ELECTRON BEAM THERAPY UNIT

• US 3,757,118 A
• Filed: 02/22/1972
• Issued: 09/04/1973
• Est. Priority Date: 02/22/1972
• Status: Expired due to Term

• Current Assignee: O'Dacre, George, Samuel B. Hodge
• Original Assignee: O'Dacre, George, Samuel B. Hodge
• Inventors: Hodge, Samuel B., O'Dacre, George
• Primary Examiner(s): Lawrence, James W.
• Assistant Examiner(s): Anderson, B. C.
• Application Number:
  US05/228,177
• Time in Patent Office: 560 Days
• Field of Search: 250/49.5TE,50,54,55,56,52,91
• US Class Current: 250/492.1
• CPC Class Codes: A61B 6/4441 the rigid structure being a C-arm or U-arm
• CPC Class Codes: A61N 2005/1089 Electrons
• CPC Class Codes: A61N 5/1077 Beam delivery systems
• CPC Class Codes: G21K 5/10 with provision for relative movement of beam source and object to be irradiated

Abstract

An electron beam therapy unit in which an electron beam source and a shield are mounted on the opposed horizontally extending arms of a U-frame mounted for rotation about a horizontal axis, and a patient support is pivotally attached at off-centre positions to three planet gears which are rotatable about fixed axis and mesh with a rotatable sun gear. As the U-frame is rotated a gear train connected to it rotates one of the planet gears, which rotates the other planet gears through the sun gear, so that the patient support is rotated along a circular path around the U-frame axis of rotation so that the patient is always diametrically opposite the electron beam source.

Claims

1. An electron beam therapy unit, comprising a support, a frame having two spaced arms extending substantially horizontally from a bridge portion, an electron beam source mounted on one arm, for directing an electron beam towards the other arm, a shield on the other arm in the path of the electron beam, a target support between the arms, and mounting means mounting said frame and the target support on said support for rotation of the arm portions and the target support along circular paths about a common horizontal axis, with the electron beam source diametrically opposite a target on the target support, and the target support maintained in the same horizontal orientation between the arms.

2. A unit according to claim 1, wherein the mounting means comprises a central, rotatable sun gear mounted on the common horizontal axis and driven by the frame, three planet gears meshing with the sun gear and pivotally mounted on the support to rotate about fixed axes, and off-centre pivots attaching the planet gears to the target support at the same angle of inclination from the centre of the planet gears.

3. A unit according to claim 1, wherein the mounting means comprises a stationary shaft on the support with the frame rotatably mounted on the stationary shaft, a stationary plate mounted on the stationary shaft, a sun gear rotatably mounted on the stationary shaft, three planet gears rotatably mounted on the stationary plate and meshing with the sun gear, a frame gear attached to the frame for rotation therewith about the axis for rotation, an intermediate gear rotatably mounted on the stationary plate and meshing with the frame gear, and a planet drive gear mounted for rotation with one of the planet gears and meshing with the intermediate gear.