-femur mean uptake ratio demonstrated the highest area under the curve value (0.955) among SPECT/CT parameters. Using a cut-off value of 5.38, the lesion-to-femur mean uptake ratio achieved a sensitivity of 94.8% and a specificity of 86.5%; Conclusions: The bone lesion-to-femur mean uptake ratio was the most effective quantitative bone SPECT/CT parameter for detecting bone metastasis in prostate cancer patients. Quantitative analysis of bone SPECT/CT images could thus play a crucial role in diagnosing bone metastasis.

Evaluation of the SwiftScan mode in bone single-photon emission computed tomography (SPECT) imaging: effect on imaging quality and a semi-quantitative analysis.

99mTc-stannous methylene diphosphonate (99mTc-MDP) bone single-photon emission computed tomography/computed tomography (SPECT/CT) imaging plays a crucial role in various clinical applications. Many strategies have been developed to reduce the injection activity and procedure time, improve the patient experience and reduce their anxiety prior to and during SPECT imaging. This study aimed to evaluate the SwiftScan mode and its effect on image quality, and diagnostic performance of malignant skeletal lesions in bone SPECT image. 99mTc-MDP SPECT/CT scans were acquired from the National Electrical Manufacturers Association (NEMA) phantom with a sphere-to-background ratio of 10:1, and 69 patients were enrolled in this retrospective study. The patients who showed abnormal uptake of focal 99mTc-MDP on whole-body bone planar scans, underwent local SPECT/CT scans. The image comparison and analysis were performed in three acquisition modes: SwiftScan; SwiftScan-50% (the SwiftScan mode with a 50% reduction in acquisition time); and step-and-shoot (SS). The image mean count, coefficient of variation (COV), radioactive concentration, and signal-to-background ratio (SBR) were measured for each phantom image. Visual assessment (using a 5-point Likert scale), semi-quantitative analysis [to determine the COV, mean of the standard uptake value (SUVmean), maximum of the standard uptake value (SUVmax), and SBR], and receiver operating characteristics (ROC) curve analysis were performed for clinical assessment. The SwiftScan mode obtained better quality images than the SwiftScan-50% and SS modes, and it also had better sphere clarity and lower background COVs (P<0.05). The mean counts of the SwiftScan, and the corresponding radioactive concentration and SBR were significantly higher than those of the SwiftScan-50% and SS (P<0.05), except in relation to the 13-10 mm spheres. A total of 101 abnormal 99mTc-MDP uptake skeletal lesions were included in the clinical study. The SwiftScan had significantly higher visual scores than both the SwiftScan-50% and SS (P<0.001). Additionally, there were significantly higher visual scores in the SwiftScan-50% than SS (P<0.05). The SwiftScan also had a lower COV, indicating reduced image noise. The SUVmax, SUVmean, and SBR for the skeletal lesions were significantly higher in the SwiftScan than the other two modes (P<0.05). The optimal diagnostic cut-off values of the SUVmax for identifying malignant skeletal lesions in the SwiftScan, SwiftScan-50%, and SS were 17.95, 14.75, and 9.94, respectively, but there was no significant difference among the three modes in terms of their differential diagnostic performance (all P>0.05). The SwiftScan showed significant improvements in image quality and the semi-quantitative analysis of bone SPECT imaging. It reduced the scanning time by 50% without compromising the image quality or diagnostic performance. These findings provide valuable insights that may inform the clinical application of the SwiftScan, enhancing qualitative and quantitative diagnosis in bone SPECT imaging.

PRIMARY scoring in 68Ga-PSMA PET/CT: correlation with prostate cancer risk groups and its potential impact on active surveillance.

The PRIMARY scoring system is a scale designed to identify clinically significant intraprostatic malignancies on 68Ga-PSMA PET/CT images. Active surveillance is a management method for patients with low-risk prostate cancer. In this study, we aimed to assess the efficacy of PRIMARY scoring in identifying appropriate candidates for active surveillance based on the distribution within prostate cancer risk groups. The data of 134 patients diagnosed with PCa by biopsy who underwent 68Ga-PSMA PET/CT imaging for post-diagnostic staging purposes were retrospectively analyzed. Age, total PSA, ISUP grade, prostate lesion SUVmax values, PI-RADS scores, and PRIMARY scores were recorded. Patients were classified into low-risk and intermediate/high-risk groups. In the intermediate/high-risk group, the PRIMARY score was 1-2 in 17.6% and 3-5 in 82.4% of patients. In the low-risk group, the PRIMARY score was 1-2 in 34.7% and 3-5 in 65.3% of patients. None of the patients in the low-risk group had a PRIMARY score of 5. The most frequent PRIMARY score in both groups was 4, and there was a significant difference between the average SUVmax values of the intermediate/high and low-risk groups with a PRIMARY score of 4 (p = 0.018). The sensitivity of PRIMARY scoring in detecting patients in the intermediate/high-risk group was 82.3%, the specificity was 34.6%, and the positive predictive value (PPV) was 68.6%. When a cut-off SUVmax value 5.0 was used for the PRIMARY score of 4, the sensitivity was 67.0%, the specificity was 65.3% and the PPV was 77.0%. In the ROC analysis, the area under the curve was 0.727 for PRIMARY scoring, 0.662 for PI-RADS, and 0.744 for their combined mean. The PRIMARY scoring system can complement PI-RADS scoring in mpMRI for selecting patients suitable for active surveillance. Revising the PRIMARY score 4 with an SUVmax cut-off value may increase the specificity.

Quantification of normal bone and osseous metastases in castration-resistant prostate cancer using SPECT/CT with xSPECT Quant: prospective imaging sub-study of a phase 2 clinical trial investigating the combination of pembrolizumab plus radium-223 compared to radium-223 alone.

The purpose of this study is to demonstrate the consistency and reproducibility of quantitative SPECT/CT by evaluating the maximum SUV (SUVmax) in normal bone, to provide the reference value of metastatic lesions, and to evaluate the clinical implication of SUVmax changes of osseous metastasis during treatment. This prospective imaging sub-study was performed as part of a phase 2 clinical trial of patients with metastatic castration-resistant prostate cancer (mCRPC) randomized to the combination of pembrolizumab plus radium-223 or to radium-223 alone (NCT03093428). The maximum standardized uptake value (SUVmax) and mean Hounsfield Unit (HUmean) of normal bone as well as metastases were measured using a 1.5cm region of interest (ROI) on CT and xSPECT Quant reconstruction on the baseline study (S0) and restaging scans. The most tracer-avid metastatic lesion in each patient on S0 was selected as a target lesion, and changes of SUVmax and HUmean of the target lesion were compared on the first restaging scan (S1). Correlations between the percentage changes of SUVmax of the target lesion with alkaline phosphatase (ALP) and prostate-specific antigen (PSA) were assessed. Twenty-one patients were enrolled on the imaging sub-study of which 15 had paired baseline S0 and S1 data. On S0, the median SUVmax and HUmean of normal bone was 5.85g/mL (0.42-14.98) and 133.03 (range, 28.47-461.91), respectively. The median SUVmax and HUmean of metastasis were 42.2g/mL (range, 17.96-143.36) and 549.58 (177.87-1107.64), respectively. There was significant reduction in SUVmax (- 40.1%, range - 86.2 to + 23.5%), p < 0.001) and increase in HUmean (+ 8.3%, range - 11.3 to + 61.7%, p = 0.0479, Wilcoxon signed-rank test) of target lesions between S0 and S1. Spearman correlation between the percentage changes of SUVmax of a target lesion and both serum PSA (r = 0.33, p = 0.226) and ALP (r = 0.45, p = 0.094) were not statistically significant. Quantitative SPECT/CT provides consistent and objective imaging parameters, which can help monitor tumor burden. The median SUVmax of metastasis at baseline was roughly 7.2-fold higher than normal bone. Quantitative SPECT/CT may help visualize the early osteoblastic treatment response in prostate cancer patients treated with radium-223 alone or combined with pembrolizumab.

Comparison of clinical performance between late and standard total-body [68Ga]Ga-PSMA-11 in biochemical recurrent prostate cancer.

Enhanced lesion detection in prostate cancer is observed with late [68Ga]Ga-PSMA-11 PET/CT imaging compared to standard [68Ga]Ga-PSMA-11 PET/CT imaging (50-100min p.i.). However, the poor image quality of late imaging using short axial field of view (SAFOV) PET/CT has hindered its sole clinical adoption. Conversely, the image quality of late imaging with a long axial field of view (LAFOV) [68Ga]Ga-PSMA-11 PET/CT fulfills clinical diagnostic requirements. Nonetheless, the diagnostic efficacy of late LAFOV [68Ga]Ga-PSMA-11 PET/CT with forced diuresis and its impact on treatment decisions, compared to standard LAFOV [68Ga]Ga-PSMA-11 PET/CT, remains unclear. This study aims to compare the rate of PET positivity between late and standard LAFOV [68Ga]Ga-PSMA-11 PET/CT and to evaluate the influence of late LAFOV [68Ga]Ga-PSMA-11 PET/CT with forced diuresis on treatment decisions relative to standard scans. From January 2021 to April 2024, 127 patients with biochemical recurrence of prostate cancer post-radical prostatectomy were enrolled to undergo both standard and late LAFOV [68Ga]Ga-PSMA-11 PET/CT scans at Shanghai Renji Hospital. We compared the rate of PET positivity between the two modalities at the patient level and across different anatomical regions. We assessed the added diagnostic value of late LAFOV [68Ga]Ga-PSMA-11 PET/CT and its impact on modifying patient treatment plans. The image quality of late LAFOV [68Ga]Ga-PSMA-11 PET/CT with forced diuresis in all patients met clinical diagnostic requirements. The rate of PET positivity of late LAFOV [68Ga]Ga-PSMA-11 PET/CT with forced diuresis were significantly higher than those of standard LAFOV [68Ga]Ga-PSMA-11 PET/CT (80.31% [102/127] vs. 65.35% [83/127]; P < 0.001). Late LAFOV [68Ga]Ga-PSMA-11 PET/CT demonstrated higher lesion SUVmax (16.69 ± 16.42 vs. 11.91 ± 10.72, P < 0.001) and TBR (6.26 ± 7.21 vs. 3.44 ± 3.57, P < 0.001) compared to standard LAFOV scans. Additionally, 14.17% (18/127) of patients experienced changes in their treatment regimen due to the superior detection capabilities of late LAFOV [68Ga]Ga-PSMA-11 PET/CT with forced diuresis compared to the standard scan. The rate of PET positivity of late LAFOV [68Ga]Ga-PSMA-11 PET/CT with forced diuresis compared to standard LAFOV [68Ga]Ga-PSMA-11 PET/CT highlight its potential as a valuable diagnostic tool for biochemically recurrent prostate cancer. This study paves the way for using late LAFOV [68Ga]Ga-PSMA-11 PET/CT with forced diuresis for prostate cancer imaging in daily clinical practice, facilitating more accurate and timely diagnoses.

PET/CT imaging of differentiated and medullary thyroid carcinoma using the novel SSTR-targeting peptide [18F]SiTATE - first clinical experiences.

The novel 18F-labeled somatostatin receptor (SSTR)-directed radiotracer [18F]SiTATE demonstrated promising results for the imaging of various SSTR-expressing tumor types. Although thyroid carcinomas (TC) express SSTR, data on [18F]SiTATE PET/CT imaging in TC are lacking. This study explores the use of [18F]SiTATE PET/CT in a patient cohort with histologically proven TC. As part of a prospective observational study at a single tertiary cancer center, 21 patients with TC (10 medullary (MTC) and 11 differentiated (DTC)) who underwent at least one [18F]SiTATE PET/CT were included (37 scans in total). Mean SUVmax and SUVmean of tumoral lesions, mean total-tumor-volume (TTV), and whole-body (WB)-SUVmax and WB-SUVmean on PET with their standard deviations (SDs) were determined. PET parameters were correlated to clinical parameters including tumor marker levels (thyroglobulin for DTC, calcitonin for MTC). 89 lesions were included in the analysis. Metastases were localized in the bone, lymph nodes, lung, soft tissue, and thyroid bed. Osseous (31 lesions; SUVmax 8.6 ± 8.0; SUVmean 5.8 ± 5.4) and nodal (37 lesions; SUVmax 8.7 ± 7.8; SUVmean 5.7 ± 5.4) metastases showed the highest uptake. The MTC disease burden on PET significantly correlated with the calcitonin tumor marker level (e.g., TTV: r = 0.771, r2 = 0.594, p = 0.002). For DTC, no such correlation was present. Our data demonstrate high feasibility of [18F]SiTATE PET/CT in a small cohort of patients with MTC and DTC. The use of [18F]SiTATE may overcome logistical disadvantages of 68Ga-based tracers and facilitate SSTR-targeted PET/CT imaging of thyroid carcinoma.

68Ga]Ga-LNC1007 versus 2-[18F]FDG in the evaluation of patients with metastatic differentiated thyroid cancer: a head-to-head comparative study.

This head-to-head comparison study aimed to compare the performance of [68Ga]Ga-FAPI-RGD (LNC1007) and 2-[18F]FDG PET/CT in the evaluation of patients with metastatic differentiated thyroid cancer (mDTC). Ten unexplained hyperthyroglobulinemia (UHTg) patients and 20 patients with definite metastatic lesions of thyroid cancer (DmDTC) were enrolled in the study. All patients underwent both [68Ga]Ga-LNC1007 and 2-[18F]FDG PET/CT within 1week. The final diagnosis was based on histopathological results and a comprehensive evaluation of laboratory tests and multimodal imaging characteristics. In patients with UHTg, [68Ga]Ga-LNC1007 PET/CT detected more metastatic lymph nodes (LNs) (17 vs. 15, P = 0.317) and lung lesions (2 vs. 0) than 2-[18F]FDG. In patients with DmDTC, [68Ga]Ga-LNC1007 PET/CT also detected more true positive lesions than 2-[18F]FDG (Total: 133 vs. 103, LN: 20 vs. 15, lung: 18 vs. 10, bone: 87 vs.73). [68Ga]Ga-LNC1007 PET/CT demonstrated significantly higher SUVmax (Total: 6.30 vs. 3.84, LN: 8.28 vs. 4.82, Lung: 3.31 vs. 1.49, Bone: 5.73 vs. 3.87, all P < 0.05) and TBR (Total: 6.92 vs. 4.93, LN: 6.48 vs. 4.16, Lung: 5.16 vs. 2.57, Bone: 7.22 vs. 5.41, all P < 0.05) in true positive lesions compared to 2-[18F]FDG. Specifically, the sensitivity of [68Ga]Ga-LNC1007 PET/CT was higher than that of 2-[18F]FDG in detecting lung and bone metastases (94.7% vs. 52.6% and 100% vs. 83.9%, all P < 0.05). [68Ga]Ga-LNC1007 PET/CT exhibited better specificity and accuracy in diagnosing LNs (96.9% vs. 66.7% and 96.3% vs. 68.5%, all P < 0.05). However, the specificity of [68Ga]Ga-LNC1007 for bone metastasis was inferior to 2-[18F]FDG (15.4% vs. 88.5%, P < 0.05). Compared with 2-[18F]FDG, [68Ga]Ga-LNC1007 PET/CT could detect more metastatic lesions, with higher SUVmax and TBR, in patients with mDTC. [68Ga]Ga-LNC1007 had better accuracy in the diagnosis of LN and lung metastasis. Trial registration ClinicalTrials.gov NCT05515783. Registered 01 May 2022. URL of registry https://classic. gov/ct2/show/NCT05515783.

Dual Somatostatin Receptor/18F-FDG PET/CT Imaging in Patients with Well-Differentiated, Grade 2 and 3 Gastroenteropancreatic Neuroendocrine Tumors.

Our purpose was to prospectively assess the distribution of NETPET scores in well-differentiated (WD) grade 2 and 3 gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) and to determine the impact of the NETPET score on clinical management. Methods: This single-arm, institutional ethics review board-approved prospective study included 40 patients with histologically proven WD GEP NETs. 68Ga-DOTATATE PET and 18F-FDG PET were performed within 21 d of each other. NETPET scores were evaluated qualitatively by 2 reviewers, with up to 10 marker lesions selected for each patient. The quantitative parameters that were evaluated included marker lesion SUVmax for each tracer; 18F-FDG/68Ga-DOTATATE SUVmax ratios; functional tumor volume (FTV) and metabolic tumor volume (MTV) on 68Ga-DOTATATE and 18F-FDG PET, respectively; and FTV/MTV ratios. The treatment plan before and after 18F-FDG PET was recorded. Results: There were 22 men and 18 women (mean age, 60.8 y) with grade 2 (n = 24) or grade 3 (n = 16) tumors and a mean Ki-67 index of 16.1%. NETPET scores of P0, P1, P2A, P2B, P3B, P4B, and P5 were documented in 2 (5%), 5 (12.5%), 5 (12.5%) 20 (50%), 2 (5%), 4 (10%), and 2 (5%) patients, respectively. No association was found between the SUVmax of target lesions on 68Ga-DOTATATE and the SUVmax of target lesions on 18F-FDG PET (P = 0.505). 18F-FDG/68Ga-DOTATATE SUVmax ratios were significantly lower for patients with low (P1-P2) primary NETPET scores than for those with high (P3-P5) primary NETPET scores (mean ± SD, 0.20 ± 0.13 and 1.68 ± 1.44, respectively; P < 0.001). MTV on 18F-FDG PET was significantly lower for low primary NETPET scores than for high ones (mean ± SD, 464 ± 601 cm3 and 66 ± 114 cm3, respectively; P = 0.005). A change in the type of management was observed in 42.5% of patients after 18F-FDG PET, with the most common being a change from systemic therapy to peptide receptor radionuclide therapy and from debulking surgery to systemic therapy. Conclusion: There was a heterogeneous distribution of NETPET scores in patients with WD grade 2 and 3 GEP NETs, with more than 1 in 5 patients having a high NETPET score and a frequent change in management after 18F-FDG PET. Quantitative parameters including 18F-FDG/68Ga-DOTATATE SUVmax ratios in target lesions and FTV/MTV ratios can discriminate between patients with high and low NETPET scores.

[18F]AlF-PSMA-11 PET in diagnosing prostate cancer: a head-to-head comparison with [68Ga]Ga-PSMA-11 PET and an exploration of dual-phase scanning

PurposeTo evaluate the physiological distribution and tumour detection ability of [18F]AlF-PSMA-11 positron emission tomography (PET) dual-phase scans in patients with prostate cancer (PCa).MethodsAs a retrospective study, clinical and PET data of PCa patients who underwent dual-phase [18F]AlF-PSMA-11 PET of routine scan (45–50 min) and delayed scan (120 min) from November 2020 to June 2021 were collected, and physiological and pathological regions of interest were quantified to determine the time-dependent maximum standardized uptake value (SUVmax) of [18F]AlF-PSMA-11. Part of the above subjects who underwent [68Ga]Ga-PSMA-11 PET in the following 6 months were included in a head-to-head comparison. The difference with a p-value < 0.05 was defined as statistical significance. Diagnosis accuracy of primary and metastatic lesions was measured referring to the surgical findings, pathology, and follow-up imaging.Results[68Ga]Ga-PSMA-11 and [18F]AlF-PSMA-11 were of the comparable uptake in glands in head, but the latter was of a significant lower distribution in liver and spleen. For the 25 patients initially diagnosed with prostate cancer and 3 patients with biochemical recurrence after radical surgery, the SUVmax of the primary lesions, lacrimal glands, parotid glands and submandibular glands was higher at 120 min compared to that at 45–50 min, but not a significant difference. SUVmax of the liver, spleen and bladder decreased significantly at 120 min, but the bladder SUVmax remained higher than that of primary lesions. SUVmax of the kidneys and centrum was the same in dual-phase scans. For the 31 primary lesions detected in [18F]AlF-PSMA-11 PET, both the SUVmax of the two phases kept the positive correlation with PSA, Gleason score and initial risk stratification. For the 39 distant metastatic lesions, 94.87% accuracy of routine scan and 100% accuracy of delayed scan were acquired, and 7.14% patients (2/28) benefited from the dual-phase [18F]AlF-PSMA-11 scans that revealed novel information on metastatic lesions compared to the routine scan.Conclusion[18F]AlF-PSMA-11 PET expanded the time window and further decreased metabolic background of [68Ga]Ga-PSMA-11 PET. The dual-phase scan of [18F]AlF-PSMA-11 PET can benefit prostate cancer diagnosis via providing more PSMA-specific information.

PSMA PET improves characterization of dural-based intracranial lesions in patients with metastatic prostate cancer

PurposeTheranostic approaches combining prostate-specific membrane antigen (PSMA)-PET/CT or PET/MRI with PSMA-targeted radionuclide therapy have improved clinical outcomes in patients with prostate cancer (PCa) especially metastatic castrate resistant prostate cancer. Dural metastases in PCa are rare but can pose a diagnostic challenge, as meningiomas, a more common dural based lesions have been shown to express PSMA. The aim of this study is to compare PSMA PET parameters between brain lesions classified as dural metastases and meningiomas in prostate cancer patients. MethodsA retrospective analysis of PSMA PET/CT scans in patients with PCa and intracranial lesions was conducted. Brain lesions were categorized as dural metastases or meningiomas based on MRI characteristics, longitudinal follow-up, and histopathological characteristics. Standardized uptake values (SUVmax) of each brain lesion were measured, along with SUV ratio referencing parotid gland (SUVR). SUVs between lesions classified as metastases and meningiomas, respectively, were compared using Mann-Whitney-test. Diagnostic accuracy was evaluated using ROC analysis. Results26 male patients (median age: 76.5 years, range: 59–96 years) met inclusion criteria. A total of 44 lesions (7 meningiomas and 37 metastases) were analyzed. Median SUVmax and SUVR were significantly lower in meningiomas compared to metastases (SUVmax: 2.7 vs. 11.5, p = 0.001; SUVR: 0.26 vs. 1.05, p < 0.001). ROC analysis demonstrated AUC 0.903; the optimal cut-off value for SUVR was 0.81 with 81.1 % sensitivity and 100 % specificity. ConclusionPSMA PET has the potential to differentiate meningiomas from dural-based metastases in patients with PCa, which can optimize clinical management and thus improve patient outcomes.

Feasibility of a deep-inspiration breath-hold [18F]AlF-NOTA-LM3 PET/CT imaging on upper-abdominal lesions in NET patients: in comparison with respiratory-gated PET/CT

PurposesTo explore the clinical feasibility and efficacy of a deep inspiration breath-hold (BH) PET/CT using [18F]AlF-NOTA-LM3 on upper abdominal lesions in patients with neuroendocrine tumors (NETs).MethodsTwenty-three patients underwent a free-breath (FB) whole-body PET/CT, including a 10 min/bed scan for the upper abdomen with a vital signal monitoring for respiratory gating (RG) followed by a 20-second BH PET/CT covering the same axial range. For the upper abdomen bed, the following PET series was reconstructed: a 2-min FB PET; RG PET (6 bins); a 20-second and 15-second BH PET (BH_15 and BH_20). Semi-quantitative analysis was performed to compare liver SUVmean, lesion SUVmax, MTV, its percentage difference and target-to-background ratio (TBR) between both BH PET and RG PET images. Subgroup analysis considered lesion location, MTV and SUVmax. A 5-point Likert scale was used to perform visual analysis and any missed or additional lesions were identified compared with RG PET.ResultsQuantitative analysis on overall lesions (n = 78) revealed higher SUVmax and TBR, and smaller MTV for both BH PET compared to FB and RG PET, with lesion location-specific variations. Neither significant difference was observed in all metrics between RG and FB PET in larger lesions, nor in MTV in lower-uptake lesions. However, both BH PET significantly enhanced these measurements. In the visual analysis, both BH PET showed noninferior performance to RG PET, and were evaluated clinically acceptable. Additional and missed lesions were observed in FB and both BH PET compared with RG PET, but didn’t alter the clinical management. The BH_15 PET showed comparable performance to BH_20 PET in any comparison.ConclusionThe BH PET/CT using [18F]AlF-NOTA-LM3 is effective in detecting upper abdominal lesions, offering more accurate quantitative measurements. Using a novel PET/CT scanner, a 15-second BH PET can provide comparable and superior performance to RG PET, indicating potential feasibility in clinical routines.

The effect of reconstruction algorithms on semi-quantitative measurements in 18F-FDG PET/CT imaging.

This study was carried out to understand whether Q.Clear and ordered subset expectation maximization (OSEM), reconstruction algorithms used in fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) applications, and parameters such as time of flight (TOF) and point spread function (PSF) cause different results in semi-quantitative measurements. Raw PET data of 264 patients who were referred to 18F-FDG PET/CT imaging with the purpose of evaluation of known or suspicious malignant disease were reconstructed separately with Q.Clear (GE Healthcare), a BPL, an OSEM algorithm, PSF (SharpIR®) and TOF (VUE Point FX®) methods. Each patient's liver, mediastinal blood pool, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and standardized uptake values (SUV) (SUVmax, SUVmean, and SUVpeak) of a total of 264 lesions selected from the patients were performed. β350+ToF yielded higher measurement results than all other variables for all of the lesion SUVmax, lesion SUVmean, L/AP SUVmax, and L/AP SUVmean parameters. OSEM+ToF and OSEM+TOF+PSF algorithms yielded higher mean and median SUVmax values for the reference structures (liver and mediastinum) and for lesions SUVmax and SUVmean values were statistically significantly lower than the β350+ToF method. The method with the lowest mean value for the L/Liver SUVmax variable was OSEM+ToF 4iter16ss (mean=1.76), while the method with the highest mean value was β350+ToF (mean=2.26). β350+ToF was the reconstruction method with the highest ratios for L/AP SUVmax and SUVmean for both lesions below and above 1 cm. β350+ToF algorithm had also statistically significantly higher results for these variables compared to all other parameters in malignant lesions. When comparing 18F-FDG PET/CT images, the use of different reconstruction algorithms may lead to misleading results, especially in the evaluation of response to treatment of malignancies.

Correlation of PSA blood levels with standard uptake value maximum (SUV max ) and total metabolic tumor volume (TMTV) in 18F-PSMA-1007 and 18F-choline PET/CT in patients with biochemically recurrent prostate cancer.

In this prospective study, we investigated the correlation between prostate-specific antigen (PSA) levels in the blood of patients with prostate cancer in biochemical recurrence after radical treatment with the semiquantitative parameters standard uptake value maximum (SUV max ) and the total metabolic tumor volume (TMTV) in the metastatic foci depicted in 18F-prostate-specific membrane antigen (PSMA)-1007 and 18F-choline PET/computed tomography (CT) imaging. We prospectively examined 104 patients with biochemical relapse of prostate cancer after primary definitive treatment. All patients underwent one 18F-PSMA-1007 and one 18F-choline PET/CT examination in randomized order within a time frame of 10 days and were followed for at least 6 months (182 ± 10 days). The semiquantitative parameters of SUV max and metabolic tumor volume (MTV) of each neoplastic lesion in PET/CT imaging were calculated, and further summation of each MTV value was done to calculate the TMTV. According to the Spearman correlation analysis, a positive correlation was found between PSA levels and SUV max and TMTV scores in the metastatic foci of 18F-PSMA-1007 PET/CT ( r = 0.24 and 0.35, respectively; P < 0.05) and SUV max in the lesions of 18F-choline PET/CT ( r = 0.28; P < 0.0239). However, a positive but NS correlation was demonstrated between values of PSA and TMTV for each lesion in the 18F-choline PET/CT study ( r = 0.22; P = 0.0795). The detection rate of the different PSA levels with a cutoff of 1 ng/ml was higher for 18F-PSMA-1007 than 18F-choline. In biochemical relapse patients there is a positive correlation between PSA levels in the blood and the semiquantitative parameters SUV max and TMTV of the metastatic foci in the 18F-PSMA-1007 and 18F-Choline PET/CT imaging.

Feasibility and therapeutic potential of [177Lu]Lu-FAPI-2286 in patients with advanced metastatic sarcoma.

The unique expression pattern of fibroblast activation protein (FAP) in stromal and tumor cells, particularly in sarcomas, and its absence in normal tissues, have positioned it as a promising theragnostic approach for the detection and treatment of various cancer types. The objective of this prospective study is to assess the feasibility, safety, biodistribution, and therapeutic efficacy of [177Lu]Lu-FAPI-2286 in patients with advanced metastatic sarcoma. Eight patients with advanced metastatic sarcoma, who were unresectable or had experienced disease recurrence following conventional treatments, underwent PTRT (peptide-targeted radionuclide therapy) using [177Lu]Lu-FAPI-2286. Prior to the treatment, confirmation of tumor uptake was obtained through [68Ga]Ga-FAPI-2286 PET/CT. After four cycles of PTRT with [177Lu]Lu-FAPI-2286 (6660-7400 MBq), with a 6-8-week interval between each cycle, no grade 3 or 4 side effects were observed in the patients, and the treatment was well tolerated by all participants. The results demonstrated a 52.37% reduction in the average volume of the primary tumor, accompanied by a significant decrease in SUVmax and TBR of the metastatic lesions (29.67% and 43.66% respectively), especially in cases of lung metastasis. Furthermore, besides the improvement in physical capacity, there was a noticeable reduction in pain, an increase in overall survival, and enhanced satisfaction with the treatment reported by the patients. [177Lu]Lu-FAPI-2286 PTRT, utilized for diverse cancer types, exhibited favorable tolerability in sarcoma patients, with minimal side effects, long-lasting retention of the radiopeptide within the tumor, and promising therapeutic effects. Preliminary findings of this prospective study need to be confirmed through further clinical trials.

Prospective investigation of amino acid transport and PSMA-targeted positron emission tomography for metastatic lobular breast carcinoma.

To explore the feasibility of imaging amino-acid transport and PSMA molecular pathways in the detection of metastatic breast invasive lobular carcinoma (ILC) and if there is superior detection compared to standard-of-care imaging [computed tomography (CT)/bone scan, or 18F-FDG positron-emission-tomography (PET)-CT]. 20 women with de-novo or suspected metastatic ILC underwent two PET-CT scans with 18F-fluciclovine and 68Ga-PSMA-11 on separate days. Uptake per patient and in 3 regions per patient - ipsilateral axillary lymph node (LN), extra-axillary LN (ipsilateral supraclavicular or internal mammary), or distant sites of disease - was compared to standard-of-care imaging (CT/bone scan in 13 patients and 18F-FDG PET-CT in 7 patients). Results were correlated to a composite standard of truth. Confirmed detection rate (cDR) was compared using McNemar's test. Mean SUVmax of 18F-fluciclovine and 68Ga-PSMA-11 in the most avid lesion for each true positive metastatic region and intact primary lesion were compared by t-test. The cDR for standard-of-care imaging was 5/20 patients in 5/60 regions. 68Ga-PSMA-11 PET-CT detected metastasis in 7/20 patients in 7/60 regions. 18F-fluciclovine PET-CT detected metastasis in 9/20 patients in 12/60 regions. The cDR for 18F-fluciclovine PET-CT was significantly higher versus standard-of-care imaging on the patient and combined region levels, while there were no significant differences between 68Ga-PSMA-11 and standard-of care imaging. 18F-fluciclovine cDR was also significantly higher than 68Ga-PSMA-11 on the combined region level. Mean SUVmax for true positive metastatic and primary lesions with 18F-fluciclovine (n = 18) was significantly greater than for 68Ga-PSMA-11 (n = 11) [5.5 ± 1.8 versus 3.5 ± 2.7 respectively, p = 0.021]. In this exploratory trial, 18F-fluciclovine PET-CT has a significantly higher cDR for ILC metastases compared to standard-of-care imaging and to 68Ga-PSMA-11. Mean SUVmax for true positive malignancy was significantly higher with 18F-fluciclovine than for 68Ga-PSMA-11. Exploratory data from this trial suggests that molecular imaging of amino acid metabolism in patients with ILC deserves further study. Early phase (I-II) clinical trial (NCT04750473) funded by the National Institutes of Health (R21CA256280).

Clinical value of 68Ga-pentixafor PET/CT in patients with primary aldosteronism and bilateral lesions: preliminary results of a single-centre study

BackgroundSubtype diagnosis of primary aldosteronism (PA) is used to determine treatment, and the potential utility of 68Ga-pentixafor PET/CT for investigation of PA has long been recognized. The study aimed to evaluate the clinical value of 68Ga-pentixafor PET/CT in the diagnosis and prognosis of patients with bilateral lesions identified by CT.MethodsIn total, 25 patients with PA and bilateral lesions on CT were retrospectively evaluated. All patients underwent 68Ga-Pentixafor PET/CT and adrenal vein sampling. The analysis focused on establishing the relationship between bilateral adrenal lesions SUVmax and the ratio of bilateral adrenal lesions SUVmax (CON) and clinical diagnosis, treatment outcomes, and KCNJ5 gene status.ResultsThe concordance rate between 68Ga-Pentixafor PET/CT and adrenal venous sampling was 65.2% (15/23). The lateralization results of 68Ga-pentixafor PET/CT supported the clinical decisions of 20 patients with PA, 90% of whom showed effectiveness in treatment. The SUVmax on the dominant side of the surgically treated patients was higher than that of patients treated with drugs. The SUVmax of the KCNJ5 mutant group was higher than that of the KCNJ5 wild group, and 68Ga-Pentixafor uptake was correlated with KCNJ5 gene status.Conclusions68Ga-Pentixafor PET/CT proves beneficial for patients with PA with bilateral lesions on CT. The treatment is generally effective based on the results of PET lateralization. Simultaneously, a certain relationship exists between 68Ga-Pentixafor PET/CT and KCNJ5 gene status, warranting further analysis.

Comparison of 68 Ga-FAPI-04 and 18 F-FDG PET/CT in Fumarate Hydratase-Deficient Renal Cell Carcinoma : A Prospective and Single-Center Study.

Fumarate hydratase-deficient renal cell cancer (FHRCC) is a rare and aggressive form of renal cell carcinoma. The diagnostic value of 68 Ga-FAPI PET/CT for FHRCC remains unexplored. Therefore, we compared the potential value of 68 Ga-FAPI-04 and 18 F-FDG PET/CT in FHRCC. Patients with FHRCC underwent 68 Ga-FAPI-04 and 18 F-FDG PET/CT from May 2022 to December 2023. The SUV max and tumor-to-liver ratio (TLR) of both tracers were compared using the Wilcoxon signed rank test. Eleven patients with 83 lesions were enrolled. The rate of 18 F-FDG PET/CT in detecting lesions was higher than that of 68 Ga-FAPI-04 PET/CT: primary tumors: 75.0% (6/8) versus 50.0% (4/8); lymph nodes: 94.9% (37/39) versus 89.7% (35/39); and bone lesions: 100.0% (21/21) versus 90.5% (19/21). The median SUV max of primary and metastatic lesions on 18 F-FDG PET/CT was comparable to 68 Ga-FAPI-04 PET/CT in semiquantitative analysis (primary lesions: 13.86 vs 16.35, P = 1.000; lymph nodes: 10.04 vs 9.33, P = 0.517; bone lesions: 13.49 vs 9.84, P = 0.107; visceral lesions: 8.54 vs 4.20, P = 0.056). However, the median TLRs of primary and metastatic lesions on 68 Ga-FAPI-04 PET/CT were higher than that of 18 F-FDG PET/CT (primary lesions: 30.44 vs 5.41, P = 0.010; lymph nodes: 17.71 vs 3.95, P = 0.000; bone lesions: 15.94 vs 5.21, P = 0.000; visceral lesions: 9.26 vs 3.44, P = 0.003). 18 F-FDG PET/CT detected more primary and metastatic FHRCC lesions than 68 Ga-FAPI-04 PET/CT. However, the higher TLR in FHRCC on 68 Ga-FAPI-04 PET/CT may indicate therapeutic potential in targeting fibroblast activation protein in FHRCC.

The value of 68Ga-PSMA PET/CT in the diagnosis of intracapsular prostate cancer with a poor prognosis

ObjectiveTo evaluate the diagnostic value of 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) for intracapsular prostate cancer with a poor prognosis (PPC) and no extracapsular invasion or distant metastasis.MethodsThe PET/CT images and clinical data of 221 patients were retrospectively analyzed. These patients all had clear pathological results. The maximum standard uptake value (SUVmax) of the main lesions was measured at the postprocessing workstation and was tested for correlation with the pathological score. The diagnostic accuracy was calculated using the receiver operating characteristic (ROC) curve, and the best diagnostic threshold was calculated. The correlation between SUVmax and the International Society of Urological Pathology Grade Group (GG) was also analyzed.ResultsThe pathological results of the 221 patients were 48 benign lesions and 173 malignant lesions, including 81 PPC. Low-, intermediate-, and high-risk prostate cancers made up 21.97% (38/173), 54.33% (94/173), and 23.70% (41/173) of the malignant lesions, respectively. SUVmax and GG were positively correlated (r = 0.54, P < 0.01). The best SUVmax thresholds for 68Ga-PSMA PET/CT for the diagnosis of intracapsular PC and PPC were 7.95 and 13.94, respectively; the specificities were 0.83 and 0.85, the negative predictive values were 0.55 and 0.87, and the areas under the ROC curves were 0.88 and 0.88, respectively.Conclusion68Ga-PSMA PET/CT has high specificity and NPV in the diagnosis of intracapsular PPC, but the sensitivity for the diagnosis of intracapsular low-risk PC is low, which may cause some cases to be undetected.

Assessment of PD-L1 Expression in Non-Small Cell Lung Cancers Using [68Ga]Ga-DOTA-WL12 PET/CT.

Assessing programmed death ligand-1 (PD-L1) expression in non-small cell lung cancer (NSCLC), particularly in metastatic cases, remains challenging. In this study, surface plasmon resonance (SPR) analysis and [68Ga]Ga-DOTA-WL12 micro-PET/CT imaging are performed. [68Ga]Ga-DOTA-WL12 PET/CT and [18F]FDG PET/CT are performed on a cohort of 20 patients with NSCLC. Semi-quantitative assessments include SUVmax, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and target-to-background ratio (TBR). DOTA-WL12 exhibits robust PD-L1 binding with a KD value of 0.2nM. Subsequent human studies reveal significant correlations between PD-L1 expression and the [68Ga]Ga-DOTA-WL12 SUVmax in primary and metastatic lesions, surpassing the [18F]FDG results (r = 0.8889, p <0.0001 vs r = 0.0469, p = 0.8127). Notably, [68Ga]Ga-DOTA-WL12 imaging discerned SUVmax and TBR differences between PD-L1 TPS ≤1% and PD-L1 TPS > 1% groups (p all <0.001). In an NSCLC patient with brain metastases, [68Ga]Ga-DOTA-WL12 shows a SUVmean of 0.04 in the brain background, with TBR values of 17 and 23, underscoring its potential for detecting brain metastases. The study provides initial evidence for the clinical utility of [68Ga]Ga-DOTA-WL12 PET/CT for lesion detection, immunotherapy selection, and therapeutic efficacy evaluation in PD-L1-expressing NSCLC, demonstrating its potential as a valuable tool in NSCLC research and management.

Imaging and clinical characteristics of incidental abnormal thyroid uptake on PSMA PET/CT.

e18077 Background: To investigate the incidence, features, and clinical characteristics of unexpected prostate-specific membrane antigen (PSMA) uptake within the thyroid gland of patients with prostate cancer (PCa) who underwent F-18 DCFPyL PSMA PET/CT. Methods: We retrospectively reviewed a cohort of 1148 PCa patients who underwent PSMA PET/CT at our institution between 11/2021 - 09/2023. Scans with abnormal thyroid uptake were identified. Clinical data included patient demographics, PCa history, Gleason score, prostate specific antigen (PSA), ultrasonography (US), fine needle aspirate (FNA) / thyroidectomy, histopathology, and history of neck radiation or prior malignancy. Each scan was further analyzed with lesion-specific iso-contour method (42% cutoff) to obtain PET parameters (most prominent nodule SUVmax, SUVmean, PSMA volume, tumor lesion PSMA, contralateral gland SUVmax, SUVmax-nodule / SUVmax-contralateral gland ratio, most prominent PCa lesion SUVmax), PCa tumor distribution, and tumor volume. CT-related variables (nodule number, dominant nodule size, short/long axis ratio, CT-HU, integral total value) were also collected. Pearson's chi-square testing and Kruskal-Wallis testing was performed for categorical and nonparametric data respectively. Receiver operating characteristic (ROC) curves with area under curve (AUC) value were determined using IBM SPSS (version 29.0). Results: Of the 1148 PSMA PET/CTs, 60 (5.2%) had abnormal thyroid uptake (nodular: 58, diffuse: 2). Diffuse uptake was found to represent thyroiditis in both patients. 43 (56.7%) had an US, 20 (33%) were biopsied (11 benign, 5 indeterminate, 4 malignant), and 5 (8.3%) pursued thyroidectomy (3 malignant, 2 benign). 22 patients (36.7%) had histopathology data and 5 malignancies (2 PCa, 1 CLL, 2 primary thyroid) were identified. Nodule size was larger in those who had an US relative to those who did not. Among those with US data, no significant differences in clinical or histopathological parameters were seen. SUVmax (p: 0.01; AUC: 0.876, 95%CI: 0.731-1.0) and SUVmean (p:0.01; AUC: 0.871, 95%CI: 0.722-1.0) were higher in the malignant group. Nodule SUVmax/contralateral gland SUVmax ratio showed borderline significance (p = 0.05). Conclusions: Incidental PSMA PET uptake in the thyroid gland is seen in approximately 5% of patients. Focal uptake should prompt consideration of US and FNA due to the possibility of prostate cancer metastasis and thyroid cancer. SUVmax/mean is higher in malignant lesions.