English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  [ 18 F]BF 4  − , the first  18 F-labelled PET imaging agent for the sodium/iodide symporter (NIS), was produced by isotopic exchange yielding a product with limited specific activity (SA, ca. 1 GBq/μmol) posing a risk of sub-optimal target-to-background ratios (TBR) in PET images due to saturation of NIS in vivo. We sought to quantify this risk and to develop a method of production of [ 18 F]BF 4  −  with higher SA.    Methods  A new radiosynthesis of [ 18 F]BF 4  −  was developed, involving reaction of [ 18 F]F −  with boron trifluoride diethyl etherate under anhydrous conditions, guided by  11 B and  19 F NMR studies of equilibria involving BF 4  −  and BF 3 . The SA of the product was determined by ion chromatography. The IC 50  of [ 19 F]BF 4  −  as an inhibitor of [ 18 F]BF 4  −  uptake was determined in vitro using HCT116-C19 human colon cancer cells expressing the human form of NIS (hNIS). The influence of [ 19 F]BF 4  −  dose on biodistribution in vivo was evaluated in normal mice by nanoPET imaging and ex vivo tissue counting.    Results  An IC 50  of 4.8 μΜ was found in vitro indicating a significant risk of in vivo NIS saturation at SA achieved by the isotopic exchange labelling method. In vivo thyroid and salivary gland uptake decreased significantly with [ 19 F]BF 4  −  doses above ca. 10 μg/kg. The new radiosynthesis gave high radiochemical purity (>99 %) and moderate yield (15 %) and improved SA (>5 GBq/μmol) from a starting activity of only 1.5 GBq.    Conclusions  [ 18 F]BF 4  −  produced at previously reported levels of SA (1 GBq/μmol) can lead to reduced uptake in NIS-expressing tissues in mice. This is much less likely in humans. The synthetic approach described provides an alternative for production of [ 18 F]BF 4  −  at higher SA with sufficient yield and without need for unusually high starting activity of [ 18 F]fluoride, removing the risk of NIS saturation in vivo even in mice.    Trial registration   ISRCTN75827286 .    Electronic supplementary material  The online version of this article (doi:10.1186/s13550-016-0188-5) contains supplementary material, which is available to authorized users.

[18F]tetrafluoroborate as a PET tracer for the sodium/iodide symporter: the importance of specific activity