Patent Number: 
Section: claims

1. A method implemented on at least one machine, each machine of the at least one machine has at least one processor and at least one storage device for adjusting a multi-leaf collimator (MLC) in a treatment process, the MLC including a plurality of cross-layer leaf pairs, each cross-layer leaf pair of the plurality of cross-layer leaf pairs includes a first leaf located in a first layer of leaves and a second leaf opposingly located in a second layer of leaves, the method comprising:for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs,determining, according to a treatment plan, an effective cross-layer leaf gap to be formed between the first leaf in the first layer and the second leaf in the second layer;causing at least one of the first leaf in the first layer or the second leaf in the second layer to move to form the effective cross-layer leaf gap; andcausing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf in the first layer and an opposing first leaf in the first layer of the MLC, the first leaf and the opposing first leaf forming an in-layer leaf pair in the first layer,wherein a size of the in-layer leaf gap is no less than a threshold. 2. The method of claim 1, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:comparing a size of the effective cross-layer leaf gap with 0. 3. The method of claim 2, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:in response to determining that the size of the effective cross-layer leaf gap is equal to 0,comparing the size of the in-layer leaf gap with the threshold; andin response to determining that the size of the in-layer leaf gap is less than the threshold, causing the in-layer leaf gap to be adjusted to no less than the threshold, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 4. The method of claim 2, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:in response to determining that the size of the effective cross-layer leaf gap is equal to 0,comparing the size of the in-layer leaf gap with the threshold; andin response to determining that the size of the in-layer leaf gap is less than the threshold, causing the in-layer leaf gap to be adjusted to no less than the threshold and no larger than a second threshold, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 5. The method of claim 2, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:in response to determining that the size of the effective cross-layer leaf gap is larger than 0,comparing the size of the effective cross-layer leaf gap with the threshold; andin response to determining that the size of the effective cross-layer leaf gap is no larger than the threshold, causing the in-layer leaf gap to be adjusted to no less than the threshold, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 6. The method of claim 2, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:in response to determining that the size of the effective cross-layer leaf gap is larger than 0,comparing the size of the effective cross-layer leaf gap with the threshold; andin response to determining that the size of the effective cross-layer leaf gap is larger than the threshold, causing the in-layer leaf gap to be adjusted to no less than the effective cross-layer leaf gap, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 7. The method of claim 2, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:in response to determining that the size of the effective cross-layer leaf gap is larger than 0,comparing the size of the effective cross-layer leaf gap with the threshold; andin response to determining that the size of the effective cross-layer leaf gap is no larger than the threshold, causing the in-layer leaf gap to be adjusted to no less than the threshold and no larger than a second threshold, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 8. The method of claim 2, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:in response to determining that the size of the effective cross-layer leaf gap is larger than 0,comparing the size of the effective cross-layer leaf gap with the threshold and a second threshold; andin response to determining that the size of the effective cross-layer leaf gap is larger than the threshold but no larger than the second threshold, causing the in-layer leaf gap to be adjusted to no less than the effective cross-layer leaf gap and no larger than the second threshold, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 9. The method of claim 2, wherein for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, the causing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf and an opposing first leaf that form an in-layer leaf pair in the first layer further comprises:in response to determining that the size of the effective cross-layer leaf gap is larger than 0,comparing the size of the effective cross-layer leaf gap with a second threshold; andin response to determining that the size of the effective cross-layer leaf gap is larger than the second threshold, causing the in-layer leaf gap to be adjusted to no less than the effective cross-layer leaf gap, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 10. The method of claim 1, further comprising:causing, based on the effective cross-layer leaf gap, a second in-layer leaf gap to be formed between the second leaf and an opposing second leaf that form a second in-layer leaf pair in the second layer. 11. The method of claim 10, wherein the causing, based on the effective cross-layer leaf gap, a second in-layer leaf gap to be formed between the second leaf and an opposing second leaf that form a second in-layer leaf pair in the second layer comprises:in response to determining that a size of the effective cross-layer leaf gap is larger than 0,comparing the size of the effective cross-layer leaf gap with the threshold;in response to determining that the size of the effective cross-layer leaf gap is no larger than the threshold,causing the second in-layer leaf gap to be adjusted to no less than the threshold, by causing the opposing second leaf of the second in-layer leaf pair in the second layer to move relative to the second leaf; andcausing the in-layer leaf gap to be adjusted to no less than the threshold, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 12. The method of claim 10, wherein the causing, based on the effective cross-layer leaf gap, a second in-layer leaf gap to be formed between the second leaf and an opposing second leaf that form a second in-layer leaf pair in the second layer comprises:in response to determining that a size of the effective cross-layer leaf gap is larger than 0,comparing the size of the effective cross-layer leaf gap with the threshold;in response to determining that the size of the effective cross-layer leaf gap is larger than the threshold,causing the second in-layer leaf gap to be adjusted to no less than the effective cross-layer leaf gap, by causing the opposing second leaf of the second in-layer leaf pair in the second layer to move relative to the second leaf; andcausing the in-layer leaf gap to be adjusted to no less than the effective cross-layer leaf gap, by causing the opposing first leaf of the in-layer leaf pair in the first layer to move relative to the first leaf. 13. The method of claim 10, further comprising:for the each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, causing at least one of the in-layer leaf pair in the first layer or the second in-layer leaf pair in the second layer to be adjusted before or during the treatment process by:causing, based on at least one of the in-layer leaf gap or the second in-layer leaf gap, the in-layer leaf pair in the first layer and the second in-layer leaf pair in the second layer to be adjusted synchronously. 14. The method of claim 1, further comprising:for the each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs, causing the in-layer leaf pair in the first layer to be adjusted before or during the treatment process. 15. The method of claim 1, wherein the threshold is larger than 0. 16. The method of claim 1, wherein the threshold is within a range from 0.1 to 2 millimeters. 17. The method of claim 1, wherein in response to determining that a size of the effective cross-layer leaf gap is equal to 0, the in-layer leaf gap is no larger than a second threshold. 18. The method of claim 17, wherein the second threshold is within a range from 2 to 3 millimeters. 19. A system for adjusting a multi-leaf collimator (MLC) in a treatment process, the MLC including a plurality of cross-layer leaf pairs and a plurality of in-layer leaf pairs, each cross-layer leaf pair of the plurality of cross-layer leaf pairs includes a first leaf located in a first layer of leaves and a second leaf opposingly located in a second layer of leaves, and each in-layer leaf pair of the plurality of in-layer leaf pairs includes the first leaf located in the first layer and an opposing first leaf that is opposingly located in the first layer, the system comprising:at least one storage device storing a set of instructions; andat 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 perform operations including:for each cross-layer leaf pair of at least one of the plurality of cross-layer leaf pairs,determining, according to a treatment plan, an effective cross-layer leaf gap to be formed between the first leaf in the first layer and the second leaf in the second layer;causing at least one of the first leaf in the first layer or the second leaf in the second layer to move to form the effective cross-layer leaf gap; andcausing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf in the first layer and the opposing first leaf in the first layer of the MLC,wherein a size of the in-layer leaf gap is no less than a threshold. 20. A non-transitory computer-readable medium storing instructions, the instructions, when executed by at least one processor, causing the at least one processor to implement a method comprising:for each cross-layer leaf pair of at least one of a plurality of cross-layer leaf pairs of a multi-leaf collimator (MLC), each cross-layer leaf pair of the plurality of cross-layer leaf pairs includes a first leaf located in a first layer of leaves of the MLC and a second leaf opposingly located in a second layer of leaves of the MLC,determining, according to a treatment plan, an effective cross-layer leaf gap to be formed between the first leaf in the first layer and the second leaf in the second layer;causing at least one of the first leaf in the first layer or the second leaf in the second layer to move to form the effective cross-layer leaf gap; andcausing, based on the effective cross-layer leaf gap, an in-layer leaf gap to be formed between the first leaf in the first layer and an opposing first leaf in the first layer of the MLC, the first leaf and the opposing first leaf forming an in-layer leaf pair in the first layer,wherein a size of the in-layer leaf gap is no less than a threshold.