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