Anti scatter radiation grid for a detector having discreet sensing elements

• US 6,366,643 B1
• Filed: 10/04/2000
• Issued: 04/02/2002
• Est. Priority Date: 10/29/1998
• Status: Expired due to Fees

• Current Assignee: Direct Radiography Corp. (Hologic Incorporated)
• Original Assignee: Direct Radiography Corp. (Hologic Incorporated)
• Inventors: Lee, Denny L. Y., Davis, James E.
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): SONG, HOON K
• Application Number:
  US09/679,234
• Time in Patent Office: 545 Days
• Field of Search: 378/154, 378/164, 378/205
• US Class Current: 378/154
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation
• CPC Class Codes: G21K 1/10 Scattering devices; Absorbing devices; Ionising radiation filters

Abstract

A shielding grid constructed of a radiation absorbing material for use with an array of discreet, non contiguous radiation sensors to protect such sensors from scattered radiation. The sensors each have a radiation sensitive area with a width and a length. In designing the grid a prototile having a prototile width and a prototile length is developed. The prototile width is equal to the radiation sensitive area width divided by an integer and the prototile length is also equal to the radiation sensitive area length divided by a integer. The prototile contains a motif contained solely within the prototile that forms a pattern when a plurality of prototiles sufficient to cover the array of discreet sensor are arrayed contiguously. The grid is constructed with the radiation absorbing material in this pattern.

Claims

1. A scattered radiation shielding grid comprising a radiation absorbing material representing a pattern corresponding to a combined motif of a plurality of tiled prototiles, each prototile comprising a width W(p), a length and a motif solely within the prototile, wherein the prototile width W(p)=W/(I±

0.05I) and W(p)≠

W+D, where W is a radiation sensitive area width of a radiation sensor of a radiation detection panel comprising a plurality of equal size radiation sensors separated by interstitial spaces having a width D, over which said grid is positioned, and I is an integer.

2. The scattered radiation grid according to claim 1 wherein W(p)=W/I.

3. A scattered radiation shielding grid comprising a radiation absorbing material, and a radiation detection panel over which said grid is positioned comprising a plurality of equal size radiation sensors having a radiation sensitive area width W, separated by radiation insensitive interstitial spaces having a width D, and wherein said grid absorbing material forms a pattern representing a combined motif of a tiled plurality of substantially identical prototiles, each prototile comprising:

(a) a width W(p)=W/I, wherein I is an integer;

(b) a length; and

(c) a motif contained solely within the prototile.

4. The scattered radiation grid and detection panel according to claim 3 further comprising a gain correction circuit associated with said detection panel and wherein W(p)=W/(I±

0.05I) and W(p)≠

W+D.

5. The scattered radiation grid and detection panel according to claim 4 further comprising a radiation source and said grid is positioned between said panel and said radiation source at a fixed, known distance from said panel, wherein said prototile width W(p) is a projected prototile width on said panel.

6. A method for designing a pattern for absorption material for a scattered radiation shielding grid for a radiation detection panel comprising an array of a plurality of sensors each having a radiation sensitive area having a width W and a length, the sensors arrayed so that each radiation sensitive area is separated by each adjacent radiation sensitive area by an interstitial space having a width D, the method comprising:

a) determining a sensor width corresponding to the width of the radiation sensitive area of the sensor

b) creating a prototile having a width W(p)=W/I wherein I is an integer;

c) producing within said prototile a motif and

d) tiling a plurality of said prototiles to produce the pattern, said pattern consisting of the combined motif of the tiled prototiles.

7. A method for manufacturing a scattered radiation shielding grid comprising a pattern of radiation absorbing material for a radiation detection panel comprising an array of a plurality of sensors each having a radiation sensitive area having a width W and a length, the sensors arrayed so that each radiation sensitive area is separated by each adjacent radiation sensitive area by an interstitial space having a width D, the method comprising:

a) determining a sensor width W corresponding to the width of the radiation sensitive area of the sensor

b) creating a prototile having a width W(p)=W/(I±

0.05I), W(p)≠

W+D and wherein I is an integer;

c) producing within said prototile a motif;

d) tiling a plurality of said prototiles to produce a pattern consisting of the combined motif of the tiled prototiles;

e) forming said radiation absorbing material in said grid in the shape of said combined motif.

8. The method according to claim 7 wherein in step (b) the prototile width:

W(p)=W/I.

9. A method for generating a radiogram with an exposure system comprising radiation source, and a radiation detection panel, wherein said radiation detection panel comprises an array of a plurality of sensors each having a radiation sensitive area having a width W and a length, the sensors arrayed so that each radiation sensitive area is separated by each adjacent radiation sensitive area by an interstitial space having a width D, the method comprising:

positioning between said radiation source and said panel a grid comprising a radiation absorbing material formed in a pattern representing a combined motif of a plurality of substantially identical tiled prototiles, each prototile comprising a width W(p), a length and said motif, said motif contained solely within the prototile, wherein the prototile width W(p)=W/I where I is an integer.

10. The method of producing a radiogram according to claim 9 wherein said system further comprises a gain correction circuit, said prototile width W(p)=W/(I±

0.05I), W(p)≠

W+D and wherein after positioning the grid between said source and said panel there is performed a calibration step comprising exposing the panel to radiation through said grid and adjusting said gain correction circuit to produce a uniform output from all sensors in said panel.