Abstract: A method of measuring a rotational position of an assembly with circumferential ferromagnetic teeth includes applying an excitation signal for a cycle to an actuator, the cycle causing a first rotational displacement of a first ferromagnetic tooth from a first rotational position to a second rotational position and a second rotational displacement of a second ferromagnetic tooth from the second rotational position to a third rotational position. The method further includes measuring a plurality of first signal outputs from a magnetoresistive sensor during the cycle; determining one or more signal offset values based on the plurality of first signal outputs; applying the signal excitation for a portion of a second cycle to the actuator; measuring second signal outputs from the magnetoresistive sensor; generating corrected signals by modifying the second signal outputs with the signal offset values; and, based on the corrected signals, determining a rotational position of the assembly.

Abstract: A method of measuring a rotational position of an assembly with circumferential ferromagnetic teeth includes applying an excitation signal for a cycle to an actuator, the cycle causing a first rotational displacement of a first ferromagnetic tooth from a first rotational position to a second rotational position and a second rotational displacement of a second ferromagnetic tooth from the second rotational position to a third rotational position. The method further includes measuring a plurality of first signal outputs from a magnetoresistive sensor during the cycle; determining one or more signal offset values based on the plurality of first signal outputs; applying the signal excitation for a portion of a second cycle to the actuator; measuring second signal outputs from the magnetoresistive sensor; generating corrected signals by modifying the second signal outputs with the signal offset values; and, based on the corrected signals, determining a rotational position of the assembly.

Abstract: A beam modifier shapes the distribution of a dose delivered to a target by a radiation beam emitted from a beam emitter of a radiotherapy device, particularly a beam that delivers a high radiation dose within a single, short period of time (e.g., less than a second). Elements of the beam modifier (e.g., rods) include material that can block or attenuate the beam. The elements can be dynamically and quickly configured to form an opening or transparent area through which a portion of the beam can pass unimpeded and to present different thicknesses of material to block or attenuate other portions of the beam, in this manner shaping the dose distribution at the target while protecting surrounding tissue.

Abstract: A beam modifier shapes the distribution of a dose delivered to a target by a radiation beam emitted from a beam emitter of a radiotherapy device, particularly a beam that delivers a high radiation dose within a single, short period of time (e.g., less than a second). Elements of the beam modifier (e.g., rods) include material that can block or attenuate the beam. The elements can be dynamically and quickly configured to form an opening or transparent area through which a portion of the beam can pass unimpeded and to present different thicknesses of material to block or attenuate other portions of the beam, in this manner shaping the dose distribution at the target while protecting surrounding tissue.