MULTIPLATE FOCUSING COLLIMATOR

• US 3,869,615 A
• Filed: 06/28/1973
• Issued: 03/04/1975
• Est. Priority Date: 06/28/1973
• Status: Expired due to Term

• Current Assignee: James H. Underwood, Richard B. Hoover
• Original Assignee: James H. Underwood, Richard B. Hoover
• Inventors: Hoover, Richard B., Underwood, James H.
• Primary Examiner(s): Lawrence, James W.
• Assistant Examiner(s): Anderson, B. C.
• Application Number:
  US05/374,441
• Time in Patent Office: 614 Days
• Field of Search: 250/355,508,505,513,482,510
• US Class Current: 378/146
• CPC Class Codes: G01T 1/166 involving relative movement between detector and subject scanners in general without using scintigraphy G01T1/2964
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation

Abstract

An appartus for scanning relatively small near sources of penetrating radiation to obtain the energy distribution thereof, wherein a collimator assembly is interposed between a radiation source and a radiation detector. The collimator assembly has a plurality of plates aligned in parallel planes with respect to a common axis normal to their centers. All the plates have similar random distribution of apertures. All apertures on each plate are the same size. The size of respective plates, the size of the apertures of said respective plates, and the spacing between said respective plates vary precisely according to a predetermined ratio to produce radiation channels which converge to a focal point through corresponding ones of the similar random distribution of apertures of the plates. The radiation incident to the radiation detector is maximized when the focal point and the radiation source are coincident.

Claims

1. In an apparatus for scanning small near sources of penetrating radiation to obtain the energy distribution thereof, wherein a collimator assembly is interposed between a radiation source and a radiation detector, the improvement comprising:

a collimator assembly having a plurality of similar plates aligned in parallel planes, said plates having a common axis through all their respective centers, said axis being normal to said parallel planes;

each said plate having a plurality of apertures the same size, the plurality of apertures on each said plate having a similar random distribution;

the relative size of said plates and the spacing between said respective plates being arranged to produce radiation channels which converge to a focal point through corresponding ones of the similar random distribution of apertures of the plates, the diameter of the apertures and the length of the sides of said respective plates being directly proportional to the distance from said respective plates to the said focal point, the radiation incident on the radiation detector being maximized when the said focal point and the radiation source coincide.

2. The apparatus as recited in claim 1 further comprising:

support means to maintain the plurality of plates in aligned position, and spacing means interposed between successive plates to maintain the required spacing therebetween to satisfy the predetermined ratio.

3. The apparatus as recited in claim 1 wherein the ratio of the diameters of the apertures of any two plates is equal to the ratio of the corresponding sides, respectively, of the same two plates.

4. The apparatus as recited in claim 1 wherein the ratio of the distance from said focal point to a first plate to the distance from said focal point to a second plate is equal to the ratio of the length of a side of said first plate to the length of the corresponding side of said second plate.

5. The apparatus as recited in claim 4 further comprising:

support means to maintain the plurality of plates in aligned position, and spacing means interposed between successive plates to maintain the required spacing therebetween to satisfy the predetermined ratio.

6. A collimator assembly for pentrating radiation comprising:

a plurality of similar plates aligned in parallel planes, said plates having a common axis through their centers, normal to said parallel planes, each said plate having a plurality of equal-sized apertures arranged in a similar random distribution;

the relative size of said plates and the spacing between said plates being arranged to produce radiation channels which converge to a focal point through corresponding apertures of said plates;

the diameter of the apertures and the length of the sides of said respective plates being directly proportional to the distance from said focal point to said respective plates.

7. The collimator assembly recited in claim 6 further comprising:

support means to maintain the plurality of plates in aligned position, and spacing means interposed between successive plates to maintain the required spacing therebetween to satisfy the predetermined ratio.

8. The collimator assembly as recited in claim 6 wherein the ratio of the diameters of the apertures of any two plates is equal to the ratio of the corresponding sides, respectively, of the same two plates.

9. The collimator assembly as recited in claim 6 wherein the ratio of the spacings between the focal point and the plane of any two plates is equal to the ratio of the aperture diameters of corresponding plates.

10. The collimator assembly recited in claim 9 further comprising:

support means to maintain the plurality of plates in aligned position, and spacing means interposed between successive plates to maintain the required spacing therebetween to satisfy the predeterminEd ratio.