US 4,507,616 AGranted

Rotatable superconducting cyclotron adapted for medical use

AssigneeBoard of Trustees operating Michigan State University

InventorsHenry G. Blosser, David A. Johnson, Jack Riedel, Richard J. Burleigh

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Abstract

A superconducting cyclotron (10) rotatable on a support structure (11) in an arc of about 180.degree. around a pivot axis (A--A) and particularly adapted for medical use is described. The rotatable support structure (13, 15) is balanced by being counterweighted (14) so as to allow rotation of the cyclotron and a beam (12), such as a subparticle (neutron) or atomic particle beam, from the cyclotron in the arc around a patient. Flexible hose (25) is moveably attached to the support structure for providing a liquified gas which is supercooled to near 0.degree. K. to an inlet means (122) to a chamber (105) around superconducting coils (101, 102). The liquid (34) level in the cyclotron is maintained approximately half full so that rotation of the support structure and cyclotron through the 180.degree. can be accomplished without spilling the liquid from the cyclotron. With the coils vertically oriented, each turn of the winding is approximately half immersed in liquid (34) and half exposed to cold gas and adequate cooling to maintain superconducting temperatures in the section of coil above the liquid level is provided by the combination of cold gas/vapor and by the conductive flow of heat along each turn of the winding from the half above the liquid to the half below.

Claims17

Dependent claims

A superconducting cyclotron (10) apparatus including ion source means (110) for providing charged atomic particles to be spirally accelerated in the cyclotron with superconducting coils (101, 102) around iron magnetic poles (110, 100a) and which can be cooled with a liquified gas to near 0.degree. K., RF generator means (24) connected (119) to dees (106, 107) for spirally accelerating the charged atomic particles to generate a beam of particles or sub-particles from the spirally accelerated charged particles, the cyclotron including a support structure (11) rotatable around a pivot axis (A--A) for the cyclotron and balanced around the pivot axis by a counterweight (14) on the support structure to thereby change the angle of the beam wherein the beam can be directed towards the axis in an arc defining a plane of rotation of the cyclotron by the support structure, the improvement in the support structure which comprises:

(a) a balance bar (13) with two ends including a counterweight (14) at one end of the balance bar opposite a pivot axis (A--A) and a cross bar (15) member at the other end opposite the counterweight, perpendicular to the balance bar and parallel to the pivot axis for supporting the cyclotron mounted on one end of the cross bar such that the beam can be generated in a plane perpendicular to and in the direction of the pivot axis;
(b) pivot means (16, 17) supporting the balance bar at the pivot axis of the balance bar with the cyclotron and cross bar balancing the counterweight and with the pivot axis providing a fulcrum such that the balance bar is rotatable in an arc of about 180.degree. in the plane perpendicular to the pivot axis;
(c) drive means (18) for rotating the balance bar in the arc as the beam is generated;
and
(d) flexible hose (25) attached at one end to the cross bar at an opposite end from the cyclotron for providing a liquified gas (34) cooled to near 0.degree. K. through the hose to the cyclotron through an inlet conduit (122) supported by the cross bar with an opposite end (31) of the hose attached to a fixed base (32) providing a mounting surface (B--B) for the support structure wherein as the cyclotron is moved in the arc the hose bends between the base and cross bar.

2 more elements

In a superconducting cyclotron (10) apparatus which generates a beam of high velocity atomic particles or subparticles (12) around and above an object to be irradiated from spirally accelerated charged atomic particles which impinge upon a target (111) to produce the beam, with a window (112) and a collimator (114) on a first side of the cyclotron tangential to the spirally accelerated charged atomic particles for defining the beam (12), including a support structure (11) having a counterweight (14) for the cyclotron rotatable on a pivot axis (A--A) between the cyclotron and counterweight (14) for changing the angle of the beam in an arc of 180.degree. defining a plane around the axis so that an object beneath the cyclotron can be irradiated around the axis the improvement in the cyclotron which comprises:

inlet means (122) for supplying liquified gas to a vessel (150) with a vent space (121) from the vessel for releasing liquified gas which becomes a gas in operation of the cyclotron adjacent the inlet means and with superconducting coils (101, 102) in the vessel vertically wound around spaced apart iron poles (100, 100a) which can generate a magnetic field between the poles and which functions to produce the spirally accelerated charged atomic particles with an oscillating electrical field, wherein the inlet means is mounted on a second side of the cyclotron opposite the window and collimator, wherein in use the liquified gas supplied by the inlet means fills up to approximately one-half of the vessel and partially covers each of the coils so that the coils are superconducting such that as the cyclotron is rotated in the arc, the liquified gas is below the inlet means and is thereby prevented from draining from the cyclotron through the vent space.

Dependencies are inferred from the claim text.