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US3909616A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for checking the superimposition of an x-ray field and a lightfield

Assignee: ELSCINT IMAGING Inc
•
Filing: 1974-09-16
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Granted: 1975-09-30
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Expires: 1994-09-16
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Abstract

Abstract A method and apparatus is disclosed for checking the alignment of various interfaced components in a conventional x-ray system. The disclosed method functions to verify the coincidence of the x-ray field, emanating from the x-ray apparatus, with the target lightfield, projecting from the x-ray collimator. If these two fields are coincident within an allowable tolerance, the x-ray apparatus, collimator and film cassette carrier are properly aligned for that particular source-to-image distance. The apparatus includes a plurality of target plates having a width equal to the allowable tolerance for the particular source-toimage distance. The method includes the steps of projecting the lightfield over the target area, and centrally positioning the plurality of target plates on the peripheral edges of the lightfield. An x-ray beam is then projected onto the film located in the target area. The exposed x-ray film is then examined to determine whether a portion of each of the target plates is located on the x-ray field. If one or more of the target plates is not located on the exposed x-ray film, the x-ray field is not superimposed on the lightfield within the allowable tolerance. The x-ray apparatus is then realigned with the collimator and the test procedure is repeated until a portion of all four target plates is located on the exposed x-ray film to denote proper alignment.

Inventors

  • 👤 Charles L Redfield
  • 👤 Robert G Schultz
  • 👤 Art Arne Van

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 10:03
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/58; A61B6/587; A61B6/08; G; G03; G03B; G03B42/00; G03B42/02; G03B42/025

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 166 words
In an x-ray system which includes a target area having a film cassette mounted thereon, an x-ray apparatus having a source of x-rays, located a specific distance from said target area, for emitting a beam of x-rays onto said target area, and a collimator having a light emitter for projecting a light beam onto said target area, a method for checkIng the superimposition of the x-ray field and the lightfield on said target area comprising the steps of: projecting a lightfield on said target area; positioning a plurality of target pieces on the outline of said lightfield, said target pieces each having a pair of indices equal to the allowable tolerance of the x-ray field position with respect to the lightfield position at the specific source-to-target area distance; projecting an x-ray field onto said target area; and developing and examining said exposed film located on said target area to determine whether a portion of each target piece is located on the outline of the x-ray field.
Claim 2
Dependent Claim 166 words
In an x-ray system which includes a target area having a film cassette mounted thereon, an x-ray apparatus having a source of x-rays, located a specific distance from said target area, for emitting a beam of x-rays onto said target area, and a collimator having a light emitter for projecting a light beam onto said target area, a method for checkIng the superimposition of the x-ray field and the lightfield on said target area comprising the steps of: projecting a lightfield on said target area; positioning a plurality of target pieces on the outline of said lightfield, said target pieces each having a pair of indices equal to the allowable tolerance of the x-ray field position with respect to the lightfield position at the specific source-to-target area distance; projecting an x-ray field onto said target area; and developing and examining said exposed film located on said target area to determine whether a portion of each target piece is located on the outline of the x-ray field.
Claim 3
Dependent Claim 21 words
The method of claim 1 wherein each target piece is centrally positioned on the lines forming the outline of said lightfield.
Claim 4
Dependent Claim 30 words
The method of claim 1 wherein said lightfield is square or rectangular and one target piece is positioned on each of the four lines forming the outline of said lightfield.
Claim 5
Dependent Claim 27 words
The method of claim 1 further including the step of mounting a piece of paper over said target area to enable the lightfield to be more visible.
Claim 6
Dependent Claim 111 words
In an x-ray system which includes a target area having a film cassette mounted thereon, an x-ray apparatus having a source of x-rays, located a specific distance from said target area, for emitting a beam of x-rays onto said target area, and a collimator having a light emitter for projecting a light beam onto said target area, an apparatus for checking the superimposition of the x-ray field and the lightfield on said target area comprising: a plurality of target pieces, said target pieces each having a pair of indices equal to the allowable tolerance of the x-ray field position with respect to the lightfield position at the specific source-to-target area distance.
Claim 7
Dependent Claim 111 words
In an x-ray system which includes a target area having a film cassette mounted thereon, an x-ray apparatus having a source of x-rays, located a specific distance from said target area, for emitting a beam of x-rays onto said target area, and a collimator having a light emitter for projecting a light beam onto said target area, an apparatus for checking the superimposition of the x-ray field and the lightfield on said target area comprising: a plurality of target pieces, said target pieces each having a pair of indices equal to the allowable tolerance of the x-ray field position with respect to the lightfield position at the specific source-to-target area distance.
Claim 8
Dependent Claim 17 words
The combination of claim 5 wherein each target piece has a width equal to said allowable tolerance.
Claim 9
Dependent Claim 13 words
The combination of claim 5 wherein each target piece is a rectangular plate.
Claim 10
Dependent Claim 21 words
The combination of claim 5 wherein each target piece includes a pair of centering notches bisecting the width of each piece.
Claim 11
Dependent Claim 13 words
The combination of claim 5 wherein the plurality of target pieces number four.

References Cited (Backward Citations)

US3156824A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-09-29 1979-03-31 1979-09-30 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-09-29 1983-03-31 1983-09-30 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-09-29 1987-03-31 1987-09-30 $7700.00 Window Closed / Lapsed

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