Closed evaporation system

A method for the automated synthesis of a radiolabelled compound within a cassette of an automated radiosynthesis apparatus wherein said method comprises:

• (i) radiolabelling a protected precursor compound in a reaction vessel of the cassette 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, wherein the hydrolysis medium is an acidic or a basic solution;
• (iii) connecting the fixed volume container via a 3-way valve to an expandable volume of the cassette and said 3-way valve has a first position and a second position, wherein said expandable volume is within a syringe and the syringe comprises a plunger whereby the automated radiosynthesis apparatus controls the plunger of the syringe to expand or collapse the expandable volume of the syringe;
• and,
• (iv) heating the radioactive fluid in the reaction vessel above its boiling point to reach the equilibrium gas/liquid phase while the 3-way valve is in the first position causing said liquid to vaporize and move into the expandable volume of the syringe where it condenses due to the drop in temperature to form a volume of radioactive fluid in the expandable volume of the syringe to form a condensed radioactive fluid, then positioning the 3-way valve to the second position to empty said condensed radioactive fluid to waste.