Aperture device of radiation diagnostic apparatus

Claim 2

An aperture device of a radiation diagnostic apparatus which defines first (64) and second (66) radiation beams emitted from two radiation focal points (R, L) spaced apart from each other along a first direction (2), comprising: first (72a) and second (80) blades, made of a radiation shielding material, for respectively defining two edges of the first radiation beam along the first direction; third (74) and fourth (82) blades, made of a radiation shielding material, for respectively defining two edges of the second radiation beam along the first direction; and fifth (76) and sixth (78) blades, made of a radiation shielding material, for respectively defining two edges of each of the first and second radiation beams along the second direction; characterized in that the first (72a), second (80), third (74) and fourth (82) blades are movable along the first direction (2) and the fifth (76) and sixth (78) blades are movable along the second direction (4), and characterized by comprising first and second driving means (112, 114, 104, 106, 118, 156, 152, 154, 160) for respectively driving said first and second blades; third and fourth driving means (116, 104, 106, 118, 158, 152, 154, 160) for respectively driving said third and fourth blades; and fifth and sixth drive means (142, 144, 134, 136, 146) for respectively driving said fifth and sixth blades, whereby the first radiation beam is defined by said first, second, fifth and sixth blades in a rectangular shape, and the second radiation beam is defined by said third, fourth, fifth and sixth blades in a rectangular shape.

Claim 3

A device according to claim 1, characterized in that each of said first to sixth drive means comprises: a pair of screw rods (104, 106, 134, 136, 152, 154) each having a round portion (108) and a screw portion (110), said pair of screw rods being parallel to each other in such a manner that said round and screw portions of one of said pair of screw rods oppose those of the other thereof; a first engaging portion (114, 116, 144, 158) into which said screw portion is screwed; a second engaging portion (112, 142, 156) slidably fitted around said round portion so as to support a corresponding one of said first to sixth blades together with said first engaging portion; and a motor (118, 146, 160) for rotating the screw rod engaged with the first engaging portion; whereby said corresponding one of said first to sixth blades is moved parallel to said pair of screw rods upon rotation of said motor and hence a corresponding one of said pair of screw rods.

Claim 4

A device according to claim 2, characterized in that said motor comprises a stepping motor (112, 142, 156).

Claim 5

A device according to claim 3, characterized by further comprising: a drive circuit (240) for generating a pulse for activating said stepping motor (112, 142, 156); a counter (242) for counting an output pulse from said drive circuit; a sensor (132, 150, 164) for supplying a detection signal to said counter when the corresponding one of said first to sixth blades is moved to a predetermined position, thereby clearing a count of said counter; and a central processing unit (250) for calculating a distance from the predetermined position of said corresponding blade in accordance with the count of said counter.

Claim 6

A device according to claim 1, characterized by further comprising: a seventh blade (84) made of a radiation shielding material and having two radiation transmission holes (176, 178) formed at positions spaced apart from each other along the first direction; and seventh drive means (174, 166, 168, 180) for driving said seventh blade between a withdrawn position and a beam shielding position where said seventh blade is located in an optical path of the radiation beam, the radiation beam being defined to form a circular radiation spot when said seventh blade is located in the beam shielding position.

Claim 7

A device according to claim 5, characterized in that said seventh drive means comprises: a pair of screw rods (166, 168) each of which has a round portion (108) and a screw portion (110), said pair of screw rods being parallel to each other in such a manner that said round and screw portions of each of said pair of screw rods oppose those of the other thereof; a third engaging portion (174) into which said screw portion is screwed; a fourth engaging portion slidably fitted around said round portion so as to support the corresponding blade together with said third engaging portion; and a motor (180) for rotating the screw rod (168) engaged with the third engaging portion (174); whereby said third and fourth engaging portions and said corresponding blade are moved parallel to said pair of screw rods upon rotation of said motor and hence a coresponding one of said screw rods.

Claim 8

A device according to claim 6, characterized in that said motor comprises a stepping motor (180).

Claim 9

A device according to claim 1, characterized by further comprising a compensation filter mechanism (210), said compensation filter mechanism having: a rotatable base (202) having a window (208) through which the radiation passes; base drive means (192, 194, 200, 204, 206) for rotating said base; a pair of filters (86, 88) arranged in said window (208) of said base (202) and made of a radiation shielding material, said filters having opposing edges which constitute the shape of a heart; and filter drive means (216, 218, 219, 220, 222 - , 224, 226) for moving said filters relative to said base, said filters being moved to come closer to or separate from each other, whereby said filters are moved closer to each other in order to prevent a halation at a lung portion when cardiac angiography is performed.

Claim 10

A device according to claim 8, characterized in that said filter drive means comprises: a round rod (219); a screw rod (216) which is parallel to the round rod; a motor (222) for rotating the screw rod; a fifth engaging portion (220) slidably fitted around the round rod; and a sixth engaging portion (218) into which said screw rod is screwed so as to support a corresponding one of said filters together with said fifth engaging portion, wherein the fifth and sixth engaging portions and the corresponding filter are moved parallel to the round rod and screw rod upon rotation of said motor.

Claim 11

A device according to claim 1, characterized in that said first to sixth blades comprise lead plates or lead-containing acrylic resin plates.

Claim 12

A device according to claim 1, characterized by further comprising: an ear (120) formed in said first blade (72a), said ear having a notch (122) extending along the first direction (2); an auxiliary blade (72b), a lock portion (130) formed in said auxiliary blade so as to engage with said notch of said ear; and auxiliary blade supporting means (124, 126, 128) for supporting said auxiliary blade so as to move in the first direction, whereby said auxiliary blade is moved by said lock portion engaged with said notch in the first direction when said first blade is moved in the first direction.

Claim 13

A device according to claim 1, which is adapted to define first (64) and second (66) radiation beams which are irradiated on an image receiving surface after being transmitted through a patient, characterized by further comprising detecting means (260, 262, 242) for detecting a distance SID from the focal points of the radiation beams to the image receiving surface, a distance H from said focal points of the radiation beams to the patient and apertures W of the first through the sixth blades, a calculating circuit (250) for calculating radiation areas at the image receiving surface and the patient on the basis of the distances SID and H and the apertures W, and display means (268, 270) for displaying the radiation areas at the image receiving surface and the patient.

Claim 14

An aperture device of a radiation diagnostic apparatus which defines edges of radiation beam (66) along a first direction (2) and a second direction (4) cross thereto, which is emitted from a focal point and irradiated on an image receiving surface after being transmitted through a patient, comprising: first (74) and second (82) blades, made of a radiation shielding material and movable along the first direction (2), for respectively defining two edges of the radiation beam along the first direction; first and second driving means (116, 104, 106, 118, 158, 152, 154, 160) for respectively driving said first and second blades; third (76) and fourth (78) blades, made of a radiation shielding material and movable along the second direction (4), for respectively defining the edges of the radiation beam along the second direction; third and fourth drive means (142, 144, 134, 136, 146) for respectively driving said third and fourth blades, whereby the radiation beam is defined by said first, second, third and fourth blades in a rectangular shape; characterized by comprising detecting means (260, 262) for detecting a distance SID from the focal point of the radiation beam to the image receiving surface, a distance H from said focal point of the radiation beam to the patient and apertures W of the first through the fourth blades; a calculating circuit (250) for calculating radiation areas at the image receiving surface and the patient on the basis of the distances SID and H and the apertures W; and display means (270) for displaying the radiation areas at the image receiving surface and the patient.

Claim 15

An aperture device of a radiation diagnostic apparatus which defines edges of radiation beam (66) along a first direction (2) and a second direction (4) cross thereto, which is emitted from a focal point and irradiated on an image receiving surface after being transmitted through a patient, comprising: first (74) and second (82) blades, made of a radiation shielding material and movable along the first direction (2), for respectively defining two edges of the radiation beam along the first direction; first and second driving means (116, 104, 106, 118, 158, 152, 154, 160) for respectively driving said first and second blades; third (76) and fourth (78) blades, made of a radiation shielding material and movable along the second direction (4), for respectively defining the edges of the radiation beam along the second direction; third and fourth drive means (142, 144, 134, 136, 146) for respectively driving said third and fourth blades, whereby the radiation beam is defined by said first, second, third and fourth blades in a rectangular shape; characterized by comprising detecting means (260, 262) for detecting a distance SID from the focal point of the radiation beam to the image receiving surface, a distance H from said focal point of the radiation beam to the patient and apertures W of the first through the fourth blades; a calculating circuit (250) for calculating radiation areas at the image receiving surface and the patient on the basis of the distances SID and H and the apertures W; and display means (270) for displaying the radiation areas at the image receiving surface and the patient.