Direct Magnification Radiography Research Articles

Microfocal Spot Magnification Mammography Using Xeroradiographic and Screen-Film Recording Systems

Direct radiographic magnification (1.5X) of the breast, using a microfocal spot x-ray tube and either a xeroradiographic or screen-film recording system, produces images superior in quality (improved resolution, reduced noise) to conventional contact mammograms. Six hundred twenty-one patients had a single magnification mammogram in addition to conventional mammography; 216 subsequently underwent biopsy within one month of study. The additional magnification mammogram increased the diagnostic accuracy of the conventional examination in 40% of the pathologically proved cases, particularly among those for which conventional mammograms were interpreted as equivocal for malignancy. The superior image quality of magnification mammograms appears useful in distinguishing malignant from benign breast disease.

Magnification Mammography: A Low-Dose Technique

Image quality and radiation exposures of a mammographic technique using direct radiographic magnification at 2 X with a microfocal spot x-ray tube and a fast, double screen-film system were compared to those of conventional contact mammography with a rare-earth screen and molybdenum target tube. The results indicate that the magnification technique yields improved detection of microcalcifications and comparable visualization of soft-tissue details, with a large reduction in radiation exposure. This technique has demonstrated the feasibility of carrying out high-quality mammography with an entrance dose of 1.35 X 10(-3) Gy (135 mrad) for the average breast.

Versatile film holding device for direct magnification radiography.

Versatile film holding device for direct magnification radiographyER Poling and M SundaramAudio Available | Share

Versatile ceiling tube mount for direct magnification radiography.

Versatile ceiling tube mount for direct magnification radiography.

The clinical value of direct magnification radiography in orthopedics

Over 700 macroradiographic examinations have been carried out using a microfocus tube with a stationary anode and a tungsten target. Several of these patients were under the direct care of the orthopedic service and the value of magnification both to the orthopedic surgeon and radiologist is discussed. It's value in trauma, tumors, infections, and in arthrography are discussed with illustrations. Erosive arthropathies, metabolic bone disease, and other osseous problems are not discussed although experience indicates that magnification has a very significant role to play in all of these entities. No technical problems have been encountered with endurance and quality of the microfocus tube. Technologic ease, any desired screen film combination and automatic processing all make direct magnification radiography a very practical and valuable complementary tool. Short exposure time is reflected by the high resolution obtained in pediatric patients.

Direct radiographic magnification for skeletal radiology. An assessment of image quality and clinical application.

Recent advances in technology have made radiographic magnification of the skeleton clinically feasible. A new electron gun micro-focal tube combined with new high-resolution recording systems were used to perform magnification radiography which was then compared with conventional contact radiography. Quantitative evaluation included measurements of speed, contrast, resolution, and noise. Qualitative evaluation included an analysis of 215 clinical cases in which both techniques were used. The superior image quality of direct radiographic magnification is confirmed and the clinical areas in which it proved most helpful are defined.

Roentgenographic aspects of calcium pyrophosphate dihydrate crystal deposition disease (pseudogout)

A comprehensive review of the roentgenographic features of calcium pyrophosphate crystal deposition disease (pseudogout) is presented. The roentgenographic techniques are reviewed. Those recommended as optimal are as follows: for small peripheral joints, industrial Type M film with contact exposure; for large central joints, direct radiographic magnification (3-4 X) with a microfocus tube. The classic appearances of articular chondrocalcinosis in fibrocartilage, hyaline cartilage, and capsular structures are discussed. Distinctive features of pyrophosphate arthropathy, including the distribution of involvement and the degree of destruction, are emphasized. Finally, the relationship among articular chondrocalcinosis, arthropathy, microscopic crystals, and symptoms is discussed.

Direct serial magnification radiography using a film changer of standard height and a tilting radiographic table.

An existing multipurpose fluoroscopic and special-procedure room with a film changer of standard height can be used for direct serial magnification radiography by adding a simple stand and a sliding plastic table top. The motor drive of the radiographic table top is used to elevate the patient, eliminating the need for special tables or cassette changers.

Short Target Film Rotating Grid Magnification

Abstract Two techniques of direct-magnification radiography are compared : (a) standard magnification using a 40 cm air gap to reduce scatter, and (b) short-target-film (STF) magnification using a 55 cm target-film distance and a rotating grid to reduce scatter. Both techniques provide nearly equal resolution, although STF magnification is slightly superior in this respect. The advantages and disadvantages of STF magnification are discussed.

Radiological Findings in Chest of Patients After Total Laryngectomy

Since 1949 we have been working on periodical examination for a large group of over 700 patients who underwent the total laryngectomy due to laryngeal cancer and have spoken by means of esophageal speech method or with a speech instrument.It was planned with a purpose of following studies:a) Estimation of general organic and functional conditions of such senile patients and guidance or controle of personal life.b) Detection of local recurrence or metastases to other organs, especially to the lung, in early stage.c) Influencet of inhalation through the stoma of the trachea on the lung.d) Roentgenologic analysis of phonation and speech mechanism by means of cinematography.e) Relation between abnormal speech methods and condtions of G-1-tract.For b) and c) we have used all sorts of roentgen examination technics, such as plain and contrast, including high-voltage and direct magnification radiography, which make us possible to interprete various abnormalities of lung markings, especially of vascular shadows. Results obtained, concerning about b) and c) are as follows:1) Recurrences or lung metastases of laryngeal cancer were chiefly concentratrated within 5 years after operation, particularly frequent in the first 2 years.2) Primary lung cancer of any other organs, for example, stomach, intestine or kidney, were revealed in relative higher incidence.3) Changes of bronchopulmonary system were found in various forms and grades:(i) chronic and recurrent inflammation, (ii) fibrotic changes, above all, of interstitial tissues, which leds to abnormalities of vascular shadow, such as irregular running course, unbalanced calibre and/or irregular contour, and(iii) emphysema.

Observations on magnification radiography. Visualization of small blood vessels and determination of focal spot size.

AS ANGIOGRAPHIC diagnosis becomes more and more refined there is a demand for radiographic demonstration of smaller and smaller vessels. The various factors restricting resolution of x-ray images are well known, and it is proposed here to make some comments on the problem of geometric unsharpness and the use of primary or direct magnification radiography in vivo. Optimal resolution of vascular detail is obtained by low kilovoltage radiography of thin specimens in contact with fine-grain emulsion film, followed by photographic enlargement. In order to apply secondary or photographic magnification to in vivo angiography, the organ to be studied must be relatively thin and placed in direct contact with the film-holder. Margulis used this method in small experimental animals and on the human bowel at surgery (5). Recently Bosniak et al. applied this method to the surgically exposed kidney and bowel of dogs, using industrial-type film (3). In both studies, film grain limited enlargement to tenfold at most. Because of limitations on the rapidity of exposure and excessive radiation dosage with fine-grain film, as well as the inconvenience of the photographic step, secondary magnification has few clinical applications. Primary or direct magnification radiography does not require fine-grain film or special screens so that the overall quantity of radiation need not be excessive. The limiting factor is geometrical blurring due to the size of the focal spot relative to the object studied. Focal spot size is limited on the small side by the concentration of heat on the anode during the x-ray exposure. Experimental tubes with ultrafine focal spots have been described but find little clinical application because of the severely restricted heat capacity (9). Recent interest in direct magnification has been stimulated by the development of x-ray tubes with improved heat dissipation and relatively small focal spots, made possible by such features as decreased anode surface angulation and increased rotor speed and surface emissivity. As a result, studies can now be performed on the human body, through even its thick parts, with acceptably short exposures, at two- to fourfold magnification (4, 8, 10). On the basis of simple geometric considerations' it is possible to estimate the size of the smallest object, relative to the focal spot, that could be demonstrated with a given primary magnification, assuming that only the umbra image is useful. Bellman noted that an image composed only of penumbra would have poor contrast (1). Milne suggested that the apparent size of an object smaller than the focal spot would actually diminish with increasing magnification, referring, of course, to the umbra component only (6). Takahashi described the disappearance of objects smaller than the focal spot as a “filter effect” (9). The validity of these theories depends on whether an image could indeed be usefully detected if it were made up entirely of penumbra.