Water “loop”-target for the In-cyclotron production of 13N by the reaction 16O(p,α)13N

Production of chemically pure gaseous [13N]NH3 pulses for PEP studies using a modified DeVarda reduction

A fast and reproducible production method for pure gaseous [13N]NH3 pulses has been developed. 13N was produced by irradiation of water with 500 nA of 16 MeV protons via the 16O(p,alpha)13N reaction. A mixture of DeVarda's alloy and NaOH was used to convert the produced nitrate/nitrite to ammonia. Pre-treatment of this mixture with water increased the concentrated production of gaseous [13N]NH3. Separation and further purification of ammonia were performed with GC, leading to 5s pulses (1.1 ml STP) with 3.5 +/- 0.5 MBq [13N]NH3 with a high chemical and radiochemical purity suited for positron emission profiling (PEP).

In-target production of [13N]ammonia: target design, products, and operating parameters

[13N]Ammonia, commonly used in PET, has been prepared in good yield in the target. Up to 800 mCi of radiopharmaceutical was obtained by in-line processing of the irradiated water. Relatively low hydrogen pressure was used to control the target chemistry. Target designs and the product dependence on beam dose, dose rate and pressure are reported. Ethanol as a target additive was also investigated. Hydrogen and ethanol together were more effective than either alone at high beam dose. Parameters are reported for production needs from single doses to synthetic applications. An incidental method for production of [13N]nitrogen gas is also reported.