The timing of imaging for 68gallium (68Ga)-PSMA and 68Ga-DOTATOC are stated to be around 60 min post-injection (p.i.). In some lesions, late imaging (3-4 h p.i.) showed advantages. The aim of our evaluation was to demonstrate the relevance of an "early" late acquisition.
We retrospectively evaluated 112 patients who underwent 68Ga-DOTATOC-PET/CT and 82 patients who underwent 68Ga-PSMA-PET/CT. The first scan was acquired 60 min (±15 min) after application. In cases of diagnostic ambiguity, a second scan was performed 30-60 min later. Pathological lesions were analyzed.
Almost half of all 68Ga-DOTATOC cases and about one-third of all 68Ga-PSMA examinations showed a change in findings due to the second acquisition. In total, 45.5% of neuroendocrine tumor (NET) patients and 66.7% of prostate cancer (PCa) patients showed relevant TNM classification changes. For 68Ga-PSMA, there were significant increases in sensitivity and specificity from 81.8% to 95.7% and from 66.7% to 100%, respectively. Statistically significant improvements in sensitivity (from 53.3% to 93.3%) and specificity (from 54.6% to 86.4%) were demonstrated for NET patients.
Early second images can improve diagnostics with 68Ga-DOTATOC and 68Ga-PSMA PET/CT.
Biomedicines. 2023 Mar 29*** epublish ***
Damiano Librizzi, Friederike Eilsberger, Stefan Ottenthaler, Ali Ebrahimifard, Markus Luster, Behrooz H Yousefi
Department of Nuclear Medicine, School of Medicine, Philipps University Marburg, 35043 Marburg, Germany.