Advancement of medical imaging in health care sector emerges new challenge of secure image transmission. Security of medical imaging is a prominent issue to keep patients information safe. In this paper an efficient and secure biomedical image encryption algorithm is proposed with two phases of encryption. In the first phase the image has to undergone a random substitution of 20 Amino Acid based Codon with one or more than alternate Codon in the form of triplets using the base DNA code (A, T, C and G) using Linear Congruential Generator. Upshot of the first phase encrypted image is divided into blocks and a logistic map is used to generate a series of unique initial condition and control parameter. Using a random ASCII character as a seed the unique initial conditions for each block is generating some Pseudo Random Number Generator. The seed is encrypted using RSA. Each block is circularly shifted using unique PRNG. These unique initial conditions and control parameters are utilized by a series of Tent Maps to perform block by block confusion in the second phase encryption using XOR operation. Keys used in both the phases are encrypted using AES technique. Proposed method is used to encrypt any biomedical and other images also. All type of security measure such as Differential attack, key space analysis to resist Brute force attack, Correlation analysis, key sensitivity test, resistance to Noise attack and plain text attack along with time analysis has been taken into consideration to test the vulnerability of the proposed algorithm. From the comparative study the proposed method outperform in many aspects than the existing methods.