Andrew H. Dowdy

Mammography as a screening method for the examination of large populations.

The technical and scientific information is presently available which, if properly utilized, could facilitate the early diagnosis of breast cancer. Hopefully, it could likewise reduce the high mortality rate of breast cancer. Due to the lack of adequately trained professional and allied health personnel, a massive screening program on a national scale is unwarranted and would be unproductive at this time. Based upon our experience in the U.C.L.A. Center for Health Sciences, the establishment of screening clinics for women 40 years of age and over in conjunction with a cervical cancer detection clinic in a number of large medical centers is indicated. Thermography as a prescreening modality should be investigated further.

Pulmonary Hypertension Due to Pulmonary Arterial Coarctation

With improved diagnostic methods many diseases which were previously grouped together as idiopathic can now be separated into etiologic categories. Essential pulmonary hypertension may succumb to reclassification, since several types are now found to be distinguishable on the basis of definite radiological and pathological changes (1, 27, 54). It is not only our duty to refine these idiopathic categories, but it is our privilege as physiologically oriented radiologists to try and understand the basic changes which make this refinement possible (49). There have been many recent reports (2, 6, 11, 14, 20, 41, 45, 48, 51, 53, 55, 58, 60) on supravalvular or postvalvular constriction, coarctation, or stenosis of the pulmonary arteries. Four mention the association of pulmonary hypertension with this condition (2, 11, 14, 41). It is our observation that the two are always associated. Four reports have appeared in the radiologic literature. This is apropos, since coarctation of the pulmonary artery can be diagn...

Lay Screeners in Mammographic Survey Programs

Abstract A secretary and a technologist trained by the tutorial method coded 337 consecutive mammograms from a mammography screening clinic as to the presence or absence of carcinoma. Of seven histologically proved cancers, each screener correctly coded six, as did the mammographer. The results indicate that selected individuals can be trained as screeners and correlate with the mammographers classification in approximately 90% of the cases.

Some Problems Peculiar to Electron Therapy

Some Idiosyncrasies of Electron Behavior The familiar concept of a sharply collimated beam of x-rays or gamma rays in air, with no significant amount of scattering outside its predetermined cross-sectional area, needs to be considerably modified in the case of electron radiation. Individual tracks of relatively low-energy electrons in a cloud chamber (1) are characterized by erratic wanderings, with numerous abrupt changes of direction even in a path length of a few centimeters. If the electron energies are increased from kilovolts to megavolts, and the range of observation from centimeters to meters, somewhat similar behavior patterns can be demonstrated on a correspondingly enlarged scale. Such air-scattering phenomena tend to diffuse and dissipate the initial collimation of an electron beam rather rapidly with increasing distance from the source, and thereby introduce additional complications to the problem of personnel protection. Since completely “shadowed” areas are not geometrically projected by in...

LogEtronic Simplification in Simulated Color Radiography

The recent introduction of the LogEtronic Contact Printer has provided a means of ready simplification in the preparation of simulated color roentgenograms. As indicated in our initial report on simulated color roentgenography (1), it is necessary first to obtain a black and white negative of the roentgenogram selected for color reproduction. From this negative an exposure is made by contact or enlargement, usually the latter, onto Matrix or Pan-Matrix film. The exposed film is then processed, by the steps specified in Table I, to produce a gelatin relief image for the addition of the Flexichrome colors as desired. The quality of the original negative is one of the most important single factors in the success of the final color preparation. A good original negative must contain and transmit all of the definition desired for proper form and value in the final result. This result is a color roentgenogram that realistically represents the selected roentgenogram as naturally as possible. The routine visual ad...

Role of the radiologist in atomic attack.

In view of great advances made in new weapons of war, the position of the radiologist is rapidly becoming more important. Because of his general medical training, supplemented by his knowledge of radioactive materials and of their inherent dangers, he will be of invaluable aid to both the military and civilian population. For some time one of us (S.L.W.) has been advocating the necessity of a well organized radiological defense program for California. Shortly after the initial attack in Korea, Governor Earl Warren of this state took an active part in mobilizing civilian personnel into a well organized civil defense organization. In the beginning, radiological defense was placed under medical control, as a part of the medical plan. It was soon realized, however, that an effective radiological defense program would of necessity have to be large in personnel, that it would require specialized training plans and equipment, and would best function as a separate entity apart from medical activities. In an actua...