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At least 127 records · Page 7Linked to original sources
PubMed1992

Demonstration of digital radiographs by means of ink jet-printed paper copies: pilot study.

Different digital medical images have been printed on paper with a continuous ink jet printer, and the quality has been evaluated. The emphasis has been on digital chest radiographs from a computed radiography system. The ink jet printing technique is described as well as the handling of the image data from image source to printer. Different versions of paper prints and viewing conditions were compared to find the optimum alternative. The evaluation has been performed to maximize the quality of the paper images to make them conform with the corresponding film prints and monitor images as much as possible. The continuous ink jet technique offers high-quality prints on paper at a considerably lower cost per copy compared with the cost of a film print. With a future switch-over from diagnosing of digital images on film to diagnosing them on monitors, hard copies for demonstration purposes will occasionally be needed. This need can be filled by ink jet-printed paper copies.

Copying Processes↗
PubMed1994

Evaluation of the image quality of ink-jet printed paper copies of digital chest radiographs as compared with film: a receiver operating characteristic study.

Paper copies of digital radiographs printed with the continuous ink-jet technique have proved to be of a high enough quality for demonstration purposes. We present a study on the image quality of ink-jet printed paper copies of digital chest radiographs, based on receiver operating characteristic (ROC) analysis. Eighty-three digital radiographs of a chest phantom with simulated tumors in the mediastinum and right lung, derived from a computed radiography (CR) system were presented in two series of hard copies as ink-jet printed paper copies and as laser recorded film. The images, with a matrix of 1,760 x 2,140 pixels, were printed with a spatial resolution of 10 pixels/mm in the CR film recorder as well as in the ink-jet printer. On film, every image was recorded in two versions, one optimized for the mediastinum and one for the lungs. On paper, only one image was printed; this constituted an effort to optimize both the mediastinum and the lungs. The ink-jet printed images, printed on a matt coated paper, were viewed as on-sight images with reflected light. The examinations were reviewed by six radiologists, and ROC curves were constructed. No significant difference was found between the performance of film and that of ink-jet paper prints. Because the cost for a paper copy is only a tenth of that of film, remarkable cost reductions can be achieved by using the ink jet technique instead. Our results show that further quality studies of ink-jet printed images are worthwhile.

Copying Processes↗
PubMed1994

Development of a digital duplication system for portable chest radiographs.

To provide high-quality duplicate chest images for the intensive care units, we have developed a digital duplication system in which film digitization is performed in conjunction with nonlinear density correction, contrast adjustment, and unsharp mask filtering. This system provides consistent image densities over a wide exposure range and enhancement of structures in the mediastinum and upper abdominal areas, improving visibility of catheters and tubes. The image quality is often superior to that of the original radiograph and is more consistent from day to day. Repeat rates for portable chest radiographs have been reduced by more than a factor of two since implementation of digitization in December 1991, and the number of repeat examinations caused by exposure errors have been substantially reduced.

Computer Systems↗
PubMed2003

Subjective image quality of digital panoramic radiographs displayed on monitor and printed on various hardcopy media.

The subjective image quality of panoramic radiographs shown on a diagnostic computer monitor were compared with professional direct thermal prints and with common inkjet prints on different paper qualities. Indirect digital panoramic radiographs were obtained from 15 patients. The images were printed with a direct thermal printer in their original format. Afterwards, these were loaded in an imaging software programme (Microsoft Photo Editor) and assessed both on computer monitor and inkjet prints on transparency, glossy, satin and regular paper. Five observers assessed subjective image quality for different regions and anatomical landmarks on a 5-point rating scale. Data were statistically analysed and inter- and intra-observer performances were calculated. Best image quality was obtained with direct thermal prints, followed in descending order by panoramic images viewed on the monitor, inkjet prints on transparencies, glossy paper, satin paper and finally regular paper. The differences were significant except for monitor images versus direct thermal prints, inkjet-transparencies and inkjet-glossy images and inkjet-satin versus inkjet-glossy images. The subjective image quality of indirect digital panoramic images is different for images shown on the computer monitor and for printed images depending on both the printer and paper type used.

Adolescent↗
PubMed2005

Photocopies yield lower digit ratios (2D:4D) than direct finger measurements.

The ratio between 2nd and 4th digit length (2D:4D) may be a negative correlate of prenatal testosterone. This possibility has led to a number of studies of 2D:4D and its relationship with sexual orientation and other sex-dependent traits. At first, 2D:4D ratio was calculated from measurements made directly on the fingers but recently a number of studies have used measurements from photocopies of the hands. Here, we compared finger lengths (2D, 3D, 4D, and 5D) and ratios obtained from these two measurement techniques. Our sample consisted of 30 homosexual men and 50 men and 70 women who were not selected for their sexual orientation. We found evidence that (1)2D:4D from photocopies tended to be lower than that from direct measurements, (2) there were differences in finger lengths such that 2D from photocopies tended to be shorter or equal in length to direct measurements, while 4D from photocopies tended to be longer or equal in length to direct measurements, (3) the sex differences in 2D:4D tended to be stronger for photocopy measurements, and (4) the pattern for length differences across 2D to 5D appeared to be different for homosexual men compared to men and women recruited without regard to sexual orientation. We conclude that there are differences in digit ratios obtained from photocopies and direct measurements, and these differences arise from length differences recorded from the different protocols. Therefore, 2D:4D ratios obtained from photocopies and direct measurements should not be combined within one study nor should they be used together in comparative studies. We suggest that finger length differences between the two techniques could result from the shapes of fat-pads at the tips of the fingers and these may be dependent on sex and sexual orientation.

Adult↗
PubMed2004

Photocopier exposure and risk of sarcoidosis in African-American sibs.

BACKGROUND: In a family study of sarcoidosis in African-Americans, we detected a positive association between sarcoidosis and ever working in a sales or clerical occupation. This finding, and case reports of granulomatous lung disease in patients with photocopier toner dust exposure, led us to hypothesize that sarcoidosis risk may increase as a result of photocopier exposure. METHODS: Retrospective data on photocopier use and maintenance were collected from African-American sarcoidosis cases and their first degree relatives. The study sample consisted of 181 African-American sibships where one or more members had a history of sarcoidosis (n = 540). RESULTS: Sarcoidosis was statistically significantly associated with ever using a photocopier (Odds Ratio [OR] = 1.74, 95% confidence interval [CI]: 1.23-2.46), and ever changing photocopier toner or carrying out photocopier maintenance (OR = 2.88, 95% CI 1.83-4.54). In a conditional logistic regression model that adjusted for age and sex, the OR associated with a sarcoidosis history and being in the highest tertile of photocopier exposure ranged from 1.83 to 2.19 depending on the exposure measure used. CONCLUSIONS: These results suggest that photocopier toner dust may be a previously unrecognized antigen in the pathophysiology of some patients diagnosed with sarcoidosis.

Adult↗
PubMed1991

Photoduplication and fluorescence measurement in polyacrylamide gel electrophoresis.

A simple method of photoduplication of gel electrophoresis, visualized with fluorescent reagents, is described. The procedure is convenient and rapid and requires no camera or expensive equipment. Using electrophoresis duplicating paper (Kodak), positive prints suitable for documentation or publication may be obtained. With usual photographic paper, negative prints may be obtained, allowing reliable measurement by scanning. The technique may be applied to protein or nucleic acid electrophoresis.

Copying Processes↗
PubMed1978

A xerographic method for the quantitative assessment of atherosclerotic lesions.

A new method has been developed for the quantitative assessment of atherosclerotic lesions, in which a conventional xerox machine is the sole equipment used. As an example, the aorta from a cholesterol-fed rabbit was removed in toto, opened longitudinally along its anterior margin, flattened in a transparent polypropylene bag and then xeroxed. The outlines of the atherosclerotic lesions were traced on translucent graph paper ruled into 1 mm squares. The squares within those outlines were counted and expressed as a percentage of the whole surface. This xerographic method is rapid and reproducible and is achieved without changing the magnification; it gives comparable or better results than other staining methods. As the aortic specimen is undamaged by fixation or staining, the specimen can be used for subsequent morphological or biochemical studies. Thus, the degree of surface involvement can be correlated with other morphological or biochemical changes in the same arterial samples.

Animals↗
PubMed1984

Duplicating maxillary complete dentures.

A technique for duplication of a maxillary complete denture has been presented. This technique requires no special equipment and can be easily completed in the dental office.

Copying Processes↗
PubMed1979

A study of the quality of duplicated radiographs.

The resolution, contrast, and clinical appearance of radiographs and duplicate radiographs made with two types of duplicating film were compared. Duplicating conditions evaluated were type and shape of light, light-film distance, type of exposure surface, and developer temperature. Major observations were as follows: both Kodak and DuPont films produced clinically acceptable duplicates; Kodak film was faster; DuPont film responded better in incandescent photoflood light than Kodak film; clear glass with appropriate light-film distance was the best exposure surface.

Absorptiometry, Photon↗
PubMed1981

Evaluation of the quality of duplicated radiographs.

This experiment evaluated the image quality of duplicated radiographs made at different ultraviolet light exposures. Image quality was measured in terms of "residual" film fog, film density, mottle, image contrast, and resolution. The "residual" fog density of duplicates decreased with increases in ultraviolet exposures until it was less than the fog density of the original. The density of duplicates decreased with increases in ultraviolet exposures until it leveled off at a certain density, depending on the density of the original film. Mottle was less on lighter duplicates than on darker duplicates. Contrast of duplicates increased initially with increases in ultraviolet exposures and later decreased with further increases in ultraviolet exposures. Resolution of duplicates was nearly the same as the original as long as the duplicate had acceptable "residual" fog density.

Copying Processes↗
PubMed1981

Duplication of dental xeroradiographs.

This study investigates the duplication of dental xeroradiographs using duplicating (copy) film, Polaroid photography, and Xerox photocopying. Quantitative studies of the image quality of duplicated images demonstrate similar image degradation with duplication film and Polaroid photography and gross degradation with a Xerox photocopier. Subjective diagnostic assessments by general dentists and dental specialists indicated that copies made with the use of duplication film or Polaroid photography were adequate for the reproduction of dental xeroradiographs, whereas Xerox paper copying was unacceptably poor.

Copying Processes↗