Aperture, collimator, and x-ray tomographic imaging apparatus

A collimator having an aperture for defining an extent of X-rays in a body-axis direction and used in an X-ray togomoraphic imaging apparatus, said X-ray togomoraphic imaging apparatus comprising:

• an X-ray tube;
• and
• an X-ray detector having a plurality of detector elements arranged in first and second directions, said first direction (10) being along a circumference of a first circle with radius r1 around a focal spot of said X-ray tube in a first plane (XY-plane) perpendicular to said body-axis direction, and said second direction (20) being parallel to said body-axis direction, said aperture comprising:
• a first blocking member for blocking X-rays;
• a second blocking member disposed in said second direction with respect to said first member, for blocking X-rays, wherein each of said first and second blocking members has:
• a first edge formed on a first arc lying on a circumference of a second circle with radius r2 (<r1) around the focal spot of said X-ray tube in said first plane (XY-plane);
• a second edge connected to one endpoint of said first edge, said second edge being formed to lie on a side of said X-ray detector with respect to a second arc lying on the circumference of said second circle and contiguous with said first arc;
• and
• a third edge connected to another endpoint of said first edge, said third edge being formed to lie on the side of said X-ray detector with respect to a third arc lying on the circumference of said second circle and contiguous with said first circle on a side opposite to said second arc.

An X-ray togomoraphic imaging apparatus comprising:

• an X-ray tube;
• an X-ray detector having a plurality of detector elements arranged in first and second directions, said first direction (10) being along a circumference of a first circle with radius r1 around a focal spot of said X-ray tube in a first plane (XY-plane) perpendicular to a body-axis direction, and said second direction (20) being parallel to said body-axis direction;
• and
• an aperture defining an extent of X-rays in the body-axis direction, said aperture comprising:
• a first blocking member for blocking X-rays;
• a second blocking member disposed in said second direction with respect to said first member, for blocking X-rays, wherein each of said first and second blocking members has:
• a first edge formed on a first arc lying on a circumference of a second circle with radius r2 (<r1) around the focal spot of said X-ray tube in said first plane (XY-plane);
• a second edge connected to one endpoint of said first edge, said second edge being formed to lie on a side of said X-ray detector with respect to a second arc lying on the circumference of said second circle and contiguous with said first arc;
• and
• a third edge connected to another endpoint of said first edge, said third edge being formed to lie on the side of said X-ray detector with respect to a third arc lying on the circumference of said second circle and contiguous with said first circle on a side opposite to said second arc.