Method and apparatus for X-ray irradiation having improved throughput and dose uniformity ratio

• US 6,940,944 B2
• Filed: 09/08/2003
• Issued: 09/06/2005
• Est. Priority Date: 09/08/2003
• Status: Expired due to Fees

• Current Assignee: Ion Beam Applications s.a.
• Original Assignee: Ion Beam Applications s.a.
• Inventors: Stichelbaut, Frederic
• Primary Examiner(s): Church, Craig E.
• Assistant Examiner(s): Artman, Thomas R.
• Application Number:
  US10/658,492
• Publication Number:
  US 20050053194A1
• Time in Patent Office: 729 Days
• Field of Search: 378/64, 378/66, 378/68, 378/69
• US Class Current: 378/68
• CPC Class Codes: A61L 2/082 X-rays
• CPC Class Codes: A61L 2202/24 Medical instruments, e.g. endoscopes, catheters, sharps
• CPC Class Codes: B65B 55/16 by irradiation
• CPC Class Codes: G21K 5/04 with beam-forming means

Abstract

The present invention is related to a method and apparatus of radiation processing of a product package in a device having a radiation source, a collimator having a variable aperture, and a turntable, said radiation processing resulting in a point in the product package where the dose is minimal (D_min point) and a point in said product package where the dose is maximal (D_max point) comprising the steps of:

• • determining a first value of the collimator aperture, by increasing said aperture from a small value, where the D_max point is located near the centre of the product package, up to a value where the D_max point moves near to the centre of a small side of said package'"'"'s rectangular horizontal cross-section;
  • determining a second value of the collimator aperture, by further increasing the collimator aperture up to a point where the D_min point moves from a point near the corner of the product package to the centre of said package;
  • processing said package with radiation, the collimator aperture being kept at a constant value comprised between said first and said second value, the turntable being rotated at a variable speed.

Claims

1. A method of radiation processing of a product package o of essentially equal rectangular size in a device having a radiation source, a collimator having a variable aperture, and a turntable, said radiation processing resulting in a point in the product package where the dose is minimal (D_min point) and a point in said product package where the dose is maximal (D_max point) comprising the stops of:

determining a first value of the collimator aperture, by increasing said aperture from a small value, where the D_max point is located near the centre of the product package, up to a value where the D_max point moves near to the centre of a small side of said package'"'"'s rectangular horizontal cross-section;

determining a second value of the collimator aperture, by further increasing the collimator aperture up to a point where the D_min point moves from a point near the corner of the product package to the centre of said package;

processing said package with radiation, the collimator aperture being kept at a constant value comprised between said first and said second value, the turntable being rotated at a variable speed.

2. The method according to claim 1, wherein the collimator aperture is selected as being said second value.

3. The method according to claim 1, wherein said product package has a mean density between 0.4 and 0.8 g/cm³.

4. Apparatus for radiation processing of package of essentially equal rectangular size, comprising a radiation source, a collimator having a variable aperture, and a turntable, adapted for supporting one of said packages during said radiation processing, wherein said apparatus comprises a means for:

determining a first value of the collimator aperture, by increasing said aperture from a small value, where a D_max point is located near tho centre of the product package, up to a value where the D_max point moves near to the centre of a small side of said package'"'"'s rectangular horizontal cross-section; and

determining a second value of the collimator aperture, by further increasing the collimator aperture up to a point where a D_min point moves from a point near the corner of the product package to the centre of said package; and

wherein said collimator is adapted far adjusting its aperture to a value comprised between said first and second value, prior to irradiation of the package.

5. The apparatus according to claim 4, wherein the ratio of collimator aperture over a distance d1 from radiation so to front face of collimator is adjustable between 0.54 and 0.73.

6. The apparatus according to claim 4, wherein the ratio of collimator aperture over a distance d2 from radiation source to centre of turntable is adjustable between 0.11 and 0.16.

7. The apparatus according to claim 4, wherein product packages having a mean density between 0.4 and 0.8 g/cm³ are irradiated.