This paper will discuss the properties of watermarking medical images. We will also discuss the possibility of such images being compressed by JPEG and give an overview of JPEG compression. We will then propose a watermarking scheme that is reversible and robust to JPEG compression. The purpose is to verify the integrity and authenticity of medical images. We used 800x600x8 bits ultrasound (US) images in our experiment. SHA-256 of the image is then embedded in the Least significant bits (LSB) of an 8x8 block in the Region of Non Interest (RONI). The image is then compressed using JPEG and decompressed using Photoshop 6.0. If the image has not been altered, the watermark extracted will match the hash (SHA256) of the original image. The result shown that the embedded watermark is robust to JPEG compression up to image quality 60 (~91% compressed).