The invention relates, in particular, to structures of dental and medical cone beam computed tomography (CBCT) imaging apparatus. The basic construction of the apparatus includes a substantially vertically extending frame part (11) which supports via a horizontally extending support construction (12) the X-ray imaging means (14, 15) of the apparatus. The apparatus includes a patient support structure (18) which extends substantially in parallel with and is essentially of the same length as the substantially vertically extending frame part (11).