Radiation systems with minimal or no shielding requirement on building

A radiation system, comprising:

• a support;
• a capsule rotatably coupled to the support;
• a radiation source movably coupled to the capsule, wherein the radiation source is configured to provide a treatment radiation beam, and the radiation source is configured to be turned on or off in response to a control signal;
• and
• a collimator located at an operative position relative to the radiation source;
• wherein the capsule includes a shielding material for attenuating radiation resulting from an operation of the radiation source, and wherein the shielding material is configured to limit a radiation exposure level to 5mR/hr or less within 3 meters from an isocenter;
• and
• wherein the capsule has a first capsule portion defining a first space, and a second capsule portion coupled to the first capsule portion, the second capsule portion defining a second space, the first space and the second space together forming a spatial region, the spatial region configured for accommodating a portion of a patient,
• the spatial region configured to accommodate a portion of a patient,
• wherein the capsule includes an opening configured to permit entry of the portion of the patient into the spatial region and located on a first side of the capsule,
• wherein the first capsule portion and the second capsule portion are connected to each other via a connection,
• wherein the capsule also includes a cover on a second side of the capsule opposite from the first side, the cover covering a part of the spatial region and configured to prevent the portion of the patient from exiting the spatial region, and
• wherein the second capsule portion is rotatable relative to the first capsule portion and has a rigid configuration.