Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

The use of Artificially Produced Radio-active Elements as Tagged Atoms in Biological Research

The use of Artificially Produced Radio-active Elements as Tagged Atoms in Biological Research The use of Artificially Produced Radio-active Elements as Tagged Atoms in Biological Research 1 William Freer Bale , Ph.D. Rochester, New York ↵ 1 Presented before the Twenty-fifth Annual Meeting of the Radiological Society of North America, at Atlanta, Dec. 11–15, 1939. Excerpt ONE might expect that the carrying out of medical and biologic research involving the radio-active elements would be quite different in method and in the apparatus from that employed for biologic and clinical research. Unfortunately for those of us who are using the radio-isotopes in biologic work, this has not been so. Work carried out with experimental animals still involves metabolism cages, dissections, extractions, and all of the apparatus (mostly beakers, volumetrics and so forth) of the biochemical research laboratory. Also, clinical work still involves collecting and homogenizing urine and feces, taking occasional blood samples, working up operative and occasional autopsy material, and the various clinical chemistry procedures so well known to everyone. The only impressive or unique apparatus we use at Rochester is the Geiger-Muller counter, the use of which is, of course, by no mcans limited to measurements of radio-activity. Perhaps most of us know it instead as a sensitive means of detecting lost radium, or as a means for measuring weak x-radiation when r meters and other ionization chambers are not sensitive enough. Figure 1 shows the type of Geiger-Muller apparatus we are using at the present time (1). In most instances, radio-activity measurements are made on substances in solution. We have persuaded ourselves that this technic most easily leads to quantitative results. Two c.c. of the solution on which activity measurements are to be made are placed in a glass cup which has an inside diameter about two millimeters larger than the radio-sensitive plunger-shaped end of the Geiger counting tube. When the cup is brought up around the tube with a rack and pinion, the solution forms a 1-mm.-thick liquid film surrounding the counting tube. This thin film of liquid, together with the thin counter wall (about 0.003 of an inch thick), only slightly absorbs the beta rays of most of the radio-active elements. Most of the beta rays that are headed in the right direction penetrate into the inside of the counter tube where they give rise to electrical impulses that are amplified and eventually recorded on a mechanical impulse counter. After subtracting a constant background due largely to cosmic rays, the number of counts per minute is proportional to the radio-activity of the solution contained in the cup. Figure 2 shows better the actual construction of the Geiger-Muller tube and the method of mounting that is used. Radio-iron ejects very soft beta rays. For this dement the sensitivity of the apparatus can be increased about five times by electroplating the iron onto the inside surface of a tin foil cylinder that will just slip over the counting cylinder. This procedure eliminates the adsorption of the beta rays by the solution in which the iron is dissolved. The beta rays of radio-sulphur are so soft and non-penetrating that this type of apparatus is not suitable for their measurement. Copyrighted 1940 by the Radiological Society of North America, Inc. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Radiology Radiological Society of North America, Inc.

The use of Artificially Produced Radio-active Elements as Tagged Atoms in Biological Research

Radiology , Volume 35 (2): 184 – Aug 1, 1940

Loading next page...
 
/lp/radiological-society-of-north-america-inc/the-use-of-artificially-produced-radio-active-elements-as-tagged-atoms-0g6neJjtA4

References

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
Radiological Society of North America, Inc.
Copyright
Copyright © 1940 by Radiological Society of North America
ISSN
1527-1315
eISSN
0033-8419
DOI
10.1148/35.2.184
Publisher site
See Article on Publisher Site

Abstract

The use of Artificially Produced Radio-active Elements as Tagged Atoms in Biological Research 1 William Freer Bale , Ph.D. Rochester, New York ↵ 1 Presented before the Twenty-fifth Annual Meeting of the Radiological Society of North America, at Atlanta, Dec. 11–15, 1939. Excerpt ONE might expect that the carrying out of medical and biologic research involving the radio-active elements would be quite different in method and in the apparatus from that employed for biologic and clinical research. Unfortunately for those of us who are using the radio-isotopes in biologic work, this has not been so. Work carried out with experimental animals still involves metabolism cages, dissections, extractions, and all of the apparatus (mostly beakers, volumetrics and so forth) of the biochemical research laboratory. Also, clinical work still involves collecting and homogenizing urine and feces, taking occasional blood samples, working up operative and occasional autopsy material, and the various clinical chemistry procedures so well known to everyone. The only impressive or unique apparatus we use at Rochester is the Geiger-Muller counter, the use of which is, of course, by no mcans limited to measurements of radio-activity. Perhaps most of us know it instead as a sensitive means of detecting lost radium, or as a means for measuring weak x-radiation when r meters and other ionization chambers are not sensitive enough. Figure 1 shows the type of Geiger-Muller apparatus we are using at the present time (1). In most instances, radio-activity measurements are made on substances in solution. We have persuaded ourselves that this technic most easily leads to quantitative results. Two c.c. of the solution on which activity measurements are to be made are placed in a glass cup which has an inside diameter about two millimeters larger than the radio-sensitive plunger-shaped end of the Geiger counting tube. When the cup is brought up around the tube with a rack and pinion, the solution forms a 1-mm.-thick liquid film surrounding the counting tube. This thin film of liquid, together with the thin counter wall (about 0.003 of an inch thick), only slightly absorbs the beta rays of most of the radio-active elements. Most of the beta rays that are headed in the right direction penetrate into the inside of the counter tube where they give rise to electrical impulses that are amplified and eventually recorded on a mechanical impulse counter. After subtracting a constant background due largely to cosmic rays, the number of counts per minute is proportional to the radio-activity of the solution contained in the cup. Figure 2 shows better the actual construction of the Geiger-Muller tube and the method of mounting that is used. Radio-iron ejects very soft beta rays. For this dement the sensitivity of the apparatus can be increased about five times by electroplating the iron onto the inside surface of a tin foil cylinder that will just slip over the counting cylinder. This procedure eliminates the adsorption of the beta rays by the solution in which the iron is dissolved. The beta rays of radio-sulphur are so soft and non-penetrating that this type of apparatus is not suitable for their measurement. Copyrighted 1940 by the Radiological Society of North America, Inc.

Journal

RadiologyRadiological Society of North America, Inc.

Published: Aug 1, 1940

There are no references for this article.