Synthesis of labeled compound

Abstract

A process for the synthesis of .sup.13 N-ammonia in target which comprises charging target water and hydrogen into a synthesis apparatus to make a pressurized condition at 0.1-5 kg/cm.sup.2 and irradiating proton beam to the target water which is circulated to produce .sup.13 N-ammonia, a process for the synthesis of .sup.13 N-ammonia in target which comprises bringing the target water containing .sup.13 N-ammonia thus produced into contact with a Na type cation-exchange resin to collect .sup.13 N-ammonia by the cation-exchange, and then bringing the cation-exchange resin into contact with a saline solution to elute the collected .sup.13 N-ammonia into the saline solution, and a process for the synthesis of a labeled compound, at the time of sucking a prescribed amount of the liquid of the target water, saline solution or the like into a syringe and injecting the liquid from the syringe into the above vessel, comprising depressing the piston of the syringe in the state that the pipe connecting the syringe and the vessel has been once closed to detect the displacement of the piston, and in the case that the displacement exceeds a prescribed value, judging that the sucked amount of the liquid into the syringe is short, on the other hand in the case that the displacement is not more than the prescribed value, opening said pipe to inject the liquid into the vessel. The method of the invention can synthesize high purity .sup.13 N-ammonia in a short time which is suitable for the PET (Positron Emission Tomography) system which is a kind of tomography utilized for the dragnosis of disease, etc.