A compression device for compressing image data generated by a computed tomography (CT) imaging system is described herein. The compression device is configured to compress the image data by implementing a method including receiving image data from the CT imaging system and requantizing the image data in a square root domain. The method further includes identifying a group of projections (GOP) in the image data, including a first projection and a plurality of subsequent projections, and performing spatial-delta encoding on the first projection and temporal-delta encoding on each of the plurality of subsequent projections. The method also includes identifying a signed value in the GOP, and converting the signed value to an unsigned value. The method further includes entropy coding the image data in the GOP, and packetizing the GOP for transmission or storage.