The present invention is directed to a system, apparatus, and method for producing gallium radioisotopes on particle accelerators using solid targets and a Ga-68 composition produced by this method. The solid target assembly apparatus has a metal disc and a zinc portion on the top of the disc. The apparatus is made by preparing a quantity of zinc, depositing it onto a metal disc, melting the zinc, and allowing it to cool and solidify. The disc surface may be prepared before applying zinc to it in order to facilitate bonding between the substrate and the zinc. Ga-68 is produced by placing the apparatus in a cyclotron target irradiation station, irradiating it, separating it from the irradiated Zn, and collecting and storing the separated Ga-68. The Ga-68 composition has the following quotient of activity quantity ratios: Ga-67/Ga-68 less than 1, and Ga-67/Ga-68 less than 1.
