RT Journal Article SR Electronic T1 Effects of Pegfilgrastim on Normal Biodistribution of 18F-FDG: Preclinical and Clinical Studies JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 950 OP 956 VO 47 IS 6 A1 Heather A. Jacene A1 Takayoshi Ishimori A1 James M. Engles A1 Sophie Leboulleux A1 Vered Stearns A1 Richard L. Wahl YR 2006 UL http://jnm.snmjournals.org/content/47/6/950.abstract AB The purpose of this study was to evaluate the effects of pegfilgrastim, a long-acting granulocyte colony-stimulating factor, on the normal biodistribution of 18F-FDG in an animal model and in humans. Methods: Two groups of 12 rats received a single subcutaneous injection of either normal saline or pegfilgrastim. One, 7, 14, and 21 d after injection, biodistribution studies were performed 1 h after 18F-FDG injection. Sixteen breast cancer patients underwent baseline 18F-FDG PET/CT and, approximately 1 wk after receiving 1 dose of docetaxel and adjunctive pegfilgrastim, follow-up 18F-FDG PET/CT (scan 2). Standardized uptake values corrected for lean body mass (SUL) were determined for several normal organs before and after therapy. Results: In rats, bone marrow 18F-FDG uptake (standardized uptake value) was higher in the pegfilgrastim group 1 d after injection (mean ± SD, 8.3 ± 4.1 vs. 2.5 ± 0.2, P < 0.05), whereas 18F-FDG uptake in blood was lower (0.41 ± 0.06 vs. 0.49 ± 0.01, P < 0.05). In patients, mean SUL was higher in bone marrow (4.49 ± 1.50 vs. 1.33 ± 0.22, P < 0.0001), spleen (3.29 ± 0.83 vs. 1.23 ± 0.23, P < 0.0001), and liver (1.45 ± 0.25 vs. 1.31 ± 0.23, P = 0.01) but lower in brain (4.18 ± 0.76 vs. 5.14 ± 1.44, P < 0.01) on scan 2 than on the baseline scan. Conclusion: In both the animal model and humans, pegfilgrastim markedly increased bone marrow uptake of 18F-FDG and reduced 18F-FDG uptake in some normal tissues. These profound alterations in 18F-FDG biodistribution induced by pegfilgrastim must be considered when one is evaluating quantitative 18F-FDG PET scans for tumor response to therapy.