@article {Odewole1668, author = {Oluwaseun Odewole and Bital Savir-Baruch and Peter Nieh and Viraj Master and Zhengjia Chen and Xiaojing Wang and Ashesh Jani and Raghuveer Halkar and Mark Goodman and David Schuster}, title = {Reproducibility of anti-3-[18F]FACBC uptake in background structures and malignant lesions on followup PET-CT in prostate carcinoma: An exploratory analysis}, volume = {55}, number = {supplement 1}, pages = {1668--1668}, year = {2014}, publisher = {Society of Nuclear Medicine}, abstract = {1668 Objectives Anti-3-[18F]FACBC is a synthetic amino-acid analog under study for the detection of prostate carcinoma [1]. Our goal was to examine the reproducibility of quantitative measurements in key background structures and untreated malignant lesions among patients with prostate cancer recurrence that underwent followup scanning. Methods Retrospective review of 14/115 patients who underwent followup anti-3-[18F]FACBC PET-CT for suspected prostate carcinoma recurrence. SUVs were measured in both original and followup scans on early (4min) and delayed (17min) images in key background structures (aorta, liver, marrow, pancreas, muscle and spleen) as well as untreated malignant lesions. Paired t test was used to determine differences in SUV between both scans. Intra-subject variability was measured using \%mean difference [2]. Interclass correlation coefficients (ICC) were calculated. Results The average time ({\textpm}SD, range) interval between both scans was 17.4 months ({\textpm}7.1, 4-29). The \%mean difference in SUVmean was less than 20\% in all background structures with relatively low absolute differences (see table1). All ICC{\textquoteright}s were \>0.6 with the exception of aortic blood pool on early imaging which had an ICC of 0.37. There was no statistically significant difference between SUV{\textquoteright}s on both original and followup scans except in the marrow at 4 minutes (p=0.04). SUVmax in malignant lesions without interim therapy increased or remained stable over time (see table2). Conclusions Despite variable time interval between scans, FACBC PET-CT demonstrates acceptable reproducible uptake in key background structures and malignant lesions. A formal test-retest study is planned. Research Support Research sponsored by the NIH (5 R01 CA 129356-01) and the Georgia Cancer Coalition.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/55/supplement_1/1668}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }