title: Imaging of cellular proliferation in liver metastasis by [18F]fluorothymidine positron emission tomography: effect of therapy.
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 temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (FLT-PET(KSF)) 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-PET(KSF) variables were determined. Visual distinction between tumor and normal liver was seen in FLT-PET(KSF) 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 post-injection (SUV(60,av): r = 0.9, SUV(60,max): r = 0.7; p < 0.0001 for both) and occurrence of high intensity voxels derived from FLT-PET(KSF) (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-PET(KSF) detected changes in proliferation in liver metastases.
authors.affiliation: Faculty of Medicine, Imperial College London, London, UK.
authors.forename: Kaiyumars
authors.initials: K
authors.lastname: Contractor
authors.forename: Amarnath
authors.initials: A
authors.lastname: Challapalli
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Tomasi
authors.forename: Lula
authors.initials: L
authors.lastname: Rosso
authors.forename: Harpreet
authors.initials: H
authors.lastname: Wasan
authors.forename: Justin
authors.initials: J
authors.lastname: Stebbing
authors.forename: Laura
authors.initials: L
authors.lastname: Kenny
authors.forename: Stephen
authors.initials: S
authors.lastname: Mangar
authors.forename: Pippa
authors.initials: P
authors.lastname: Riddle
authors.forename: Carlo
authors.initials: C
authors.lastname: Palmieri
authors.forename: Adil
authors.initials: A
authors.lastname: Al-Nahhas
authors.forename: Rohini
authors.initials: R
authors.lastname: Sharma
authors.forename: Federico
authors.initials: F
authors.lastname: Turkheimer
authors.forename: R Charles
authors.initials: RC
authors.lastname: Coombes
authors.forename: Eric
authors.initials: E
authors.lastname: Aboagye
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000473:pathology*; D015224:Dideoxynucleosides; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology / Q000556:secondary; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D016896:Treatment Outcome
chemical_list: D015224:Dideoxynucleosides; C002854:alovudine