A multi leaf collimator MLC for collimating a therapeutic radiation beam, comprising: a plurality of movable leaves having a length of travel, wherein each leaf comprises: a blocking portion having a length L and a width W and being radio opaque, the blocking portion configured to block the therapeutic radiation, a drive portion having a length L' and a width W', the drive portion attached to the blocking portion, and a conductive coil operatively connected to an electrical current source, wherein the conductive coil is positioned within the drive portion of the leaf along at least a portion of length L', and wherein electrical current passing through the conductive coil generates a first magnetic field; a leaf guide configured to support the plurality of leaves; a magnetic drive module configured to move the plurality of leaves, wherein the leaf guide and magnetic drive module are supported in alignment by a support frame (97A, 97B); and a plurality of stationary magnets positioned within the magnetic drive module, each magnet positioned adjacent to the drive portion of at least one leaf, wherein each stationary magnet has a second magnetic field configured to operate in conjunction with the first magnetic field to exert a force on the drive portion, and wherein the conductive coil moves with the leaf when a force is exerted on the drive portion, wherein each leaf has a tapered cross section resulting in a varying thickness of the blocking portion and drive portion. a plurality of movable leaves having a length of travel, wherein each leaf comprises: a blocking portion having a length L and a width W and being radio opaque, the blocking portion configured to block the therapeutic radiation, a drive portion having a length L' and a width W', the drive portion attached to the blocking portion, and a conductive coil operatively connected to an electrical current source, wherein the conductive coil is positioned within the drive portion of the leaf along at least a portion of length L', and wherein electrical current passing through the conductive coil generates a first magnetic field; a blocking portion having a length L and a width W and being radio opaque, the blocking portion configured to block the therapeutic radiation, a drive portion having a length L' and a width W', the drive portion attached to the blocking portion, and a conductive coil operatively connected to an electrical current source, wherein the conductive coil is positioned within the drive portion of the leaf along at least a portion of length L', and wherein electrical current passing through the conductive coil generates a first magnetic field; a leaf guide configured to support the plurality of leaves; a magnetic drive module configured to move the plurality of leaves, wherein the leaf guide and magnetic drive module are supported in alignment by a support frame (97A, 97B); and a plurality of stationary magnets positioned within the magnetic drive module, each magnet positioned adjacent to the drive portion of at least one leaf, wherein each stationary magnet has a second magnetic field configured to operate in conjunction with the first magnetic field to exert a force on the drive portion, and wherein the conductive coil moves with the leaf when a force is exerted on the drive portion, wherein each leaf has a tapered cross section resulting in a varying thickness of the blocking portion and drive portion.