摘要:
An X-ray image pick-up method causes X-rays from an X-ray source to be irradiated on an object for picking up its image as passed through a filter capable of restricting any fluctuation in effective X-ray energy within ±10%, and then the X-rays thus penetrated through the object to be picked up by an image pick-up means. Radiation dose with respect to patients as the object and eventually to doctors or X-ray operators is thereby minimized, while the image pick-up can be realized with a high resolution.
摘要:
This invention relates to design and fabrication of broad-band X-ray focussing devices useful in lithographic production of structures of submicron dimension. Such as those employed in integrated electronic circuits. The designs given here exploit the diffractibility of X-radiation by obstacles and apertures (Figure 1), specifically in the Fresnel or nearfield regime. Devices are described that concentrate at least twofold the intensity of white incident X-radiation whose bandwidth may exceed one octave (Figure 6). Their fabrication requires no methods not already in wide use.
摘要:
An alloy filter (16) in the form of a plate made from a homogeneous alloy comprising 85-95 wt.% cadmium and 5-15 wt.% copper is interposed between a collimator (12) and sodium iodide crystal (18) of a gamma camera. The alloy filter improves image resolution by allowing the passage only of emissions (A,C) which impinge substantially perpendicularly on the collimator, while filtering out others (B,D) which impinge obliquely.
摘要:
Des masques de compensation de rayons X (51) sont préparés en exposant un objet cible (43), tel qu'un patient, à un premier faisceau de rayons X. Le flux de rayons X provenant du patient est reçu par un récepteur d'image électronique (44) qui produit un signal de sortie indiquant l'intensité des rayons X dans toutes les positions du champ d'image. Les informations d'image sont converties par un processeur d'image (47) en des valeurs transformées d'intensité de rayons X pour une pluralité de "pixels" qui couvrent le champ d'image. Un contrôleur de production de masque (48) détermine la valeur minimale d'intensité transformée pour chaque pixel, attribue à chaque pixel un nombre d'atténuation qui est proportionnel à la différence entre la valeur d'intensité transformée pour le pixel et la valeur minimale d'intensité transformée, et envoie des signaux de commande à un dispositif de formage de masque (49) qui dépose sur un substrat non-atténuateur (50) des masques d'atténuation selon une matrice bidimensionnelle de pixels, l'épaisseur de la masse dans chaque pixel étant proportionnelle au nombre d'atténuation. Lorsque le masque (51) est inséré dans le faisceau provenant de la source de rayons X (41), et lorsqu'on procède à une deuxième exposition, le flux de rayons X traversant aussi bien le masque atténuateur (51) que le patient (43) est sensiblement égalisé sur tout le champ d'image.
摘要:
Curved x-ray filter elements are arranged circularly around a drum (40). Alternate circumferentially adjacent elements have different attenuation properties. Diametrically opposite elements have the same properties. An x-ray source (11) provides a sequence of alternate low and high energy x-ray beam pulses. A multicell x-ray detector (18) produces x-ray attenuation data for each pulse and the data is switched to altemate memories (1, 2). A drum drive motor (55) is energized at power line frequency. A pinion on the motor shaft turns a gear. A lug that is mounted for angular adjustment on the gear drives the drum (40). A multiple blade shutter is also mounted on the gear for angular adjustment and rotation with the gear. The shutter alternately interrupts and restores a light beam to a photosensitive device which produces corresponding signal state changes or trigger signals (95). The signals are used to synchronize the low and high energy x-ray pulses, the filter elements angular locations and memory switching with power line frequency.