Scanning Microdensitometer Research Articles

Cytoarchitectonic mapping by microdensitometry.

Functional differences among various portions of the cerebral cortex are often correlated with differing cortical layering patterns. Convenient, accurate techniques for scoring layering should therefore prove useful in electrophysiological as well as anatomical investigations. We report the application of a computer-controlled scanning microdensitometer as a means of rapid measurement of optical densities in histological sections of monkey visual cortices, areas 17 and 18. The technique readily permits recognition of the previously defined cortical layers and suggests that still finer consistent layering patterns exist; it provides objective "fingerprints" of cortical regions which facilitate comparisons of structure from area to area and from animal to animal. The procedure should serve also to score the positions of autoradiographic grains, degenerating axonal terminals, and other labeled structures, and to allow the comparison of preparations stained by various techniques.

Particle characterization using the photoscan

A unique image analysis system for particle characterization is in use at the Du Pont Engineering Test Center. It consists of an Optronics scanning microdensitometer and a Du Pont computer program. It performs quantitative measurements of particle size, shape, and edge texture from photographs. This paper describes the hardware, software, and operation of the system and typical applications related to bulk density, agglomeration and filtration.

Automatic analysis of interferograms: optical waveguide refractive index profiles

Compensation of mode velocities in optical waveguides can be achieved by fabricating fibers having graded refractive index cores. One technique for measuring these index profiles is interference microscopy. We have developed a machine aided method for analysis of interference micrographs for the rapid determination of optical waveguide refractive index profiles. Our method consists of digitizing the interference micrograph with a scanning microdensitometer, followed by computer determination of the position of the center line of each fringe. The data obtained are then converted into refractive index and fiber radius information, which is used to calculate a best fit power law function.

Quantitative use of Guinier X-ray cameras in solid state reaction kinetics

Monochromated Guinier-deWolff and Guinier-Lenne x-ray powder cameras and a scanning microdensitometer have been combinedinto a data system for the study of solid state reaction kinetics. Application of the room-temperature and high temperature cameras to both interface-controlled and diffusion-controlled kinetics is discussed. A graphical analysis method is presented.

The measurement of integrated intensities from polymeric-fibre X-ray diffraction photographs

A method is described whereby integrated intensities can be obtained from X-ray diffraction photographs of polymeric fibres. Contour maps of optical density are produced using a digital microdensitometer and `Photowrite' manufactured by Optronics International, Inc., and the total intensity obtained by integrating round contour lines. The method takes less time than making radial scans through the peak intensity of each reflection arc with a scanning microdensitometer, and correcting for the spread in the circumferential direction.

Practical Resolution Enhancement in Bright Field Electron Microscopy by Computer Processing

The arguments and methods previously given have been converted into a full set of programs for the 360/91 or 360/195 computers. The input data is a tape (Photo-Scan or Boiler and Chivens) bearing optical density values (the image function , obtained by a scanning micro-densitometer. Program XFøRM obtains the Fourier transform of a selected data square (2M × 2M points, where M ≤ 11) and deposits the resulting on disk and/or tape. Program SPEC obtains the power spectrum of the data and deposits it on disk and/or tape. Program FILT analyzes by the methods of Refs. 1 and 2 to obtain the required approximation to the Wiener filter function , which is then deposited on disk and/or tape.

乳房撮影に関する研究 その2 : XeromammographyとFilmmammographyの画像の比較検討

The xerox 125 system was used to make a comparative image quality study between xeroradiography (XR) and industrial type MR film which is approximately equivalent to Kodak type AA film. The comparison of the image quality was made by objective and subjective methods at the visual threshold, since diagnostic details in actual mammograms are often marginably detectable. 1) Dependence of the output density distribution on edge gradient is studied in the spatial and the spatial frequency domain. The test objects employed are aluminum rods having square and round cross-sections of 200 μ which simulate calcification in X-ray absorption. The infinite edge gradient of the square alumiunm rod narrows the width at the image with a wide deletion of the powder outside the boundary, while the alumiunm cylinder increases its image width by attracting extra powder inside the boundary. Density distributions of the alminum test objects are converted to spatial frequency spectra by means of Fourier transformation. The use of a square bar results in an excessive decrease of the output amplitude at low spatial frequencies though greater in amplitude in the intermediate to high spatial frequencies than the cylindrical object. 2) RMS granularity σ(D) is determined by a scanning microdensitometer with a 10×150 μ wide scanning slit adjusted with respect to eye's line spread function. Ganularity of the 125 system is dramatically improved than other xeroradiographic systems which have been seen. It may be due to plastic coating on the transfer paper and smaller toner particle size. However, XR is grainiest among the four imaging systems tested. The density fluctuation of the XR is 4 times greater than MR film. This greater density fluctuation may be a result of the high grain pattern contrast since the effective grain sizes are as small as MR film. 3) The concept of "signal-to-noise ratio" is applied to the imaging systems in order to obtain results from objective methods correlated with subjective results or visibility. The output density distributions of alumiunm cylinders ranging from 100 to 1,000 μ in diameter are taken as the inputs to the visual system, and σ(D), as noise. Physiological contrast D/ΔD min. is also taken into consideration for XR in which the surrounding density of an object varies with the magnitude of the edge-effect. The result reveals that XR provides a higher ratio than MR film for aluminum cylinders smaller than 1,000 μ in diameter. XR differs the most from MR film in the radio at 700 μ diameter or so where XR is considered to show the best visibility of calcifications. 4) Visibility is defined here as the adiliity to detect minute calcification in mammary carcinoma ranging 90〜400 μ in diameter, and comparison of visibility between XR and film is made with following factors ; exposure time, radiographic density and geometrical condition. As a whole, XR is superior to film in visibility at both 30 kVp providing additional detectability for smaller calcification by roughly 20 μ in diameter. When visibility of XR is related to varing exposure time, it is far less sensitive than film, but on the contrary more sensitive than film to the radiographic density. Optimum density for XR is very low as 0.3 were the XR print provides the maximum visibility, while 1.5 for film at 7,000 lux rear illumination. XR is less affected by penumbral effects than film, since the visibility of XR depends much more on the contrast than the shapness for the object larger than 100 μ in diameter. It is concluded that the 125 system satisfied an indespensable necessity of mammography for finding small objects in the breast which a patient or her doctor could not find.

Characteristics of organic colorants transferred by laser scanning

This paper discusses two characteristics necessary for efficient laser-induced transfer of organic colorants. Results analyzed on a scanning electron microscope and scanning microdensitometer suggest that the material transfer is caused by melting and vaporization.

Measurement of Apparent Vessel Width in Fluorescence Angiography of the Fundus oculi

A method of measuring the width of photographic images of the retinal blood vessels obtained by fluorescence angiography, using a scanning micro-densitometer, is described. The technique is less tedio

The crystal and molecular structure of a heptacoordinated molybdenum compound, mononitrosylmolybdenum tris(NN-di-n-butyldithiocarbamate)

The crystal structure of tris(N,N-di-n-butyldithiocarbamato) molybdenum(II) nitrosyl has been determined from the three dimensional X-ray data collected by precession methods and measured with a scanning microdensitometer. The material crystallizes in the space group P2 1/c with four molecules per unit cell, a = 15.078(9), b = 27.590(7), c = 9.502(4) Å, and β = 92.33(8)°. Anisotropic refinement of all non-hydrogen atoms by block diagonal least-squares methods led to final residuals of R 1 = 8.1% and R 2 = 10.3 per cent for 2185 non-zero reflections for which F⩾ 2σ. The structure consists of discrete monomers, each composed of three bidentate dithiocarbamato ligands and one nitrosyl group. The donor atoms surrounding the central metal are arranged in a pentagonal bipyramidal configuration which is somewhat distorted due to the small and rigid bite of the dithiocarbamato ligands, two of which occupy four of the basal plane positions while the third one spans an axial to equatorial pair of sites. The nitrosyl ligand coordinates through the nitrogen and ocupiecs the second axial position. The MoN and NO distances, 1.731(8) and 1.154(9) Å respectively, are relatively short and the MoNO angle is slightly bent (173.2(7)°). Adjacent S…S contacts in the equatorial plane are quite short, ranging from 2.809 to 3.080 Å, suggesting sizable non-bonded interactions. The molecule has the following mean bond lengths: MoS, 2.518; SC, 1.715; CN, 1.296 Å. the three S 2CNC 2 fragments are planar and the canonical from (—)S 2CN(+)R 2 makes an important contribution to the electronic structure of the dithiocarbamato ligands. There are weak intermolecular interactions between the nitrosyl oxygen atoms and alkyl hydrogen atoms.

Feeding and lipid synthesis of Ancylostoma tubaeforme preinfective larvae.

The growth curve, rate of neutral unbound lipid synthesis, and relationship between morphogenesis and lipid reserve have been studied at 30 °C. The feeding process, including a theoretical calculation of bacterial requirements of preinfective larvae, is presented, together with some measurements of the most important variables in ingestion, expulsion of water through the anus, and its dependence on larval posture is described.Larval stages have been tracked on agar; L1 are so inactive that no tracks were obtained; L2 show short, irregular tracks, and infective larvae strong, long and straighter tracks. The locomotory activity of L2s is primarily for feeding, whereas L2s are adapted for dispersion and host location.I thank Mr J. M. Smith for tracking the larvae and Mrs Helen Foreman for staining them, Dr Elizabeth U. Canning for making available the scanning microdensitometer and Professor G. S. Nelson and Dr D. A. Denham for enabling us to establish A. tubaeforme in cats. Finally the generous support of the British Medical Research Council is appreciated.

Nuclear DNA contents of Pisum genotypes grown in vivo and in vitro

The nuclear DNA content of prophase nuclei in root tips of two cultivars and two primitive lines of Pisum sativum and of Pisum fulvum have been determined, using a scanning microdensitometer. The nuclear DNA contents differed significantly between the genotypes investigated but there was no correlation with their supposed phylogenetic positions.A loss of 73% of the DNA from cells of aseptically cultured excised pea roots has been recently reported (Abbott, 1971). In marked contrast to this claim, our measurements of the nuclear 4C DNA content of root tip meristematic cells have shown that there is no significant loss in excised roots compared with attached roots.

Image quality of the cat eye measured during retinal ganglion cell experiments

1. The modulation transfer function (MTF) of the dioptrics of fifteen cat eyes was determined. The aerial image, formed by the eye of a standard object (a 0.5-1.0 degrees annulus), was photographed. The transmission of the film negative was measured with a scanning microdensitometer to yield the light distribution within the aerial image. Correcting for the double passage, this experimentally determined light distribution and the known object light distribution were used to obtain the MTF, applying Fourier methods. Each MTF was used to calculate the light distribution within the retinal image of stimuli of various geometry used in experiments on retinal ganglion cells in the same eye.2. When the eye was equipped with an artificial pupil of the same size as that used in the neurophysiological experiments (4.0-4.8 mm diam.) the MTF had fallen to 0.5 at 2.43 c/deg. When the pupil was removed the MTF had fallen to 0.5 at a much lower spatial frequency (1.0 c/deg). This shows that even when one uses an artificial pupil too large to provide optimal image quality there is a vast improvement over using no pupil.3. These image quality measurements were prompted by the need to know the actual stimulus image in experiments on the functional organization of the receptive field, a need exemplified in this paper by a few specific physiological results. The full neurophysiological results appear in the next two papers.

Tract orientation and the intensity of myelin staining.

When frozen sections of brain are stained by the usual techniques for lipids some myelinated tracts react more intensely than others; up to 30% more in a M85 scanning microdensitometer.

A Wide Dynamic Range Photometer for Film Densitometry

A wide dynamic range photometer has been designed with a photomultiplier operated at constant anode current by means of a feedback circuit. The output of the photometer is accurately proportional to the logarithm of light intensity over a range as great as eight decades. The internal feedback loop is stable, with a unity-gain bandwidth up to 100 kHz, depending on the photomultiplier type and anode current. Day-long stability is better than 1% or 0.004 log units. The photometer is being used in a photographic film scanning microdensitometer.

Crop surveys from multiband satellite photography using digital techniques

Multiband and Multibase photography of the Imperial Valley, California, taken during the Apollo 9 mission was analyzed using statistical multispectral pattern recognition techniques. With a scanning microdensitometer, 70-mm frames were converted into digital form and stored on magnetic tape. All analysis was conducted using a digital computer which enabled rapid automatic processing of any of over five million film density measurements. Automatic recognition of fields of barley, sugar beets, and alfalfa was attempted, and the recognition accuracies were 75% for barley, 59% for sugar beets, and 27% for alfalfa. Highly accurate detection of bare soil, salt flats, and water was achieved. Low percentage ground cover crops such as lettuce, onions, carrots, and cabbage were indistinguishable from bare soil. Results using multiband photography are compared with results using color separations of color infrared photography which covered approximately the same bands.

The DNA content of sperm of Drosophila melanogaster.

Amounts of Feulgen staining in individual sperm nuclei of Drosophila melanogaster were determined with a scanning microdensitometer and compared with the DNA-Feulgen levels found for hen erythrocyte nuclei, taken as a presumed cytophotometric standard of 2.5×10−12 g DNA per cell. Under these conditions, the amount of DNA estimated for the haploid male genome of Drosophila was about 0.18×10−12 g DNA, corresponding to a molecular weight of roughly 11× 1010 daltons. From a comparable series of measurements on Feulgen-stained nuclei of hemocytes and epithelial cells of the imaginal soma, values of approximately 0.35–0.36×10−12 g DNA were estimated for the diploid or 2C male genome of this species.

Quantitative microdensitometric x-ray analysis of vertebral trabecular bone. A preliminary report.

Previous radiographic methods for the in vivo quantitation of bone mineral have generally expressed the radiographic density of a scan path across bone in terms of the thickness of reference material which gives the same attenuation of the same heterogeneous x-ray beam (4). The attenuation of the x-ray beam under such conditions is related to the amount of soft tissue over the bone and to the amount of cortical and trabecular bone present. Thus, such methods virtually ignore the relatively minor contribution of the trabecular pattern per se to the overall attenuation of the x-ray beam. In addition, x-ray fields sufficiently large to include the reference wedge add large amounts of x-ray scatter as an additional variable. Known data demonstrate that trabecular bone is more metabolically active than is cortical bone, in terms of mineral turnover rate (1, 3). Since vertebral trabecular bone has been shown to be the most informative to study, with regard to bone mineral metabolism (7), a method has been developed which is designed to permit quantitation of the changes in trabecular architecture which occur in the vertebrae of intact patients. This method, because it does not need a reference wedge, permits the utilization of films made with field sizes no larger than a vertebral body, thus eliminating most x-ray scatter. The method is based upon the hypothesis that vertical orientation of trabeculae is uniform when a vertebral body is viewed from the front or side, but the orientation of the trabeculae is nonuniform when the vertebral body is viewed from the top. This hypothesis appears reasonable, on the basis of the roentgenographic appearance of the trabeculae of excised vertebrae made from the side and top and also on the basis of the pathologic aspect of vertebral-body horizontal and vertical sections (6). The method is also based upon the hypothesis that it is possible to superimpose on a raw densitometric scan a continuously computed, weighted mean line along which the “width” of trabeculae can be determined and which, because it follows the regional density changes, is relatively independent of the regional alterations in optical density in any given roentgenogram. Methods A scanning microdensitometer,3 built for the specific research requirements of this laboratory and de-scribed previously (5), is being utilized for analysis of the roentgenograms. The output signals from the densitometer are fed simultaneously into an analog-to-digital converter,4 into a single channel strip-chart recorder,5 and into two TR-20 analog computers.6 The single channel strip-chart recorder displays the raw densitometric scan information. The analog computers have been programed so that the raw densitometric scan is smoothed, removing the high frequency fluctuations.

Measurement of Dose Distributions with Red Perspex

The radiation-induced increase in the optical density of red Perspex is shown to provide a reliable method of determining spatial dose distributions for high energy radiation in the megarad range. The technique has particular advantages in the examination of dose variations on a microscopic scale, an automatic scanning microdensitometer being utilized for these measurements. Several practical examples are discussed.

Contour mapping microdensitometer

The instrument described in the present paper is basically a scanning microdensitometer in which a gating circuit is utilized in conjunction with an optical printing system to plot automatically a contoured density map of the photograph which is being scanned. The gating circuit used is comparatively simple and extremely stable and permits the insertion of as many contours as are required, at specified values of density.