Patent ID: 8139705

Claim:
A treatment facility comprising a shielded chamber for use in conjunction with an ion therapy beam, wherein the shielded chamber comprises: two opposed side walls; an entrance to the shielded chamber, wherein the entrance is defined between the opposed side walls at a first end of the shielded chamber; a treatment room for a patient to be exposed to the ion therapy beam, wherein the treatment room is defined between the opposed side walls at a second end of the shielded chamber; a shielding door at the entrance to the shielded chamber, wherein the shielding door comprises a layer of hydrogen-containing material; and a labyrinthine passage to enter and exit the treatment room, wherein the labyrinthine passage leads from the entrance of the shielded chamber to the treatment room and is defined by at least a first labyrinth wall and a second labyrinth wall that: (a) extend transversely inward, one from each side wall; (b) are longitudinally displaced with respect to each other along the side walls, wherein the first labyrinth wall is closer to the treatment room than the second labyrinth wall; (c) each cross a central axis that aligns with peak propagation of the ion therapy beam when a patient is being irradiated thereby in the treatment room; and (d) each comprise at least two layers of shielding, including: (i) a spallation layer for causing spallation reactions wherein incident relatively high-energy neutrons interact with atomic nuclei to generate relatively low-energy neutrons, wherein the spallation layer of the first labyrinth wall and the spallation layer of the second labyrinth wall overlap each other; and (ii) a neutron moderating and absorbing layer for moderating and absorbing the relatively low-energy neutrons generated in the spallation reactions in the spallation layer, wherein the neutron moderating and absorbing layer of the first labyrinth wall and the neutron moderating and absorbing layer of the second labyrinth wall overlap each other.