In the medical field, telemedicine, smart health and e-health, are cutting-edge technologies. These technologies utilize digital medical information for end-user communication. Even though this digitalization reduces time, it is a open source for hackers. Hence, hackers can tamper the digital medical image during broadcast. In the medical field, most of the investigations are done through X-rays, MRI and CT scan images. Security must be provided to maintain secrecy of diseases for avoiding the panic in the patients and for improving the degree of security in the image broadcast through internet. The DNA cryptography provides powerful security to enhance the probability of preventing from the brute-force and statistical analysis attacks. In this paper, two level security is provided using DNA codons. In first level, image is encrypted into DNA sequences by selecting key. In second level, codons are generated with dynamic numbers for encryption of image and construct DNA alphabets. In this technique, the encrypted image is in hidden format so that it is very difficult for attacker with known image attacks. The experimental results of the proposed technique are investigated with histogram based method and statistical analysis attacks and confirmed the superior security level in the protection of the image transmission.