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Physical Measurements and Comparative Technic in Relation to Biological Dosage

Physical Measurements and Comparative Technic in Relation to Biological Dosage Physical Measurements and Comparative Technic in Relation to Biological Dosage 1 Preliminary Report H. N. Beets , M.S , Physicist and Robert A. Arens , M.D. , Roentgenologist Michael Reese Hospital, Chicago ↵ 1 Read before the Chicago Roentgen Society, May 9, 1924. Excerpt THE general subject of treatment technic is an important one. In the early phase of roentgen deep therapy, technics were transferred in toto from Europe to America, and again in this country from one operator to another. The German school emphasized massive doses delivered in one application, and the production of weeping erythemas, but fortunately its influence is waning both here and abroad. Most roentgenologists have abandoned these foreign teachings and the tendency is to give moderate, short applications either daily or at short intervals, and away from the production of a dangerous erythema. The reason for the wild plunge into foreign technic with American apparatus was because we translated too freely and accepted at face value the reports of visitors to the foreign clinics who knew nothing, or very little, about X-ray apparatus or the application thereof. It was not until men actually in the X-ray field made their own investigations that the fallacy of the massive dose and its technic was shown. The erythema, or skin toleration, dose is, however, a very important unit and its limitations should be known with fair definition if for no other reason than that it cannot he exceeded without dire results. Technic, or dosage, is generally stated in the following terms: peak voltage, milliamperes, skin target distance, filter, size of field and time. It has been frequently noted that although the first five of these factors may be constant, the time required to deliver an erythema dose varies from one machine to another. It was our opinion that if the doses of experienced roentgenologists were compared as to actual amounts of X-ray energy delivered to the surface of the patient, apparent discrepancies in milliampere minutes would disappear, and that a further investigation might disclose the sources of these discrepancies. It was our good fortune to obtain access to eight high voltage transformers and to measure their output under actual treatment conditions with one and the same measuring device; to directly compare five different new X-ray tubes operating under identical conditions and also six tubes that had been in constant use for various periods of time; to check daily one high grade European iontoquantimeter over a sixty-day period. The instrument used in these measurements was the electroscope reported by us at the Rochester meeting of the Radiological Society of North America last December. The sensitivity 2 of the electroscope was checked with a definite quantity of mesothorium in all instances. Checks were made at the beginning and end of each measurement and in no case did the initial and final discharge times of the electroscope differ by more than 2 per cent. The results in tabulated form will be found on the next page. 3 What part of the output differences should be ascribed to the transformer, rectifier and filter, what part to the X-ray tubes, personal equations, and what part to the measuring devices used? Copyrighted by the Radiological Society of North America http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Radiology Radiological Society of North America, Inc.

Physical Measurements and Comparative Technic in Relation to Biological Dosage

Beets, H. N.; Arens, Robert A.
Radiology , Volume 3 (4): 293 – Oct 1, 1924
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Publisher
Radiological Society of North America, Inc.
Copyright
Copyright © 1924 by Radiological Society of North America
ISSN
1527-1315
eISSN
0033-8419
DOI
10.1148/3.4.293
Publisher site
See Article on Publisher Site

Abstract

Physical Measurements and Comparative Technic in Relation to Biological Dosage 1 Preliminary Report H. N. Beets , M.S , Physicist and Robert A. Arens , M.D. , Roentgenologist Michael Reese Hospital, Chicago ↵ 1 Read before the Chicago Roentgen Society, May 9, 1924. Excerpt THE general subject of treatment technic is an important one. In the early phase of roentgen deep therapy, technics were transferred in toto from Europe to America, and again in this country from one operator to another. The German school emphasized massive doses delivered in one application, and the production of weeping erythemas, but fortunately its influence is waning both here and abroad. Most roentgenologists have abandoned these foreign teachings and the tendency is to give moderate, short applications either daily or at short intervals, and away from the production of a dangerous erythema. The reason for the wild plunge into foreign technic with American apparatus was because we translated too freely and accepted at face value the reports of visitors to the foreign clinics who knew nothing, or very little, about X-ray apparatus or the application thereof. It was not until men actually in the X-ray field made their own investigations that the fallacy of the massive dose and its technic was shown. The erythema, or skin toleration, dose is, however, a very important unit and its limitations should be known with fair definition if for no other reason than that it cannot he exceeded without dire results. Technic, or dosage, is generally stated in the following terms: peak voltage, milliamperes, skin target distance, filter, size of field and time. It has been frequently noted that although the first five of these factors may be constant, the time required to deliver an erythema dose varies from one machine to another. It was our opinion that if the doses of experienced roentgenologists were compared as to actual amounts of X-ray energy delivered to the surface of the patient, apparent discrepancies in milliampere minutes would disappear, and that a further investigation might disclose the sources of these discrepancies. It was our good fortune to obtain access to eight high voltage transformers and to measure their output under actual treatment conditions with one and the same measuring device; to directly compare five different new X-ray tubes operating under identical conditions and also six tubes that had been in constant use for various periods of time; to check daily one high grade European iontoquantimeter over a sixty-day period. The instrument used in these measurements was the electroscope reported by us at the Rochester meeting of the Radiological Society of North America last December. The sensitivity 2 of the electroscope was checked with a definite quantity of mesothorium in all instances. Checks were made at the beginning and end of each measurement and in no case did the initial and final discharge times of the electroscope differ by more than 2 per cent. The results in tabulated form will be found on the next page. 3 What part of the output differences should be ascribed to the transformer, rectifier and filter, what part to the X-ray tubes, personal equations, and what part to the measuring devices used? Copyrighted by the Radiological Society of North America

Journal

Radiology – Radiological Society of North America, Inc.

Published: Oct 1, 1924

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