This paper is concerned with the radiotherapy pre-treatment patient scheduling. Radiotherapy pre-treatment deals with localisation of the area to be irradiated and generation of a treatment plan for a patient. A genetic algorithm is developed for patient scheduling which evolves priority rules for operations of radiotherapy pre-treatment. The fitness function takes into consideration the waiting time targets of patients and also the early idle time on resources. Real world data from a hospital in the UK are used in experiments.