This invention directed to a computer tomography imaging apparatus designed for dental use as well as to methods realizable by it, especially to a method for relative positioning of the imaging means and the patient for imaging. A relevant feature of the computer tomography imaging device according to the invention is an arm construction consisting of turnable arm parts. The use of the construction enables implementation of, particularly, a so-called Cone Beam computer tomography apparatus (CBCT) as lighter, and more inexpensive realization of it, than has been the case regarding CT devices of prior art, especially when thinking of their use in odontology.