Abstract: The motors of a multi-leaf collimator for driving the leaves are tilted away from horizontal. The motors are oriented at an angle upwards from the top or downwards from the bottom of a plane formed by the leaves of the multi-leaf collimator. By tilting or angling the motors relative to the multi-leaf collimator, motors with a single standard or a few different shaft lengths may be used. The motors may be more tightly packed, allowing for shorter leaves. Since Tungsten is expensive, costs may be saved by the shortening of the leaves. Standardization of the motor parts may also reduce costs. Due to the reduced weight of the resulting multi-leaf collimator, wear of the bearings of the linac or gantry arm may be reduced.