Spallation reaction opens new additional possibilities for production of a number of medical useful isotopes. In some cases all the present world demand in produced through spallation. Because of the high transmission of targetmaterials for medium or high energy protons lower cross-sections may be more than compensated by using massive targets. The unspecific nuclear reaction as well as the radiochemical processing of such massive targets lead to several difficulties. New ways for processing of large spallation targets are required. The possibilities of modern ISOL-techniques(ISOL = Isotope Separator On-Line) for the production of medical useful radio-isotopes will be discussed in some detail. Corresponding cross-section data are reviewed and discussed in relation to physico-chemical data requirements. In detail the following radio-isotopes will be discussed: 81-Rb, 82-Sr, 123-I, 167-Tm and 211-At.