Method and an arrangement for defining a radiation treatment field

• US 3,950,651 A
• Filed: 11/06/1974
• Issued: 04/13/1976
• Est. Priority Date: 11/05/1974
• Status: Expired due to Term

• Current Assignee: Rune E. Flocee
• Original Assignee: Rune E. Flocee
• Inventors: Flocee, Rune E.
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US05/521,276
• Time in Patent Office: 524 Days
• Field of Search: 250/505, 250/514
• US Class Current: 378/147
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61N 5/1042 with spatial modulation of the radiation beam within the treatment head
• CPC Class Codes: G21F 1/085 Heavy metals or alloys
• CPC Class Codes: G21F 5/04 Means for controlling exposure, e.g. time, size of aperture controlling exposure to X-radiation H05G1/30
• CPC Class Codes: G21K 1/02 using diaphragms, collimators
• CPC Class Codes: G21K 1/04 using variable diaphragms, shutters, choppers
• CPC Class Codes: G21K 5/04 with beam-forming means

Abstract

A method of defining the radiation beam for medical therapy in which the beam is shaped by an aperture in an easily formable, radiation absorbing member. The member is formed by compressing a mixture of granulated heavy metal, such as tungsten, with powdered pressure sensitive adhesive into a shape-retaining box. The member is cut to define the aperture desired, and preferably the cutting is done so that the aperture walls parallel the beam that will pass therethrough.

Claims

1. The method of shaping a radiation beam for the treatment of patients so that the beam cross-section conforms to the target area to be treated, comprising, in combination, the steps of mixing a volume of fine grain, heavy metal powder with a quantity of pressure sensitive, non-curing adhesive so as to form a mass of plastically deformable, radiation absorbable material, compressing said material into a block-like member of sufficient area to block said beam and sufficient thickness, considering the compressed density of the material, to absorb the radiation energy of said beam, said compression having the effect of increasing the density of said member and making that member geometrically stable, removing material from said member to form an aperture therethrough having a peripheral contour corresponding to the contour of said target area, and mounting said member in said beam so that said aperture permits a beam of the desired cross sectional shape and size to fall on said target area.

2. The method of claim 1 including the step of facilitating handling of said plate by supporting the member on a radiation transparent support plate, and covering said member with a radiation transparent cover plate, so as to protect the formed periphery of said aperture.

3. The method of claim 1 in which said powder is tungsten in a grain size on the order of 200-325 mesh, and said adhesive is present in an amount in the order of 1 to 10% by weight.