[en] Analytical models were developed that describe the basic elements for metal targets irradiation in cyclotrons. Important parameters such as maximum beam current value and thermal power deposited on target were obtained and compared with practical situations. In an unprecedented way, were determined analytically the features found in intense thermal transient situations, when high protons concentrations in a small region of the beam cause intense temperature gradients in small regions of the target. Comparing with results found in the literature showed that the developed models are satisfactory, in view of all limitations of the proposed model. (author)