1. Imaging of cellular proliferation in liver metastasis by [18F]fluorothymidine positron emission tomography: effect of therapy.
- Author
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Contractor, Kaiyumars, Challapalli, Amarnath, Tomasi, Giampaolo, Rosso, Lula, Wasan, Harpreet, Stebbing, Justin, Kenny, Laura, Mangar, Stephen, Riddle, Pippa, Palmieri, Carlo, Al-Nahhas, Adil, Sharma, Rohini, Turkheimer, Federico, Coombes, R. Charles, and Aboagye, Eric
- Subjects
MEDICAL imaging systems ,CELL proliferation ,LIVER metastasis ,POSITRON emission tomography ,KINASES ,CANCER chemotherapy ,MATHEMATICAL variables - Abstract
Although [
18 F]fluorothymidine positron emission tomography (FLT-PET) permits estimation of tumor thymidine kinase-1 expression, and thus, cell proliferation, high physiological uptake of tracer in liver tissue can limit its utility. We evaluated FLT-PET combined with a temporalintensity information-based voxel-clustering approach termed kinetic spatial filtering (FLT-PETKSF ) for detecting drug response in liver metastases. FLT-PET and computed tomography data were collected from patients with confirmed breast or colorectal liver metastases before, and two weeks after the first cycle of chemotherapy. Changes in tumor FLT-PET and FLT-PETKSF variables were determined. Visual distinction between tumor and normal liver was seen in FLT-PETKSF images. Of the 33 metastases from 20 patients studied, 26 were visible after kinetic filtering. The net irreversible retention of the tracer (Ki; from unfiltered data) in the tumor, correlated strongly with tracer uptake when the imaging variable was an unfiltered average or maximal standardized uptake value, 60 min postinjection (SUV60,av : r = 0.9, SUV60,max : r = 0.7; p < 0.0001 for both) and occurrence of high intensity voxels derived from FLT-PETKSF (r = 0.7, p < 0.0001). Overall, a significant reduction in the imaging variables was seen in responders compared to non-responders; however, the two week time point selected for imaging was too early to allow prediction of long term clinical benefit from chemotherapy. FLT-PET and FLT-PETKSF detected changes in proliferation in liver metastases. [ABSTRACT FROM AUTHOR]- Published
- 2012
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