Abstract: A method of reducing image artifacts in tomographic, projection imaging systems due to periodic motion of the object being imaged includes the acquisition of a signal indicative of the periodic motion. This signal is used to identify a quiescent period in the periodic motion so that the acquisition of projection data may be coordinated to be centered within the quiescent period. The sequence of the angles at which projection data is acquired is controlled so that the primary axis of periodic motion is perpendicular to the axis of projection at the center of the quiescent period. Multiple periodic signals may be coordinated by awaiting their best alignment over a fixed number of cycles of one of the periodic motions.

Abstract: An X-ray apparatus has motors for moving its components in different directions. Sensors are provided to detect a collision between a motor driven component and an object, such as a patient being examined. In response to a collision being detected, a normal motor power supply is disconnected from the motor and another power supply is connected to the motor to move the component in the reverse direction. A safeguard is incorporated to insure that both power supplies cannot be coupled to the motor at the same time. For components which can strike a patient when moving in either of two directions, different collision sensors are provided for each direction. For this configuration, a mechanism also is provided to inhibit the connection of the other power supply when collisions are simultaneously detected each direction of component movement.

Abstract: An x-ray diagnostics installation has a detector for the mean image brightness in a predetermined region which is within the x-ray beam path. The detector is formed by a matrix of individually activateable detector elements. A control unit, connected to the detector, has a memory in which data sets are stored respectively corresponding to different anatomical parts and positions of those parts. A selection unit identifies and selects a data set corresponding to the anatomical part currently being examined, and the detector elements in the array corresponding to that part are then activated via the control unit. The radiation incident on the acitvated detector elements is then compared, in the aggregate, to a rated value, and the radiation dose is controlled on the basis on the comparison.

Abstract: The fluoroscopic signal is supplied to A/D converter and converted into a digital signal. The digital signal is input to selection circuit, memory and display control circuit. Selection circuit detects the brightness of each frame of the fluoroscopic signal and comprises accumulator, reference register, comparator, and AND gate. Accumulator accumulates digital signal of each frame, and detects the brightness of each frame. Register multiplies the brightness of any frame of image formed before the injection of a contrast medium into the blood vessel, with a suitable coefficient, and holds the product as a reference value. Comparator compares the reference value with the output data of accumulator. A trigger signal is externally input to AND gate, and the output of accumulator is supplied to AND gate. When the output of comparator is not less than the reference value, the comparator outputs the detection signal and the write-enable terminal WE of memory rises to a high level.

Abstract: A collision preventive device for medical equipment (such as readiotherapy equipment) having moving parts to which accessaries are disengageably attached includes a contact detection circuit in which the normally closed contact detector switches disposed on the moving part and on the accessary are all coupled in series, so that an occurrence of contact of the moving part or of the accessary attached thereto can be detected by a relay coupled across a current source in series with the contact detector switches.

Abstract: An x-ray diagnostics installation has an x-ray source, an x-ray image intensifier connected to a video chain and a processing circuit which controls various components of the installation. The processing circuit includes a weighting circuit which allocates an individual weighting factor to different regions of the x-ray image. The processing circuit also includes an evaluation circuit, connected to the weighting circuit, which combines the signals from the weighted image regions to form an actual value signal, which is used to control certain of the components of the installation.

Abstract: An apparatus for diagnosing a pulmonary ventilation function includes a flow sensor for detecting a breathing cycle of a patient, a gas regulator for supplying a gaseous contrast medium to the patient, and a CT scanner for performing X-ray scanning and photography of a patient's lungs during one breathing cycle, in response to an output signal from the flow sensor and for outputting a plurality of tomographic images including X-ray absorbance components (CT value information components). The tomographic images generated by the CT scanner are stored in an image file memory. The CT value of the tomographic image read out from the image file memory is compared with a threshold value, and a region required for checking the pulmonary ventilation function is extracted as a result of comparison. The extracted region is displayed on a monitor.

Abstract: An irradiation apparatus including an x-ray or gamma-ray source, an optical distance and surface profile measuring device, and means for adjusting the dose of radiation delivered to a target surface by the source based on a precise measured distance from the source to the target surface. The measuring device has a laser or other beam source and photodetector in known fixed relationship to the radiation source, and a pair of mirrors which are turnable to direct the laser beam from the laser to a sequence of selected spots on the target surface and then to the photodetector. Knowing the geometry of the system, the distance from the radiation source to the sequence of spots on the target surface can be computed. In one embodiment the two mirrors define a baseline of a triangle, with the laser and photodetector lying proximate to the baseline. One mirror rotates at a known speed and sensors determine the orientation of the mirror when that mirror directs light reflected from the target onto the photodetector.

Abstract: In preparation for a scan, a camera head (B) is positioned (30, 32, 34, 36) about a patient on a patient table (20) to determine the minor axis (54) and major axis (56). Based on a comparison (60) of a difference in the major and minor axes with preselected standards (62a, 62b, . . . ) one of a corresponding plurality of correction factor tables (64a, 64b, . . . ) is selected. During a scan as the camera head is rotated about the patient by an angular position clock (70). The radial distances of the camera head from the scan center are calculated (72, 74, 78) which cause the camera head to follow a generally ellipsoidal path. The size of the ellipse is adjusted (74, 78) in accordance with the major and minor axes. At each of a plurality of angular positions, the enabled correction factor table is addressed by the angular position and a corresponding correction factor is combined (80) with the radius. In this manner, the shape, as well as the size, of the orbit is adjusted.

Abstract: A dynamic coronary roadmap of the coronary artery system is produced by recording and storing a visual image of the heart creating a mask sequence, recording and storing another dynamic visual image of the heart after injection of a contrast medium thereby creating a contrast sequence, matching the different durations of two sequences and subtracting the contrast sequence from the mask sequence producing a roadmap sequence. The roadmap sequence is then replayed and added to live fluoroscopic images of the beating heart. Replay of the roadmap sequence is triggered by receipt of an ECG R-wave. The result is a dynamically moving coronary roadmap image which moves in precise synchronization with the live incoming fluoroscopic image of the beating heart.

Abstract: A radiation image recording and read-out apparatus comprises a circulation transfer means for transferring a stimulable phosphor sheet along a predetermined circulation path; an image recording section which is disposed in the circulation path and in which a radiation image of an object is recorded on the stimulable phosphor sheet by exposing the stimulable phosphor sheet to radiation passing through the object; an image read-out section which is disposed in the circulation path for scanning the stimulable phosphor sheet with stimulating rays and detecting light emitted from the stimulable phosphor sheet to obtain an image signal; and an erasing section which is disposed in the circulation path and releases residual radiation energy in the stimulable phosphor sheet before the stimulable phosphor sheet is returned to the image recording section. The radiation image recording and read-out apparatus further includes a radiation quality changing filter for changing the quality of the radiation.

Abstract: A programmable X-ray film changer for use, for example, in making angiograms, is provided with an improved pressure plate mechanism, feed and removal mechanism, photographic plate indexing mechanism, a clutched single cycle drive mechanism, a receiving photographic plate cassette and control methodology. The improvements in combination permit a substantial reduction of the number of parts in the film changer resulting in increased reliability, a decrease in the expense of manufacture, and decreased weight. Furthermore, the X-ray photographic film changer is arbitrarily orientable in space and independent of gravity feed mechanisms or the interference of gravity with respect to its operation. The improved pressure plate is normally substantially flat and is bowed to form a convex surface by a pressure plate bowing mechanism. Misfeeds of multiple numbers of photographic plates are thus tolerated by the natural resiliency of the pressure plate.

Abstract: A structure and method for providing optimum recording of X-ray images without need for experimenting to learn optimum X-ray tube voltage, current, anode focal spot size and exposure time. The method and structure of this invention sample the radiation passed through an object to be radiographed during a short portion of the total exposure time and adjust voltage, current and focal spot size so that the radiation delivered by the X-ray tube during the remainder of the exposure time will produce optimum contrast between structures within the object being radiographed, also optimum sharpness of the image and optimum darkening of a film, xerographic picture, fluoroscopic image, or other recording medium. The method and structure of this invention account for variations in absorption coefficient between one object to be radiographed and the next. This invention is particularly useful for medical applications, and in the medical field, particularly important in mammography.

Abstract: A positioning control system controls the shifting of one of a plurality of radiation filters into the ray path. Transducers provide an electric density signal which is dependent upon the density of the examination subject. The control system has an electromotor activated by a control circuit to which the density signal is applied and which activates the motor corresponding to the respective density signal for the purpose of selection of the correct filter. The transducers may be coupled with a device physically acting in compression on a body part of the patient to be examined such that the degree of resistance of the body part to compression is sensed by the transducers as a measure of patient density.

Abstract: A switch mechanism for an image intensifier hood in an x-ray diagnostics system is connected to a motor for moving the x-ray image intensifier toward and away from an examination subject. If the hood inadvertently comes into contact with the examination subject or a technician, the hood is displaced thereby actuating the switch mechanism and disengaging the motor to stop movement of the x-ray image intensifier, thereby avoiding injury to the examination subject and technician and avoiding damage to the x-ray image intensifier. The switch mechanism is constructed such that actuation thereof occurs upon the presence of forces acting on the hood in the direction of the luminescent screen surface or a direction perpendicular thereto, and each intermediate direction.

Abstract: In a digital subtraction imaging apparatus, the digital subtraction between mask images and contrast images is carried out in synchronism with cardiac beats of an object under medical examination such as a patient. The subtraction-imaging apparatus includes a first memory, a second memory, a cardiac-synchronized subtraction unit, and a central processing unit. When the number of the contrast images acquired within one cardiac cycle is smaller than that of the mask images, for example, when four contrast images and five mask images are obtained, the digital subtraction by the subtraction unit, under the control of the central processing unit, is performed between four contrast images and only four mask images, without using the fifth mask image.

Abstract: An x-ray diagnostics installation for subtraction angiography has an image memory connected to an output of an x-ray image intensifier video chain which has a number of addresses for storing individual x-ray video signals obtained during a dynamic body cycle of a patient under observation. A differencing unit receives stored signals from the image memory as well as current video signals and substracts those signals to form a superimposed image. Entry and readout of signals to and from the image memory is under the command of a control unit which is connected to the patient through, for example, an EKG circuit for identifying selected occurrences in the body cycle under observation. Entry and readout of data from the image memory is thereby controlled in synchronization with the selected occurrences in the cycle.

Abstract: A method and apparatus for examining a subject by applying radiation to the subject in synchronism with a cardiac beat phase of the subject, wherein a digital subtraction is carried out between a mask image and a contrast image derived from the detected radiation which passed through the subject. Cardiac beat phase is detected by measuring the time-elapse characteristic data of image concentration. Based on the measuring time-elapse characteristic data, amplitude and phase images of the cardiac are calculated and displayed.

Abstract: Computed tomography apparatus in which data is acquired during one or more full rotational cycles and suitably stored by scanning a beating heart or similar objects and in which a complete image corresponding to a cross section of the beating heart is produced on a CRT screen and is correlated with a specific portion of the heart cycle reconstructed from the limited data taken during a time interval which is a small fraction of the duration of the heart cycle. Advantageously, the apparatus presents the cross section image of the beating heart and reference data correlated with certain parameters of the cross-section display on the same CRT screen.

Abstract: In an angiographic apparatus, operation timings of an entire system, e.g., an X-ray generator, an X-ray detector, a transmission image processor, and an injector for X-ray contrast medium are controlled in synchronism with cardiac beat waves of a biological object.

Abstract: Disclosed is automated setting of x-ray technic factors (e.g., KV, MA and exposure time) on the basis of (a) automated determination of the thickness of the body part to be imaged by a non-contact ranging system, (b) push button selection for the type of examination, and (c) push button selection for the type of body physique. The automatically determined technic factors and/or thickness are displayed to allow for manual override, and other failsafe features are provided as well. For better results, the ranging transducer is in the path of, and aligned with the axis of, the x-ray beam while producing ranging information, but is out of the x-ray beam path for the actual x-ray examination. An interlock is provided so that the x-ray beam is not on when the ranging transducer is in the beam path.

Abstract: The patient's ECG signal is employed in a traverse-and-rotate type CT scanner as a time base for triggering the beginning of a traverse such that the traveling beam reaches the heart at a desired phase of the cardiac cycle. For a purely-rotational-type CT scanner, continuously generated scan data is only stored for corresponding phases of successive cardiac cycles. Alternatively, gating of the beams themselves can be controlled by the ECG signal. The use of a pacemaker to stabilize the cardiac period is described along with a system for recognizing unacceptable variations in the cardiac period. In a traverse-and-rotate-type fan-beam CT scanner, the effective beam width is narrowed to hasten the traverse of the heart.

Abstract: Tomodensitometer, particularly for examining bodies which perform cyclic movements such as the heart and the pericardiac tissues. To eliminate blurring caused by the heart movements the rotation of the radiodensitometric measuring system is synchronized with the movements in such a way that at the time when the periodic movement of the tissue is at its maximum amplitude the projection direction substantially coincides with the direction of the movement and that the start and finish of the measurements coincide respectively with the start and finish of the immobility periods adjacent to the movement period.

Abstract: An exemplary embodiment comprises a patient support, an x-ray tube supplied by an x-ray generator, an x-ray image intensifier with a series connected television chain, a control loop for the controlling the mean image brightness, a syringe for contrast medium injection, and a program memory for storing several radiographic exposure programs. A time measuring device is present which is started by the syringe and is stopped by an evaluation unit when the mean image brightness varies to a predetermined extent. A computer calculates the contrast medium velocity from the measured time and the distance (x) between the injection location and the measuring location. On the basis of the calculated contrast medium velocity, an optimum program calculation, or program selection, respectively, is possible.

Abstract: An exemplary embodiment includes an x-ray image intensifier television chain, an image memory, and a subtraction device which subtracts the stored and the current video signals. A radiographic control device derives control pulses for controlling image storage from the EKG of the patient. A second image memory is connected with the output of the subtraction device. The radiographic control device is connected to both image memories and is designed in such a manner that it triggers the storage at selected different times during a heart cycle.

Abstract: A dental tomography apparatus comprises three drive motors for displacing the film and the X-ray source in two mutually perpendicular directions in a horizontal plane and for pivoting the carrier which connects the film and the X-ray source. The control signals for the motor drives are derived from the contour of the dentition by means of a plate which is covered by contacts on which the patient exerts a pressure by biting, so that the contacts whose position corresponds to the shape of the dentition are actuated. Therefrom, the contour of the dentition is determined by an arithmetic unit which supplies the control signals for the drive motors.

Abstract: Disclosed is automated setting of x-ray technic factors (KV, MA and exposure time) on the basis of (a) automated determination of the thickness of the patient part to be imaged by a non-contact, sonic ranging system, (b) push button selection for the type of examination, and (c) push button selection for the type of patient physique. The automatically determined technic factors and/or thickness are displayed to allow for manual override, and other failsafe features are provided as well.

Abstract: An inspection system is provided to simultaneously X-ray inspect hand carried articles and provide metal detection of the person of the carrier. These different inspections are independent, and may be carried out separately from one another. The X-ray inspection involves the insertion of a hand carried item into a chamber, and guiding it along the X-ray inspection station by holding a handle outside of the detector. Metal detection of the person may be accomplished independently by walking through a metal detector arch.

Abstract: An arrangement for determining a medium by means of a temperature sensor which is kept at a given excess temperature, in which the power to maintain the given excess temperature is determined, which includes a source of measuring radiation, a source of auxiliary radiation and the temperature sensor being exposed to a ray path of the measuring radiation and the auxiliary radiation, and means for generating a signal representative of a property of the medium, such as its absorptive or reflective capacity, its polarization properties, as well as correlative properties derivable therefrom.