An automated radiosynthesis of 2-[11C]thymidine using anhydrous [11C]urea derived from [11C]phosgene

Appl Radiat Isot. 1999 Oct;51(4):377-88. doi: 10.1016/s0969-8043(99)00051-2.


2-[11C]Thymidine has been produced from [11C]methane via [11C]phosgene and [11C]urea. Anhydrous [11C]urea was prepared from [11C]phosgene by reaction with liquid ammonia. This novel approach avoids the problems associated with the synthesis of anhydrous [11C]urea from [11C]cyanide. A fully automated system based on a modular approach and under PLC control has been developed. The system provides 2-[11C]thymidine reliably and reproducibly for clinical PET studies. The radiosynthesis takes 45-50 min from [11C]methane and the average yield was 1.5-3.3 GBq (40-90 mCi). The specific radioactivity was typically in the range 29.6-51.8 GBq mumol-1 (0.8-1.4 Ci mumol-1) at EOS corresponding to 6-12 micrograms of stable thymidine. The radiochemical yield of 2-[11C]thymidine was ca. 14% from [11C]methane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Radioisotopes / chemistry*
  • Carbon Tetrachloride / chemical synthesis
  • Chromatography, High Pressure Liquid
  • Isotope Labeling / methods
  • Methane / chemical synthesis
  • Phosgene / chemical synthesis*
  • Quality Control
  • Radiochemistry
  • Radiopharmaceuticals / chemical synthesis*
  • Thymidine / chemical synthesis*
  • Urea / chemical synthesis*


  • Carbon Radioisotopes
  • Radiopharmaceuticals
  • Phosgene
  • Urea
  • Carbon Tetrachloride
  • Methane
  • Thymidine