Closed evaporation system

Abstract

The present invention provides a system for evaporating a radioactive fluid, a method for the synthesis of a radiolabelled compound including this system, and a cassette for the synthesis of a radiolabelled compound comprising this system. The present invention provides advantages over known methods for evaporation of a radioactive fluid as it reduces drastically the amount of radioactive gaseous chemicals that are released in the hot cell. It is gentler and more secure compared to the known process and provides access to radiosyntheic processes that may not been acceptable for safety reasons related to release of volatile radioactive gases during evaporation. In addition, the process yields are higher because the radioactive volatiles are labelled intermediate species.

1 . A system for evaporating a radioactive fluid wherein said system comprises:
 (i) a fixed volume hot zone which comprises a fixed volume container and a heating means;   (ii) an expandable volume;   (iv) a 3-way valve which in a first position fluidly connects said fixed volume container and said an expandable volume and which in a second position fluidly connects said an expandable volume to waste.   
     
     
         2 . The system as defined in  claim 1  wherein said fixed volume container is a reaction vessel. 
     
     
         3 . The system as defined in  claim 1  wherein said heating means can heat said radioactive fluid to above its boiling point to reach the equilibrium gas/liquid phase of said radioactive fluid. 
     
     
         4 . The system as defined in  claim 1  wherein said expandable volume is a syringe. 
     
     
         5 . A method for the synthesis of a radiolabelled compound wherein said method comprises:
 (i) radiolabelling a protected precursor compound to obtain a protected radiolabelled compound;   (ii) deprotecting the protected radiolabelled compound obtained from radiolabelling step (i) to obtain said radiolabelled compound wherein said deprotection is effected using a hydrolysis medium; and,   (iii) evaporating the hydrolysis medium following deprotection step (ii) wherein said evaporating is carried out using the system as defined in  claim 1 .   
     
     
         6 . The method as defined in  claim 5  wherein said radiolabelled compound is a radiopharmaceutical. 
     
     
         7 . The method as defined in  claim 6  wherein said radiopharmaceutical is a diagnostic radiopharmaceutical. 
     
     
         8 . The method as defined in  claim 7  wherein said diagnostic radiopharmaceutical is either a single photon emission tomography (SPECT) tracer or a positron emission tomography (PET) tracer. 
     
     
         9 . The method as defined in  claim 8  wherein said diagnostic radiopharmaceutical is a PET tracer. 
     
     
         10 . The method as defined in  claim 9  wherein said PET tracer comprises a  11 C-labelled compound or an  18 F-labelled compound. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . A cassette for the synthesis of a radiopharmaceutical wherein said cassette comprises:
 (i) a vessel containing a protected precursor compound;   (ii) means for eluting the vessel of step (i) with a suitable source of a radiolabel; and,   (iii) the system as defined in  claim 1 .   
     
     
         15 . The cassette as defined in  claim 14  wherein said radiopharmaceutical is a diagnostic radiopharmaceutical. 
     
     
         16 . The cassette as defined in  claim 15  wherein said diagnostic radiopharmaceutical is either a SPECT tracer or a PET tracer. 
     
     
         17 . The cassette as defined in  claim 16  wherein said diagnostic radiopharmaceutical is a PET tracer. 
     
     
         18 . The cassette as defined in  claim 17  wherein said PET tracer comprises a  11 C-labelled compound or an  18 F-labelled compound. 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled)