Abstract Background Primary central nervous system lymphoma (PCNSL) can be differentiated from glioblastoma multiforme (GBM) using positron emission tomography (PET) with [18F]fluoro-2-deoxy-D-glucose (FDG). However, differentiation is often difficult with magnetic resonance imaging (MRI) or FDG PET alone. We have used various PET tracers to aid glioma diagnosis; here, we assessed whether multiple PET tracers improve the distinction between GBM and PCNSL. Methods We studied 148 patients with newly diagnosed brain tumors: 96 with GBM and 52 with PCNSL (according to the 2016 World Health Organization classification). Tumor-to-normal tissue ratios (TNRs) were calculated for FDG, L[methyl[11C]]methionine, and 3′deoxy3′[18F]fluorothymidine (FLT). Tumor-to-blood ratio (TBR) was measured for [18F]fluoromisonidazole (FMISO). Results Median FDG TNR was 1.52 (interquartile range [IQR], 1.13–2.13) for GBM and 2.89 (IQR, 1.95–3.85) for PCNSL. MET TNR was 6.38 (IQR, 4.68–7.48) for GBM and 4.01 (IQR, 3.28–7.52) for PCNSL. FLT TNR was 17.35 (IQR, 11.10–22.28) for GBM and 25.61 (IQR, 15.91–55.30) for PCNSL. FMISO TBR was 2.72 (IQR, 2.22–3.62) for GBM and 1.58 (IQR, 1.04–1.93) for PCNSL. Receiver operating characteristic analysis showed areas under the curve of 0.78 (FDG), 0.62 (MET), 0.69 (FLT), and 0.85 (FMISO). FLT TNR had the highest sensitivity of 83.2% while FMISO TBR had the highest specificity of 84.2%. Among the four tracers, FLT showed the highest sensitivity and FMISO showed the highest specificity. Dual‑tracer combinations did not improve overall diagnostic accuracy beyond the best single tracers. Conclusions Among four PET tracers, FMISO was most effective in distinguishing GBM from PCNSL. Diagnostic accuracy was highest when each tracer was used individually.

Quantitative imaging of cerebral blood flow (CBF), oxygen extraction fraction (OEF), cerebral metabolic rate of oxygen (CMRO 2 ), and cerebral blood volume (CBV) using 15 O-labeled compounds is useful for evaluating cerebral ischemia. However, quantitative PET requires measurement of blood activity concentration, which is typically obtained by arterial blood sampling. Although image-derived input function methods have been developed for CBF, OEF, and CMRO 2 quantification, a non-invasive method for obtaining blood activity concentration for CBV measurement has not been established. This study aimed to develop and validate a reference-based method for estimating blood activity concentration from C 15 O PET images. Among 186 subjects, mean CBV and the coefficient of variation (CV) were calculated for each brain segment in 64 subjects (Group A; moyamoya disease (MMD) present/absent, 20/44 ) . In an independent cohort of 122 subjects (Group B; MMD present/absent, 35/87), blood activity concentration was estimated for each brain segment by reproducing the reference mean CBV obtained from Group A. The segment-based estimates were combined using CV-weighted averaging. The estimated blood activity concentrations were compared with those obtained by arterial blood sampling. The mean ± SD of CBV across all segments in Group A was 0.039 ± 0.011 ml/g overall, 0.037 ± 0.009 ml/g in subjects without MMD, and 0.043 ± 0.012 ml/g in subjects with MMD. In Group B, the percentage differences between image-derived and measured blood activity concentrations were 0.35 ± 9.8%, − 1.4 ± 8.8%, and 4.8 ± 10.6% in the overall, MMD-absent, and MMD-present groups, respectively, using the all-segment approach. When the CBV-matched segment approach was applied, the corresponding differences were − 0.60 ± 8.8%, − 1.4 ± 8.4%, and 1.5 ± 9.4%, respectively. The image-derived blood activity concentrations showed good agreement with those obtained by arterial blood sampling, and the CBV-matched segment approach reduced the difference in the MMD-present group. The proposed method may enable non-invasive and automated estimation of blood activity concentration for quantitative CBV measurement without arterial blood sampling.

Quantitative measurements of cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2) using 15O-labeled PET generally require an arterial input function (AIF) obtained via invasive arterial blood sampling. This study aimed to develop a fully noninvasive method to reconstruct an image-derived input function (IDIF) directly from dynamic 15O2-H215O PET data. Using a reference-based approach, data from 186 subjects with suspected cerebrovascular disease were analyzed. Segment-based reference values of CBF and OEF derived from 60 subjects were used to reconstruct IDIFs in the remaining 126 subjects through coefficient-of-variation weighted averaging of segmental tissue time-activity curves. The estimated IDIFs showed strong agreement with measured AIFs, yielding minimal bias (⩽0.005) and high correlations (r = 0.88, p < 0.001) for CBF, OEF, and CMRO2. No significant differences were observed between IDIF- and AIF-based quantitative values. However, the reconstructed IDIFs exhibited mild regression-to-the-mean behavior, likely due to temporal smoothing. These findings demonstrate that input functions for labeled water and oxygen can be reliably estimated from tissue curves without blood sampling. The proposed method enables fully noninvasive quantification of CBF, OEF, and CMRO2, supporting its clinical feasibility for 15O PET studies, but not for quantitative parameter estimation under stimulation.

Delayed appearance of blood in the brain may be a pathophysiological indicator of stenosis or occlusion. Image computation for blood appearance generally requires considerable time. Therefore, in this study, we aimed to shorten the computation time using several algorithms and tested their accuracy and precision using examination data and simulations, as well as the computation time. We retrospectively analyzed the images of patients with suspected cerebrovascular disorders who underwent PET study with 15O-labeled tracers. The blood appearance time images were computed by fitting a stepwise time-shifted tissue curve and applying a single-tissue compartment model with several modes of fixing or not fixing the washout rate and/or blood volume terms. The appearance times in images for these modes were compared with the time obtained by ROI-based non-linear fitting in several brain regions. The effects of noise and parameter fixation are assessed using a simulation study. The computation time was 28.2 ± 6.2 min, 16.6 ± 3.9 min, and 2.6 ± 1.1 min for modes without fixing, with fixing blood volume, and washout rate, respectively. The mean difference in the appearance time against ROI-based non-linear fitting was less than 1 s with a standard deviation (SD) of approximately 2.5 s for those modes. The images obtained were similar for all three modes. The simulation showed that SD on the estimated appearance times were acceptable, namely < 1.5 s, for these modes. This study suggests the possibility of visualizing appearance time images in the brain with a reasonable computation time of approximately 2.5 min at the minimum and 30 min at the most.

Background. The appearance time of blood components in the brain provides complementary information about cerebral microvascular dynamics. Plasma and red blood cells (RBCs) behave differently in the microcirculation: while plasma can pass through peripheral layers of capillaries, RBCs carry oxygen and are affected by phenomena such as the Fåhræus-Lindqvist effect and plasma skimming. Our study aims at visualizing these differencesin vivousing H215O PET to assess plasma appearance time (ATPlasma) and15O2PET to assess RBC appearance time (ATRBC), and demonstrated that the relative delay of RBCs compared with plasma correlates with the oxygen extraction fraction (OEF).Methods. We retrospectively analyzed PET images obtained with15O2and H215O administration in 40 patients, comprising a total of 63 scan data. Appearance time images were generated by fitting tissue curves both for the15O2(ATRBC) and H215O phases (ATPlasma). ATRBCand ATPlasmavalues were extracted from regions of interest (ROIs) and compared. Additionally, differences between ATRBCand ATPlasma(ΔAT) were analyzed in relation to OEF.Results. ATRBCand ATPlasmaimages exhibited similar spatial distributions. A strong correlation was observed between them as ATRBC= 0.80·ATPlasma+ 1.8,r= 0.86), with a slope significantly less than unity, suggesting that RBCs flow faster than plasma. The difference between the two (ΔAT) showed a moderate correlation with OEF (r= 0.44), suggesting that higher OEF values are associated with slower RBC movement relative to plasma. This finding suggests that under certain ischemic conditions, RBC flow is more severely impaired than plasma flow.Conclusion. This study demonstrates that ATRBCand ATPlasmaare closely related measures of cerebral blood appearance time. The observed association between their difference and OEF suggests a potential link to ischemic pathology.

Background . The appearance time of blood components in the brain provides complementary information about cerebral microvascular dynamics. Plasma and red blood cells (RBCs) behave differently in the microcirculation: while plasma can pass through peripheral layers of capillaries, RBCs carry oxygen and are affected by phenomena such as the Fåhræus–Lindqvist effect and plasma skimming. Our study aims at visualizing these differences in vivo using H 2 15 O PET to assess plasma appearance time (AT Plasma ) and 15 O 2 PET to assess RBC appearance time (AT RBC ), and demonstrated that the relative delay of RBCs compared with plasma correlates with the oxygen extraction fraction (OEF). Methods . We retrospectively analyzed PET images obtained with 15 O 2 and H 2 15 O administration in 40 patients, comprising a total of 63 scan data. Appearance time images were generated by fitting tissue curves both for the 15 O 2 (AT RBC ) and H 2 15 O phases (AT Plasma ). AT RBC and AT Plasma values were extracted from regions of interest (ROIs) and compared. Additionally, differences between AT RBC and AT Plasma (ΔAT) were analyzed in relation to OEF. Results . AT RBC and AT Plasma images exhibited similar spatial distributions. A strong correlation was observed between them as AT RBC = 0.80·AT Plasma + 1.8, r = 0.86), with a slope significantly less than unity, suggesting that RBCs flow faster than plasma. The difference between the two (ΔAT) showed a moderate correlation with OEF ( r = 0.44), suggesting that higher OEF values are associated with slower RBC movement relative to plasma. This finding suggests that under certain ischemic conditions, RBC flow is more severely impaired than plasma flow. Conclusion . This study demonstrates that AT RBC and AT Plasma are closely related measures of cerebral blood appearance time. The observed association between their difference and OEF suggests a potential link to ischemic pathology.

As glioblastoma IDH-wild type (GBM) patients age, preserving cognitive function is as crucial as improving prognosis. At our institution, 46% of GBM cases since 2020 involved patients aged 75 or older. However, comprehensive cognitive assessment is often impractical in this population. We examined whether PET imaging could serve as a noninvasive, objective proxy for evaluating cognitive function. We retrospectively reviewed 27 GBM patients (mean age: 71.6; 12 aged ≥75; 14 men, 13 women) treated from February 2020 to April 2025. Diagnoses were biopsy-confirmed. Patients were categorized into three groups: KPS <60 (n=12), KPS ≥60 (n=8), and neoadjuvant (n=7), defined as KPS <60 with bevacizumab prior to tumor resection. PET tracers included FDG, MET, FLT, and THK5351 (tumor-to-normal ratio) and FMISO (tumor-to-blood ratio). Metabolic Tumor Volume (MTV) was defined as uptake >42% of SUV max. MTV/FLAIR and MTV/T1Gd ratios were calculated. Cognitive function was assessed using MMSE, TMT-A/B, and FAB. MMSE improvement was noted in 4, 5, and 5 patients; TMT-A in 3, 4, and 6; TMT-B in 1, 6, and 3; and FAB in 2, 2, and 3 patients, respectively, in the KPS <60, KPS ≥60, and neoadjuvant groups. MMSE correlated with FDG and FLT MTV/FLAIR and THK5351 MTV (p<0.05). TMT-A correlated with FDG MTV/FLAIR, TMT-B with THK5351 MTV, and FAB with FDG, MET, THK5351 MTV/T1Gd, and FMISO MTV. FDG and THK5351 PET imaging may offer a practical, noninvasive alternative for assessing cognitive function in elderly GBM patients.

With the aging of glioblastoma (GBM) patients, maintaining QOL and higher-order cognitive function has become increasingly important. However, evaluating these aspects and providing ongoing support is often challenging. This study investigated whether serial changes in tau PET imaging using THK5351 could serve as a surrogate marker for cognitive function during treatment in elderly GBM patients, and whether PET uptake patterns might influence prognosis and the need for care support. We retrospectively analyzed 14 patients aged ≥75 years who received bevacizumab (Bev) as initial therapy between February 2020 and March 2025. All patients were diagnosed with GBM via biopsy and were classified into two groups based on KPS: ≥60 and <60. Patients with KPS <60 who underwent tumor resection after Bev were defined as the neoadjuvant group. Cognitive function was evaluated after Bev and before discharge using the MMSE, TMT, and FAB, and findings were correlated with clinical course and support systems. The KPS ≥60 group included 2 patients (mean age 77.5), the KPS <60 group 9 patients (82.6), and the neoadjuvant group 3 patients (76.3). No post-Bev KPS deterioration was observed. Among KPS <60 patients, 4 with THK5351 uptake in the corpus callosum or hippocampus showed declines in MMSE. In contrast, the neoadjuvant group showed no hippocampal uptake and MMSE improvement. TMT-A was improved in 2 neoadjuvant cases. All KPS <60 patients failed TMT-B. FAB showed impairment in 2 KPS <60 cases, while the neoadjuvant case improved in all domains. Seven KPS <60 patients died in long-term care; others died at home. THK5351 PET uptake in the corpus callosum or hippocampus may reflect cognitive decline and predict difficulty with home discharge, offering a useful tool for planning treatment and supportive care.

Abstract OBJECTIVE Positron Emission Tomography (PET) may be useful in diagnosing glioblastoma, determining resection areas, and evaluating therapeutic efficacy. This study evaluated the usefulness of PET scans using 11C-Methionine (MET) to assess amino acid metabolism and 18F-Fluoromisonidazole (FMISO) to assess hypoxic regions in glioblastoma treatment. METHODS Thirty glioblastoma patients who underwent MET and FMISO PET studies from July 2013 to March 2024 were included. Patients underwent the Stupp regimen post-tumor resection and were treated with temozolomide (TMZ) and bevacizumab (Bev) upon recurrence. PET scans were performed before and after two courses of Bev treatment. Changes in tumor to normal ratio (TNR) for MET, tumor to blood ratio (TBR) for FMISO, and metabolic tumor volume (MTV) for both MET and FMISO were evaluated. Progression-free survival (PFS) and overall survival (OS) were compared based on the rate of change in MTV for MET and FMISO. RESULTS The residual volumes (contrast-enhanced MRI, MET, and FMISO) with a MET removal rate of >90% were 0.08 ml, 0.1 ml, and 0.08 ml, respectively. For FMISO removal rates of >90%, residual volumes were 0.36 ml, 1.54 ml, and 0.05 ml, respectively. Groups with a decreased rate of change in MET MTV had significantly better outcomes: PFS (months) 10.7 vs. 2.8 (p=0.19) and OS (months) 18.6 vs. 4.9 (p=0.09). In the FMISO groups, decreased TBR change rates correlated with better outcomes: PFS (months) 16.6 vs. 2.5 (p<0.01) and OS (months) 22.8 vs. 4.9 (p<0.01). MTV change rates also showed significant differences in outcomes: PFS (months) 10.5 vs. 3.7 (p=0.76) and OS (months) 14.9 vs. 7.0 (p=0.87). CONCLUSION Higher MET removal rates correlate with fewer contrast-enhanced MRI and FMISO accumulation areas, suggesting MET as a reliable tumor removal indicator. Both MET and FMISO PET scans are valuable in determining glioblastoma treatment response.

BACKGROUND There is limited literature on the use of positron emission tomography (PET) for benign tumors originating in the brain ventricles, and the use of multiple tracers for subependymal giant cell astrocytoma (SEGA) has not been reported. The authors compared the PET findings in two SEGA cases with past reports and literature, exploring the distinctive characteristics of SEGA on PET. OBSERVATIONS In a 21-year-old female with SEGA, the authors utilized 18F-fluorodeoxyglucose (18F-FDG), 11C-methionine (11C-MET), 18F-fluorothymidine (18F-FLT), 18F-fluoromisonidazole, and 18F-THK5351 tracers. Additionally, in a 6-year-old girl, the authors performed 11C-MET PET. LESSONS The results indicated the accumulation of all tracers except 18F-FDG, with particularly intense accumulation noted with 18F-FLT. In particular, 18F-FLT demonstrated accumulation comparable to that observed in malignant tumors. This study suggests that multiple PET tracers can provide valuable insights into the characterization of SEGA, with 18F-FLT showing particular promise as a distinctive marker of blood-brain barrier disruption. Further research in larger cohorts may enhance our understanding of metabolic patterns in SEGA and aid in its diagnosis and treatment.

ABSTRACT:A teenager who suffered from left hemiparesis after traumatic brain injury underwent 18F-THK5351 PET 48, 286, and 810 days after the injury. The first scan showed slight uptake in the right corticospinal tract (CST), and the second scan showed intense uptake along the CST, which was significantly reduced in the third scan. The hemiparesis has improved between the first and second scans. 18F-THK5351 binds to monoamine oxidase B, which is expressed in reactive astrocytes (RAs). Recently, the beneficial role of RAs in plasticity and reconstruction after traumatic brain injury has been reported. 18F-THK5351 uptake may represent axonal remodeling accompanied with RAs in the CST.

Abstract OBJECTIVE Meningiomas are the most common primary brain tumors, typically following a benign course. However, some cases recur after surgery, necessitating further treatment or reoperation. This study aims to examine the relationship between PET studies and pathological findings, and their impact on recurrence. METHODS We included cases of newly diagnosed meningiomas treated surgically in our department from August 2008 to August 2022. The correlation between preoperative FDG-PET and methionine-PET accumulations with pathological findings (WHO grade, Ki-67 index), as well as the impact on recurrence, was investigated. RESULTS The study included 55 cases (22 males, 33 females), aged 17-87 years (median 61.8). The WHO grade was grade 1 in 34 cases and grade 2 in 21 cases, with no grade 3 cases observed. Recurrence occurred in 20 cases during follow-up, necessitating additional treatment. A significant correlation was observed between the tumor T/N ratio and the Ki-67 index for both tracers. Regarding WHO grade, the T/N ratio for FDG was 0.64 in the grade 1 group and 1.04 in the grade 2 group (p<0.01), while for MET, it was 4.8 in the grade 1 group and 6.39 in the grade 2 group (p<0.01), with both tracers showing significantly higher values in the grade 2 group. For postoperative recurrence, the T/N ratio for FDG was 0.97 in the recurrence group and 0.69 in the non-recurrence group (p=0.01), while for MET, it was 6.38 in the recurrence group and 4.66 in the non-recurrence group (p<0.01), with both tracers showing significantly higher values in the recurrence group. CONCLUSION The study demonstrated a significant correlation between preoperative PET studies and pathological findings in meningiomas, as well as an association with recurrence. PET studies were significantly correlated with the tumor malignancy and were considered predictors of postoperative recurrence.

Abstract INTRODUCTION Cancer treatment-related higher brain dysfunction significantly impacts quality of life (QOL) and social life. This study investigates the relationship between PET accumulation areas and advancing cognitive assessment in glioblastoma IDH-wild type (GBM) patients using the PET tracer THK5351, developed to detect tau protein. METHODS Twenty-four GBM patients who underwent changes in tumor to normal ratio (TNR) and metabolic tumor volume (MTV) for THK5351 evaluation before and after temozolomide (TMZ), bevacizumab (Bev), and radiation therapy from February 2020 to March 2024 were included. Cognitive assessments included the Mini-Mental State Examination (MMSE), Trail Making Test (TMT), Frontal Assessment Battery (FAB), Raven’s Coloured Progressive Matrices (RCPM), and Kohs block-design test (Kohs), administered at admission and discharge. RESULTS The mean age of the patients was 70.5 years (14 males, 10 females). All patients were diagnosed with GBM and received TMZ, Bev, and radiation therapy. In 11 patients, a reduction in THK5351 MTV correlated with MMSE improvement. However, 5 patients showed TMT deterioration, with a significant increase in THK5351 TNR change. FAB scores increased in 3 patients, while RCPM and Kohs scores deteriorated in 1 patient, alongside an increase in THK5351 TNR change. Among the 13 patients with enlarged THK5351 MTV, 5 showed decreased MMSE scores, and 3 showed decreased TMT and FAB scores. These cases exhibited an increased THK5351 TNR change, with accumulation expanding from the medial thalamus to the anterior nuclei of the thalamus, hypothalamus, caudate nucleus, hippocampus, and corpus callosum. Patients with reduced THK5351 TNR but enlarged THK5351 MTV had improved MMSE scores but decreased motivation and cognitive function. CONCLUSION Improving the GBM removal rate and preserving function requires attention to THK5351 accumulation in the corpus callosum, hippocampus, and hypothalamus for advancing cognitive assessment.

Imaging examination of cerebral blood flow (CBF), oxygen extraction fraction (OEF), and metabolic rate of oxygen is crucial for understanding the normal functioning and pathophysiology of the brain. A recently developed method estimates the appearance time of cerebral blood (ATB) pixel-wise from the imaging examination of CBF alone. In this study, we aimed to test the potential of ATB as an indicator of OEF. We retrospectively reviewed patients (n = 62) with suspected cerebrovascular disorders including steno-occlusive disease who underwent positron emission tomography (PET) with 15O-labelled tracers. Regarding the generated OEF and ATB images, a visual assessment was performed to test the consistency of the elevated OEF and delayed ATB. The OEF and ATB values and the absolute differences between their ipsilateral and contralateral sides were extracted and obtained for the entire hemisphere and the middle, anterior, and posterior cerebral arterial regions. Consistency was observed in 52 PET scans (83.9

Distinguishing between primary central nervous system lymphoma (PCNSL) and isocitrate dehydrogenase (IDH)-wildtype glioblastoma is important for therapeutic decision-making. This study aimed to compare the performance of 11C-methionine (MET) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for distinguishing between these two major malignant brain tumors. We retrospectively conducted qualitative and semiquantitative analyses of pre-treatment MET and FDG PET/computed tomography (CT) images of 22 patients with PCNSL and 64 patients with IDH-wildtype glioblastoma. For semiquantitative analysis, we calculated the tumor-to-normal tissue (T/N) ratio by dividing the maximum standardized uptake value (SUV) for the tumor (T) by the average SUV for the normal tissue (N). For performance evaluation, we employed receiver operating characteristic curve analysis and calculated the areas under the curve (AUC) values. In the qualitative analysis, all PCNSLs and IDH-wildtype glioblastomas were MET-positive, while 95

Abstract OBJECTIVE PET scans are crucial for glioma diagnosis and treatment planning, but assessing the efficacy of Bevacizumab (Bev) treatment using MRI alone is challenging. Our study aimed to evaluate the effectiveness of Bev-based glioblastoma treatment using PET scans. METHODS We included ninety glioblastoma patients treated with Bev between July 2013 and May 2023. Patients were divided into three groups: the first group received Bev in addition to the Stupp regimen after biopsy or subtotal resection (first-dose group), the second group received Bev after biopsy followed by tumor resection (neoadjuvant group), and the third group received the Stupp regimen followed by TMZ + Bev at recurrence (recurrent group). PET scans (FDG, MET, FLT, and FMISO) were performed before and 4 weeks after starting Bev treatment. Tumor-to-normal ratio (TNR) was calculated for FDG, MET, and FLT, and tumor-to-blood ratio (TBR) was determined for FMISO. We used the Cox proportional hazards model to assess the percent change in TNR, TBR, and metabolic tumor volume (MTV) as prognostic factors. RESULTS The median PFS and OS (month) from Bev treatment were as follows: first-dose group (PFS: 8.87, OS: 12.53), neoadjuvant group (PFS: 16.53, OS: 22.13), and recurrent group (PFS: 4.0, OS: 8.0). In the first-line group, significant differences were found in the percent change in MTV for MET, FLT, and FMISO. In the recurrent group, significant differences were observed in the percent change in MTV for FDG and MET, as well as in FDG TNR and FMISO TBR. In the neoadjuvant group, significant differences were found in the percent change in MTV for MET and FLT. CONCLUSION Neoadjuvant Bev treatment led to prolonged PFS and OS in glioblastoma patients. Decreases in MET MTV change rate and FMISO TBR change rate were identified as potential indicators for assessing Bev treatment efficacy after recurrence.

Abstract OBJECTIVE This study aims to assess the efficacy of Bevacizumab (Bev) therapy, ten years after its initiation in treating glioblastoma patients at our department. METHODS Eighty-four patients treated with Bev from July 2013 to December 2022 were classified into three groups: the initial treatment group given the Stupp regimen with Bev (first-dose group), the group given the Stupp regimen plus Bev followed by tumor resection (neoadjuvant group), and those receiving the Stupp regimen post tumor resection (recurrence group). PET scans were conducted pre- and post- Bev therapy, and variations in Tumor-to-Normal ratio (TNR), Tumor-to-Blood ratio (TBR), and Metabolic Tumor Volume (MTV) were investigated. RESULTS The median Progression-Free Survival (PFS) and Overall Survival (OS) rates in the first, neoadjuvant, and recurrence groups were respectively (7.86, 14.27, 4.33) and (12.53, 21.57, 13.23) months. Notably, changes in MET and FMISO MTV in the first-treatment group, MET MTV and FMISO TBR changes in the recurrence group, and MET MTV change in the neoadjuvant group significantly influenced prognosis. In the recurrence group, patients who underwent total resection during initial treatment experienced a prolonged period of 25.9 months from initial treatment to the administration of Bev due to recurrence. Furthermore, cases where the FMISO TBR at recurrence was higher than at the initial treatment observed an extended median OS of 18.63 months upon administering Bev treatment at recurrence. CONCLUSION Bev neoadjuvant therapy demonstrated a significant correlation with enhanced PFS and OS outcomes, notably in patients subjected to total resection. In the context of recurrent disease, while the initiation of Bev administration was delayed, a distinct elevation in treatment effectiveness was observed in patients exhibiting an augmented FMISO TBR at the point of recurrence. The observed decreases in MET MTV and FMISO TBR emerge as robust predictors of the efficacy of Bev treatment.