CT (Computed Tomography) data compression method and method for acquiring original projection data

The invention relates to a CT (Computed Tomography) data compression method and a method for acquiring original projection data, belongs to the technical field of CT image processing, and solves the problem that the original projection data cannot be acquired after CT data compression in the prior art. The compression method comprises the following steps: sequentially carrying out preprocessing, reconstruction operation and compression on first projection data acquired by a detector, and storing compressed second reconstruction data into a preset storage memory; performing inverse operation processing of decompression, projection operation and preprocessing on the second reconstruction data in sequence to obtain fourth projection data; performing subtraction on the fourth projection data and the first projection data to obtain first difference data; and based on a preset lossless compression algorithm, compressing the first difference data to obtain second difference data, and storing the second difference da