1-¹¹C-Acetate Kinetics of Prostate Cancer

Abstract

18 F-FDG is in widespread use in cancer imaging but has limited utility in staging and monitoring of prostate cancer. 1-11 CLabeled acetate, a substrate for the citric acid cycle, is superior. The kinetics of prostate tumors were investigated. Methods: Ten patients with primary prostate cancer, 10 with recurrent tumor, and 2 men with benign prostate hypertrophy were studied. After administration of 5.5 MBq/kg 1-11 C-acetate, dynamic PET of the pelvis was acquired for 20 min. Images were reconstructed with iterative algorithms, and corrections for attenuation and scatter were applied. Factor analysis produced factor images, representing iliac vessels and the prostate from which blood-input and tissue-output functions were derived with simple thresholding techniques. Five different kinetic models were applied to the dynamic data to estimate the rate constants. Results: The standard 3-compartment, 2-tissue model was able to describe 1-11 C-acetate kinetics of the prostate. The model could be reduced to 3 parameters by setting the tissue blood fraction and release from the second tissue compartment (k 4 ) to zero. Correction for metabolites appeared to be necessary. This reduced model performed marginally better than a 2-compartment model. A significant correlation was found between the influx rate constant (K) and acetate uptake (standardized uptake value) for primary tumors (r 5 0.91), whereas there was no correlation for recurrent tumors (r 5 20.17). Patlak graphical analysis provided accurate parameter estimates. Conclusion: A 3-compartment, 3-parameter model is able to describe adequately the acetate kinetics in prostate cancer. Significant differences between primary and recurrent cancer were found for transport k 1 , influx K, distribution volume V d , as well as early (6-10 min) and late (15-20 min) 1-11 C-acetate uptake.

Long-Term Post-Treatment MR and PET/CT Imaging in Prostate Cancer Patients in Complete Remission after Curative Radiotherapy with or without Androgen Deprivation: The Image of Cure

“…after AC injection showing an optimized power to differentiate benign hyperactivity in early imaging from recurrent cancer. Schiepers et al reported that the acetate kinetics of prostate cancer can be adequately described by a 3-compartement model and that early and late SUV are significantly different in primary and recurrent prostate cancer [28]. In the present study we have been able to show that limiting the study to the first PET frame 5 min.…”

Image-Derived Input Function for Brain PET Studies: Many Challenges and Few Opportunities

“…Schiepers et al used an IDIF method based on factor analysis to study patients with brain tumors using [ 18 F]-fluorothymidine (Schiepers et al, 2007b) and [ 18 F]-FDOPA (Fueger et al, 2010;Schiepers et al, 2007a). Although this method was never validated for brain studies against a reference input function, especially vis-à-vis the recovery coefficient used for partial volume correction, Schiepers et al had previously shown that it yielded reliable input functions for bone disorders with [ 18 F]-fluoride (Schiepers et al, 1997), in breast cancer with [ 18 F]-FDG (Schiepers et al, 1998), in prostate cancer with [ 11 C]-acetate (Schiepers et al, 2000(Schiepers et al, , 2002b(Schiepers et al, , 2008 (Schiepers et al, 2002a;Wu et al, 1995).…”

Tumor Cell Metabolism Imaging

“…After intravenous injection, 11 C-acetate is thus rapidly taken up by the myocardium, but the activity concentration in the myocardium decreases within minutes as radioactivity is released in the form of 11 C-O 2 . In contrast, 11 C-acetate has been shown to steadily accumulate in prostate cancer and other malignant tumors (114,123,127), indicating that the metabolic fate of acetate in cancer cells is fundamentally different. In cancer cells, an anabolic pathway seems to dominate, which uses acetate for synthesis of fatty acids and lipids.…”