1. A CT apparatus without a gantry, comprising: a scanning passage; a stationary X-ray source arranged around the scanning passage and comprising a plurality of ray emission focal spots; and a plurality of stationary detector modules arranged around the scanning passage and disposed opposite the X-ray source, wherein first detector modules of the plurality of detector modules are arranged in a first direction, second detector modules of the plurality of detector modules are arranged in a second direction, and the first detector modules and the second detector modules are disposed substantially in an L shape, a first straight line can be formed by connecting central points of ray receiving surfaces of the first detector modules, a second straight line can be formed by connecting central points of ray receiving surfaces of the second detector modules and the first straight line and the second straight line intersect at a point when viewed in a plane intersecting the scanning passage, and the ray receiving surfaces of the first detector modules are inclined relative to the first direction and substantially face the X-ray source, and the ray receiving surfaces of the second detector modules are inclined relative to the second direction and substantially face the X-ray source.