1930s medical physics

X-rays in pure science

X-rays were used in both pure and applied sciences and papers on both aspects appeared in the pages of the BJR. G Shearer from the National Physical Laboratory gave the Mackenzie Davidson memorial Lecture in 1938 (Shearer BJR 1939; 12(139): 419-431) on the use of X-rays in pure science and demonstrated the use of x-ray diffraction.

Xray patterns of an alloy system

Image source: Shearer BJR 1939; 12(139): 419-431

The Presidential Address of 1930 was given by the pioneering medical physicist from the Cancer Hospital (Royal Marsden Hospital) Major CES Phillips (Phillips BJR 1931; 4(37): 6-17). The address is a masterly account of the current state and development of medical physics. There is a nice account of the origins of the Radium Commission. The Presidential Address for 1932 (Hopwood BJR 1933; 6(61): 33-38) delivered by FL Hopwood had an interesting account of ultrasound which was demonstrated at the lecture. Hopwood made the important point about how the boundaries of science were no longer well defined and also that never were the potentials of radiation, for good or evil, so great as at this moment and that it was very important that members of the Institute should take care to control the potent agents that were then becoming available, and to educate themselves and other people in their proper use. These words could have been spoken by a later president Joseph Rotblat and was the reason for him founding the Pugwash conferences.

Many physicists were members of the BIR even though we would not consider them hospital or medical physicists today.

 

Sir Ernest Rutherford

Sir Ernest Rutherford was a member of the BIR and was created a Baron in 1930.

 

Silvanus Thompson

W Hale-White wrote about The BIR first president Silvanus Thompson in January 1930 in a well known letter from the Lancet (Hale-White BJR1931; 4(37): 2) describing Thompson as “a prince among lecturers.”

The first communication of WC Rontgen “On a new kind of rays” is reprinted in January 1931 (Rontgen BJR1931; 4(37): 32-33) followed by an interesting discussion of the mathematical discovery of the X-rays by AW Crane (Crane BJR1931; 4(37): 33-35

 

Sir James Jeans

Sir James Jeans made significant contributions to our knowledge of the universe and several papers appeared in 1931. He wrote about “Electrons and Protons” in January 1931 (Jeans BJR 1931; 4(37): 35-37) discussing current ideas of atomic theory. He gave the Rede Lecture in Cambridge in November 1930 and this fascinating talk is reprinted (Jeans BJR 1931; 4(43): 351-354). Jeans gave the Silvanus Thompson Memorial Lecture in 1931 (Jeans BJR 1932; 5(49): 21-38) and discussed the nature of radiation including corpuscular and wave theories and recent discoveries.

 

Arthur Stanley Eddington

Of particular interest is the 1929 Silvanus Thompson Memorial Lecture given in December 1929 by Arthur Stanley Eddington (Eddington BJR 1930: 3(27): 99-111) on “X-rays in the Stars.”  Arthur Eddington made major contributions to physics and helped to verify Einstein’s theory of relativity. At that time Eddington was Plumian Professor of Astronomy at Cambridge.

 

J Chadwick

The1932 Mackenzie Davidson Memorial Lecture for 1932 was given by J Chadwick who discovered the neutron (Chadwick BJR 1933; 6(61): 24-32). Chadwick was from the Cavendish Laboratory and his lecture is a masterful account of his understanding of the neutron. At that time the neutron was of no practical relevance to radiology but that was to change.

 

Sir W H Bragg

WH Bragg made fundamental discoveries relating to the structure of matter using X-ray crystallography. He gave the Mackenzie Davidson Memorial Lecture in 1934 (Bragg BJR 1935; 8(87): 144-154) on X-rays and the coarse structure of material.  X-rays had many uses other than the medical and Sir William Bragg OM reviewed the uses of X-rays in factories in 1931 (Bragg BJR 1931; 4(46):513-516).

 

G P Thompson

GP Thompson from Imperial College gave his Mackenzie Davidson Memorial Lecture in December 1930 (Thompson BJR1931; 4(38): 52-59) on recent experiments on cathode rays. This was a lecture on pure physics with a discussion on the nature of electrons as particles or waves and discusses the work of de Broglie.

 Cathode rays

Image source: Thompson BJR1931; 4(38): 52-59

 

W V Mayneord

W Valentine Mayneord made many contributions the BJR. In August 1931 he wrote an interesting paper on secondary radiation (Mayneord BJR 1931; 4(44): 369-386) with a mathematical analysis of the principles involved. He attended the 3rd International Congress of Radiology in Paris in July 1931 and reported back to the BJR on the apparatus that was exhibited (Mayneord BJR 1931; 4(): 589-591). In the December 1931 he was writing about the measurement of radiation intensity around a radium source (Mayneord BJR 1931; 4(48): 693-710) based on his experimental work. This was an important topic since at that time there was little knowledge of dose distributions around radium needles in different tissues and the mathematical and physical results were not presented in a form suitable to assist the therapist. In September 1932 he returned to the topic (Mayneord BJR 1932; 5(57): 677-716) analysing the dose distributions around a variety of simple sources.

In October 1933 he discusses problems in gamma ray therapy (Mayneord BJR 1933; 6(70): 598-614). He returned to radium in November publishing depth dose data for teleradium units with Joan Honeyburne (Mayneord and Honeyburne BJR 1938; 11(131): 741-754). 

In the 1930s high-voltage apparatus for radiotherapy was developed. Up to this point the maximum voltage used for radiotherapy was about 200kV. Apparatus had recently been installed at the Cancer Hospital (free) (now the Royal Marsden Hospital) that could be used up to 400kV and in June 1933 WV Mayneord and JE Roberts (Mayneord and Roberts BJR 1933; 6(66): 321-344) gave a detailed account of the apparatus and measured the radiation obtained. In June 1935 Mayneord and Roberts then assessed the ‘quality’ of these high voltage radiations (Mayneord and Roberts BJR 1935; 8(90): 341-364) and he returned to the subject in March 1939 (Clarkson and Mayneord BJR 1939; 12(135): 168-180).

Mayneord reviewed the measurement of low-voltage (about 50kV) treatment in April 1936 (Mayneord BJR 1936; 9(100): 215-238).

 

 Measurement of low dose xrays

Image source: Mayneord BJR 1936; 9(100): 215-238

By the end of the 1930s the practice of radiotherapy had reached a remarkable degree of sophistication. This is illustrated by the contributions of Mayneord to the May 1939 BJR when he wrote on beam alignment (Mayneord BJR 1939; 12(137): 257-258), electric adding (Mayneord BJR 1939; 12(137): 260-262) and three-dimensional contour projection (Mayneord BJR 1939; 12(137): 262-268). There then followed a symposium on three-dimensional radiation distributions (Honeyburne, Lamerton, Smithers and Mayneord BJR 1939; 12(137): 269-302) with contributions from Joan Honeyburne, LF Lamerton, DW Smithers and WV Mayneord. Complex images were shown including anatomical cross-sections with superimposed isodose curves.

 

John Read

John Read was a physicist working at Mount Vernon Hospital and in 1931-34 he was at the California Institute of Technology. In May 1936 (Read BJR 1936; 9(101): 324-334) and July 1936 (Read BJR 1936; 9(103): 442-455) he reported to the BJR about the use of high-voltage tubes in the USA. In January 1939 Read wrote, with JC Mottram, a study of the effects of radon in the atmosphere (Read and Mottram BJR 1939; 12(133): 54-60). This topic was of considerable importance to the work of radium workers. In November 1939 he considered the problem of potential radium poisoning due to the release of radium during bombing (Read BJR 1939; 12(143): 632-637).

 

J D Cockcroft

J D Cockcroft gave the Mackenzie Davidson Memorial Lecture in 1936 on high-velocity positive ions (Cockcroft BJR 1937; 10(111): 159-170). He was interested in the application of high-velocity positive ions to the transmutation of atomic nuclei and the production of artificial radioactivity.

 

LH Gray

LH Gray from Mount Vernon Hospital in Northwood wrote a study of radiation dosimetry in August 1937 (Gray BJR 1937; 10(116): 600-612) with the second part appearing in October 1937 (Gray BJR 1937; 10(118): 721-742). He said that an agreed system of dosimetry would be “a matter of some importance to the progress of Radiology.” The paper discussed the relation between ionisation and absorbed energy.  In January 1939, with Herbert Crabtree, Gray described the influence of wavelength on the biological effectiveness of radiation (Crabtree and Gray BJR 1939; 12(133): 39-53). At that time the data on the effects of wavelength was conflicting.

 

X-ray tubes

The company Philips made many contributions to the development of the X-ray tube and W R Gray described a new hot cathode (Coolidge tube) with a rotating anode (Gray BJR 1930; 3(28): 171-177). There is an interesting paper on the self-protecting Multix tube by FD Owen-King in May 1931 (Owen-King BJR 1931; 4(41): 218-231). The tube was a Coolidge tube and was the standard apparatus for many years. 

The greatly improved images obtained using the “Rotalix” rotating anode X-ray tube designed by A Bouwers was discussed by H Franke in March 1933 (Franke BJR 1933; 6(63): 179-187). The tube used the principle of line focus and by having a rotating anode the specific load of the focal spot could be considerably increased.

In March 1932 G Grossmann from Berlin published an interesting account of the equipment then available to radiotherapy (Grossmann BJR 1932; 5(51): 252-268) with interesting diagrams and photographs of the apparatus.

 Siemans tube boxes for deep therapy

Image source: Grossmann BJR 1932; 5(51): 252-268

A Bouwers from Eindhoven gave the Silvanus Thompson Memorial Lecture in 1933 (Bouwers BJR 1935; 7(73): 21-32). Bouwers made major contributions to the design of X-ray tubes and in this lecture discussed improvements to the rotating anode X-ray tube. He also reviewed developments in techniques for therapy and possibility of high tension apparatus working at a million volts. In July 1936 he described a tube working at 700kV (Bouwers and van der Tuuk BJR 1936; 9(103): 431-441) and in December 1939 a tube working at one million volts (Bouwers and van der Tuuk BJR 1939; 12(144): 658,666).

 

The measurement of radiation

Prof. EA Owen from Bangor in North Wales made a review of the ionisation chambers used to measure radiation dosage in July 1931 (Owen and Jones BJR 1931; 4(43): 309-338). The paper is detailed and an interesting account of the current knowledge.

GWC Kaye worked for the National Physical Laboratory (NPL) and made major contributions to standard setting and measurements and  his paper with W Binks (also from the National Physical Laboratory) on the international comparison of the röntgen (r) which was the unit then used for the quantity of radiation (Kaye and Binks BJR 1933;  6(64): 195-206). The paper described “thimble” ionisation chambers and the experimental realisation of the röntgen using the free air ionisation chamber. There is a description of the work at the NPL and the standards used. A longer paper again with W Binks on the experimental realisation of the röntgen (r) appeared in September 1933 (Kaye and Binks BJR 1933; 6(69): 530-556). Progress in radiotherapy had been set back because of the absence of accurate methods of measuring radiation. Biological methods were inaccurate and the most accurate technique was the measurement of the ionisation of air. The Second International Congress of Radiology in 1928 had defined the röntgen (r) as a dose but specified no specific design of measuring apparatus. In this important paper of September 1933 Kaye and Binks described such a standard apparatus used at the NPL for the realisation of the röntgen.  The obituary of Kaye appeared in July 1941 ( BJR 1941: 14(163): 242-243).

In April 1934 WV Mayneord and JE Roberts (Mayneord and Roberts BJR 1934; 7(75): 158-175) compared the ionisation of air for X-rays and gamma rays. The paper was contributing towards the unification of X-rays and gamma rays. WV Mayneord and JE Roberts were to return to the subject of the precise measurement of gamma rays in May 1937 (Mayneord and Roberts BJR 1937; 10(113): 365-388).

 Ionisation produced by gamma rays

Image source: Mayneord and Roberts BJR 1934; 7(75): 158-175

 



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