Tumor SUVmax Research Articles

Comparative Study of [18F]AlF-LNC1007, [18F]FDG, and [18F]AlF-NOTA-FAPI-04 PET/CT in Breast Cancer Diagnosis: A Methodological Exploration and Analytical Insight.

Objective: To compare the diagnostic value of [18F]AlF-LNC1007, [18F]FDG, and [18F]AlF-NOTA-FAPI-04 PET/CT in breast cancer. Methods: 33 patients with highly suspected or already diagnosed but untreated breast cancer were enrolled in the study and underwent [18F]AlF-LNC1007 (30 patients), [18F]FDG (22 patients), and [18F]AlF-NOTA-FAPI-04 (8 patients) PET/CT. Quantitative measurements included the SUVmax and tumor-to-background ratio (TBR) for all lesions and background tissues. The Chi-square test was used for intergroup diagnostic efficacy, and the Wilcoxon test was used for intergroup SUVmax or TBR. Diagnostic efficacy for lymph node metastasis was evaluated using receiver operating characteristic (ROC) analysis. Results: Compared to [18F]FDG, [18F]AlF-LNC1007 had a higher positive predictive value (100% vs 91%, P = 0.0004) in lymph node metastases (42 vs 46) and higher sensitivity (100 vs 76%, P = 0.0003) in bone metastases (33 vs 25) but lower sensitivity (93 vs 100%, P = 0.001) in liver metastases. Apart from liver metastases, [18F]AlF-LNC1007 PET/CT had higher SUVmax in primary tumor and other metastases, with no statistical difference in TBR. Compared to [18F]AlF-NOTA-FAPI-04 PET/CT, [18F]AlF-LNC1007 had less false-positive and a higher positive predictive value in bone metastases (99 vs 95%, P = 0.0003) but had lower SUVmax(P < 0.01) in all primary and metastases lesions. The TBR difference between [18F]AlF-LNC1007 and [18F]AlF-NOTA-FAPI-04 was statistically significant only in bone metastases (5.97 vs 5.02, P = 0.001). The comparison of lymph node detection efficacy between [18F]AlF-LNC1007 and [18F]FDG PET/CT showed significant differences in SUVmax cutoff values for diagnosing lymph node metastases (2.62 vs 3.90), sensitivity (95.2% vs 66.67), and specificity (100% vs 85.00) (all P < 0.001). Conclusion: [18F]AlF-LNC1007 demonstrated superior efficacy compared to [18F]FDG and [18F]AlF-NOTA-FAPI-04 and higher uptake than [18F]FDG in primary tumor, lymph node and bone metastases, and higher TBR than [18F]AlF-NOTA-FAPI-04, especially in bone metastases. [18F]AlF-LNC1007 also showed high specificity in differentiating inflammatory and metastatic lymph nodes.

Predictive Model of Paraaortic Lymph Node Involvement in cN0 Locally Advanced Cervical Cancers: PET/CT Technology Matters.

Background: The aim is to propose a model for predicting occult paraaortic lymph node (PALN) involvement in locally advanced cervical cancer (LACC) patients by including parameters such as reconstruction detection technology (use of time-of-flight) and parameters related to the primary tumor. This model will then be compared with the scores used in routine clinical practice; Methods: This retrospective observational cohort study included patients diagnosed with LACC who underwent 18F-FDG PET/CT prior to PALN surgical staging between February 2012 and May 2020. The following parameters were collected on PET/CT: tumor SUVmax, tumor MTV, number of common and distal pelvic node involvements. A multivariate regression analysis estimating the probability of PALN involvement was performed, with optimal thresholds determined via ROC curves; Results: In total, 71 patients met the inclusion criteria. Occult PALN involvement was detected in 12.7% of patients. A derived multivariate PET model selected four variables: number of common and distal iliac lymph nodes (OR 5.9 and 2.7, respectively), tumor-to-liver SUV ratio (OR 0.9) and the use of time-of-flight technology (OR 21.4 if no time-of-flight available). At the optimal threshold, a sensitivity of 77.8% and specificity of 88.7% was found. The model's performances varied significantly between patients whose PET/CT used time-of-flight and those whose PET/CT did not. No significant differences were found between our model and the one used in clinical practice (p = 0.55); Conclusions: This study shows that PET/CT technology influences the ability to detect occult PALN involvement in LACC. This parameter should be considered in the regular revision of PET-based scores.

Clinical significance of PET/CT in the diagnosis of primary adrenal malignancies

Background. According to the literature, the role of combined positron-emission and X-ray computed tomography (PET/CT) in diagnosing primary adrenal tumors (AT) remains limited due to both the frequency of these neoplasms and the availability of the method. Various research is required to assess the diagnostic resources of PET/CT with 18-fluorodeoxyglucose (18F-FDG). Aim. To evaluate the clinical role of PET/CT with 18F-FDG in the diagnosis of primary adrenal malignancies (PAM). Materials and methods. The study included 9 patients, 5 males and 4 females aged 44–76, with a median age of 59.3 years, with a morphologically confirmed diagnosis of the PAM. All patients underwent PET/CT with 18F-FDG. Visual and quantitative analysis of the obtained images was performed, including determination of the standardized maximum accumulation coefficient (SUVmax) in the tumor, liver, and spleen, the ratio of SUVmax of the primary tumor to SUVmax in the liver and spleen. Tumors were more often localized on the right (5/55.6%), and one case was bilateral. The maximum size of the adrenal mass averaged 6.8 cm (3.2–11.2) and the minimum size was 6.0 cm (2.3–9.0). The median SUVmax in AT was 10.0 (3.54–22.29), while in liver and spleen, it was 3.16 and 2.34, respectively, and the ratio of tumor SUVmax to liver and spleen SUVmax was 3.33 and 4.48, respectively. Conclusion. Hybrid PET/CT with 18F-FDG is a medical imaging method with a high diagnostic accuracy of PAM. PET/CT showed significant 18F-FDG tumor uptake, with a median SUVmax of 10.0 and a ratio of tumor SUVmax to liver and spleen SUVmax of 3.33 and 4.48, respectively. PET/CT with 18F-FDG may be a method of choice for diagnosing primary ATs.

Predictors for Disease-Free and Progression-Free Survivals in Metabolic Responders and Non-Responder on Follow-Up 18FDG PET/CT after Chemoradiation in Patients With Nasopharyngeal Cancer.

To determine disease free survival (DFS) and progression free survival (PFS) and their predictors in patients with nasopharyngeal cancer (NPC) having achieved complete (CMR) and partial metabolic response (PMR) on post-chemoradiation (CRT) 18FDG PET/CT. Retro-prospective study conducted at PET/CT Section of JCIA accredited healthcare facility of Pakistan. Total 73 patients of NPC patients who had baseline and post-CRT 18FDG PET/CT were included and prospectively followed till predefined study end points of recurrence or disease progression or death from April-2016 till January 2024. Based on CMR on post-CRT 18FDG PET/CT, 45 patients labelled as responders while 28 with PMR as non-responders. Using logistic regression and ROC analysis, the predictors of recurrence and disease progression were analyzed in both groups. Kaplan Meier's survival plots were analyzed to measure DFS in responders and PFS in non-responders respectively. Body mass index (BMI), SUVmax and Stage-IV disease were found significantly higher in non-responder group. DFS in responders was significantly higher than PFS in non-responder (60.157 month ± 8.047 Vs 8.145 months ± 1.851). DFS was seen in 84% of responder group with 16% recurrence (7/45). Baseline SUVmax >14.2 and primary tumor size (PTS) > 41 mm were found significant predictors of recurrence in responder group. In the non-responder group, the PFS was found in 54% patients while 46% patients (n=13/28; 2 expired) had disease progression. No significant predictor was found for PFS in the non-responder group. In DFS the mean survival was significantly higher in patients with SUVmax ≤14.2 versus >14.2 (Mean Survival 67.390 vs. 38.283 months; Logrank 9.899; p=0.0017*). However, near significant difference was observed in non-responder group in their PFS at SUVmax ≤11.9 vs. >11.9 (Mean Survival 10.00 vs. 7.05 months; Logrank=3.096; p=0.0798). 18FDG PET/CT scan precisely stratifies the treated NPC patients into responders having longer DFS and non-responders having shorter PFS. Higher BMI, SUVmax of primary tumor and metastatic disease were found to have significant association in non-responders. In responders, PTS >41 mm and its SUVmax >14.2 were found significant predictors of recurrence. In non-responders, SUVmax >11.9 was found to have near significant association with disease progression.

Impact of Primary Tumor Diameter and SUVmax on Pathological Lymph Node Involvement in Non-small Cell Lung Cancer

Impact of Primary Tumor Diameter and SUVmax on Pathological Lymph Node Involvement in Non-small Cell Lung Cancer

Prognostic Value and Clinical Implication of Lymph Node-to-Primary Tumor SUV Ratio in Node-Positive Hypopharyngeal Squamous Cell Carcinoma Treated With Radiotherapy With or Without Chemotherapy.

The aim of this was to evaluate the prognostic significance of the nodal-to-primary tumor SUVmax ratio (NTR) in patients with node-positive hypopharyngeal squamous cell carcinoma (HPSCC) treated with radiotherapy with or without concurrent chemotherapy. The study aims to enhance prognostic accuracy by incorporating NTR into the American Joint Committee on Cancer (AJCC) staging system. This retrospective study included 191 patients with biopsy-proven node-positive HPSCC treated from 2005 to 2013. NTR was calculated as the ratio of SUVmax of metastatic lymph nodes to the primary tumor's SUVmax. Survival analyses were conducted using Cox regression models and Kaplan-Meier analysis. Receiver operating characteristic analysis compared the prognostic performance of the modified and AJCC staging systems. The median follow-up was 8.27 years, with 135 deaths (70.7%). High NTR (≥0.63) was significantly associated with worse overall survival (OS) and was an independent prognostic factor in multivariable analysis (adjusted hazards ratio [HR] = 1.63, P = 0.007). Median OS for high NTR was 17.4 months, compared with 75.2 months for low NTR. High NTR significantly predicted worse OS within AJCC stage IVA patients (HR = 6.09, P = 0.014). Patients in modified stage IVA (AJCC stage IVA with low NTR) had significantly longer OS than those in modified stage IVB (AJCC stage IVA with high NTR and AJCC stage IVB) (HR = 8.62, P = 0.003). The modified staging system incorporating NTR showed superior prognostic performance compared with the AJCC staging system. NTR is a significant independent prognostic factor for OS in node-positive HPSCC patients. Integrating NTR into the AJCC staging system improves prognostic accuracy.

The prognostic role of whole-body volumetric positron emission tomography/computed tomography parameters in treatment naive colorectal cancer patients with liver metastases.

The present study aimed to predict the prognostic role of quantitative 18F-fluorodeoxyglucose PET/computed tomography parameters such as maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) obtained from primary tumor, lymph node metastases, and liver metastasis (LM) in patients with colorectal LM (CLM). The research was designed as a retrospective study and 66 patients with CLM were enrolled between January 2017 and December 2018. Primary tumor SUVmax (PSUVmax), liver SUVmax (LSUVmax), and lymph node SUVmax (LnSUVmax) values obtained from the primary tumor, liver, and lymph nodes were recorded. In addition, total MTV (TMTV) and total TLG (TTLG) values were obtained by summing the values obtained from the primary tumor (PMTV and PTLG), lymph nodes (LnMTV and LnTLG), and liver (LMTV and LTLG). Univariate and multivariate Cox regression analysis was used to measure the effects of prognostic variables on mortality and survival. In univariate Cox regression analysis, PMTV (P = 0.001), LnMTV (P = 0.008), LnTLG (P = 0.008), LnSUVmax (P = 0.047), and TTLG (P = 0.038) were identified as prognostic factors for overall survival. No statistically significant relationship was found between MTV and TLG values of LM and overall survival. In multivariate analysis, PMTV (P = 0.022) was identified as an independent prognostic factor. In conclusion, our study demonstrated that the PMTV value used in evaluating treatment-naive patients diagnosed with CLM is an independent prognostic factor for survival. Our results need to be confirmed with more studies involving more patients.

Negative-predictive value of SUVmax for Ascertaining the efficacy of osimertinib in EGFR mutation-positive non-small cell lung cancer

BackgroundFluorine-18 2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) is routinely used to stage non-small cell lung cancer (NSCLC). However, whether 18F-FDG accumulation in primary tumors affects the efficacy of osimertinib in patients with epidermal growth factor receptor (EGFR) mutation-positive NSCLC remains unclear. MethodsWe retrospectively investigated 74 patients with advanced or postoperative recurrent EGFR mutation-positive NSCLC who underwent 18F-FDG PET/CT and were treated with osimertinib as first-line therapy between September 2018 and March 2023 at Kumamoto University Hospital. The maximum standardized uptake value (SUVmax) of each primary tumor was measured, and the patients were divided into two groups according to the median SUVmax. The effects of SUVmax on progression-free survival (PFS) and overall survival (OS) were assessed using a multivariate Cox proportional hazards model. ResultsThe median SUVmax was 8.2 (interquartile range: 5.5–11.4). The median PFS in the high SUVmax group (≥8.2) was significantly shorter than that in the low SUVmax group (<8.2). The respective median PFSs were 11.2 months (95% confidence interval [CI]: 3.1–19.3 months) vs. 22.9 months (95% CI: 12.4–33.4 months) (P = 0.015), although the OS values did not differ significantly. Multivariate analysis showed that a high SUVmax was an independent negative predictive factor for PFS in patients treated with osimertinib (hazard ratio, 2.25; 95% CI: 1.15–4.39, P = 0.017). ConclusionsHigh primary-lesion SUVmax in patients with EGFR mutation-positive NSCLC correlated with shorter PFS with first-line osimertinib therapy, suggesting that SUVmax is a useful predictive marker for the antitumor efficacy of osimertinib.

Predicting invasiveness of ground-glass nodules in lung adenocarcinoma: based on preoperative 18 F-fluorodeoxyglucose PET/computed tomography and high-resolution computed tomography.

This study was conducted to explore the differential diagnostic value of PET/computed tomography (PET/CT) combined with high-resolution computed tomography (HRCT) in predicting the invasiveness of ground-glass nodules (GGNs). This retrospective analysis included 67 patients (mean age 62.5 ± 8.4, including 45 females and 22 males) with GGNs who underwent preoperative 18 F-fluorodeoxyglucose ( 18 F-FDG) PET/CT and HRCT examinations between January 2018 and October 2022. Based on the postoperative pathological results of lung adenocarcinoma, the patients were classified into two groups: invasive adenocarcinoma (IAC) and non-IAC. Besides, the clinical and imaging information of these patients was collected. HRCT signs include the existence of air bronchial signals, vascular convergence, pleural indentation, lobulation, and spiculation. Moreover, the diameter of solid components (D Solid ), diameter of ground-glass nodules (D GGN ), and computed tomography values of ground-glass nodules (CT GGN ) were measured concurrently. Furthermore, the mean standardized uptake value, maximal standardized uptake value (SUVmax), metabolic tumor volume, and total lesion glycolysis were assessed during PET/CT. Associations between invasiveness and these factors were evaluated using univariate and multivariate analyses. The results of logistic regression analysis demonstrated that D GGN , D Solid , consolidation tumor ratio (CTR), CT GGN , and SUVmax were independent predictors in the IAC group. The combined diagnosis based on these five predictors revealed that area under the curve was 0.825. The D GGN , D Solid , CTR, CT GGN , and SUVmax in GGNs were independent predictors of IAC, and combining 18 F-FDG PET/CT metabolic parameters with HRCT may improve the predictive value of pathological classification in lung adenocarcinoma.

Device-Less Data-Driven Cardiac and Respiratory Gating Using LAFOV PET Histo Images.

Background: The outstanding capabilities of modern Positron Emission Tomography (PET) to highlight small tumor lesions and provide pathological function assessment are at peril from image quality degradation caused by respiratory and cardiac motion. However, the advent of the long axial field-of-view (LAFOV) scanners with increased sensitivity, alongside the precise time-of-flight (TOF) of modern PET systems, enables the acquisition of ultrafast time resolution images, which can be used for estimating and correcting the cyclic motion. Methods: 0.25 s so-called [18F]FDG PET histo image series were generated in the scope of for detecting respiratory and cardiac frequency estimates applicable for performing device-less data-driven gated image reconstructions. The frequencies of the cardiac and respiratory motion were estimated for 18 patients using Short Time Fourier Transform (STFT) with 20 s and 30 s window segments, respectively. Results: The Fourier analysis provided time points usable as input to the gated reconstruction based on eight equally spaced time gates. The cardiac investigations showed estimates in accordance with the measured pulse oximeter references (p = 0.97) and a mean absolute difference of 0.4 ± 0.3 beats per minute (bpm). The respiratory frequencies were within the expected range of 10-20 respirations per minute (rpm) in 16 out of 18 patients. Using this setup, the analysis of three patients with visible lung tumors showed an increase in tumor SUVmax and a decrease in tumor volume compared to the non-gated reconstructed image. Conclusions: The method can provide signals that were applicable for gated reconstruction of both cardiac and respiratory motion, providing a potential increased diagnostic accuracy.

Comparison of PSMA immunohistochemistry scoring systems to parametric [18F]PSMA-1007 PET/MRI in primary prostate cancer.

Quantification of PSMA expression via PSMA PET is well-established, however quantification of PSMA via immunohistochemistry (IHC) is not standardized. Our aim was to determine the most optimal PSMA IHC scoring system to quantify PSMA expression with PSMA PET as reference standard. Primary intermediate- and high-risk prostate cancer patients received an [18F]PSMA-1007 PET/MRI followed by radical prostatectomy. SUVmax, SUVmean and Ki of the prostate tumor was determined. Prostate tumors were stained with anti-PSMA antibodies and scored by 2 readers via 10 IHC scoring systems: histochemical score (H-score), immunoreactivity scorepredominant intensity (IRSpredominant intensity), IRS classificationpredominant intensity, IRSmean intensity, IRS classificationmean intensity, Allred score, predominant expression pattern, Shannon diversity index (SDI), percentage negatively stained cells and total percentage positively stained cells. Spearman's rank correlation coefficients (ρ) were calculated between PET parameters and IHC scoring systems. Interreader agreement for the IHC scoring systems was measured by the intraclass correlation coefficient (ICC). Fifty tumors in 46 patients were analysed. H-score had the best correlation with SUVmax (ρ 0.615 p < 0.0001) and SUVmean (ρ 0.570, p < 0.0001) and the second best correlation with Ki (ρ 0.411, p = 0.0030). SDI had the best correlation with Ki (ρ -0.440, p = 0.0014) and the second best correlation with SUVmax (ρ -0.516, p = 0.0001) and SUVmean (ρ -0.490, p = 0.0003). A moderate interreader agreement was observed for H-score (ICC 0.663, 95% CI 0.495-0.797) and SDI (ICC 0.546, 95% CI 0.354-0.725). H-score had the best correlation with PSMA PET quantification and an acceptable interreader agreement. Therefore, we deem H-score the most optimal PSMA IHC scoring system.

Prediction of biochemical recurrence after radical prostatectomy from primary tumour characteristics.

To construct and externally calibrate a predictive model for early biochemical recurrence (BCR) after radical prostatectomy (RP) incorporating clinical and modern imaging characteristics of the primary tumour. Patients who underwent RP following multiparametric magnetic resonance imaging, prostate biopsy and prostate-specific membrane antigen-positron emission tomography/computed tomography (PSMA-PET/CT), from two centres in Australia and the Netherlands. The primary outcome was biochemical recurrence-free survival (BRFS), where BCR was defined as a rising PSA level of ≥0.2 ng/mL or initiation of postoperative treatment per clinician discretion. Proportional hazards models to predict time to event were developed in the Australian sample using relevant pre- and post-surgical parameters and primary tumour maximum standardised uptake value (SUVmax) on diagnostic PSMA-PET/CT. Calibration was assessed in an external dataset from the Netherlands with the same inclusion criteria. Data from 846 patients were used to develop the models. Tumour SUVmax was associated with worse predicted 3-year BRFS for both pre- and post-surgical models. SUVmax change from 4 to 16 lessened the predicted 3-year BRFS from 66% to 42% for a patient aged 65 years with typical pre-surgical parameters (PSA level 8 ng/mL, Prostate Imaging-Reporting and Data System score 4/5 and biopsy Gleason score ≥4 + 5). Considering post-surgical variables, a patient with the same age and PSA level but pathological stage pT3a, RP Gleason score ≥4 + 5 and negative margins, SUVmax change from 4 to 16 lessened the predicted 3-year BRFS from 76% to 61%. Calibration on an external sample (n = 464) showed reasonable performance; however, a tendency to overestimate survival in patients with good prognostic factors was observed. Tumour SUVmax on diagnostic PSMA-PET/CT has utility additional to commonly recognised variables for prediction of BRFS after RP.

Low dose optimization for total-body 2-[18F]FDG PET/CT imaging: a single-center study on feasibility based on body mass index stratification.

Implementing personalization protocol in clinical routine necessitates diverse low-dose PET/CT scan protocols. This study explores the clinical feasibility of one-third (1/3) dose regimen and evaluates the diagnostic image quality and lesion detectability of BMI-based 1/3-injection doses for 2-[18F]FDG PET/CT imaging. Seventy-four cancer patients underwent total-body 2-[18F]FDG PET/CT examination, with 37 retrospectively enrolled as full-dose group (3.7 MBq/kg) and 37 prospectively enrolled as the 1/3-dose group (1.23 MBq/kg). The 1/3-dose group was stratified by BMI, with an acquisition time of 5 min (G5), 6 min (G6), and 8 min (G8) for BMI < 25, 25 ≤ BMI ≤ 29, and BMI > 29, respectively. Image quality was subjectively and objectively assessed, and lesion detectability was quantitatively analyzed. Subjective assessments of 1/3-dose and full-dose PET images showed strong agreement among readers (κ > 0.88). In the 1/3-dose group, the Likert scores were above 4. G5, G6, and G8 showed comparable image quality, with G5 demonstrating higher lesion conspicuity than G6 and G8 (p = 0.045). Objective evaluation showed no significant differences in SUVmax, liver SUVmean and TBR between 1/3- and full-dose groups (p > 0.05). No statistical differences were observed in the SUVmax of primary tumor, SUVmean of liver and TBR across all BMI categories between the 1/3-dose and full-dose groups. Lesion detection rates showed no significant difference between the 1/3-dose (93.24%, 193/207) and full-dose groups (94.73%, 198/209) (p = 0.520). A BMI-stratified 1/3-dose regimen is a feasible low-dose alternative with clinically acceptable lesion detectability equivalent to full-dose protocol, potentially expanding the applicability of personalized protocols. This study demonstrated that BMI-stratified 1/3-dose regimens for [18F]FDG total-body PET/CT yielded equivalent outputs compared to the full-dose regimen, which aligns with clinical needs for personalization in dose and BMI. Currently, limited personalized low-dose total-body PET/CT protocols are available, particularly for patients with varied BMI. Reducing the radiotracer dose to 1/3 the standard demonstrated comparable image quality and lesion detectability equivalent to full dose. BMI-stratified 1/3-dose regimen is a clinically feasible low-dose alternative.

Retrospective evaluation of the predictive value of tumour burden at baseline [68 Ga]Ga-DOTA-TOC or -TATE PET/CT and tumour dosimetry in GEP-NET patients treated with PRRT

PurposeThere is a lack of validated imaging biomarkers for prediction of response to peptide receptor radionuclide therapy (PRRT). The primary objective was to evaluate if tumour burden at baseline PET/CT could predict treatment outcomes to PRRT with [177Lu]Lu-DOTA-TATE. Secondary objectives were to evaluate if there was a correlation between tumour burden and mean tumour absorbed dose (AD) during first cycle, and if mean tumour AD or the relative change of tumour burden at first follow-up PET/CT could predict progression free survival (PFS) or overall survival (OS).MethodsPatients with gastroenteropancreatic neuroendocrine tumour (GEP-NET) treated with [177Lu]Lu-DOTA-TATE PRRT were retrospectively included. Tumour burden was quantified from [68 Ga]Ga-DOTA-TOC/TATE PET/CT-images at baseline and first follow-up and expressed as; whole-body somatostatin receptor expressing tumour volume (SRETVwb), total lesion somatostatin receptor expression (TLSREwb), largest tumour lesion diameter and highest SUVmax. The relative change of tumour burden was evaluated in three categories. Mean tumour AD was estimated from the first cycle of PRRT. PFS was defined as time from start of PRRT to radiological or clinical progression. OS was evaluated as time to death. Kaplan Meier survival curves and log-rank test were used to compare PFS and OS between different groups.ResultsThirty-one patients had a baseline PET/CT < 6 months before treatment and 25 had a follow-up examination. Median tumour burden was 132 ml (IQR 61–302) at baseline and 71 ml (IQR 36–278) at follow-up. Twenty-two patients had disease progression (median time to progression 17.2 months) and 9 patients had no disease progression (median follow-up 28.7 months). SRETVwb dichotomized by the median at baseline was not associated with longer PFS (p = 0.861) or OS (p = 0.937). Neither TLSREwb, largest tumour lesion or SUVmax showed significant predictive value. There was a moderately strong correlation, however, between SUVmax and mean tumour AD r = 0.705, p < 0.001, but no significant correlation between SRETVwb nor TLSREwb and mean tumour AD. An increase of SRETVwb, TLSREwb or largest tumour lesion at first follow-up PET/CT was significantly correlated with shorter PFS/OS.ConclusionTumour burden at baseline showed no predictive value of PFS/OS after PRRT in this small retrospective study. An increase of tumour burden was predictive of worse outcome.

Impact of definitive radiotherapy on metabolic response measured with 68Ga-PSMA-PET/CT in patients with intermediate-risk prostate cancer.

To assess the early metabolic response of the primary tumor using Gallium-68 (68Ga)-labeled-prostate-specific membrane antigen positron emission tomography (68Ga-PSMA-PET/CT), as well as the relationship between PSMA change in the primary tumor and PSA response after definitive radiotherapy (RT), either alone or in combination with androgen deprivation therapy (ADT) in intermediate risk prostate cancer (IR-PCa) patients. The clinical data of 71 IR-PCa patients treated with RT alone (36 patients, 50.7%) or RT and ADT (35 patients, 49.3%) were retrospectively analyzed. The difference between pre- and Posttreatment primary tumor PSMA expression and serum PSA values measured 4 months after completion of treatment were compared between treatment arms. Correlation between primary tumor metabolic response and serum PSA changes was analyzed. The median duration between pre- and Posttreatment 68Ga-PSMA-PET/CT for the entire patient population was 6.9 months (range, 5.6-8.4 months), and it was similar in both treatment arms. A decrease in primary tumor maximum standardized uptake value (SUVmax) was seen in 66 patients (93.0%), with a median value of 61.2%, which is significantly lower in patients undergoing RT alone than those undergoing RT and ADT (45.1 ± 30.6% vs. 59.1 ± 24.7%; p = 0.004). The complete metabolic response rate was significantly higher in patients undergoing RT and ADT than those treated with RT alone (40% vs. 0%; p < 0.001). Although moderate and positive correlation between pretreatment SUVmax and oosttreatment SUVmax was observed, there was no significant correlation between SUV change and PSA change. For patients treated with RT and ADT, posttreatment SUVmax was significantly lower and SUV change was significantly higher in patients with PSA nadir than in those without. Our preliminary results show that RT, with or without ADT, significantly reduces primary tumor SUVmax and serum PSA levels. Nonetheless, our findings indicate that early treatment response using 68Ga-PSMA-PET/CT is not feasible for those treated with RT alone, and it may only be useful in better distinguishing patients with and without PSA nadir for those who received both RT and ADT.

The Contribution of 68 Ga-FAPI-04 PET/CT to Staging and Prognosis in Gastric Cancer.

This study aimed to compare the diagnostic capabilities of 18 F-FDG PET/CT and 68 Ga-FAPI-04 PET/CT imaging in staging gastric carcinoma, exploring the impact of 68 Ga-FAPI-04 PET/CT on treatment planning and its prognostic significance. The research included 31 patients undergoing staging for gastric cancer, who received both 18 F-FDG PET/CT and 68 Ga-FAPI-04 PET/CT scans. We compared the SUV max and SUV mean of the primary tumor and lymph nodes, the count of organ metastases, tumor-to-background ratios, and overall staging accuracy. Additionally, the study evaluated radiological progression-free survival and overall survival rates. The 68 Ga-FAPI-04 PET/CT demonstrated superior efficacy in identifying the primary tumor compared with 18 F-FDG PET/CT, particularly in cases of poorly cohesive, signet-ring cell, and mucinous subtypes, with detection rates of 96.7% versus 77.4% ( P = 0.006 and P = 0.008, respectively). Analysis of lymph nodes showed a significantly higher detection of positive nodes with 68 Ga-FAPI-04 ( P = 0.026), although no significant differences were observed in SUV max and tumor-to-background ratio on a patient basis ( P > 0.05). SUV max and tumor-to-background ratios for peritoneal involvement were notably higher with 68 Ga-FAPI-04 PET/CT compared with 18 F-FDG PET/CT ( P = 0.04 for both). No significant differences were found in the detection of organ metastases and disease stage between the 2 imaging modalities ( P > 0.05). Primary tumor uptake did not significantly impact radiological progression-free survival or overall survival in either modality. 68 Ga-FAPI-04 PET/CT imaging surpasses 18 F-FDG PET/CT in detecting the primary tumor, especially in poorly cohesive and signet-ring cell gastric cancer types, and offers improved accuracy in disease staging. This indicates its potential to enhance treatment management and prognostic assessment in gastric cancer patients.

The value of net influx constant based on FDG PET/CT dynamic imaging in the differential diagnosis of metastatic from non-metastatic lymph nodes in lung cancer.

This study aims to evaluate the value of the dynamic and static quantitative metabolic parameters derived from 18F-fluorodeoxyglucose (FDG)-positron emission tomography/CT (PET/CT) in the differential diagnosis of metastatic from non-metastatic lymph nodes (LNs) in lung cancer and to validate them based on the results of a previous study. One hundred and twenty-one patients with lung nodules or masses detected on chest CT scan underwent 18F-FDG PET/CT dynamic + static imaging with informed consent. A retrospective collection of 126 LNs in 37 patients with lung cancer was pathologically confirmed. Static image analysis parameters include LN-SUVmax and LN-SUVmax/primary tumor SUVmax (LN-SUVmax/PT-SUVmax). Dynamic metabolic parameters including the net influx rate (Ki) and the surrogate of perfusion (K1) and of each LN were obtained by applying the irreversible two-tissue compartment model using in-house Matlab software. Ki/K1 was then calculated as a separate marker. Based on the pathological findings, we divided into a metastatic group and a non-metastatic group. The χ2 test was used to evaluate the agreement of the individual and combined diagnosis of each metabolic parameter with the gold standard. The receiver-operating characteristic (ROC) analysis was performed for each parameter to determine the diagnostic efficacy in differentiating non-metastatic from metastatic LNs with high FDG-avid. P < 0.05 was considered statistically significant. Among the 126 FDG-avid LNs confirmed by pathology, 70 LNs were metastatic, and 56 LNs were non-metastatic. For ROC analysis, in separate assays, the dynamic metabolic parameter Ki [sensitivity (SEN) of 84.30%, specificity (SPE) of 94.60%, accuracy of 88.89%, and AUC of 0.895] had a better diagnostic value than the static metabolic parameter SUVmax (SEN of 82.90%, SPE of 62.50%, accuracy of 74.60%, and AUC of 0.727) in differentiating between metastatic from non-metastatic LNs groups, respectively. In the combined diagnosis group, the combined SUVmax + Ki diagnosis had a better diagnostic value in the differential diagnosis of metastatic from non-metastatic LNs, with SEN, SPE, accuracy, and AUC of 84.3%, 94.6%, 88.89%, and 0.907, respectively. When the cutoff value of Ki was 0.022ml/g/min, it had a high diagnostic value in the differential diagnosis between metastasis and non-metastasis in FDG-avid LNs of lung cancer, especially in improving the specificity. The combination of SUVmax and Ki is expected to be a reliable metabolic parameter for N-staging of lung cancer.

Prognostic Importance of 18F-FDG Positron Emission Tomography in Uterine Cervical Cancer.

The aim of this study was to evaluate the prognostic value of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the uterine cervix cancer patients. Thirty-two women (mean age: 52.7±12.6) who underwent 18F-FDG PET/CT for staging of uterine cervix cancer were retrospectively recruited for the study. Maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for primary tumors, lymph nodes, and distant metastases were calculated from 18F-FDG PET/CT images using the 40% threshold. Patients were divided into groups according to the presence of pelvic and para-aortic lymph node involvement on 18F-FDG PET/CT images. Life tables and Kaplan-Meier analyses were performed to compare the mean survival times of the different groups. Primary tumor of 27 (84%) patients were 18F-FDG avid. The median SUVmax, SUVmean, MTV, and TLG of the primary tumors were 12.4, 6.1, 13.2 cm3 and 87.8 g/mL x cm3 respectively. Pathological uptake was detected in pelvic 14 (44%) patients and in paraaortic lymph nodes in 3 (10%) para-aortic lymph nodes. The median whole-body MTV and TLG were 21.7 cm3 and 91.1 g/mL x cm3. Disease progression was detected in 7 (22%) patients within a median follow-up period of 20.9 (minimum-maximum: 3-82) months. The only significant PET parameter to predict progression-free survival was SUVmax in the primary tumor (p=0.038). During follow-up period 8 patients died. SUVmax (p=0.007), MTV (p=0.036), TLG (p=0.001) of primary tumor, presence of pathological uptake on pelvic or paraaortic lymph nodes (p=0.015), whole-body MTV (p=0.047) and whole-body TLG (p=0.001) were found statistically significant PET parameters to predict overall survival. Metabolic parameters of primary tumors derived from 18F-FDG PET/CT images have prognostic importance for patients with uterine cervical carcinoma. In patients with metastatic disease, higher whole-body MTV and TLG are also associated with poor prognosis.

Utility of PSMA-PET derived volumetric parameters in initial risk stratification and prediction of prostate cancer metastasis - a head-to-head comparison of the radiotracers 18F-PSMA-1007 and 68Ga-PSMA-11.

This study aimed to explore and compare the utility of baseline 18F-PSMA-1007 and 68Ga-PSMA-11 PET/computed tomography (CT) derived volumetric parameters in initial risk stratification and prediction of prostate cancer (PCa) metastasis. Forty treatment-naïve, biopsy-proven intermediate-/high-risk PCa patients were prospectively recruited. Each patient underwent PET/CT with 68Ga-PSMA-11 and 18F-PSMA-1007 (within 2 weeks). The maximum and mean standardized uptake values (SUVmax and SUVmean) of primary tumor, prostate PSMA-tumor volume (PSMA-TVp), and prostate total lesion PSMA (TL-PSMAp) were measured. PSMA-TVp and TL-PSMAp (with both radiotracers) mostly exhibited moderate-to-strong correlation with Gleason score, serum prostate-specific antigen level and clinical tumor stage (Spearman ρ = 0.361-0.783, P-values ≤0.022). Primary tumor SUVmax values were similar across initial risk categories. PSMA-TVp and TL-PSMAp, however, were significantly higher in high-risk PCa compared to intermediate-risk PCa (P-values ≤0.001). Receiver operating characteristic (ROC) curve analysis revealed that F-PSMA-TVp, Ga-PSMA-TVp, F-TL-PSMAp, and Ga-TL-PSMAp (optimal cutoff values of 20.9, 23.4, 142.5, and 144.8, respectively) could effectively differentiate high-risk from intermediate-risk PCa [area under the ROC curve (AUCs) 0.859-0.898, P-values <0.001] with high sensitivity (~68.8-75%) and excellent specificity (100%). PSMA-TVp and TL-PSMAp (with both radiotracers) could predict presence of regional and extraregional nodal metastasis (AUCs 0.703-0.801, P-values ≤0.03) with moderate sensitivity (~47.8-70.6%) and excellent specificity (~82.6-94.1%). Our results suggest that baseline PSMA-PET primary tumor volumetric parameters provide a noninvasive, objective, and accurate index for initial risk stratification and can predict presence of regional and extraregional nodal metastasis in PCa patients. Larger studies are warranted to evaluate their incremental role over conventional parameters.

Baseline Ga-68 PSMA PET-Derived Primary Tumor Parameters in Patients with Prostate Cancer and Their Association with Clinical Risk Stratification and Clinicopathologic Features

Abstract Aim This article evaluates whether parameters derived from the gallium-68-labeled prostate-specific membrane antigen (68Ga-PSMA) positron emission tomography/computed tomography (PET/CT) imaging studies of primary prostate cancer (PCa) lesions were associated with Gleason score (GS), D'Amico risk class, Candiolo nomograms, and the metastatic status of the disease. Methods We retrospectively evaluated newly diagnosed PCa patients who underwent 68Ga-PSMA PET/CT before therapy. Age, baseline serum prostate-specific antigen (PSA), and metastatic status were recorded. Maximal standardized uptake value (SUVmax), mean SUV (SUVmean), total lesion PSMA (TL-PSMA), and PSMA-derived tumor volume (PSMA-TV) were analyzed. The patients were grouped according to GS (GS ≤ 7 and GS ≥ 8), D'Amico risk classes (low intermediate and high-risk), and also based on their results with the Candiolo nomogram which normally creates five risk classes. For Candiolo classes, very-low risk and low-risk patients were pooled into the low-risk Candiolo (LRC) group, high and very high-risk patients were pooled into the high-risk Candiolo (HRC) group. The intermediate-risk Candiolo group was utilized as-is (IRC). Results Mean age was 67 ± 8 years, median PSA value was 14.3 (3–211). There were 82 patients with GS ≤ 7 and 38 patients with GS ≥ 8; intermediate D'Amico class comprised 32 patients, while the high D'Amico class comprised 88 patients. For Candiolo, there were 23 LRC, 40 IRC, and 57 HRC patients. PSMA-positive metastases were detected in 44 (36.7%) patients. The SUVmean, SUVmax, PSMA-TV, and TL-PSMA values of the primary tumor demonstrated significant differences when compared according to classifications for GS, D'Amico, LRC versus HRC, and metastatic versus nonmetastatic patients. Of note, TL-PSMA was the only parameter that varied significantly among all risk groups. Conclusion Primary tumor parameters obtained from baseline 68Ga-PSMA PET/CT are useful to distinguish PCa patients in terms of GS, D'Amico, Candiolo nomogram, and metastatic states. TL-PSMA appears to be the best parameter as it is the only parameter that can distinguish all risk groups from each other.