High-speed energy switching

Abstract

An example particle therapy system may include: a synchrocyclotron to produce a particle beam; a scanner to move the particle beam in one or more dimensions relative to an irradiation target; and an energy degrader that is between the scanner and the irradiation target. The energy degrader may include multiple plates that are movable relative to a path of the particle beam, with the multiple plates each being controllable to move while in the path of the particle beam and during movement of the particle beam. An aperture may be between the energy degrader and the irradiation target. The aperture being may be to trim the particle beam prior to the particle beam reaching the irradiation target.

What is claimed is: 
     
         1 - 38 . 
     
     
         39 . An energy degrader comprising:
 a first structure comprised of a beam-energy absorbing material that is controllable by a control system to move across at least part a beam field in a first direction while a radiation beam is incident on a surface of the first structure and while the radiation beam is moved across the surface of the first structure, where movement of the radiation beam across the surface of the first structure is at least partly in the first direction, and   a second structure comprised of a beam-energy absorbing material that is controllable by the control system to move across at least part of the beam field while the radiation beam is incident on the surface of the first structure, the second structure being controllable to trail or to lead the first structure in the first direction such that the radiation beam does not pass through the second structure during at least part of movement of the first structure and the second structure.   
     
     
         40 . The energy degrader of  claim 39 , wherein the first structure comprises a first plate and the second structure comprises a second plate. 
     
     
         41 . The energy degrader of  claim 39 , wherein the energy degrader is smaller in size than the beam field. 
     
     
         42 . The energy degrader of  claim 39 , wherein the first structure comprises a first sensor to detect a position of the first structure relative to, and within, the beam field, and to relay the position of the first structure to the control system. 
     
     
         43 . The energy degrader of  claim 42 , wherein the second structure comprises a second sensor to detect a position of the second structure relative to, and within, the beam field, and to relay the position of the second structure to the control system. 
     
     
         44 . The energy degrader of  claim 39 , wherein the first structure and the second structure move are controllable by the control system to move at different speeds. 
     
     
         45 . The energy degrader of  claim 39 , wherein the second structure is controllable by the control system to trail the first structure during movement. 
     
     
         46 . The energy degrader of  claim 39 , wherein the first structure and the second structure are controllable by the control system to move between a starting position and an ending position, the starting position corresponding to a point where the radiation beam beings moving at least partly in the first direction and the ending position corresponding to a point where the radiation beam stops moving. 
     
     
         47 . The energy degrader of  claim 39 , wherein the first structure comprises a plate having a first thickness, the second structure comprises a plate having a second thickness, and the first thickness and the second thickness are different. 
     
     
         48 . The energy degrader of  claim 39 , further comprising multiple plates, the multiple plates comprise one or more first plates including the first structure and one or more second plates including the second structure, the one or more first plates and the one or more second plates being controllable by the control system to move relative to the radiation beam, each of one or more first plates having a thickness that is less than thicknesses of the one or more second plates. 
     
     
         49 . The energy degrader of  claim 39 , wherein control over movement of the multiple plates by the control system comprises sequencing movement of the multiple plates so that each of multiple layers of an irradiation target is subjected to the particle beam. 
     
     
         50 . The energy degrader of  claim 49 , wherein control over movement of the multiple plates by the control system comprises sequencing movement of the multiple plates so that the multiple layers of the irradiation target are treated with the particle beam non-sequentially. 
     
     
         51 . An energy degrader comprising:
 first absorbing means for changing an energy of a particle beam, the first absorbing means being controllable by control means to move across at least part a beam field in a first direction while the particle beam is incident on the first absorbing means and while the particle beam is moved across the surface of the first absorbing means, where movement of the particle beam across the surface of the first absorbing means is at least partly in the first direction, and   second absorbing means that is controllable by the control means to move across at least part of the beam field while the particle beam is incident on the surface of the first structure, the second absorbing means being controllable to trail or to lead the first absorbing means in the first direction such that the particle beam does not pass through the second absorbing means during at least part of movement of the first absorbing means and the second absorbing means.   
     
     
         52 . An energy degrader comprising:
 a first structure comprised of a beam-energy absorbing material that is controllable by a control system to move across at least part of a beam field; and   a second structure comprised of a beam-energy absorbing material that is controllable by a control system to move across at least part of the beam field;   wherein the first structure and the second structure are controllable to move at a same time and in a same direction while at least partly overlapping such that, at a first time, an irradiation target associated with the beam field is subjected to radiation passing through one of, but not both, the first structure or the second structure and, at a second time, the irradiation target is subjected to radiation passing through both the first structure and the second structure.   
     
     
         53 . The energy degrader of  claim 52 , wherein at least part of the first structure and the second structure overlap. 
     
     
         54 . The energy degrader of  claim 52 , wherein the first structure comprises a first plate and the second structure comprises a second plate. 
     
     
         55 . The energy degrader of  claim 52 , wherein a surface area of the energy degrader is less than ¼ of an area of the beam field. 
     
     
         56 . The energy degrader of  claim 52 , wherein the first structure comprises a first sensor to detect a position of the first structure relative to, and within, the beam field, and to relay the position of the first structure to the control system; and
 wherein the second structure comprises a second sensor to detect a position of the second structure relative to, and within, the beam field, and to relay the position of the second structure to the control system.   
     
     
         57 . The energy degrader of  claim 52 , wherein at least one of the first structure or the second structure is controllable by the control system to move in the same direction at a same speeds as a particle beam comprising the radiation moves in the same direction. 
     
     
         58 . The energy degrader of  claim 52 , wherein the first structure comprises a first plate, the second structure comprises a second plate, and, when the irradiation target is subjected to radiation passing through the first plate but not the second plate, the second plate is controllable by the control system to move at a speed that is greater than the first plate for at least part of a time.