Patent Number: 
Section: claims

1. A multi-leaf collimator (MLC) comprising:a driving array comprising a plurality of motors;a leaf array comprising a plurality of leaves; anda plurality of elongated flexible transmission units, each connected to one of the leaves of the leaf array to form a collimator unit such that motors of the driving array are operably connected with leaves of the leaf array through the transmission units to form a MLC array that comprises a plurality of collimator units;wherein in each collimator unit, the motor transmits motion from the motor to the leaf through the transmission unit to adjust the position of each leaf independently, andwherein the transmission unit comprises a transmission line and an elastic piece operably connected to the transmission line, and the transmission line provides the leaf a first force, and the elastic piece provides the leaf a second force. 2. The collimator of claim 1, having a pair of driving arrays and a pair of leaf arrays paired up to form a pair of MLC arrays. 3. The collimator of claim 1, wherein the transmission unit includes a transmission shaft. 4. The collimator of claim 3 further comprising a connection unit configured to connect the transmission unit and the leaf, wherein the leaf has a groove, the connection unit has an expansion bump, and the expansion bump matches the groove. 5. The collimator of claim 1, wherein the MLC is used in a device having a magnetic field and the transmission units are angular and create a distance between the motors and the magnetic field to reduce the interferences between the motor and the magnetic field. 6. The collimator of claim 1, wherein the elastic piece of the transmission unit is a spring having a first end and a second end, the first end of the spring is fixed, the second end of the spring is connected to the leaf, and the spring is in a compressed state. 7. The collimator of claim 1, wherein the leaf has a thickness in a range from 0.8 mm to 2.2 mm. 8. The collimator of claim 1 further comprising a conversion unit configured to change a rotational motion of the motor to a linear motion. 9. The collimator of claim 8, wherein the conversion unit comprises a gear and a worm, the worm is connected to the motor, and the gear is driven by the worm. 10. The collimator of claim 9, wherein the gear and the worm have a self-locking function. 11. The collimator of claim 1 further comprising a guiding unit configured to control a movement path of the transmission unit. 12. The collimator of claim 1 further comprising a feedback module configured to detect a movement of the leaf. 13. A collimator system comprising:a leaf array comprising a plurality of leaves operated by a leaf module;a driving array comprising a plurality of motors operated by a driving module wherein each motor of the driving array is operably connected to one of the leaves of the leaf array through elongated flexible transmission unit to create a distance between the motor and the leaf and form a collimator unit such that the motors of the driving array are connected with leaves of the leaf array to form a MLC array that comprises a plurality of collimator units, with each motor transmitting motion to one of the leaves to adjust the position of each leaf independently; anda processing module to generate a leaf movement profile based on an initial location, a current location, and a target location for each of the leaf such that the motor of the driving module drives each leaf according to the leaf movement profile;wherein the movement profile of the motor includes a first speed of the motor during a first stage, a second speed of the motor during a second stage, and a third speed of the motor during a third stage, the first speed increases with time, the second speed is constant, and the third speed decreases at a variable rate with time, andwherein the transmission unit comprises a transmission line and an elastic piece operably connected to the transmission line, and the transmission line provides the leaf a first force, and the elastic piece provides the leaf a second force. 14. The collimator system of claim 13, wherein the variable rate is determined based on a distance between the leaf current location and the leaf target location. 15. The collimator system of claim 13 further comprising a feedback module configured to detect a movement of the leaf. 16. The collimator system of claim 15, wherein the feedback module comprises a first feedback unit and a second feedback unit, the first feedback unit is configured to detect the movement of the leaf, and the second feedback unit is configured to detect a movement of the motor. 17. The collimator system of claim 16, wherein the processing module detects a status of the leaf based on the movement of the leaf and the movement of the motor. 18. The collimator system of claim 13, wherein the transmission unit is flexible and is in turn connected to a connection unit that is connected to one of the leaves of the leaf array to form the collimator unit. 19. The collimator system of claim 13, further comprising a protection module configured to detect whether the motor is running normally. 20. The collimator system of claim 13, wherein the processing module obtains a trajectory traveled by the leaf based on the initial, current, and target locations of each of the leaves to provide different movement speeds for the leaf during different stages of travel.