Effects of Fasting on F-DCFPyL Uptake in Prostate Cancer Lesions and Tissues with Known High Physiologic Uptake.

In the literature, a 4- to 6-h fast is recommended before a patient undergoes PET/CT with 2-(3-(1-carboxy-5-[(6-F-fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid (F-DCFPyL); however, a scientific underpinning for this recommendation is lacking. Therefore, we performed a study to determine the impact of fasting on F-DCFPyL uptake. The study included 50 patients who fasted at least 6 h before F-DCFPyL administration and 50 patients who did not. Activity (SUV) was measured in lesions characteristic of prostate cancer and in normal tissues known to express high physiologic uptake. Uptake in suspected lesions did not differ between the cohorts. F-DCFPyL uptake in the submandibular gland, liver, and spleen was significantly higher in the fasting than the nonfasting cohort. Our data show that fasting does not significantly affect F-DCFPyL uptake in suspected malignant lesions but does result in significantly lower F-DCFPyL uptake in tissues with high physiologic uptake. The absolute differences in uptake were relatively small; therefore, the effects of fasting on the diagnostic performance can be considered negligible.

© 2018 by the Society of Nuclear Medicine and Molecular Imaging.