Three groups of radioisotopes were studied as a function of the demand and production possibilities for different irradiation schedules. The specific activities obtained were compared with postulated demands to establish a method of optimizing the schedules. Two criteria were followed: the first compared the available irradiation volume in our reactor with the theoretically calculated volume that satisfies the different demands; the second compared this theoretical volume with the volume needed if we were to use the specific activity available from other laboratories to satisfy the different demands.