A dosimeter assembly being placed within an inner volume of a test article for evaluating an image produced by an x-ray computed tomography (CT) system. The dosimeter assembly includes: a dosimeter having a display, a dosimeter shelf that supports the dosimeter; and an alignment bracket that positions the dosimeter on the dosimeter shelf. The dosimeter shelf is operable to be mounted within the x-ray computed tomography system test article, and the display of the dosimeter is viewable through a dosimeter window which is disposed at a front end of the x-ray computed tomography system test article, wherein the dosimeter assembly is accessible through an access panel directly beneath the dosimeter assembly, the access panel being an opening which is disposed on a base of the x-ray computer tomography system test article. The dosimeter is operably connected to a connection interface which is configured to exchange communication with an external device.