Particle beam therapy system and magnetic resonance imaging apparatus
The system includes a bed on which an irradiation target is mounted, an irradiation device that irradiates the irradiation target with a particle beam, and a magnetic resonance imaging apparatus that captures an image of an irradiation object and includes a magnet that generates a static magnetic field in an image capturing space in which the irradiation target is disposed, and a yoke disposed outside the image capturing space and through which a magnetic flux of the generated magnetic field passes. The irradiation device 21 is disposed on a back surface side of the yoke when viewed from the image capturing space, and irradiates the irradiation target with the particle beam from a through-hole or gap provided in the yoke. A direction in which the particle beam enters the image capturing space intersects with a direction of a static magnetic field applied to the image capturing space by the magnet.
1. A particle beam therapy system comprising:
a bed on which an irradiation object is mounted;
an irradiation device that irradiates an irradiation target in the irradiation object with a particle beam;
a rotary gantry on which the irradiation device is mounted and which rotates around the bed; and
a magnetic resonance imaging apparatus that captures an image of the irradiation object,
wherein the magnetic resonance imaging apparatus includes a static magnetic field generation device,
wherein the static magnetic field generation device includes:
a magnet that generates a static magnetic field in an image capturing space in which the irradiation target is disposed, and
a yoke that is disposed outside the image capturing space and through which a magnetic flux of the magnetic field generated by the magnet passes,
wherein the irradiation device is disposed on a back surface side of the yoke when viewed from the image capturing space, and irradiates the irradiation target with the particle beam through a through-hole provided in the yoke or a gap provided in the yoke,
wherein a direction in which the particle beam enters the image capturing space is perpendicular with a direction of a magnetic flux of the static magnetic field applied to the image capturing space by the magnet,
wherein the magnetic resonance imaging apparatus is disposed in a space on an inner side of the rotary gantry,
wherein the irradiation device includes a particle beam monitor that is disposed on a central axis of the particle beam and detects the particle beam, and
wherein the particle beam monitor is disposed between the yoke and the rotary gantry.
2. The particle beam therapy system according to claim 1 ,
wherein a pair of the magnets are disposed facing each other with the image capturing space interposed between the magnets, and
wherein the yoke has a columnar shape disposed between the pair of magnets.
3. The particle beam therapy system according to claim 2 ,
wherein the through-hole is provided at a center of the columnar yoke in a width direction, and
wherein the columnar yoke on both sides of the through-hole is provided with a protrusion having a width or a depth more than a width or a depth of a portion at which the through-hole is not disposed.
4. The particle beam therapy system according to claim 1 , further comprising:
a rotary gantry on which the irradiation device is mounted and which rotates around the bed,
wherein the magnetic resonance imaging apparatus is disposed in a space on an inner side of the rotary gantry, is supported by the rotary gantry, and rotates around the bed together with the irradiation device.
5. The particle beam therapy system according to claim 3 ,
wherein the rotary gantry includes:
a support that detachably supports the magnetic resonance imaging apparatus, and
a rail that moves the magnetic resonance imaging apparatus detached from the rotary gantry, in a direction separated from the bed.
6. The particle beam therapy system according to claim 5 ,
wherein a direction in which a transport mechanism transports the magnetic resonance imaging apparatus is an axial direction of the rotary gantry.
7. The particle beam therapy system according to claim 1 ,
wherein in the irradiation device, a chamber filled with a gas is further disposed on the central axis of the particle beam between the particle beam monitor and the yoke, and
wherein the chamber guides the particle beam having passed through the particle beam monitor to the through-hole and emits the particle beam from a tip of the chamber toward the irradiation target.
8. The particle beam therapy system according to claim 7 ,
wherein the tip of the chamber is inserted into the through-hole.
9. The particle beam therapy system according to claim 7 ,
wherein the tip of the chamber is configured to be able to have a structure of being retracted outward from the through-hole.
10. The particle beam therapy system according to claim 6 ,
wherein the magnet is a superconducting magnet including a superconducting coil or a normal conducting magnet including a normal conducting coil, and
wherein the magnetic resonance imaging apparatus includes a demagnetization device that demagnetizes the magnet by stopping a current flowing through the superconducting coil or the normal conduction coil when a transport mechanism transports the magnetic resonance imaging apparatus.
11. The particle beam therapy system according to claim 1 , further comprising:
a controller that controls an irradiation timing of the particle beam based on an image captured by the magnetic resonance imaging apparatus.
12. The particle beam therapy system according to claim 1 ,
wherein a direction of the magnetic field of the magnet is reversed to change a direction of curvature of the particle beam.
13. The particle beam therapy system according to claim 1 ,
wherein the magnet has a cylindrical shape,
wherein the image capturing space is formed inside the cylindrical magnet,
wherein the yoke is disposed on an outer surface of the cylindrical magnet,
wherein a second through-hole is provided in the cylindrical magnet so as to overlap the through-hole of the yoke, and
wherein the particle beam passes through the first and second through-holes and is applied to an irradiation target in the image capturing space.
14. A particle beam therapy system, comprising:
a bed on which an irradiation object is mounted;
an irradiation device that irradiates an irradiation target in the irradiation object with a particle beam;
a rotary gantry on which the irradiation device is mounted and which rotates around the bed;
a magnetic resonance imaging apparatus, which includes:
a magnet that generates a static magnetic field in an image capturing space in which an irradiation target of a particle beam is disposed; and
a yoke through which a magnetic flux generated from the magnet passes,
wherein the yoke is provided with a through-hole through which the particle beam passes,
wherein a direction in which the particle beam enters and passes through the through-hole to the image capturing space is perpendicular with a direction of a magnetic flux of the static magnetic field applied to the image capturing space by the magnet,
wherein the irradiation device includes a particle beam monitor that is disposed on a central axis of the particle beam and detects the particle beam, and
wherein the particle beam monitor is disposed between the yoke and the rotary gantry.