A radiation delivery system comprising: an imaging system; a gantry; a therapeutic radiation source mounted on the gantry and configured to apply radiation in a radiation treatment beam plane; a platform movable relative to the gantry; and a controller in communication with the imaging system, the gantry, the radiation source, and the platform, wherein the controller is configured to: move a patient located on the platform from a first location to a second location such that the patient passes through the radiation treatment beam plane while acquiring a first set of imaging data; apply a first quantity of radiation with the radiation source as the patient passes through the radiation treatment beam plane, wherein the first quantity of radiation is derived from the first set of imaging data; the system being characterised in that the controller is further configured to: move the patient from the second location to the first location such that the patient passes through the radiation treatment beam plane while acquiring a second set of imaging data; and apply a second quantity of radiation with the radiation source as the patient passes through the radiation treatment beam plane, wherein the second quantity of radiation is derived from the second set of imaging data and is different from the first quantity of radiation. an imaging system; a gantry; a therapeutic radiation source mounted on the gantry and configured to apply radiation in a radiation treatment beam plane; a platform movable relative to the gantry; and a controller in communication with the imaging system, the gantry, the radiation source, and the platform, a gantry; a therapeutic radiation source mounted on the gantry and configured to apply radiation in a radiation treatment beam plane; a platform movable relative to the gantry; and a controller in communication with the imaging system, the gantry, the radiation source, and the platform, wherein the controller is configured to: move a patient located on the platform from a first location to a second location such that the patient passes through the radiation treatment beam plane while acquiring a first set of imaging data; apply a first quantity of radiation with the radiation source as the patient passes through the radiation treatment beam plane, wherein the first quantity of radiation is derived from the first set of imaging data; move a patient located on the platform from a first location to a second location such that the patient passes through the radiation treatment beam plane while acquiring a first set of imaging data; apply a first quantity of radiation with the radiation source as the patient passes through the radiation treatment beam plane, wherein the first quantity of radiation is derived from the first set of imaging data; the system being characterised in that the controller is further configured to: move the patient from the second location to the first location such that the patient passes through the radiation treatment beam plane while acquiring a second set of imaging data; and apply a second quantity of radiation with the radiation source as the patient passes through the radiation treatment beam plane, wherein the second quantity of radiation is derived from the second set of imaging data and is different from the first quantity of radiation. move the patient from the second location to the first location such that the patient passes through the radiation treatment beam plane while acquiring a second set of imaging data; and apply a second quantity of radiation with the radiation source as the patient passes through the radiation treatment beam plane, wherein the second quantity of radiation is derived from the second set of imaging data and is different from the first quantity of radiation.