Systems and methods for adjusting multi-leaf collimator

Abstract

The present disclosure provides systems and methods for adjusting a multi-leaf collimator (MLC) in a treatment process according to a treatment plan or a portion thereof. The method may comprise: moving one or more leaves of a multi leaf collimator (MLC), and forming one or more closed leaf pairs in moving process, the moving including: obtaining an offset for each closed leaf pair of the one or more closed leaf pairs, wherein the offset is no larger than a predetermined threshold, and the predetermined threshold is determined in a treatment planning process that generates a radiation treatment plan; and causing the one or more closed leaf pairs to move based on one or more offsets corresponding to the one or more closed leaf pairs, before or during a implementation of the radiation treatment plan.

What is claimed is: 
     
         1 . A radiation treatment method implemented on at least one machine, each machine having at least one processor and at least one storage device, comprising:
 moving one or more leaves of a multi leaf collimator (MLC), and forming one or more closed leaf pairs in moving process, the moving including:   determining at least one closed leaf pair from the one or more closed leaf pairs that are uncovered by a jaw;   obtaining an offset for each closed leaf pair of the at least one closed leaf pair; and   causing the at least one closed leaf pair to move based on at least one offset corresponding to the at least one closed leaf pair, before or during a implementation of the radiation treatment plan.   
     
     
         2 . The method of  claim 1 , further comprising:
 designating a random value as the offset for each closed leaf pair.   
     
     
         3 . The method of  claim 2 , further comprising:
 generating the random value for each closed leaf pair by a random number generator.   
     
     
         4 . The method of  claim 1 , wherein the implementation of the radiation treatment plan includes one or more treatment fractions, at least one treatment fraction of the one or more treatment fractions includes a beam delivery, and the method further comprises:
 generating the offset for each closed leaf pair before or at a beginning of the beam delivery in the at least one treatment fraction of the one or more treatment fractions.   
     
     
         5 . The method of  claim 1 , wherein the offset for each closed leaf pair is determined in the treatment planning process. 
     
     
         6 . The method of  claim 5 , further comprising:
 in the treatment planning process, evaluating or adjusting one or more parameters of the radiation treatment plan based on a leakage distribution associated with a dose leakage of each closed leaf pair after determining the offset.   
     
     
         7 . The method of  claim 1 , wherein the implementation of the radiation treatment plan includes one or more treatment fractions, and the causing the one or more closed leaf pairs to move comprises:
 causing at least one closed leaf pair of the one or more closed leaf pairs to move, based on at least one offset corresponding to the at least one closed leaf pair, dynamically within at least one treatment fraction of the one or more treatment fractions.   
     
     
         8 . The method of  claim 1 , wherein the implementation of the radiation treatment plan includes one or more treatment fractions, at least one treatment fraction of the one or more treatment fractions include a beam delivery, and the causing the one or more closed leaf pairs to move comprises:
 causing at least one closed leaf pair of the one or more closed leaf pairs to move, based on at least one offset corresponding to the at least one closed leaf pair, dynamically during the beam delivery in the at least one treatment fraction of the one or more treatment fractions.   
     
     
         9 . The method of  claim 1 , wherein the implementation of the radiation treatment plan includes one or more treatment fractions, the one or more offsets at least include a first offset and a second offset, and the causing the one or more closed leaf pairs to move comprises:
 causing a first closed leaf pair of the one or more closed leaf pairs to move by the first offset in a first treatment fraction of the one or more treatment fractions; and   causing the first closed leaf pair of the one or more closed leaf pairs to move by the second offset in a second treatment fraction of the one or more treatment fractions.   
     
     
         10 . The method of  claim 9 , wherein the one or more offsets further include a third offset and a fourth offset, and the causing the one or more closed leaf pairs to move further comprises:
 causing a third closed leaf pair of the at least one closed leaf pair to move by the third offset in a third treatment fraction of the one or more treatment fractions; and   causing a fourth closed leaf pair of the at least one closed leaf pair to move by the fourth offset in the third treatment fraction of the one or more treatment fractions.   
     
     
         11 . The method of  claim 1 , wherein the MLC further including one or more open leaf pairs, and the method further comprising causing the one or more open leaf pairs to move according to the radiation treatment plan, wherein the causing the one or more closed leaf pairs to move comprises:
 causing the one or more closed leaf pairs to move based on the one or more offsets corresponding to the one or more closed leaf pairs, synchronously or asynchronously with the moving of the one or more open leaf pairs.   
     
     
         12 . The method of  claim 1 , wherein the offset is no larger than a predetermined threshold, and the predetermined threshold is determined in a treatment planning process that generates a radiation treatment plan. 
     
     
         13 . The method of  claim 1 , further comprising:
 determining, from the one or more closed leaf pairs, a first leaf pair whose state is changed from open to closed; and   after the first leaf pair is closed, causing the first leaf pair to move by a first offset of the one or more offsets.   
     
     
         14 . The method of  claim 1 , further comprising:
 determining, from the one or more closed leaf pairs, a first leaf pair whose status is changed from closed to open;   during a period in which the first leaf pair is closed, causing the first leaf pair to move by a first offset of the one or more offsets;   prior to opening the first leaf pair, causing the first leaf pair to move to a prescribed position according to the radiation treatment plan; and   causing the first leaf pair to move from the prescribed position according to the radiation treatment plan.   
     
     
         15 . The method of  claim 1 , wherein each closed leaf pair of the one or more closed leaf pairs includes a gap between each closed leaf pair, and the causing the one or more closed leaf pairs to move comprises:
 causing the one or more closed leaf pairs to move based on the one or more offsets corresponding to the one or more closed leaf pairs, so that a position of the gap between each closed leaf pair is adjusted by the offset corresponding to each closed leaf pair.   
     
     
         16 . The method of  claim 1 , wherein the MLC includes at least two layers of leaves, the at least two layers of leaves including a first layer and a second layer, the one or more closed leaf pairs including a first closed leaf pair and a second closed leaf pair, the first layer including the first closed leaf pair, the second layer including the second closed leaf pair, the method further comprising:
 generating a first random value and a second random value independently;   causing the first closed leaf pair in the first layer to move based on the first random value; and   causing the second closed leaf pair in the second layer to move based on the second random value.   
     
     
         17 . A radiation treatment system comprising:
 a drive mechanism configured to drive one or more closed leaf pairs of a multi leaf collimator (MLC) to move, and one or more closed leaf pairs are formed in moving process; and   a controller configured to:   determining at least one closed leaf pair from the one or more closed leaf pairs that are uncovered by a jaw;   obtaining an offset for each closed leaf pair of the at least one closed leaf pair; and   causing the at least one closed leaf pair to move based on at least one offset corresponding to the at least one closed leaf pair, before or during a implementation of the radiation treatment plan.   
     
     
         18 . The system of  claim 17 , wherein the controller is further configured to:
 designating a random value as the offset for each closed leaf pair.   
     
     
         19 . The system of  claim 18 , wherein the controller is further configured to:
 generating the random value for each closed leaf pair by a random number generator.   
     
     
         20 . A radiation treatment system, comprising:
 at least one storage device storing a set of instructions; and   at least one processor in communication with the at least one storage device, wherein when executing the set of instructions, the at least one processor is configured to cause the system to perform operations including:   moving one or more leaves of a multi-leaf collimator (MLC), and forming one or more closed leaf pairs in moving process, the moving including:   determining at least one closed leaf pair from the one or more closed leaf pairs that are uncovered by a jaw;   obtaining an offset for each closed leaf pair of the at least one closed leaf pair; and   causing the at least one closed leaf pair to move based on at least one offset corresponding to the at least one closed leaf pairs, before or during a implementation of the radiation treatment plan.