Systems and methods for generating radionuclides, such as radium-224. Systems herein may include a first cartridge having a first opening, a second opening, and a chamber therebetween having a first resin having affinity for thorium-228 and bismuth-212; a second cartridge having a first opening, a second opening, and a chamber therebetween having a second resin having affinity for thorium-228 and bismuth-212, a third cartridge having a first opening, a second opening, and a chamber therebetween comprising a third resin having affinity for thorium-228 and bismuth-212, a fourth cartridge having a first opening, a second opening, and a chamber therebetween having a third resin having affinity for lead-212; wherein a continuous flow path is formed from a top of the first cartridge though the second cartridge, through the third cartridge, and to a bottom of the fourth cartridge during system use.

Systems and methods for generating radionuclides, such as radium-224. Systems herein may include a first cartridge having a first opening, a second opening, and a chamber therebetween having a first resin having affinity for thorium-228 and bismuth-212; a second cartridge having a first opening, a second opening, and a chamber therebetween having a second resin having affinity for thorium-228 and bismuth-212, a third cartridge having a first opening, a second opening, and a chamber therebetween comprising a third resin having affinity for thorium-228 and bismuth-212, a fourth cartridge having a first opening, a second opening, and a chamber therebetween having a third resin having affinity for lead-212; wherein a continuous flow path is formed from a top of the first cartridge though the second cartridge, through the third cartridge, and to a bottom of the fourth cartridge during system use.

Processes for the synthesis of [.sup.89Zr]ZrCl.sub.4 from [.sup.89Zr][Zr(oxalate).sub.4].sup.4 salt are provided. The [.sup.89Zr]ZrCl.sub.4 can be reacted with biomarker targeting agents to produce .sup.89Zr labelled radiopharmaceuticals. The .sup.89Zr labelled radiopharmaceuticals find use in, for example, non-invasive molecular imaging.