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Objective: To design a novel ex-vivo acquisition technique to establish a common framework to validate different segmentation techniques for oncological PET images. To evaluate several automatic segmentation algorithms on this set of images., Material and Methods: In 15 patients with cancer, ex-vivo PET studies of surgical specimens removed during surgery were performed after injection of (18)F-FDG. Images were acquired in two scanners: a clinical PET/CT and a high-resolution PET scanner. Real tumor volume was determined in each patient, and a reference image was generated for segmentation of each tumor. Images were segmented with 12 automatic algorithms and with a standard method for PET (relative threshold at 42%) and results were evaluated by quantitative parameters., Results: It has been possible to demonstrate by segmentation of PET images of surgical specimens that on high resolution PET images, 8 out of 12 evaluated segmentation techniques outperformed the standard method, whose value is 42%. However, none of the algorithms outperformed the standard method when applied on images from the clinical PET/CT. Due to the great interest of this set of PET images, all studies have been published on the Internet in order to provide a common framework for validation and comparison of different segmentation techniques., Conclusions: We have proposed a novel technique to validate segmentation techniques for oncological PET images, acquiring ex-vivo PET studies of surgical specimens. We have demonstrated the usefulness of this set of PET images by evaluating several automatic segmentation algorithms., (Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.)

Background: Accuracy in the quantification of the SUV is a critical point in PET because proper quantification of tumor uptake is essential for therapy monitoring and prognosis evaluation. Recent advances such as time-of-flight (TOF) and point-spread-function (PSF) reconstructions have dramatically improved detectability. However, first experiences with these techniques have shown a consistent tendency to measure markedly high SUV values, bewildering nuclear medicine physicians and referring clinicians., Purpose: We investigated different reconstruction and quantification procedures to determine the optimum protocol for an accurate SUV quantification in last generation PET scanners., Methods: Both phantom and patient images were evaluated. A complete set of experiments was performed using a body phantom containing 6 spheres with different background levels and contrasts. Whole-body FDG PET/CT of 20 patients with breast and lung cancer was evaluated. One hundred five foci were identified by 2 experienced nuclear medicine physicians.Each acquisition was reconstructed both with classical and advanced (TOF, PSF) reconstruction techniques. Each sphere and each in vivo lesion was quantified with different parameters as follows: SUV(max), SUV(mean), and SUV(50) (mean within a 50% isocontour)., Results: This study has confirmed that quantification with SUV(max) produces important overestimation of metabolism in new generation PET scanners. This is a relevant result because, currently, SUV(max) is the standard parameter for quantification. SUV(50) has been shown as the best alternative, especially when applied to images reconstructed with PSF + TOF., Conclusions: SUV(50) provides accurate quantification and should replace SUV(max) in PET tomographs incorporating advanced reconstruction techniques. PSF + TOF reconstruction is the optimum for both detection and accurate quantification.

Background: This study analysed the correlation between [(18)F]fluorodeoxyglucose (FDG) uptake assessed by positron emission tomography (PET) in breast tumours, and histopathological and inmunohistochemical prognostic factors., Methods: FDG-PET was performed before surgery in 275 women with primary breast cancer. The standarized uptake value (SUV) was compared with histopathological findings after surgery., Results: A positive relationship was found between the SUV and tumour size (r = 0.46, P < 0.001), axillary lymph node status (P < 0.001), histological type (P < 0.001), histological grade (P < 0.001), oestrogen receptor status (P < 0.001), p53 (P < 0.001) and Ki-67 (P < 0.001) expression. Multivariable linear regression showed that tumour size, histological grade, Ki-67 expression, oestrogen receptor status and histological type were significantly related to the SUV., Conclusion: The SUV is a preoperative and non-invasive metabolic factor that relates to some prognostic factors in breast cancer.

PET18FDG is an imaging diagnostic technique that shows changes in glycolitic metabolism that appear at a very early phases in the tumoral process. The main limitation of PET in breast cancer is the detection of small tumor lesions and axillary micrometastases. However it offers important information in the staging of high risk patients, in clinical relapse or in therapeutic evaluation. The new PET-CT devices offer advantages over conventional techniques. It provides a greater precision in the localization of tumoral foci. In spite of current difficulties for clinical applications, fluoro-estradiol (18F-ES) offers the possibilty of studying the presence of estrogenic receptors both in the primary and in the metastases. It may prove to be a useful tool to obtain information about therapeutic management and prognosis of breast cancer.

Background: This study analysed the value of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) in detecting axillary lymph node involvement in women with breast cancer., Methods: In the first 150 women in this prospective study, axillary lymph node dissection (ALND) was performed regardless of the PET results. In a second group (125 women) FDG-PET was complemented with sentinel lymph node biopsy (SLNB) only in those who did not have pathological axillary uptake., Results: The sensitivity and specificity of FDG-PET in detecting axillary involvement was 84.5 and 98.5 per cent respectively in the whole series of 275 patients, with two false-positive and 22 false-negative results. False-negative results were associated with some intrinsic tumour characteristics. In 21 women, PET revealed pathological uptake, suggesting involvement of the internal mammary lymph node chain. Whole-body PET identified a second synchronous tumour in five asymptomatic patients and haematogenous metastases in two patients., Conclusion: The high positive predictive value of PET (98.4 per cent) suggests that FDG uptake in the axilla could be an indication for full ALND without previous SLNB., (Copyright (c) 2006 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.)