RADIOACTIVE DIAGNOSTIC IMAGING AGENT

摘要

[PROBLEMS] To provide a composition comprising a radioactive fluorine-labeled amino acid compound, which can prevent the occurrence of radiation degradation. [MEANS FOR SOLVING PROBLEMS] Disclosed is a composition comprising a solution containing a radioactive fluorine-labeled amino acid compound as an active ingredient. The pH value of the solution is kept at a value falling within the range from 2.0 to 5.9, more preferably a value falling within the range from 2.0 to 4.9, thereby preventing the occurrence of radiation degradation. When a pharmaceutical additive capable of preventing the occurrence of radiation degradation, such as a sugar, a sugar alcohol or a sugar lactone, is added to the solution while keeping the pH value of the solution at a value falling within the range from 2.0 to 5.9, the occurrence of radiation degradation can be prevented in a superimposed manner.