In the age of increasing digital data transmission through network, the data security measures have become very important and crucial issue. Two main security schemes are used to protect sensitive data: cryptography and steganography. A good imperceptibility and appropriate data capacity are the two important properties that characterize Steganography technique. In this paper, a hybrid technique is proposed that utilizing the Steganography and Cryptography, to hide sensitive patient's data into pixel values of medical colored image. The medical colored image is chosen as a cover image of lossless compression PNG format. The sensitive data; which is the patient's data and the examination data, is firstly encrypted using 'Block Encryption Method' and then embedded in the image. This will make it harder to recognize or interpret it when it is attacked. In embedding algorithm, the pixels of medical cover image are chosen randomly based on the values, which are produced using primitive root numbers. The two least significant bits of the blue and alpha channels are used to hide the encrypted patient's sensitive medical data. The experimental results shows that the quality of stego-image is relatively less distortive, highly imperceptible to human eye, has good data hiding capacity, and assure more security.