Non-circular emission computed tomography

Claim 2

In a radiographic imaging device of the type having a circularly rotatable scintillation detector adapted for emission computed tomography by orbiting about a subject, the improvement comprising: a) means for rotating said scintillation detector a predetermined angular increment along said circular orbit; b) means for displacing the subject relative to the center of radius of said circular orbit during at least a portion of said orbit; and ' c) synchronous control means in communicating relationship with said rotating means and said displacing means for controlling the sequence and duration of said rotation and displacement until a prescribed non-circular orbit is circumscribed by said scintillation detector with respect to said subject.

Claim 3

In a radiographic imaging device of the type having a circularly rotatable scintillation detector adapted for emission computed tomography and a movable base member adapted for area scanning studies, the improvement comprising: a) means for rotating said scintillation detector a predetermined angular increment along said circular orbit; b) means for moving said base member a predetermined linear increment; and c) synchronous control means in communicating relationship with said rotating means and said translating means for controlling the sequence and duration of said rotation and translation until a prescribed non-circular orbit is circumscribed by said scintillation detector.

Claim 4

In a radiographic imaging device of the type having a circularly rotatable scintillation detector adapted for emission computed tomography and a movable base member adapted for area scanning studies, the improvement comprising: a) means for rotating said scintillation detector a predetermined angular increment along said circular orbit; b) means for moving said base member a predetermined linear increment; and c) synchronous control means in communicating relationship with said rotating means and said translating means for controlling the sequence and duration of said rotation and translation until a prescribed non-circular orbit is circumscribed by said scintillation detector.

Claim 5

The apparatus according to claim 2 wherein said rotatinq means and said translating means are operable in unison.

Claim 6

The apparatus according to claim 2 wherein said rotating means and said translating means operate in alternating sequence.

Claim 7

5; In a curved beam apparatus for supporting and positioning a scintillation detector to a desirable location relative to a subject to detect radiation emitted by said subject for subsequent reconstruction into a -tomogram, said apparatus including a generally C-shaped support member having means for pivotally supporting the scintillation detector at one end portion thereof, a rotatable carrier member slidably engaging said support member for retaining said support member and permitting orbital movement of said support member along a circular path about a section of the subject, the radius of said circular path being determined by the position of said support member relative to said carrier member, a base member for rotatably supporting said carrier member and means for providing linear translation of said base member, the improvement comprising: a) rotational control means coupled to said carrier member for rotating said scintillation detector a predetermined angular increment along a circular orbit; b) translational control means coupled to said base member for translating said scintillation detector a predetermined incremental linear distance between a first and a second end point; and c) synchronous control means in communicating relationship with said rotational control means and said translational control means for coordinating said rotation and translation until a prescribed non-circular orbit is circumscribed by said scintillation detector about a section of the subject.

Claim 8

5; In a curved beam apparatus for supporting and positioning a scintillation detector to a desirable location relative to a subject to detect radiation emitted by said subject for subsequent reconstruction into a -tomogram, said apparatus including a generally C-shaped support member having means for pivotally supporting the scintillation detector at one end portion thereof, a rotatable carrier member slidably engaging said support member for retaining said support member and permitting orbital movement of said support member along a circular path about a section of the subject, the radius of said circular path being determined by the position of said support member relative to said carrier member, a base member for rotatably supporting said carrier member and means for providing linear translation of said base member, the improvement comprising: a) rotational control means coupled to said carrier member for rotating said scintillation detector a predetermined angular increment along a circular orbit; b) translational control means coupled to said base member for translating said scintillation detector a predetermined incremental linear distance between a first and a second end point; and c) synchronous control means in communicating relationship with said rotational control means and said translational control means for coordinating said rotation and translation until a prescribed non-circular orbit is circumscribed by said scintillation detector about a section of the subject.

Claim 9

In the apparatus according to claim 5 wherein said rotational control means includes means for controlling the rotational velocity of said carrier member during an incremental rotation and said-translational control means includes means for controlling the translational velocity of said base member during an incremental linear translation.

Claim 10

In the apparatus according to claim 5 or claim 6 wherein said non-circular orbit is traced out in intermittent increments with each increment having at least one of an angular and a linear component and wherein radiation is detected in time between increments.

Claim 11

8 . In the apparatus according to any one of claims 5 to 7 wherein said non-circular orbit is a step wise alternating linear/circular approximation of an ellipse.

Claim 14

In the method according to claim 9 wherein the relative path of said scintillation detector approximates the boundary of the patient at the tomographic section being studied and wherein the distance between the scintillation detector and the patient is relatively short and generally approximately constant during the path.