Radiographic measurement device

Claim 1

A device for aiding accurate measurement of the distance between two points within the body of a patient in conjunction with an imaging technique which produces a two-dimensional image that includes a representation of said distance, said two-dimensional image being produced by a beam passing through said body in a predetermined direction, said two points lying in a plane generally perpendicular to said predetermined beam direction, said device comprising: a planar scale having a series of opaque regions along the length of said scale, a boundary between each opaque region and the next opaque region being perpendicular to said length of said scale, and wherein there is a difference in opacity between each opaque region and the next adjacent opaque region, whereby distances along the length of said scale are accurately represented with reference to said boundaries, and a support attached to said scale and adapter for affixing said scale on the outside of said body, said support including a rigid member having a contact surface that is perpendicular to said plane of said opaque regions and adapted to rest against an external surface of said body so that, notwithstanding motion of said body, said opaque regions on said planar scale are held in the same plane as said two points and in a location such that said scale will be represented in said image, and a means for imparting in said image a visual indication of whether or not the orientation of the plane of said scale relative to the plane of said two-dimensional image is greater than a predetermined amount.

Claim 2

A device for aiding accurate measurement of the distance between two points within the body of a patient in conjunction with an imaging technique which produces a two-dimensional image that includes a representation of said distance, said two-dimensional image being produced by a beam passing through said body in a predetermined direction, said two points lying in a plane generally perpendicular to said predetermined beam direction, said device comprising: a planar scale having a series of opaque regions along the length of said scale, a boundary between each opaque region and the next opaque region being perpendicular to said length of said scale, and wherein there is a difference in opacity between each opaque region and the next adjacent opaque region, whereby distances along the length of said scale are accurately represented with reference to said boundaries, and a support attached to said scale and adapter for affixing said scale on the outside of said body, said support including a rigid member having a contact surface that is perpendicular to said plane of said opaque regions and adapted to rest against an external surface of said body so that, notwithstanding motion of said body, said opaque regions on said planar scale are held in the same plane as said two points and in a location such that said scale will be represented in said image, and a means for imparting in said image a visual indication of whether or not the orientation of the plane of said scale relative to the plane of said two-dimensional image is greater than a predetermined amount.