Abstract: A focused radiation collimator for collimating radiation emitted from a radiation point source located at a substantially known focal distance from the collimator is disclosed. In one embodiment of the disclosed collimator, the collimator is formed by at least two collimator layer groups, aligned, stacked and bonded together immediately adjacent to one another. Each of the collimator layer groups have a plurality of layer group passages arranged there through in a predetermined pattern which is unique to the layer group but which, with the passages of the other collimator layer group in the aligned stack, additively form a plurality of collimator through channels which are substantially aimed at the radiation point source. Each collimating layer group is formed by at least two substantially identical radiation absorbing layers, aligned, stacked and bonded together immediately adjacent to one another.

Abstract: An inhalation device for use in breathing exercises is described. The exerciser includes a thin-walled bellows whose upper end is attached to a top housing member and whose lower end deflects upward upon withdrawal of air from an opening in the upper end of the bellows. Deflection of the bellows allows accurate measurement of the volume of air inhaled by a patient and a true indication whether an inhaled breath is being held. Slotted support arms connecting the top housing member and a bottom housing member permit collapse of the device for storage and shipment of the exerciser as a compact unit. A weight attached to the lower end of the bellows provides a biasing force to assure return of the bellows to a fully extended position even after long-term storage of the device in collapsed form.