Zinc Isotopes are used extensively in both industrial and medical applications. Depleted Zn-64 is added to the cooling water of nuclear reactors in the form of oxide or acetate to prevent stress corrosion cracking. It also reduces the release of (stable) Co-59 into the cooling water by forming a thin spinel layer on the Co containing steel surfaces. Neutron irradiation of Co-59 will result in the formation of Co-60, a radioisotope which emits high energy gamma radiation and is a major contributor to the dose rate of personnel working in the reactor. Enriched Zn-67 is often used in biological research into the uptake of Zn in the human body. It can also be used for the production of radioactive Ga-67 in smaller cyclotrons. However, by far most Ga-67 is made from Zn-68. Zn-67, Zn-68 and Zn-70 can all be used for the production of the therapeutic isotope Cu-67. Zn-66 has been proposed as an alternative target for the production of Cu-64 and Ga-67. Finally Zn-70 is also used in biological research and in research into super-heavy elements.