Optimising the Azeotropic Drying of 18F-Fluorine Wayto Improve the 18F-Fluorocholine Radiochemical Yield

BACKGROUND AND OBJECTIVE: 18F-Fluorocholine has been suggested as one of the reputable imaging tracers for diagnosis of prostate tumour in Positron Emission Tomography / Computed Tomography (PET/CT) modality. Nevertheless, it has never been synthesised in Malaysia. We acknowledged that the major problem with 18F-Fluorocholine is due to its relatively low radiochemical yield at the end of synthesis (EOS). Therefore, this article presents improved 18FFluorocholine radiochemical yields after carrying out optimisation on azeotropic drying of 18F-Fluorine.

METHODS: In the previous study, the azeotropic drying of non-carrier-added (n.c.a) 18F-Fluorine in the reactor was conducted at atmospheric pressure (0 atm) and shorter duration time. In this study, however, the azeotropic drying of non-carried-added (n.c.a) 18FFluorine was made at a high vacuum pressure (- 0.65 to - 0.85 bar) with an additional time of 30 seconds. At the end of the synthesis, the mean radiochemical yield was statistically compared between the two azeotropic drying conditions so as to observe whether the improvement made was significant to the radiochemical yield.

RESULTS: From the paired sample t-test analysis, the improvement done to the azeotropic drying of non-carrier-added (n.c.a) 18F-Fluorine was statistically significant (p < 0.05). With the improvement made, the 18F-Fluorcholine radiochemical yield was found to have increase by one fold.

CONCLUSION: Improved 18F-Fluorocholine radiochemical yields were obtained after the improvement had been done to the azeotropic drying of non-carrier-added (n.c.a) 18F-Fluorine. It was also observed that improvement made to the azeotropic drying of non-carrier-added (n.c.a) 18F-Fluorine did not affect the 18F-Fluorocholine quality control analysis.