X-ray CT apparatus

An X-ray CT apparatus comprising:

• an X-ray tube;
• an X-ray detector, oppositely provided to the X-ray tube, that detects an X-ray generated with the X-ray tube and transmitted through a subject;
• a main memory that stores projection data generated from spatial distribution of the transmission X-ray detected with the X-ray detector;
• a cache memory to which the projection data is previously transferred from the main memory;
• and
• a processor that, when the projection data used in reverse projection processing has been transferred to the cache memory, performs the reverse projection processing, with the projection data stored in the cache memory, and generates tomographic image data of the subject,
• wherein a first plurality of segments are set based on an image position with respect to original projection data of continuous views from the X-ray detector, and first tomographic image data is generated by reverse-projecting projection data of the first plurality of segments in accordance with first view weights set by the first plurality of segments,
• wherein a second plurality of segments are set based on an image position with respect to original projection data, and second tomographic image data is generated by reverse-projecting projection data of the second plurality of segments in accordance with second view weights set by the second plurality of segments,
• wherein the processor generates rearranged projection data in which the first plurality of segments and the second plurality of segments are overlaid and extracted from the original projection data and stores the generated rearranged projection data into the main memory, and generates third view weights in which the first view weights are made to correspond with the rearranged projection data, and generates fourth view weights in which the second view weights are made to correspond with the rearranged projection data,
• wherein the rearranged projection data stored in the main memory is previously transferred to the cache memory, and
• wherein the processor generates the first tomographic image data with the rearranged projection data and the third view weights, and generates the second tomographic image data with the rearranged projection data and the fourth view weights.