Laser targeting device for use with image intensifiers in surgery

A laser targeting device for use during surgical procedures and adapted for attachment to an x-ray image intensifier comprising:

• a. a laser light source and laser beam directing means for a laser beam emanating therefrom adapted to permit continuously variable reciprocating motion in the x-y plane about the z axis and in the x-z plane about the y axis but substantially excluding motion in the y-z plane about the x axis, said directing means being additionally adapted to provide mounting means for said laser light source;
• b. a housing for said laser light source and said directing means adapted by the provision of mounting means such that said housing is always outside that part of the path of an x-ray beam produced by an x-ray source cone and which impinges upon the working area of the target head or receiver of said image intensifier;
• c. a case characterized by upper and lower bounding surfaces disposed in a substantially flat and parallel manner and spaced apart by a wall suitably adapted by the provision of a hole constituting aperture means and receival means suitably disposed about said aperture means for the attachment of said mounting means of said housing, said aperture means being so sized as to permit the entry of said laser beam to the interior of said case which is adapted by the provision of adjustable mounting means which cooperate with clamping means for attachment of said laser targeting device to said target head such that said flat upper bounding surface is permitted to lie substantially flush against said target head of said image intensifier, said case being further adapted by the provision of a further hole located substantially centrally in said lower bounding surface and which is adapted to receive;
• d. a plain substantially parallel sided transparent window to fit accurately said hole in said lower bounding surface said window constituting part of an assembly providing mounting means for a reflecting mirror disposed at an angle of 45 degrees to the plane in which said lower bounding surface of said case lies and also at 45 degrees to said x axis of said directing means such that when said laser beam is directed along said x-axis, through said aperture means into said case said mirror redirects said laser beam through said window along a path normal to it, said assembly being constructed from a small mass of thin walled substantially radiolucent materials and adapted to receive within that part of it which lies directly behind said mirror, a target;
• said adjustable mounting means of said case permitting limited variation in the disposition of the axis normal to the centre of said window about an axis normal to the geometric centre of said target head of said image intensifier, that part of said upper and said lower bounding members of said case which overlie the working area of said target head being substantially radiolucent;
• e. substantially radio-opaque target means so positioned behind said mirror within said assembly that a ray path normal to the window, if extended backwards through said mirror would pass centrally through said target means;
• and
• f. separate calibrating means in the form of a radio-opaque marker within a suitable housing and marking guide such that when said calibration means is applied to the source cone, the point of emanation of an x-ray beam therefrom may be determined and marked,
• Said means being adapted to co-operate together such that said laser beam may be rendered substantially co-axial with said x-ray beam directed towards said target head to which said laser targeting device is attached such that the path of said x-ray beam may be illuminated at its point of impingement upon an object interposed between said source cone and said target of said x-ray beam and further providing a visible reference point corresponding to the effective centre of said x-ray beam on a monitor screen with said x-ray image intensifier.