Biomedicines (Mar 2023)

Diagnostic Impact of Dual-Time PET/CT with <sup>68</sup>Gallium-PSMA in Prostate Cancer and <sup>68</sup>Gallium-DOTATOC in Neuroendocrine Tumors

  • Damiano Librizzi,
  • Friederike Eilsberger,
  • Stefan Ottenthaler,
  • Ali Ebrahimifard,
  • Markus Luster,
  • Behrooz H. Yousefi

DOI
https://doi.org/10.3390/biomedicines11041052
Journal volume & issue
Vol. 11, no. 4
p. 1052

Abstract

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Background: 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. Methods: 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. Results: 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. Conclusion: Early second images can improve diagnostics with 68Ga-DOTATOC and 68Ga-PSMA PET/CT.

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