Two radiolabeled bicyclic nucleoside analogues (BCNAs) were synt
hesized, namely 3-(2'-deoxy-

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D-ribofuranosyl)-6-(3-[
18F]fluoroet
hoxyp
henyl)-2,3-di
hydrofuro[2,3-
d]pyrimidin-2-one ([
18F]-
2) and 3-(2'-deoxy-

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D-ribofuranosyl)-6-(3-[
11C]met
hoxyp
henyl)-2,3-di
hydrofuro[2,3-
d]pyrimidin-2-one ([
11C]-
3), and evaluatedas PET reporter probes for varicella-zoster virus t
hymidine kinase (VZV-tk) gene expression imaging inbrain. [
18F]-
2 and [
11C]-
3 were synt
hesized starting from p
henol precursor
1. T
he p
henol precursor
1 wasconverted to stable as well as to radiolabeled compounds
2 and
3 using
19/18FCH
2CH
2Br or
12/11CH
3I asalkylating agent. In vitro evaluation of [
18F]-
2 and [
11C]-
3 in 293T cells s
howed a 4.5 and 53-fold
hig
heruptake, respectively, into VZV-tk gene-transduced cells compared to control cells. However, biodistributionstudies in mice demonstrated low uptake of t
hese tracers in t
he brain. RP-HPLC analysis of plasma andurine samples of mice injected wit
h [
11C]-
3 revealed t
hat t
his tracer is very stable in vivo. T
hese data warrantfurt
her evaluation of t
hese tracers as noninvasive imaging agents for VZV infection and VZV-tk reportergene expression in vivo.