Effects of fasting on 18 F-DCFPyL uptake in prostate cancer lesions and tissues with known high physiologic uptake

Abstract

In the literature, a 4- to 6-h fast is recommended before a patient undergoes PET/CT with 2-(3-(1-carboxy-5-[(6- 18 F-fluoro-pyridine-3- carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid ( 18 F-DCFPyL); however, a scientific underpinning for this recommendation is lacking. Therefore, we performed a study to determine the impact of fasting on 18 F-DCFPyL uptake. Methods: The study included 50 patients who fasted at least 6 h before 18 F-DCFPyL administration and 50 patients who did not. Activity (SUVmax) was measured in lesions characteristic of prostate cancer and in normal tissues known to express high physiologic uptake. Results: Uptake in suspected lesions did not differ between the cohorts. 18 F-DCFPyL uptake in the submandibular gland, liver, and spleen was significantly higher in the fasting than the nonfasting cohort. Conclusion: Our data show that fasting does not significantly affect 18 F-DCFPyL uptake in suspected malignant lesions but does result in significantly lower 18 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.