X-ray aiming fixture

Claim 1

A lithotripter having an x-ray aiming system and comprising a table for supporting a patient having a kidney stone, said table having an opening therein with the patient located on said table so that the kidney stone is disposed above said opening, support means disposed below said table and being horizontally movable, a shock wave generator supported by said support means and including an upwardly opening truncated ellipsoidal reflector with a vertical axis and having a spark gap at the first focus point of the ellipsoidal reflector with the second focus point of the ellipsoidal reflector to coincide with the kidney stone, said support means being horizontally movable to align said vertical axis with the kidney stone, means for disposing an x-ray film in alignment with said table opening, x-ray apparatus disposed above said table and aligned with said opening for cooperating with the x-ray film to produce an x-ray picture, an x-ray opaque aiming member, means supporting said x-ray opaque aiming member from said first mentioned support means below said x-ray apparatus to produce a shadow on an x-ray picture, said x-ray opaque aiming member being fixed in alignment with said reflector vertical axis, said x-ray opaque aiming member thus shadowing said kidney stone when said vertical axis passes through said kidney stone and displaying in the event of misalignment how far and in what direction said supporting means must be moved to effect such shadowing and alignment.