A controller for a device for administering to a patient a contrast medium comprising a radiocontrast agent, using an injector, said controller comprising: a) input means that allow the patient's specific physiological parameters to be introduced, said parameters comprising specific physiological of the patient at least the heart rate, height and weight of the patient; b) a processor configured to calculate the optimal volume of contrast medium based on said specific physiological parameters of the patient; and c) a connection to the injector, configured to control the volume of contrast medium to be injected to the patient before administration, based on said optimum volume calculated by said processor; wherein the controller is configured to use the patient's height and weight to determine the patient's ASC body surface area, and said optimal volume of contrast medium is calculated based on both the ASC and the heart rate of the patient. said patient; and wherein the calculation of said optimal volume of contrast medium comprises starting from an initial volume of contrast medium, and adjusting said volume based on said specific parameters of the patient.Un controlador para un dispositivo para administrar a un/a paciente un medio de contraste que comprenda un agente de radiocontraste, usando un inyector, comprendiendo dicho controlador: a) medios de entrada que permiten introducir parámetros fisiológicos específicos del/la paciente, comprendiendo dichos parámetros fisiológicos específicos del/la paciente al menos la frecuencia cardíaca, la altura y el peso del/la paciente; b) un procesador configurado para calcular el volumen óptimo de medio de contraste en función de dichos parámetros fisiológicos específicos del/la paciente; y c) una conexión al inyector, configurada para controlar el volumen de medio de contraste a inyectar al/la paciente antes de la administración, en función de dicho volumen óptimo calculado por dicho procesador; en donde el controlador está