George Jacobson

The prevalence of coal workers' pneumoconiosis in US coal miners.

The National lnstitute of Occupational Safety and Health of the US public Health Service recently completed the first round of a large field study to determine the prevalence of coal workers, pneumoconiosis in working US coal miners. Between October 1969 and July 1971 a total of 9,076 miners from 29 bituminous and 2 anthracite mines were examined. An overall prevalence of nearly 30% was found. However, progressive massive fibrosis occurred in only 2.5% of the sample. when the data were broken down according to the geographic region in which the mine is situated, marked regional differences in prevalence were apparent. Thus, while 45% of the Eastern Pennsylvania anthracite miners had simple pneumoconiosis and a further 14% had progressive massive fibrosis, the comparable figures for bituminous miners in Colorado were 4.6% and 0%. No obvious cause for these disparities in prevalence was apparent.

Pulmonary artery to vein shunts in obstructive pulmonary disease

Abstract Forty-six patients with chronic respiratory disease were studied; all but two had obstructive pulmonary disease. In none were intracardiac shunts or pulmonary arteriovenous fistulas detected. In four patients with obstructive pulmonary disease a direct pulmonary artery to vein connection was identified by peripheral pulmonary wedge arteriography. The findings in these four patients (history, physical examination, electrocardiography, chest roentgenography, cardiac catheterization, pulmonary function studies and angiography), compared with those in the remaining patients in whom no shunt was visualized, revealed no discriminating differences. All patients with pulmonary artery to vein connections had moderately severe obstructive pulmonary disease and moderate degrees of pulmonary hypertension. Pulmonary vascular resistance was significantly increased. When measured, the arterial blood pO 2 at the end of a twenty minute period of oxygen breathing was significantly decreased. However, many patients without definitely identifiable shunts showed similar degrees of abnormality. Since many of the latter had arterial blood pO 2 of from 134 to 350 mm. Hg during 100 per cent oxygen breathing, it is likely that arteriovenous shunts were present but not identified by the method of pulmonary arteriography employed.

Cardiac catheterization in interatrial septal defect

Abstract 1.1. Ten proven and seven presumptive cases with atrial septal defects have been presented. 2.2. The importance of catheterization of the left auricle is emphasized, together with the differential diagnosis of atrial septal defect from transposed pulmonary veins. 3.3. A rise of oxygen content in the right atrium in comparison to the oxygen content of the superior vena cava is not necessarily present in proven atrial septal defects. 4.4. The cause for cyanosis in atrial septal defect lies primarily in the presence of a right to left shunt. 5.5. The direction of shunt is determined by the pressure gradient between the atria during the cardiac cycle. 6.6. Pulmonary vascular disease may contribute to the pulmonary resistance but is not a significant factor in the production of cyanosis.

Optimization of Electrostatic Imaging Systems for Minimum Patient Dose or Minimum Exposure in Mammography

The x-ray photon energies that give the highest signal-to-noise ratios per unit of exposure or average dose in mammography are significantly greater than those used in current film/screen systems. Optimum photon energies for detection of calcifications in a range of thicknesses of water and fat were calculated. Soft-tissue targets were also considered. Comparison of the theoretical results and those obtained experimentally with the Stanton mammography phantom indicate that operation at less than optimum photon energies is a major cause of inefficiency in film/screen mammography. On the other hand, electrostatic imaging systems, because of their processing flexibility, can operate at the optimum photon energy levels, thus minimizing either dose or exposure.

Electronic Grids for Electrostatic Imaging Systems

Electronic grids have been substituted for conventional grids in an electrostatic imaging system and have been useful in chest radiography. Electronic grids also appear to be useful for clean-up of small amounts of scattered radiation in radiographs of the extremities. More clinical work is needed before a statement about the use of electronic grids for other examinations can be made.

PERIPHERAL PULMONARY (WEDGE) ARTERIOGRAPHY--A STANDARDISED TECHNIQUE FOR THE SINGLE FILM ARTERIOGRAM.

Summary Peripheral pulmonary or wedge arteriography, recorded by either single film or cineradiography, is a safe simple procedure by means of which very small pulmonary vessels can be studied in vivo. Arteries with an internal diameter as small as 0.1 mm. can be visualised. A standardised technique for single film radiography is described. When performed in conjunction with drugs and gases, it may be possible to distinguish reversible vascular abnormalities.

Electron Radiography: A New Method of Radiographie Imaging

Images are produced by utilizing a photoemissive process in an imaging chamber. The image receptor is a low-cost plastic film. At its current state of development, the systems gray scale, sensitivity and resolution are comparable to conventional par speed screen-film combinations, but with controllable edge and very low fog characteristics. The process is entirely light insensitive and utilizes standard radiation-producing equipment but eliminates conventional darkroom and wet-developing procedures. Quantum efficiency is close to 50% over the important energy range, and radiation reduction for equivalent density has been obtained on prototype models.

Preliminary studies using electron radiography for mammography.

An electron radiography mammography system was used for phantom studies and to obtain 230 craniocaudal view patient studies, of which 140 were compared to xeroradiographs for their ability to visualize 7 features of diagnostic importance. The average exposure of the electron radiographs was 89 mR. The technique was considered equal or superior to xeroradiography in 58% of the compared diagnostic features, while patient dose was reduced.

Analysis of the Rejection Rate of Chest Radiographs Obtained during the Coal Mine “Black Lung” Program

Approximately 3% of the radiographs taken as part of the current coal mine “black lung” survey were rejected by B and C readers as being of poor quality. No single factor can be pinpointed as the cause of rejection; rather, the real difficulty is the willingness of many A readers to accept films of poor quality. The authors suggest that quality control programs will not be solved until all A readers understand what is required by the B readers and refuse to accept films which do not meet stringent quality standards.

Sarcoidosis of the Nose and Paranasal Sinuses

A case of severe involvement of the nose and paranasal sinuses by sarcoidosis is presented. In addition to soft-tissue manifestations, there is rather marked osseous destruction. Its differentiation from other destructive processes in this area, particularly other granulomatous diseases, must be made in relation to the entire spectrum of systemic involvement as well as histologic identification.