Patent Number: 
Section: claims

1. A patient positioning assembly comprising:a patient support device to support a patient thereon;a robotic arm assembly coupled to the patient support device, wherein the robotic arm assembly comprises:a base member;a plate member rotatably mounted on said base member, wherein the plate member is configured to rotate about a first axis to translate the patient support device in a first degree of freedom;an arm extending between a first end and a second end, wherein said first end is rotatably attached to said plate member, wherein the arm is configured to rotate about a second axis to translate the patient support device in a second degree of freedom, wherein the first and second degrees of freedom are used for translations along mutually orthogonal x-, y-, and z-coordinate axes, and wherein said second end is a wrist assembly rotatably connected to the patient support device to allow the patient support device to rotate about roll-, pitch-, and yaw-axes for third, fourth, and fifth degrees of freedom. 2. The patient positioning assembly of claim 1, wherein said base member is configured to be rotatably mounted on a plinth. 3. A patient positioning assembly according to claim 1 further comprising a controller operatively connected to said robotic arm assembly to control the movement of said robotic arm assembly. 4. A patient positioning assembly according to claim 3, wherein said patient positioning assembly further comprises a sensor system to detect the position of said patient support device relative to a treatment coordinate system, and wherein said controller is operatively connected with said sensor system to receive position data of said patient support device. 5. A patient positioning assembly according to claim 1, wherein said patient support device comprises a seat with a back. 6. A patient positioning assembly comprising:a patient support device to patient support a patient thereon;a robotic arm assembly coupled to the patient support device, wherein the robotic arm assembly comprises:a base member;a plate member rotatably mounted on said base member, wherein the plate member is configured to rotate about a first axis to translate the patient support device in a first degree of freedom;a first arm having a first end rotatably attached to said plate member, and a second end, wherein the first arm is configured to rotate about a second axis to translate the patient support device in a second degree of freedom;a second arm having a first end rotatably attached to the second end of said first arm, and a second end, wherein the second arm is configured to rotate about a third axis to translate the patient support device in a third degree of freedom, wherein the first, second, and third degrees of freedom are used for translations along mutually orthogonal x-, y-, and z-coordinate axes, and wherein said second end is a wrist assembly rotatably connected to the patient support device to allow the patient support device to rotate about roll-, pitch-, and yaw-axes for third, fourth, and fifth degrees of freedom. 7. A patient positioning assembly according to claim 6, wherein said base member is configured to be rotatably mounted on a plinth. 8. A patient positioning assembly according to claim 6 further comprising a controller operatively connected to said robotic arm assembly to control the movement of said robotic arm assembly. 9. A patient positioning assembly according to claim 8, wherein said patient positioning assembly further comprises a sensor system to detect the position of said patient support device relative to a treatment coordinate system, and wherein said controller is operatively connected with said sensor system to receive position data of said patient support device. 10. A patient positioning assembly according to claim 6, wherein said patient support device comprises a seat with a back.