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AIM: The aim of this paper was to assess the prognostic role of pretherapy partial volume corrected (PVC) 18F-fluorodeoxyglucose mean standardized uptake value (SUV) in breast cancer (BC). METHODS: Forty oncological patients, BC diagnosed by biopsy, with breast tumor mass diameter >1 cm measured to the mammography, designed for surgical intervention, underwent a pretherapy semi-quantitative 18F-FDG positron emission tomography/computed tomography (18F-FDG PET/CT) whole-body study for tumor staging. Mean Body-Weight Standardized Uptake Value with Correction for Partial Volume effect (PVC- SUVBW-mean) was calculated in all mammary detected lesions. Excised tissues from primitive BC were sectioned and classified according to the WHO guidelines, evaluating biological features. Univariate (Mann-Withney/Kruskal-Wallis) and multivariate (linear regression, hierarchical clustering) statistical tests were performed between PVC-SUVBW-mean and biological indexes. ROC analysis was performed. PVC-SUVBW-mean thresholds were derived allowing to distinguish groups of BC patients with different biological characteristics. Specificity and Sensitivity were also calculated. RESULTS: Statistical and multiple correlations between pretherapy 18F-FDG PET PVC-SUVBW-mean and histological type, grade, ER/PgR hormone receptors and Mib-1 cellular proliferation index were found. In our samples, PVC-SUVBW-mean ?7.00 is associated to BC patients with moderately and poorly differentiated IDC, negative expression of ER and PgR and a positive expression of MiB-1. CONCLUSION: Pretherapy PVC 18F-FDG PET PVC-SUVBW-mean measurement correlates with prognostic factors in BC and could be used to stratify patients before intervention.

Partial Volume Effect (PVE) in PET-CT oncological studies affects the estimation of quantitative parameters useful for lesion malignancy differentiation and for monitoring disease and response to therapy. The aim of this work was to investigate the clinical feasibility and accuracy of PVE correction methods based on Recovery Coefficients (RC) as function of measured Lesion-to-Background ratio (L/B)m and measured lesion volume (V)m. PET-CT measurements were performed. The radioactivity concentration (C)m and Vm were measured from images using Operator-Dependent and Operator-Independent (OI) techniques. RC curves were obtained combining RC from NEMA 2001 IQ phantom measurements as function of Sphere-to-Background ratio (S/B)m and sphere Vm. PVE correction was applied to PET-CT studies of anthropomorphic oncological phantoms and to PET-CT oncological studies (basal and follow up). The underestimation of Cm due to PVE in the NEMA IQ spheres (up to 80%) confirmed the severity of the error. The more feasible (always applicable, noise insensitive, reproducible) way to measure radioactivity was found by the use of an OI threshold technique. Our results showed that this measurement technique allows to achieve a PVE correction accuracy > 87% (error in radioactivity estimate < 13%) for a sphere diameter > 1 cm. In patient studies the PVE correction was found to modify both SUV and SUV variations during patient follow up and our analysis showed that a PVE corrected SUV quantification increases the diagnostic confidence of oncological PET-CT studies.