Search

Purpose: To evaluate the biodistribution of [18F]Florastamin, a novel 18F-labelled positron emission tomography (PET) tracer for prostate-specific membrane antigen (PSMA) for the diagnosis of prostate cancer. Methods: PET was performed for five healthy controls and 10 patients with prostate cancer at 0, 10, 30, 70, and 120 mins after injecting 370 MBq of [18F]Florastamin. The maximum standardised uptake value (SUVmax) was evaluated in the primary tumour. The mean SUVmax (SUVmean) was evaluated in normal organs. Furthermore, the residence time was evaluated by assessing radioactivity in each organ. The internal radiation dosimetry was calculated using the OLINDA/EXM software. Results: The SUVmax in primary tumours increased with time. A favourable tumour to background ratio was also observed over time. Multiple lymph nodes and bone metastases were also evaluated and showed a similar pattern to SUVmax in the primary tumour. In one patient, a tiny lymph node metastasis was identified using [18F]Florastamin PET, which was not observed using other modalities, and was histologically confirmed. The highest absorbed dose was observed in the kidney (0.062 ± 0.015 mGy/MBq), followed by the bladder (0.032 ± 0.013 mGy/MBq), liver (0.022 ± 0.006 mGy/MBq), and salivary gland (0.018 ± 0.006 mGy/MBq). The effective dose with a 370 MBq injection of [18F]Florastamin was 1.81 mSv. No adverse events related to [18F]Florastamin were reported. Conclusion: We identified a novel PSMA-targeted PET ligand, [18F]Florastamin, for imaging prostate cancer. [18F]Florastamin showed a high SUVmax and relatively high tumour to background ratio in both primary tumour and metastatic lesions, which suggests its high sensitivity to detect tumours without any adverse events. Trial registration: KCT0003924 registered at https://cris.nih.go.kr/. [ABSTRACT FROM AUTHOR]

Purpose: We evaluated the ability of pretreatment F-FDG uptake by regional lymph nodes to predict the survival of patients with resectable colorectal cancer. Methods: The records of 78 patients with AJCC stage III colorectal cancer (pathologically confirmed node-positive disease without evidence of distant metastasis) treated with surgery and adjuvant chemotherapy were retrospectively reviewed. The maximum standardized uptake values of the primary tumor (SUVp) and regional lymph nodes (SUVn) were measured by pretreatment F-FDG PET/CT. The ROC curve analyses and the Cox proportional hazard model were used to analyze whether SUVp, SUVn, and clinicopathologic parameters could predict disease-free survival. Results: Although there were no significant differences between the median SUVp in the event group and that in the non-event group, the median SUVn was significantly higher in the event group (1.7) than in the non-event group (0.8, p = 0.023). Based on the ROC curve analysis, SUVn predicted the event for disease-free survival (AUC = 0.668, p = 0.02) with the optimal criterion, sensitivity, specificity, and accuracy of > 1.2, 71 %, 63 %, and 65 %, respectively. However, SUVp did not predict disease-free survival (AUC = 0.570, p = 0.349). Univariate analysis revealed that SUVn ( p = 0.011) and venous invasion ( p = 0.016) were associated with disease-free survival, but pathologic N stage was not ( p = 0.09). By multivariate analysis, only SUVn > 1.2 independently shortened the disease-free survival (relative risk, 2.97; 95 % CI, 1.14-7.74, p = 0.026). Conclusion: SUVn before surgery may be a useful prognostic marker in patients with AJCC stage III colorectal cancer. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the potential of FDG PET/CT and MRI in predicting disease-free survival (DFS) after neoadjuvant chemotherapy (NAC) and surgery in patients with advanced breast cancer. Methods: The analysis included 54 women with advanced breast cancer. All patients received three cycles of NAC, underwent curative surgery, and then received three cycles of additional chemotherapy. Before and after the first cycle of NAC, all patients underwent sequential PET/CT and MRI. All patients were analysed using a diverse range of parameters. including maximal standardized uptake value (SUV), percent change in SUV (ΔSUV), initial slope of the enhancement curve (MRslope), apparent diffusion coefficient (ADC), tumour size, change in MRslope (ΔMRslope), change in ADC (ΔADC), change in tumour size (Δsize) and other clinicopathological parameters]. The relationships between covariates and DFS after surgery were analysed using the Kaplan-Meier method and the multivariate Cox proportional hazards model. Time-dependent receiver operating characteristic curves were used to determine the optimal cut-off values of imaging parameters for DFS. Results: Of the 54 patients, 13 (24 %) experienced recurrence at a median follow-up of 38 months (range 25 - 45 months). Univariate and multivariate analyses showed that a lesser decline in SUV, a lesser decline in MRslope, a lesser increase in ADC, and ER negativity were significantly associated with a poorer DFS ( P = 0.0006, ΔSUV threshold −41 %; P = 0.0016, ΔMRslope threshold −6 %; P = 0.011, ΔADC threshold 11 %; and P = 0.0086, ER status, respectively). Patients with a combination of ΔSUV >−41 % and ΔMRslope >−6 % showed a significantly higher recurrence rate (77.8 %) than the remaining of patients (13.3 %, P < 0.0001). Conclusion: Functional parameters of both FDG PET and MRI after the first cycle of NAC are useful for predicting DFS in patients with advanced breast cancer. This approach could lead to an improvement in patient care because ineffective NAC agents could be avoided and more aggressive therapy could be used in high-risk patients. [ABSTRACT FROM AUTHOR]

Purpose: We evaluated the potential of sequential fluorine-18 fluorodeoxyglucose ( F-FDG) positron emission tomography (PET)/computed tomography (CT) and MRI (PET/MRI) after one cycle of neoadjuvant chemotherapy to predict a poor histologic response in osteosarcoma. Methods: A prospective study was conducted on 30 patients with osteosarcoma treated with two cycles of neoadjuvant chemotherapy and surgery. All patients underwent PET/MRI before, after one cycle, and after the completion of neoadjuvant chemotherapy, respectively. Imaging parameters [maximum standardized uptake value (SUV), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and tumor volume based on magnetic resonance (MR) images (MRV)] and their % changes were calculated on each PET/MRI data set, and histological responses were evaluated on the postsurgical specimen. Results: A total of 17 patients (57 %) exhibited a poor histologic response after two cycles of chemotherapy. Unlike the little volumetric change in MRI, PET parameters significantly decreased after one and two cycles of chemotherapy, respectively. After one cycle of chemotherapy, SUV, MTV, and TLG predicted the poor responders. Among these parameters, either MTV ≥ 47 mL or TLG ≥ 190 g after one cycle of chemotherapy was significantly associated with a poor histologic response on multivariate logistic regression analysis (OR 8.98, p = 0.039). The sensitivity, specificity, and accuracy of these parameters were 71 %, 85 % and 77 %; and 71 %, 85 % and 77 %, respectively. Conclusion: The histologic response to neoadjuvant chemotherapy in osteosarcoma can be predicted accurately by FDG PET after one course of chemotherapy. Among PET parameters, MTV and TLG were independent predictors of the histologic response. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the usefulness of the maximum standardized uptake value (SUVmax) as a measure of histologic response to neoadjuvant chemotherapy in patients with extremity osteosarcoma. The correlation between [ F]FDG PET SUVmax values and histologic response to preoperative chemotherapy was also assessed prospectively using PET/MRI. Methods: A total of 26 consecutive patients with high-grade osteosarcoma were prospectively enrolled. All patients underwent parallel PET and MRI scans before and after neoadjuvant chemotherapy. Using the PET and MRI images and pathologic mapping, we assessed the percentage necrosis by histology at the highest metabolic activity point in the tumors. This was defined as the minimum histologic response. The predictive values of SUVmax before (SUV1) and after (SUV2) chemotherapy and the SUV change ratio were determined. Correlations were also investigated among SUV2, minimum histologic response and histologic response. Results: Histologically, 13 patients were classified as good responders and 13 as poor responders. Patients with an SUV2 of >5 showed a poor histologic response. A significant correlation was found between SUV2 and histologic response (Spearman's rho −0.642; P < 0.001), and SUV2 and histologic response were both found to be significantly correlated with minimum histologic response (Spearman's rho −0.515 and 0.911; P = 0.007 and P < 0.001, respectively). Conclusion: A SUVmax of more than 5 after neoadjuvant chemotherapy identified the majority of histologic nonresponders (sensitivity 61.3 %, PPV 88.9 %). Tumor necrosis at the point of maximum metabolic activity was found to be significantly correlated with the histologic response of entire resected specimen. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare I whole-body scintigraphy (WBS), WBS with I single photon emission computed tomography/computed tomography (SPECT/CT), and F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in the detection of distant metastases of differentiated thyroid cancer (DTC). Methods: A total of 140 patients with 258 foci of suspected distant metastases were evaluated. I WBS, I SPECT/CT, and F-FDG PET/CT images were interpreted separately. The final diagnosis was obtained from histopathologic study, serum thyroglobulin level, other imaging modalities, and/or clinical follow-up. Results: Of the 140 patients with 258 foci, 46 patients with 166 foci were diagnosed as positive for distant metastasis. The sensitivity, specificity, and diagnostic accuracy of each imaging modality were 65, 55, and 59%, respectively, for I WBS; 65, 95, and 85% for I SPECT/CT, respectively; and 61, 98, and 86%, respectively, for F-FDG PET/CT in patient-based analyses. Lesion-based analyses demonstrated that both SPECT/CT and PET/CT were superior to WBS ( p<0.001) in all patient groups. SPECT/CT was superior to WBS and PET/CT ( p<0.001) in patients who received a single challenge of radioiodine therapy, whereas PET/CT was superior to WBS ( p=0.005) and SPECT/CT ( p=0.013) in patients who received multiple challenges. Conclusion: Both SPECT/CT and PET/CT demonstrated high diagnostic performance in detecting metastatic thyroid cancer. SPECT/CT was highly accurate in patients who underwent a single challenge of radioiodine therapy. In contrast, F-FDG PET/CT presented the highest diagnostic performance in patients who underwent multiple challenges of radioiodine therapy. [ABSTRACT FROM AUTHOR]