US4901335A — Mammography apparatus

Claim 1

Independent Claim 123 words

A method of performing a mammography examination on a human subject, the method comprising the steps of: generating x-rays from an x-ray source; exposing an image receptor to x-ray radiation from an x-ray source through a breast of the subject; suppressing scattered x-ray radiation produced in the breast relative to the image receptor with a slot grid of circular section centered on an axis through the x-ray source; moving the slot grid during the mammography examination to blur areas of negative density cast by the slot grid on the image receptor; and initiating and interrupting the generation of x-ray radiation during movement of the slot grid as a function of slot grid position to provide for cumulative homogeneous exposure of the image receptor.

Claim 2

Independent Claim 123 words

A method of performing a mammography examination on a human subject, the method comprising the steps of: generating x-rays from an x-ray source; exposing an image receptor to x-ray radiation from an x-ray source through a breast of the subject; suppressing scattered x-ray radiation produced in the breast relative to the image receptor with a slot grid of circular section centered on an axis through the x-ray source; moving the slot grid during the mammography examination to blur areas of negative density cast by the slot grid on the image receptor; and initiating and interrupting the generation of x-ray radiation during movement of the slot grid as a function of slot grid position to provide for cumulative homogeneous exposure of the image receptor.

Claim 3

Dependent Claim 32 words

The method of claim 1 wherein the step of moving the slot grid includes reciprocation of the slot grid along a circular travel centered on the focus spot of the x-ray source.

Claim 4

Dependent Claim 129 words

A radiographic apparatus comprising: a source of x-ray radiation; the ratio of the height of each of an adjacent pair of lamellae to the width of the respective defined gap being at least 7:1; a travel for the slot grid around the axis; and an x-ray source actuation controller including: means for indicating the position of the slot grid; means responsive to the means for indicating the position of the slot grid for enabling the generation of x-ray radiation such that the areas of negative density cast by the lamellae on an image receptor at the moment of interruption of x-ray generation substantially abut, but do not overlap the areas of negative density cast by the lamellae on the image receptor at the moment of initiation of x-ray generation.

Claim 5

Dependent Claim 129 words

A radiographic apparatus comprising: a source of x-ray radiation; the ratio of the height of each of an adjacent pair of lamellae to the width of the respective defined gap being at least 7:1; a travel for the slot grid around the axis; and an x-ray source actuation controller including: means for indicating the position of the slot grid; means responsive to the means for indicating the position of the slot grid for enabling the generation of x-ray radiation such that the areas of negative density cast by the lamellae on an image receptor at the moment of interruption of x-ray generation substantially abut, but do not overlap the areas of negative density cast by the lamellae on the image receptor at the moment of initiation of x-ray generation.

Claim 6

Dependent Claim 29 words

The grid of claim 3 wherein the lamellae are disposed at a radial density of at least three and no more than six lamellae per cm. at the circumference.

Claim 7

Dependent Claim 19 words

The slot grid of claim 4 wherein the thickness of the lamellae is between 0.075 mm and 0.25 mm.

Claim 8

Dependent Claim 43 words

The slot grid of claim 5 and further including upper and lower polyester sheets enclosing the lamellae and air gaps, opposing faces of the upper and lower polyester sheets being substantially covered with an adhesive layer for affixing the sheets to the lamellae.

Claim 9

Dependent Claim 150 words

A mammography apparatus comprising: a source of x-ray radiation; a cylindrical section slot grid centered on an axis through the source of x-ray radiation; breast compression plates adapted to position a subject's breast between the source of x-ray radiation and the cylindrical section slot grid; an image receptor positioned to receive x-rays transmitted through the slot grid; the cylindrical section slot grid including a plurality of x-ray radiation absorbing lamellae disposed parallel to and aligned radially from the axis, the lamellae defining an x-ray transmitting air spaced gap between adjacent lamellae; a travel for the slot grid centered on the axis; a prime mover for moving the slot grid along its travel; and an x-ray source actuation controller responsive to the position of the slot grid while moving in its travel to control the periods of x-ray radiation generation to insure a substantially homogeneous cumulative exposure of the image receptor.

Claim 10

Dependent Claim 150 words

A mammography apparatus comprising: a source of x-ray radiation; a cylindrical section slot grid centered on an axis through the source of x-ray radiation; breast compression plates adapted to position a subject's breast between the source of x-ray radiation and the cylindrical section slot grid; an image receptor positioned to receive x-rays transmitted through the slot grid; the cylindrical section slot grid including a plurality of x-ray radiation absorbing lamellae disposed parallel to and aligned radially from the axis, the lamellae defining an x-ray transmitting air spaced gap between adjacent lamellae; a travel for the slot grid centered on the axis; a prime mover for moving the slot grid along its travel; and an x-ray source actuation controller responsive to the position of the slot grid while moving in its travel to control the periods of x-ray radiation generation to insure a substantially homogeneous cumulative exposure of the image receptor.

Claim 11

Dependent Claim 33 words

The mammography apparatus of claim 7 wherein the slot grid further includes at least 3 lamellae per centimeter around the circumference of the cylindrical section and no more than six lamellae per cm.

Claim 12

Dependent Claim 32 words

The mammography apparatus of claim 8 wherein the ratio of the height of each of an adjacent pair of lamellae to the width of the respective defined gap is at least 7:1.

Claim 13

Dependent Claim 20 words

The mammography apparatus of claim 9 wherein the thickness of the lamellae is between about 0.075 mm and 0.25 mm.

Claim 14

Dependent Claim 53 words

The mammography apparatus of claim 7 wherein the slot grid further includes upper and lower polymeric sheets of not greater than 0.17 mm thickness enclosing the lamellae and air gaps, opposing faces of the upper and lower polymeric sheets being substantially covered with an adhesive layer for affixing the sheets to the lamellae.

Claim 15

Dependent Claim 38 words

The mammography apparatus of claim 7 and further including a lower breast support plate and an upper breast compression plate, the support plate and the compression plate being formed of polymeric sheets of between 0.025 and 0.127 mm.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-02-12	1993-08-14	1994-02-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-02-12	1997-08-14	1998-02-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-02-12	2001-08-14	2002-02-13	$7700.00	Window Closed / Lapsed

Mammography apparatus

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