Abstract: A method for aligning a patient for radiation treatment based on an earlier tomographic scan of the patient uses projection images used to reconstruct a tomographic image rather than reconstructed images and compares the projection images directly to projection images taken at the time of the radiation therapy to determine a series of offsets of the patient which may be used to characterize and correct for motion of the patient between the initial tomographic scan, used for treatment planning, and one or a series of subsequent radiation treatment sessions.

Abstract: A method of proton tomotherapy provides uniform dose placement within a tumorous area on a slice by slice basis by locating a Bragg peak of the proton beam at the distal edge of the tumor and irradiating the tumor from a number of different angles without sweeping the range of the protons at the given angle. Uniform dose is provided by simultaneous intensity modulation of the beams. Treatment of the tumor in slices eliminates the need for a rotating gantry but allows the patient to be rotated instead. Accurate range placement is provided by a preliminary proton verification tomogram obtainable on the same equipment. A set of standard blocks permits this technique to be used with standard irradiation zones without additional range or intensity adjusting mechanism.

Abstract: The note path of a banknote validator has a U-shaped transverse cross section. A transverse strip of the note path is illuminated by light from a light transmitting station by means of a unitary light guide which has an arcuate portion conforming to the transverse cross section of the note path. Light reflected from a banknote within the note path, is captured by the light guide and guided to a light receiving station. The light guide is shaded such that a transverse strip of the note path is substantially evenly illuminated. The U-shape of the note path also assists the insertion of notes into the validator, as an inserted note is used to bow during insertion thereby increasing its rigidity.

Abstract: A radiation therapy machine has a constrained angular freedom to produce a beam only within a gantry plane. A radiation shield may be stationary and not attached to the gantry or rotating to always block the primary beam. The constrained motion reduces the risk of patient/gantry collision and provides for extremely accurate radiation therapy planning. The therapy machine, so constrained, may include a tomographic imaging system on a single gantry. The two systems cooperate and employ many of the same hardware components to both plan and carry out therapy sessions in which irregularly shaped treatment volumes are accurately irradiated while tissue surrounding those volumes is minimally irradiated.

Abstract: A radiation therapy apparatus includes a compensator having a plurality of leaves to divide the radiation beam into rays each of which may be effectively and individually attenuated over a range of attenuations by controlling the duty cycle of the leaves position between the open and closed states. An apparatus for controlling the compensator accounts for scattering of radiation through the deconvolution of a terma map and calculates a sinogram for controlling the compensator at a variety of angles about a patient using iterated forward and back projections efficiently calculated in frequency space.

Abstract: A radiation therapy apparatus includes a collimator that changes the width of a fan beam of radiation as a treatment volume of the patient crosses the volume exposed by the beam so as to minimize the irradiation of healthy tissue at the front and back of the tumor. The width of the fan beam may also be controlled to treat multiple adjacent, similar slices of the patient at one time reducing the treatment duration.

Abstract: A radiation therapy apparatus includes a compensator with moving leaves to attenuate a radiation beam and a compensator verification system to determine if the attenuating leaves are moving in accordance with desired position signals. Two radiation intensity monitoring chambers, one chamber on either side of a patient within a radiation beam, produce beam fluence data used by a computer to construct radiation absorption images and to evaluate the functionality of the compensator. The absorption image can be used for both radiation dose verification and planning of suitable subsequent therapy sessions.

Abstract: A radiation therapy apparatus includes a compensator having a plurality of leaves to divide the radiation beam into rays each of which may be effectively and individually attenuated over a range of attenuations by controlling the duty cycle of the leaves position between the open and closed states. An apparatus for controlling the compensator accounts for scattering of radiation through the deconvolution of a terma map and calculates a sinogram for controlling the compensator at a variety of angles about a patient using iterated forward and back projections efficiently calculated in frequency space.