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needed retreatment, and 2 percent had permanent myxedema. They had the feeling that after thiouracil preparation, radioiodine was picked up and retained by the thyroid gland much longer, there was less variabiality in the percent pickup, clinical relief was much quicker, and that many of the patients could be treated entirely as out patients without radiation hazard.

Pahaut and Govaerts (Liege, Belgium) presented a system of following the course of the patient on the basis of urinary excretion studies.

In talks with many other clinics using radioiodine in France, Germany, Italy, Sweden, and England, I found no outstanding new developments or problems that lems that are not already under investigation in this country.

In the use of P 32, Low-Beer (San Francisco) presented an excellent summary of the phosphorus 32 problem. His paper is to be published soon and will be given in the medical course at ORINS next month.

Perussia (Milan, Italy) discussed the results of experimental work on the interpretation of distribution patterns in plasma, blood cells, and a few selective tissues of P 32 following intravenous administration. While the methods and experimental results have been presented many times in the literature, they have attempted to present a simplified theoretical system of the dynamics of phosphorus before it reaches the steady state.

A paper was presented by Christiansen (Denmark) on the treatment of polycythemia vera with P 32. Nothing unusual was brought out.

Using red cells labeled with P 32, Bohr (Denmark) has determined the blood volume in patients with polycythemia vera before and after treatment with P 32. He found that in patients with polycythemia vera the red blood corpuscular volume is raised whereas the plasma volume remains approximately normal. He also felt that there was a definite relation between the red blood corpuscular volume and the hematocrit.

Graul (Munster, Germany) described an intercutaneous injection method with P 32 to measure the circulation of the skin.

Jones and Rotblat (London) investigated the fate of radioactive phosphorus injected as phosphate into pleural spaces containing effusions caused by metastatic tumors. They found that a large proportion of radioactive phosphorus was being taken up directly by the metastases. On analysis of the distribution of P 32 activity they found a depletion from the effusion first of all by a rapid uptake into some component other than blood followed by a slower turnover into the blood. They felt that their evidence of neoplastic uptake and that the concentration of P 32 in the metastases appeared to be sufficiently high to justify therapeutic application.

Hahn (Nashville) presented his material on silver-coated radioactive gold colloids for the treatment of broncheogenic carcinoma. The silver-coated gold colloid is administered by the intrapulmonary route through a bronchoscope. Hahn found that the colloid is rapidly removed from the lung parenchyma and appears in considerable proportion in the lymph nodes draining the lung region, While it is well known from many previous studies that this will occur in normal dogs there is some question that the lymphatic uptake could be repeated in a patient with a tumor-laden lymphatic system.

Poppe (Gottingen) presented some of the theoretical advantages of the interstitial injection of radiogold. In 24 patients, in which radioactive gold was infiltrated into carcinoma of the tongue, they had 21 excellent results after 1 year.

Scheer (Heidelberg) described an interstitial use of radioactive phosphorus similar to the techniques used with gold and following the chromic phosphate idea in this country. Scheer used magnesium ammonium phosphate in an isotonic colloidal suspension. Like all of the suggestions that are coming out of Heidelberg, this technique seems well worth further consideration.

Muller, of Switzerland, presented work with intraperitoneal and intrapleural zinc 63 and gold 198. He gave the entire history of his discovery of the possibility of doing intracavitary therapy with radioactive colloids starting as far back as 1945.

Wuerff (Nijmegen, Holland) presented his work with synchrocyclotron produced gallium 66 and gallium 67 isotopes. He has repeated some of Dudley's work with gallium 72. Most of his preliminary results are a confirmation of our report a year and a half ago in Chicago.

Pahaut (Liege) described the use of strontium 89 in bone tumors. The distri. butions of radiation which they demonstrated were not at all impressive.

Lajtha (Oxford) reported some careful work on the uptake of S 35 sulfate by human bone marrow cells in vitro. In human bone marrow cultures, autoradiographs have shown that large amounts of sulfur 35 sulfate are taken up by the cytoplasm of early myeloid cells only. Polymorphonuclears and leukocytes showed little or no uptake; nucleated red cells never showed an uptake. He felt that S 35 sulfate in the cytoplasm of the early myeloid cells exists in an inorganic form not soluable in water or the other usual solvents but is removed by normal hydrochloric acid and solutions of sodium hydroxide. He found that the S 35 sulfate was not removable by hyaluronidase. The uptake appeared to be inhibited by barbiturates but not by X-irradiation. He felt that the results suggest a relationship with the sulfur containing polysaccharids and indicate a hitherto unknown function of early myeloid cells.

Roswit and Wisham (New York) described their now well known skin radiosodium clearance studies. They have applied these studies to irradiated skin and feel that the changes due to radiation must be the result of direct impact of radiation on the individual epidermal cells and not to an impairment of their vascular supply. They feel that within the range of present therapeutic dose levels the effect of blood flow to irradiated tissues in tumors as well cannot be altered.

Lassen and nck (Copenhagen) described the Kety method of determining cerebral blood flow following inhalation of nitrous oxide. Since the exact determination of the nitrous oxide concentration is difficult and time wasting, they used radioactive krypton and took multiple samples of arterial and venous blood.

Walton (London) described some of his experiments on the effect of an electric current in producing movement of associated ions through artificial media and tissues. It is his opinion that some such technique might be applied to the treatment of malignant disease. The future development of this idea should be interesting.

Millen (Belfast, Ireland) described the use of a central radiation source in intracavitary irradiation of bladder tumors. A thin stainless steel catheter was manufactured with a latex balloon on the tip. With the balloon empty the catherer could be passed easily through the male urethra. After insertion the balloon is distended (with a solution of sodium iodide and a dye) to a volume of 150 to 250 milliliters. The shape of the balloon is checked radiographically and, when correctly positioned, a 100 to 150 millicurie small source of cobalt 60 is inserted into the stainless steel catherer and positioned in the center of the bladder. He felt that technique was suitable for the treatment of only the superficial types of bladder tumor, and should not be applied to the treatment of infiltrating growths.

Green (London) described the use of radiactive tantalum wire for implantation and intracavitary irradiation of corpus uterine cancer. Tantalum was irradiated to an activity equivalent to 1 milligram per centimeter of radium in a wire of thickness under 1 millimeter in diameter. The wire was plated with 0.1 millimeter of platinum to filter beta particles and provided a flexible source much thinner than radon seeds but used for much the same type of purpose. Small cannulae are used to introduce wires. Both Smithers and Sinclair have reported elsewhere the same type of use of tantalum wire for the use in bladder lesions. Green also described other uses of tantalum 182 in combination with various kinds of applicators for treating concer of the uterus.

Kottmeier (Stockholm) presented a general paper on the modern trends in treatment of cancer of the cervix. It was his feeling that radiotherapy should be the primary treatment in every case of invasive carcinoma and surgery should be limited to radioresistant cases. Patterson (Manchester) had just pre viously spoken on the same subject and seemed to have the same feeling on the relative value of radiation and surgery. On the other hand, Patterson was preceded by Brunschwig (New York) who leaned somewhat in the other direction. Kottmeier made some remarkable statements among which was his feeling that a fixed cancer dosage does not exist nor is there an equivalence in the radiation effect of the tumor cells to the calculated dose in gamma or roentgen tissue dosage. It is likely, according to Kottmeier, that the peripheral part of a growing carcinoma does not need such a heavy dose as the central part. He gave no evidence to support this contention. He felt that the combination of radium and rotational X-ray therapy was of great value in selected cases.

Lamerton (London) described comparisons between the effect of uniform whole body X-irradiation and of nonuniform irradiation achieved either by shielding parts of the body during external irradiation or by administration of various radioactive isotopes which are preferentially localized in various sites in the body.

IX. HIGH-ENERGY ACCELERATORS

One of the intense fields of concentration is on the problem of high-voltage particle accelerators. Howard-Flanders (London) described the recent work at the Hammersmith Hospital where an 8 mev. linear accelerator has been built especially for clinical use. Another 13 mev. machine is partly constructed and a 4 mev. linear accelerator has been designed to be moved in an arc around the patient. Howard-Flanders is concerned about the problem of integral dose and feels that this is one of the major arguments in favor of the high-energy machines.

Grivet (Paris) discussed a 4 mev. electron accelerator. Gund (Erlangen) talked about the new Seimens medical betatron. This is a 15 mev. machine which is compact, has a high output, and is suspended so that can perform pendulum therapy. Weideroe (Switzerland) described a 31 mev. Brown-Boveri betatron and its adaptation to radiotherapy. Schubert and Paul (Hamburg) discussed some of the basic problems of using fast electrons from a 6 mev. betatron.

Mitchell and his group (Cambridge) presented the development of a 30 mev. syncrotron as a radiotherapeutic instrument. A large amount of ther utic physics has already been accomplished with this machine and clinical trials are well underway. Mitchell also stresses the substantial reduction of the integral dose in the radical treatment of otherwise inaccessible tumors. He points out, however, a great disadvantage in the clinical estimation of maximum tissue reaction since the reaction occurs at a depth where it can not be seen by the therapist. He also admitted the mechanical difficulty of keeping the machine running. (For example, when I visited Cambridge the machine was temporarily out of operation.)

Joyet (Zurich) described and discussed the problem of the induced activities in tissue from radiation with the 31 mev. Zurich betatron. There was also a discussion by the Zurich bettaron group on the very difficult problem of physical and biological dosage at 32 mev. energies. Wood and Newberry (London) presented the techniques being used with the 8 mev. linear accelerator at the Hammersmith Hospital. Bloomfield (Sheffield) talked on the Sheffield National Center's 2 million volt Van der Graff and the results on the first 3 years experi. ence and 1,200 patients. The largest portions of their experience has been with intracranial tumors, carcinoma of the mouth, larynx, esophagus, bronchus and lungs, rectum, bladder, and cervix, and a number of patients treated for artificial menopause. They were enthusiastic about the results but again stressed the point that Mitchell made on the reactions which are out of sight but cannot be neglected.

Uhlmann (Chicago) discussed some of the theoretical problems in the use of fast electrons from the 20-million-electron-volt betatron. Birge (Berkeley) presented the biological research being done with the 190-million-electron-volt deuteron beam and the problems that will come up with the use of the machine in human beings. Human application of this machine, however, is not anticipated for some time. A contribution by Schubert and Hohne (Hamburg) was on the genetic research they are doing with their 6-million-electron-volt betatron. Newbery (Harrow) spoke on some of the physical measurements that were made on the 8-million-electron-volt linear accelerator at Hammersmith Hospital. Bewley presented the techniques and measurements and the isodose charts measured with a water phantom with the Hammersmith 8-million-electron-volt accelerator. Motz and Wyckoff (NBS, United States of America), described their precise work on the measurement of the million-volt X-ray spectrum and a number of the new methods that have been developed at the National Bureau of Standards for application to other machines with other energies. Braams (Utrecht) offered a number of absorption and scattering measurements made on the Cambridge 30-million-electron-volt cyclotron. He gave serious criticism of the current method of deriving absorption coefficients from depth dose curves. The essence of Braams' criticism is found in K. Z. Morgan's papers and implies the same problem of scattered radiation buildup previously brought up by Tubiana's group in Paris and by many others who have considered the extended source problem. A beam of external energy can in this sense be considered an extended source.

Wheatley (London) discussed the correlation between energy flux in ergs per square centimeter and the dose in roentgens. The effect of the spectral distribution of radiation, especially in the supervoltage range, makes necessary certain corrections for absorption by the process of photodisintegration. Wheatley discussed a number of experimental measuring tools, including a microcalorimeter within an insulated absorber. If the new “rad” unit of ergs per gram is to be used as a unit of energy absorption, Wheatley's methods are worthy of careful review.

Laughlin (New York) and his group discussed the problems of dosimetry of high energies. They have measured the specific ionization from high-energy electrons from 10 million electron-volts to 22 million electron-volts in air and related this to the problems of dosage in tissue.

Kelliher (England) described a 15-million-electron-volt linear accelerator used as a source for supervoltage X-rays which gave an output of over 2,000 r/min 1 meter from the target. A clinical machine has been made in which the X-ray head is rotatable through a 135o of arc. There are full facilities for varying the size of the field. The New York and Chicago group discussed the use of highenergy electron beams from 2 to 22 million electron-volts. The problems of the extraction of the electron beam from the betatron and the absolute energy and some of the measurement problems were discussed.

Miller (Manchester) described some of the problems in the design of linear accelerators for X-ray therapy.

Van Dorsten (Eindhoven) described a deuteron accelerator which he felt could produce a fast neutron flux of 10 10 neutrons per second originating fron

a D-D reaction. The present machine has almost reached this desired figure, and it was his opinion that this fast neutron beam would be of ultimate value in therapeutic research.

Munson (Harwell) described some of his current measurments with a homogenous ionization chamber of atomic composition C-H. The ionization due to slow neutrons and gamma rays accompanying the fast neutrons were determined by simultaneous measurements with chambers filled with boron, trichloride, and argon. He reviewed the recent experimental evidence concerning the dependence upon speed of the ionizing efficiency of charged particles in gases and its effect upon dosage calculation.

Simons (London) presented a series of measurements of the total absorption coefficient for slow neutrons of both an artificial tissue and some simpler hydrocarbons.

X. RADIATION PROTECTION LEGISLATION One of the most important of the general meetings held at the congress was the meeting on the state control of protection against ionizing radiation. Lauriston Taylor, of Washington, D. C., presented a complete summary of the legal philosophies within many different countries concerning radiation-protection control. In his summary he showed that the systems of rules, licenses, and regulations ran all the way from the system followed in the United States with no national laws or licensing system and where control is based upon voluntary compliance with the National Committee on Radiation Protection recommendations, to the very formal and detailed code followed in New Zealand. He also summarized the reasons why strict police power was almost theoretically impossible and pointed out where abuses of and the privilege of using radiation could easily occur. Dr. Taylor's remarks have been distributed in mimeograph form to the members of the National Committee on Radiation Protection and will presumably be published for general distribution in the near future. It is a necessary piece of reading matter for anyone who is using radiation.

Dr. Zakobsky (Vienna) followed Dr. Taylor with a statement which seemed to stress the need for a stricter state control and policing system of radiation usage. He described the system now in use in Austria. He did, however, point out the necessity for any single state system of regulations to follow a set of recommendations agreed to by all nations. He seemed to feel that some organizations, such as the World Health Organization, should take up the problem.

Dr. Sievert, of Stockholm, presented a statement on the informal regulation system which is being followed in Sweden. Radiation-protection problems in the Swedish regulations are generally defined with a recognition of the lack of fundamental information on the questions of where protection is necessary, where the threshold dose biological action passes from a less to a more harmful stage, the definitions of measuring tools, etc. Dr. Sievert pointed out the necessity for more reesarch in radiophysics, radiobilology, and radiomedicine. Such research would allow us to continue practical radiation protection and still leave room for changing ideas as the knowledge of the fundamentals of radiation hazards progresses.

At a different session of the meeting Dr. Roth, of New Zealand, described the Radioactive Substances Act of 1949 of the New Zealand House of Representatives. He described the definition and operation of a strict radiation protection legislation and his impressions of its succcess over the past few years.

The CHAIRMAN. Are there any questions, gentlemen During the testimony of Dr. Brucer and the testimony of others who have preceded him, and I am sure the same will be true of those who will follow, I have been deeply impressed with the character of service that is being rendered.

In the first instance, the average person looks upon the Atomic Energy Commission as an organization set up to advance the cause of security by the use and development of weapons that kill. However, the testimony this morning with respect to this department or Division of Biology and Medicine of the Atomic Energy Commission indicates that a great service is being rendered to the people of this Nation, and ultimately to the world, by the research work that is being carried on, not to kill but to preserve life.

It seems almost paradoxical that there could be these different aspects, and it is extremely gratifying as I have listened this morning to realize that men of your standing and your ability and of your interest are engaged in making a study of this kind, taking what probably in the public mind, at least, is considered a death-dealing agency and making out of it a life-preserving agency.

I have been further impressed this morning by the fact that you give attention to the lost cases—the cases of cancer that too frequently are sent back home to die because there is no remedy and there is no help and there are not sufficient beds, there is not sufficient medical assistance to care for them, but you people are giving your attention to cases of that type. You are taking the hard part of the problem to work upon, and as a Member of Congress, and I know that I express the feeling that exists with other Members, it is highly pleasing and gratifying to realize that in our Government there are those agencies that are working for the common good and to promote the welfare of the people; that their whole time and whole attention and our whole expenditure is not merely to devise better and more effectual means of killing as a source of security, but that emphasis is being placed upon promoting the welfare of our people, by improving their health.

We are deeply appreciative today for the appearance of you gentlemen as a panel before us to inform us, and I trust through us to inform the people generally, of the fine work that is being done and which gives such great promise for the future.

You have inspired us with the inspiration and the spirit that I am sure each of you possesses as you carry on this splendid work, when, if you so desire, your talents could be probably used in a more lucrative way by giving of your time and your talents and your ability in this work that you are carrying on, and which I trust will always continue to be an inspiration to you, and that it will likewise create interest upon the part of others who will be helpful in this great matter of promoting the health of our people.

Doctor, I should not have said all that, but it was in my heart and mind to say it, and I want you to proceed with the balance of the hearing.

Dr. BUGHER. Thank you, sir.

The CHAIRMAN. Are there any questions? Mr. Dolliver has a question.

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