In this study, a safety mechanism is used for the transmission of medical data with disturbance and unknown parameters and unknown time delays using a new communication method. A new synchronization method for Fractional Order Systems (FOCS) for encryption of medical images based on the Coullete system with unknown time delay is proposed. In the proposed method, the control laws are determined using the Lyapunov stability theorem such that the convergence of the synchronization error to zero is guaranteed. In this study, multiple state synchronization is performed in the presence of disturbance and unknown time delay. The control laws are determined using the Lyapunov function such that the synchronization and estimation errors converge to zero. For medical color images encryption, we use the fractional-order chaotic synchronization system alongside the chaos masking technique. To test the efficiency of the proposed method in medical image transmission, various statistical parameters such as histogram, correlation, number of pixel change rate (NPCR), signal to peak noise ratio (PSNR), and information entropy are calculated. According to the values obtained for Entropy=7.8596, Correlation=0.9999, etc., the results show successfully encrypts the medical color images. Manuscript profile