A fully automated apparatus for the routine synthesis and
formulation of short-lived 11C (t1/2=20 min) labelled radiopharmaceuticals
for positron emission tomography (PET) has
been developed. [11C]Carbon dioxide is converted to [11C]methyl
iodide, which can be used to label a wide variety of substrates by
methylation at C, N, O, or S electron rich centres. The apparatus,
MIASA (methyl iodide automated synthesis apparatus), was
designed to operate as part of an automated labelling system in a
shielded ‘hot’ laboratory. The apparatus was designed without the
size constraints of typical instrumentation used in hot cells, although
it is compact where necessary. Ample use of indicators and sensors,
together with compact design of the reaction flasks for small dead
space and efficient evaporation, led to good reliability and
performance. The design of the hardware and software is described
in this paper, together with a preparation of 3-N-[11C]methylspiperone
as a sterile injectable solution in physiological saline.