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At least 37 records · Page 2Linked to original sources

PubMed1976

[Interpretation of autoradiogramms and images of biological objects with the electronically operating image analyzer. "Densitron II". 1. The mode of work, efficiency, and possibilities of application of the apparatus (author's transl)].

Mode of operation and general parameters of efficiency of the Densitron II, an automated, electronically operating image analyzer, are demonstrated in autoradiographs and histological preparations, as an example. In this apparatus, a condensation and preparation of data is effected by isolated representation on a TV colour monitor of all the image - points whose transparency is the same or lies within a determined, freely selected interval. Simultaneous estimation of both transparency and area is possible.

Autoradiography↗

PubMed1977

Myocardial imaging with thallium-201: an experimental model for analysis of the true myocardial and background image components.

The true myocardial and background components of a resting thallium-201 myocardial image were determined in an experimental dog model. True background was determined by imaging after the heart had been removed and replaced with a water-filled balloon of equal size and shape. In all studies, the background estimated from the region surrounding the heart exceeded true background activity. Furthermore, the relationship between true myocardial background and that estimated from the pericardiac region was inconsistent. Background estimates based on the activity surrounding the heart were not accurate predictors of true background activity.

Animals↗

PubMed1979

Right-sided spleen with partial situs inversus of the abdominal viscera: visualization of the spleen by dynamic and static 99mTc-sulfur colloid imaging and 51Cr-labeled red blood cell sequestration imaging.

In a patient with right-sided stomach and malrotation of the small bowel and cecum visualized by gastrointestinal x-ray studies using barium, a right-sided spleen was demonstrated by 99mTc-sulfur colloid and 51Cr-labeled red blood cell imaging. The sulfur colloid study also demonstrated that the liver was in its usual right upper quadrant location.

Adult↗

PubMedDate not supplied

Image resolution of a microchannel plate x-ray image intensifier.

The resolution has been evaluated for an experimental x-ray image intensifier employing three microchannel plates (MCPs) as the photon absorber and electron multipliers. The line spread function (LSF) was measured and used for determination of the modulation transfer function (MTF). The MTF was found to be independent of the incident photon energy from 20 to 150 keV. An additional measurement using a lead-bar test pattern showed that the resolution exceeded 7 line pairs (lp)/mm. The factors influencing the resolution capabilities of the intensifier are discussed. The resolution is limited primarily by the 53-micron center-to-center separation of the channels of the MCPs.

Energy Transfer↗

PubMed1977

Nuclear imaging, tomographic nuclear imaging, and gray scale ultrasound in the evaluation of the porta hepatis.

Twenty-six patients with an eqivocal portal defect on conventional nuclear images were evaluated with a multiplane tomographic nuclear scanner and gray scale ultrasound. In most cases the correct determination (normal or abnormal) for an area of decreased uptake could be made from the multiplane tomographic scans. When an abnormality was thus confirmed, further characterization was provided by ultrasound.

Adult↗

PubMed1979

[Typical presentation of sequential scintigraphy images in the diagnosis of cyanotic heart disease in the newborn, using a computer-assisted imaging technique (author's transl)].

The technique of sequential scintigraphy in investigating newborn infants in order to exclude or detect cyanotic congenital heart disease has been improved. The primary scintigraphic data are recorded digitally (list mode, 1 ms, 128 by 128 pixels) and evaluated automatically as a sequence of 1/2 s frames in 1/8 s increments. A 35 mm film is exposed to a scanning pulsed light spot on a CRT-screen with quantitative correspondence between local count density and the local number of light pulses. A series of highly resolved images of the rapidly changing scintigraphic pattern is achieved in 30 min. The results of 3 investigations are discussed. They prove the importance of adequate spatial resolution and definition in time in nuclear angiocardiography in infancy. Three case results are discussed in detail. In one case cardiac catheterisation and angiocardiography had been omitted, since the radioisotopic findings excluded cyanotic congenital heart disease. Two further investigations are discussed with reference to the findings at cardiac catheterisation.

Angiocardiography↗

PubMedDate not supplied

Dynamic nuclear-medicine image display system using standard multiformatter images.

There is much interest in visualizing dynamic physiological function using nuclear-medicine techniques. In particular, these methods are used in cardiac studies, but it is likely that many other functions will be better visualized with cinematographic-type displays. A new instrument is described which takes a sequence of images, records on a single sheet of film by standard formatting devices and, by means of digitally controlled mirrors, projects them in rapid sequence onto a screen to produce the dynamic movie display.

Analog-Digital Conversion↗

PubMed1977

[Cell image analysis on the PDP-12 computer: a software system for processing the image information from a scanning microscope photometer (author's transl)].

A system of computer programs is introduced which allows image analyzing of cytological or histological preparations. The software system was especially developed for a microprocessor (PDP-12, Digital Equipment Corporation) which is often implied in connection with microscope photometers (SMP 05, Carl Zeiss). Users need not to know anything about computer programming because the computer gives the necessary orders via CRT-display or printer. The different descriptors as they are available after different cytochemical or histochemical staining procedures are combined to a pattern vector which is to be a numerical equivalent of cell morphology. A novel method in numerically describing the fine structure of cell nuclei is emphasized. Different cell populations are compared by means of a simplified multivariate discrimiatory analysis. All programs are written in assembler language and they are stored on LINC tapes (Digital Equipment Corporation). Copies of system tapes respectively tapes with the source programs are available from the authors on sending of blank magnetic tapes (2,000 blocks marked). Description and print out of individual programs are published in the dissertation cited in References. Changes and additions of the system which have been done mean-while will be summarized, and lateron such summaries are available on request.

Cell Nucleus↗

PubMed1976

[Interpretation of autoradiographs and images of biological objects with the electronically operating image analyzer "Densitron II'". 2. Evaluation of the specific and total radioactivity of single cells (author's transl)].

Using the TV image analyzer Densitron, transparencies and areas can be measured by the grey value discrimination method equidensitometry. The time, necessary for one measurement, is approximately 1 min, the standard deviations do not exceed 2%. 2. Also microscopical objects such as single cells can be analyzed by this method. We measured photo-blackings and areas in autoradiographs of goldfish brain-sections after injection of 3H-phenylalanine. As a parallel, blacking and area calibration curves were obtainable and allowed a conversion of the relative values into absolute ones. 3. Using this conversion method, neurons of different brain regions were in the range from 104 to 1476 mum2 in area and from 4.17 to 14.43 muCi-cm-3 in specific radioactivity. After 10 repeated measurements of one and the same cell, the standard deviations of the absolute values were 6 and 4.5%, respectively, on an average. 4. On the basis of these and additional values (thickness of section, number of sections per cell), calculations of the total radioactivity of a cell section or the whole cell can be made.

Animals↗

PubMed1979