Tomography system having nonconcurrent, compound axial scanning

A method of successively scanning the interior section of a body with an X-ray beam for determining the coefficients of absorption or transmission at spaced points in a plane through the body, the beam emanating from a source and detected by a detector in a source-detector assembly which maintains the detector diametrically spaced about the body in beam receptive alignment with the source, the assembly being rotatable through a set of angles .gamma..sub.j about the body for orbiting the source and the detector through approximately 180.degree. about the body and being rotatable about the source through a set of angles .phi..sub.i, where i and j are series of integers, comprising the steps of:

• (a) rotating said assembly about the body through the angles .gamma..sub.j for a first preselected value of the angles .phi..sub.i ;
• (b) measuring the intensity of said beam at a first set of values of the angles .gamma..sub.j ;
• (c) after completion of said step of rotating, incrementally rotating the assembly about the source to a new value of the angle .phi..sub.i ;
• (d) re-rotating said assembly about the body through the angles .gamma..sub.j ;
• and,
• (e) during the step of re-rotating, measuring the intensity of the beam at a second set of values of the angles .gamma..sub.j, the values of said second set being different from the values of said first set.

A method of successively scanning the interior section of a body with an X-ray beam for determining the coefficients of absorption or transmission at spaced points in a plane through the body, the beam emanating from a source and detected by a detector in a source-detector assembly which maintains the detector diametrically spaced about the body in beam receptive alignment with the source, the assembly being rotatable through a set of substantially uniformly spaced angles .gamma..sub.j about the body for orbiting the source and the detector through approximately 180.degree. about the body and being rotatable about the source through a set of substantially uniformly spaced angles .phi..sub.i, where i and j are series of integers and the angles (.phi..sub.i+1, .phi..sub.i) are spaced by an amount .DELTA..phi., comprising the steps of:

• (a) rotating said assembly about the body through the angles .gamma..sub.j for a first preselected value of the angles .phi..sub.i ;
• (b) measuring the intensity of said beam at substantially each of the angles .gamma..sub.j ;
• (c) after completion of said step of rotating, rotating the assembly about the source by the amount .DELTA..phi.;
• (d) rotating said assembly about the body through the angles (.gamma..sub.j + .DELTA..phi.);
• and,
• (e) measuring the intensity of the beam at substantially each of the angles (.gamma..sub.j + .DELTA..phi.).

Apparatus for repetitiously scanning an interior section of a body with a beam of radiation which passses through spaced coplanar points in a plane containing the section comprising:

• (a) rotatable support structure providing a source axis transverse to said plane, the source axis being orbital through a sequence of angles .gamma..sub.j around an area in the plane including said origin, where j is a series of integers;
• (b) radiation source means rotatably coupled to said support structure for rotation through a sequence of substantially uniformaly spaced angles .phi..sub.i around said source axis, the radiation source means being orbital with the source axis and positioned to transmit a beam of radiation through a body having a section under investigation in said plane, said beam being of relatively small cross-sectional area compared to the body, where an angle .phi..sub.O references zero rotation of the beam about said source axis and i is at least one integer;
• (c) radiation detector means connected to the support structure and disposed for receiving said beam after it passes through the body under investigation;
• (d) control means coupled to said support means for effecting successive orbits of said source means through the angles .gamma..sub.j around said area and for establishing and maintaining said radiation source means at each of a series of different predetermined angles of rotation .phi..sub.j about said source axis during successive orbits;
• and,
• (e) data collection means, including said radiation detector means, for measuring intensity values of said beam at a first set of values of the angles .gamma..sub.j for the orbit during which the angle .phi..sub.i is a first value and for measuring intensity values of said beam at a second set of values of the angle .gamma..sub.j for another orbit during which the angle .phi..sub.i is a second value, the values of said first and second sets being different and said first and second values being different.

Apparatus for repetitiously scanning an interior section of a body with a beam of radiation which passes through substantially uniformly spaced coplanar points spaced about an origin in a plane containing the section comprising:

• (a) rotatable support structure providing a source axis transverse to said plane, the source axis being orbital through a sequence of angles .gamma..sub.j around an area in the plane including said origin, where j is a series of integers;
• (b) radiation source means rotatably coupled to said support structure for rotation through a sequence of substantially uniformly spaced angles .phi..sub.i around said source axis, the radiation source means being orbital with the source axis and positioned to transmit a beam of radiation through a body having a section under investigation in said plane, said beam being of relatively small cross-sectional area compared to the body, where an angle .phi..sub.0 references zero rotation of the beam about said source axis and i is at least one integer;
• (c) radiation detector means connected to the support structure and disposed for receiving said beam after it passes through the body under investigation;
• (d) control means coupled to said support means for effecting successive orbits of said source means through the angles .gamma..sub.j around said area and for establishing and maintaining said radiation source means at each of a series of different predetermined angles of rotation .phi..sub.i about said source axis during successive orbits;
• and,
• (e) data collection means, including said radiation detector means, for measuring intensity values of said beam at a first set of values of the angles .gamma..sub.j for the orbit during which the angles .phi..sub.i equals .phi..sub.0, and for measuring intensity values of said beam at a second set of values of the angles .gamma..sub.j for successive orbits, where the values of the first and second sets are equal.

Apparatus for repetitiously scanning an interior section of a body with a beam of radiation which passes through substantially uniformly spaced coplanar points spaced about an origin in a plane containing the section comprising:

• (a) rotatable support structure providing a source axis transverse to said plane, the source axis being orbital through a sequence of angles .gamma..sub.j around an area in the plane including said origin, where j is a series of integers;
• (b) radiation source means rotatably coupled to said support structure for rotation through a sequence of substantially uniformly spaced angles .phi..sub.i around said source axis, the radiation source means being orbital with the source axis and positioned to transmit a beam of radiation through a body having a section under investigation in said plane, said beam being of relatively small cross-sectional area compared to the body, where an angle .phi..sub.0 references zero rotation of the beam about said source axis and i is at least one integer;
• (c) radiation detector means connected to the support structure and disposed for receiving said beam after it passes through the body under investigation;
• (d) control means coupled to said support means for effecting successive orbits of said source means through the angles .gamma..sub.j around said area and for establishing and maintaining said radiation source means at each of a series of different predetermined angles of rotation .phi..sub.i about said source axis during successive orbits;
• and,
• (e) data collection means, including said radiation detector means, for measuring intensity values of said beam at substantially all of the angles .gamma..sub.j for the orbit during which the angles .phi..sub.i equals .phi..sub.0, and for measuring intensity values of said beam at substantially all of the angles [.gamma..sub.j + (.phi..sub.i -.phi..sub.0)] for successive orbits.