Servo controlled isocenter diagnostic x-ray examination apparatus

A diagnostic X-ray apparatus, comprising:

• a C-shaped arm member having an arc portion and for supporting an X-ray source for radiating an X-ray to an object and a detector for detecting the X-ray transmitted through the object, the X-ray source and the detector mounted at ends of the C-shaped arm member so as to face each other with the object therebetween;
• an arm holder for supporting said C-shaped arm member such that said arm member can be slid along the arc portion and rotated around a horizontal axis contained in a plane of said arm member so as to change a directional relationship between the X-ray tube and the object, the X-ray apparatus having an isocenter at an intersection of a line connecting the X-ray source and the detector, and said horizontal axis;
• a vertical suspension pole, offset from said isocenter such that an axis of said suspension pole is without an intersection with said isocenter, for suspending said arm holder from a ceiling;
• means for moving said suspension pole within a ceiling plane in an X direction;
• means for moving said suspension pole within a ceiling plane in a Y direction, parallel to said X direction;
• rotating means for rotating said suspension pole and thereby rotating said arm holder and said C-shaped arm member;
• means for detecting an angle .theta. of the suspension pole;
• means for setting a velocity of the suspension pole in the X and Y directions such that as the angle .theta. of the suspension pole changes, the isocenter remains in substantially a same position, the means for setting a velocity including:
• means for setting the velocity in the X direction such that:
• Velocity.sub.x =K.sub.x *(X-X.sub.o)
• and the velocity in the Y direction is set such that:
• Velocity.sub.y =K.sub.y * (Y-Y.sub.o)
• where K.sub.x is a constant, X is a detected position in the X direction and Xo is predetermined locus data, and K.sub.y is a constant, Y is a detected position in the Y direction and Yo is a predetermined locus position.