Assessment of 68Ga-PSMA-11 PET positivity predictive factors in prostate cancer. / Valoración de factores predictivos de positividad en PET con 68Ga-PSMA-11 en el cáncer de próstata.

PURPOSE: Positron emission tomography (PET) studies with 68Ga-PSMA-11 (68Ga-HBED-CC-PSMA) have earned the attention of researchers, due to overexpression of PSMA in the tumoral tissues of prostate cancer. Our aim was to analyse the potential benefit of this radiotracer in the biochemical relapse of prostate cancer. MATERIAL AND METHODS: This retrospective analysis included 53 studies, performed on 50 male prostate cancer patients referred due to biochemical recurrence. In all cases, previous imaging techniques were negative or inconclusive. RESULTS: Of the 53 studies, 36 (68%) were positive. Significant differences were found between the positive and negative PET groups in Gleason's scale, PSA levels, PSAdt, late acquisition and the administration of androgen deprivation therapy during treatment (P<.05). Regarding PSA levels, 10 (48%) of the 21 patients with PSA<1ng/ml, obtained a pathological PET result. When the PSAdt was below six months, 86.7% of the patients obtained an abnormal PET. In the multivariate analysis, only Gleason's scale was associated independently with an abnormal PET result. CONCLUSIONS: 68Ga-PSMA-11 PET shows a high disease detection rate in patients where other techniques showed negative or doubtful images. Almost 50% of patients with prostate cancer biochemical recurrence and low PSA levels (<1ng/ml) have active disease on 68Ga-PSMA-11 PET, precisely where other radiotracers lack sensitivity.

[Iatrogenic lung microembolism detected by 18FDG PET/CT]. / Microembolia pulmonar iatrogénica detectada mediante 18F-FDG PET/TC.

We present the cases of two oncology patients: a male with Hodgkin's disease after completion of chemotherapy, and a woman recently diagnosed of melanoma, who underwent positron emission tomography/computed tomography (PET/CT) with 18F-FDG for therapeutic monitoring and initial staging, respectively. In both cases, hypermetabolic foci of 18F-FDG in lung parenchyma were found, without morphologic abnormalities in CT. These findings would have been consistent with lung pathology in the absence of any anatomic correlation. Combined PET/CT interpretation was of lung microembolisms probably originated at the injection site.