RT Journal Article
SR Electronic
T1 Evaluation of 68Ga-PSMA I&T PET/CT in 240 Patients with Biochemical Relapse After Primary Therapy for Prostate Cancer : Intraindividual Comparison between Standard and Delayed Imaging
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 710
OP 710
VO 58
IS supplement 1
A1 Derlin, Thorsten
A1 Schmuck, Sebastian
A1 Klot, Christoph
A1 Ross, Tobias Ludwig
A1 Wester, Hans
A1 Bengel, Frank
YR 2017
UL http://jnm.snmjournals.org/content/58/supplement_1/710.abstract
AB 710Objectives: 68Ga-Labelled prostate-specific membrane antigen (PSMA) ligands have gained increased interest as highly sensitive imaging agents for evaluation of biochemical recurrence in patients after primary therapy for prostate cancer. Delayed imaging has been suggested to improve lesion-to-background ratios using other radiotracers. In this study, we sought to determine the value of additional delayed abdominal imaging inPET/CT for detection of biochemically recurrent prostate cancer, using the ligand 68Ga-PSMA I&T.Methods: The study population consisted of 240 men (69.8±7.5 years; range, 46.4-89.8 years) who were referred for a 68Ga-PSMA I&T PET/CT for detection of biochemical recurrence after primary therapy for prostate cancer. Imaging consisted of a standard whole-body PET/CT (1h p.i.), followed by delayed (3h p.i.) imaging of the abdomen. PSA-stratified proportions of positive PET/CT results, standardized uptake values and lesion-to-background ratios were analyzed, and compared between standard and delayed imaging.Results: The overall detection efficacy of 68Ga-PSMA I&T PET/CT was 94.2%, 71.8%, 58.6% and 50.0% for PSA levels of 蠅2, 1 to <2, 0.5 to <1, and 0.01 to <0.5 ng/mL, respectively. Although the target-to-lesion ratio improved significantly over time (P<0.0001), the majority (1096 of 1134 lesions; 96.6%) of all lesions suggestive of recurrent disease could already be detected in standard imaging. Delayed imaging at 3h p.i. exclusively identified pathologic findings in 5.4% (10/184) of abnormal 68Ga-PSMA I&T PET/CT scans, and exclusively detected 38 of 1134 (3.4%) of all lesions suggestive of recurrent disease. The intensity of 68Ga-PSMA I&T accumulation was significantly higher in patients receiving ADT (P≤0.004), but not significantly higher in patients with higher Gleason scores (P蠅0.07)Conclusion: 68GaPSMA I&T PET/CT shows high detection rates in patients with biochemical relapse after primary therapy for prostate cancer. Delayed imaging can detect lesions with improved contrast compared to standard imaging. However, the impact on detection efficacy is limited. Standard imaging at 1 h p.i. is sufficient when using the ligand 68GaPSMA I&T. Research Support: None