Rodolfo Silva

Superiority of 18F-FNa PET/CT for Detecting Bone Metastases in Comparison with Other Diagnostic Imaging Modalities

INTRODUCTION The 18F-NaF positron emission tomography/computed tomography is being considered as an excellent imaging modality for bone metastases detection. This ability was compared with other imaging techniques. MATERIAL AND METHODS We retrospectively evaluated 114 patients who underwent 18F-NaF positron emission tomography/ computed tomography. Of these, 49 patients also had bone scintigraphy, 61 18F-FDG positron emission tomography/computed tomography and 10 18F-FCH positron emission tomography/computed tomography. We identified the technique that detected the largest number of bone metastases. For the detection of skeletal metastases with the 18F-NaF positron emission tomography/computed tomography study, the contribution of the positron emission tomography component was compared with the contribution of the computed tomography component. Cases in which 18F-NaF positron emission tomography/computed tomography and bone scintigraphy required further additional tests for diagnosis clarification were registered. RESULTS The 18F-NaF positron emission tomography/computed tomography was superior to bone scintigraphy in 49% of the patients (p < 0.001); it was superior to 18F-FDG positron emission tomography/computed tomography in 59% of the patients (p < 0.001) and it was superior to 18F-FCH positron emission tomography/computed tomography in 40% of the patients (p < 0.001). None of the compared imaging techniques were superior to 18F-NaF positron emission tomography/computed tomography. The positron emission tomography component was superior to computed tomography in 35% of the cases (p < 0.001). Further investigation was suggested in only 3.5% of patients who underwent 18F-NaF positron emission tomography/computed tomography (45% for bone scintigraphy) (p < 0.001). DISCUSSION As with other authors, our experience also confirms that 18F-NaF positron emission tomography/computed tomography is an excellent imaging modality for the detection of bone metastases, detecting lesions in more patients and more lesions per patient. CONCLUSION The 18F-NaF positron emission tomography/computed tomography showed a superior ability for the detection of bone metastases when compared with bone scintigraphy, 18F-FDG positron emission tomography/computed tomography and 18F-FCH positron emission tomography/computed tomography.

PET/CT with 18F-Fluorocholine in Patients with Prostatic Cancer in Biochemical Recurrence

INTRODUCTION In prostate cancer, after therapy with curative intent, biochemical recurrence frequently occurs. The purpose of this study was to evaluate the impact of PET/CT with 18F-fluorocholine in restaging these patients and in their orientation, and to analyze the effect of the risk stratification, the values of PSA and the hormone suppression therapy, in the technique sensitivity. MATERIAL AND METHODS Retrospective analysis of 107 patients with prostate carcinoma in biochemical recurrence who underwent PET/CT with 18F-fluorocholine in our hospital, between December 2009 and May 2014. RESULTS The overall sensitivity was 63.2% and 80.0% when PSA > 2 ng/mL. It was possible to identify distant disease in 28% of the patients. The sensitivity increased from 40.0%, in patients with low and intermediate risk, to 55.2% in high-risk patients. Without hormonal suppression therapy, the sensitivity was 61.8%, while in the group under this therapy, was 67.7%. DISCUSSION PET/CT with 18F-fluorocholine provided important information even in patients with low levels of PSA, however, with significantly increased sensitivity in patients with PSA > 2 ng/mL. Sensitivity was higher in high-risk patients compared with low and intermediate risk patients, however, without a statistically significant difference. The hormone suppression therapy does not appear to influence uptake of 18F-fluorocholine in patients resistant to castration. CONCLUSIONS In this study, PET/CT with 18F-Fluorocholine showed good results in restaging patients with prostate cancer biochemical recurrence, distinguishing between loco regional and systemic disease, information with important consequences in defining the therapeutic strategy.