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 multi-leaf attenuator having a first plurality of radiation attenuating leaves and a second plurality of radiation attenuating leaves. The first plurality of leaves is spaced with gaps between adjacent leaves within a radiation beam so that the leaves and the gaps therebetween divide the radiation beam into rays. The second plurality of leaves is disposed directly under gaps in the first plurality of leaves so that each ray of the beam can be occluded by a leaf in either the first or second plurality. The gaps eliminate interference between leaves; the staggering prevents radiation leakage between leaves. Each leaf, in both groups, may be moved between a first open state on one side of the beam, a closed state within the beam thus occluding one ray of the beam, and a second open state on the other side of the beam.

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 vapor horn-packing bed assembly for a chemical process tower incorporating a plurality of directional flow vanes within a 360 degree annular housing. A structured packing bed is disposed centrally of the annular housing and the vapor horn is disposed in flow communication with the packing bed wherein discharged vapor will ascend therethrough. The vapor horn includes a plurality of equally spaced flow vanes positioned for intercepting and diverting the vapor flow downwardly within the tower for generating a substantially homogenous vapor region beneath the packing bed. The homogenous vapor generated by such a vapor horn will comprise a turbulent, gaseous region having sufficiently uniform kinetic energy to present a substantially even ascension front into the packing bed of the vapor horn assembly and other packing beds thereabove.