Radiology Information Systems (RIS) involves the transmission of medical images between the PACS server and the workstation over the network for analysis. The images during transmission are vulnerable due to the intruders, and it is essential to secure the images. Because processing the adulterated images is unethical and can mislead the radio diagnosis. The combination of image processing and the cryptographic techniques can resolve this problem to some extent. Over a period, the technology has improved a lot, and several images securing methods are discussed by various researchers. This review paper is an effort in reviewing the existing secured image transmission technologies, their pros, and cons and the scope of the future work.