68Ga-PSMA-11 Dynamic PET/CT Imaging in Primary Prostate Cancer.
OBJECTIVE
The aim of our study is to assess the pharmacokinetics and biodistribution of Ga-PSMA-11 in patients suffering from primary prostate cancer (PC) by means of dynamic and whole-body PET/CT.


METHODS
Twenty-four patients with primary, previously untreated PC were enrolled in the study. All patients underwent dynamic PET/CT (dPET/CT) scanning of the pelvis and whole-body PET/CT studies with Ga-PSMA-11. The evaluation of dPET/CT studies was based on qualitative evaluation, SUV calculation, and quantitative analysis based on two-tissue compartment modeling and a noncompartmental approach leading to the extraction of fractal dimension (FD).


RESULTS
A total of 23/24 patients (95.8%) were Ga-PSMA-11 positive. In 9/24 patients (37.5%), metastatic lesions were detected. PC-associated lesions demonstrated the following mean values: SUVaverage = 14.3, SUVmax = 23.4, K1 = 0.24 (1/min), k3 = 0.34 (1/min), influx = 0.15 (1/min), and FD = 1.27. The parameters SUVaverage, SUVmax, k3, influx, and FD derived from PC-associated lesions were significantly higher than respective values derived from reference prostate tissue. Time-activity curves derived from PC-associated lesions revealed an increasing Ga-PSMA-11 accumulation during dynamic PET acquisition. Correlation analysis revealed a moderate but significant correlation between PSA levels and SUVaverage (r = 0.60) and SUVmax (r = 0.57), and a weak but significant correlation between Gleason score and SUVaverage (r = 0.33) and SUVmax (r = 0.28).


CONCLUSIONS
Ga-PSMA-11 PET/CT confirmed its capacity in detecting primary PC with a detection rate of 95.8%. Dynamic PET/CT studies of the pelvis revealed an increase in tracer uptake in PC-associated lesions during the 60 minutes of dynamic PET acquisition, a finding with potential applications in anti-PSMA approaches.
From the *Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center (DKFZ), Heidelberg, Germany; †Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; ‡Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg; §Department of Urology, University Hospital Heidelberg, Heidelberg; ∥Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg; and ¶Department of Nuclear Medicine, University of Heidelberg, Heidelberg, Germany.
Christos
C
Sachpekidis
Klaus
K
Kopka
Matthias
M
Eder
Boris A
BA
Hadaschik
Martin T
MT
Freitag
Leyun
L
Pan
Uwe
U
Haberkorn
Antonia
A
Dimitrakopoulou-Strauss
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004492:Edetic Acid / Q000031:analogs & derivatives; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D000072078:Positron Emission Tomography Computed Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D009842:Oligopeptides; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid