@article {Al-Faham70, author = {Zaid Al-Faham and Prashant Jolepalem and John Rydberg and Ching-Yee O. Wong}, title = {Optimizing 18F-FDG Uptake Time Before Imaging Improves the Accuracy of PET/CT in Liver Lesions}, volume = {44}, number = {2}, pages = {70--72}, year = {2016}, doi = {10.2967/jnmt.115.169953}, publisher = {Society of Nuclear Medicine}, abstract = {18F-FDG PET/CT has emerged as one of the fastest-growing imaging modalities. A shorter protocol results in a lower target-to-background ratio, which can increase the challenge of identifying mildly 18F-FDG{\textendash}avid lesions and differentiating inflammatory or physiologic activity from malignant activity. The purpose of this study was to determine the delay between radiotracer injection and imaging that optimizes target-to-background ratio while maintaining counts high enough to ensure scan sensitivity. Methods: The study included 140 patients (66 male and 74 female; age range, 42{\textendash}95 y) with suspected hepatic lesions as seen on an 18F-FDG PET scan. SUV was determined as region-of-interest activity/(dose/total body weight). Results: The mean injected dose was 610 {\textpm} 66.6 MBq (16.5 {\textpm}1.8 mCi), with a mean glucose level of 107 {\textpm} 26.6 mg/dL (standardized to 90 mg/dL). The uptake time before imaging ranged from 61 to 158 min, with a mean of 108.8 {\textpm} 24.8 min. The P values for the correlation of SUV to time were 0.004, 0.003, and 0.0001 for malignant lesions, benign lesions, and background hepatic tissue, respectively. Conclusion: An approximately 90-min time window from 18F-FDG injection to PET imaging would significantly improve target-to-background ratio and, thus, quantitation and visual interpretation. This benefit outweighs the minimal loss in patient throughput.}, issn = {0091-4916}, URL = {https://tech.snmjournals.org/content/44/2/70}, eprint = {https://tech.snmjournals.org/content/44/2/70.full.pdf}, journal = {Journal of Nuclear Medicine Technology} }