Nuklearmedizin 2019; 58(02): 154
DOI: 10.1055/s-0039-1683618
Poster
PET und SPECT: Prostata-Karzinom
Georg Thieme Verlag KG Stuttgart · New York

Quantitative and qualitative analysis of biodistribution and image quality of 18F- rhPSMA7 as novel radiohybrid PSMA-ligand

SW Oh
1   Klinikum rechts der Isar, TUM, Nuclear Medicine, München, Germany
,
M Krönke
1   Klinikum rechts der Isar, TUM, Nuclear Medicine, München, Germany
,
G Buschner
1   Klinikum rechts der Isar, TUM, Nuclear Medicine, München, Germany
,
A Wurzer
2   TUM, Radiopharmacy, München, Germany
,
E Teoh
3   Oxford University Hospitals NHS Foundation Trust, Radiology and Nuclear Medicine, Oxford, UK
,
M Herz
1   Klinikum rechts der Isar, TUM, Nuclear Medicine, München, Germany
,
W Weber
1   Klinikum rechts der Isar, TUM, Nuclear Medicine, München, Germany
,
M Eiber
1   Klinikum rechts der Isar, TUM, Nuclear Medicine, München, Germany
,
HJ Wester
2   TUM, Radiopharmacy, München, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
27 March 2019 (online)

 

Ziel/Aim:

Biodistribution and image quality of 18F-rhPSMA7 as lead compound in the new class of radiohybrid PSMA-ligands (rhPSMA) was evaluated to determine adequate activity and best imaging time point.

Methodik/Methods:

12 different groups were retrospectively determined by administered activity (low:222 – 296MBq, moderate:297 – 370MBq, high:371 – 444MBq) and uptake time (short:50 – 70 min, intermediate:71 – 90 min, long:91 – 110 min, longest:3111 min) using 20218F-rhPSMA7 PET/CT scans. SUVmean and tumor-to-background (T/B) were calculated for background (gluteus muscle), normal organs and 377 tumor lesions. Overall image quality, non-specific blood pool activity and background uptake in bone were assessed using 3 or 4-point scales with low numbers indicating favorable impression.

Ergebnisse/Results:

Biodistribution of liver, spleen, pancreas, and duodenum was similar for all uptake times and administered activities. SUVmean of bladder increased with uptake time (3.94 ± 2.16; 5.48 ± 5.22; 5.38 ± 2.79; 8.22 ± 5.71, p < 0.0001). In non-diseased bone SUVmeanwas constantly increasing with uptake time, but not statistically significant (1.06 ± 0.27; 1.12 ± 0.27; 1.13 ± 0.28; 1.20 ± 0.43, p = 0.11). SUVmean of tumor lesions (13.3 ± 12.0; 9.1 ± 7.5; 12.1 ± 11.8; 13.8 ± 16.4; p = 0.15) and T/B (22.8 ± 19.1; 18.1 ± 17.5; 22.9 ± 22.4; 26.3 ± 33.2; p = 0.34) were not significantly different for different uptake times. Qualitative analysis revealed statistically significant trends towards increasing non-specific bone (2.23 ± 0.46; 2.33 ± 0.54; 2.378 ± 0.52; 2.65 ± 0.80, p < 0.0001) and decreasing blood pool uptake (2.75 ± 0.51; 2.72 ± 0.61; 2.64 ± 0.67; 2.23 ± 0.82, p = 0.0005) with increasing uptake time. Overall image quality was highest in the low uptake time group, however not statistically significant (1.55 ± 0.60; 1.78 ± 0.56; 1.71 ± 0.56; 1.85 ± 0.73, p = 0.09).

Schlussfolgerungen/Conclusions:

Quantitative uptake in tumor lesions is stable at all uptake times and activities. Least tracer retention in bladder and non-diseased bone as important features for PSMA ligand imaging and highest overall image quality are achieved at short uptake time. Thus, the use of low activities (222 – 296MBq) at early imaging time point (50 – 70 min) is preferable for 18F-rhPSMA7.