A proton treatment system, comprising: a proton beam nozzle to emit a proton beam to a targeted region of a patient; a gantry wheel having a front face to support the proton beam nozzle to direct the proton beam approximately to an isocenter of the gantry wheel corresponding to the targeted region, wherein the gantry wheel rotates the proton beam nozzle around the isocenter about a rotation axis of the gantry wheel; and a moving floor having an upper surface to support an operator of the proton treatment system, the moving floor being configured to move across the front face laterally relative to the rotation axis, the moving floor including an opening having a width through which the proton beam nozzle protrudes when at least a portion of the proton beam nozzle is located below the upper surface of the moving floor; characterised in that the moving floor comprises: a first section having one end portion rotatably mounted on a take-up roll (908a, 908b) and defining an opposite end portion terminating in an opening end of the first section, a second section having one end portion rotatably mounted on a take-up roll and defining an opposite end portion terminating in an opening end which cooperates with the opening end, and a drive mechanism for selectively discharging and taking up the first and the second sections of the moving floor onto and from the respective take-up rolls (908a, 908b), wherein the opening is selectively defined between the opening ends of the first and the second section (906a, 906b), the width of the opening being selected for receiving the proton beam nozzle therethrough as the proton beam nozzle mounted on the gantry wheel passes below and above the moving floor during rotation of the proton beam nozzle about a patient during proton treatment. a proton beam nozzle to emit a proton beam to a targeted region of a patient; a gantry wheel having a front face to support the proton beam nozzle to direct the proton beam approximately to an isocenter of the gantry wheel corresponding to the targeted region, wherein the gantry wheel rotates the proton beam nozzle around the isocenter about a rotation axis of the gantry wheel; and a moving floor having an upper surface to support an operator of the proton treatment system, the moving floor being configured to move across the front face laterally relative to the rotation axis, the moving floor including an opening having a width through which the proton beam nozzle protrudes when at least a portion of the proton beam nozzle is located below the upper surface of the moving floor; characterised in that the moving floor comprises: a first section having one end portion rotatably mounted on a take-up roll (908a, 908b) and defining an opposite end portion terminating in an opening end of the first section, a second section having one end portion rotatably mounted on a take-up roll and defining an opposite end portion terminating in an opening end which cooperates with the opening end, and a drive mechanism for selectively discharging and taking up the first and the second sections of the moving floor onto and from the respective take-up rolls (908a, 908b), a first section having one end portion rotatably mounted on a take-up roll (908a, 908b) and defining an opposite end portion terminating in an opening end of the first section, a second section having one end portion rotatably mounted on a take-up roll and defining an opposite end portion terminating in an opening end which cooperates with the opening end, and a drive mechanism for selectively discharging and taking up the first and the second sections of the moving floor onto and from the respective take-up rolls (908a, 908b), wherein the opening is selectively defined between the opening ends of the first and the second section (906a, 906b), the width of the opening being selected for receiving the proton beam nozzle therethrough as the proton beam nozzle mounted on the gantry wheel passes below and above the moving floor during rotation of the proton beam nozzle about a patient during proton treatment.