In, J Radramn Onmlo~y Bwl Pnnted ,n the U.S.A. All nghts
??1990
Ph.v.\, Vol. reserved.
20, pp.
I171-1116 Copyright
0360-3016/91 $3.W i .oO RI I99 Pergamon Prew plc
I
ASTRO Special Features PRESIDENTIAL ADDRESS: THE PAST IS PROLOGUE CARL R. BOGARDUS JR., M.D.
Dept. of Radiological
Sciences,
The University
of Oklahoma
Health Sciences Ctr., P.O. Box 2690 1, Oklahoma
the purpose ofgenerating X rays, and the science of Rontgenology was born (Fig. 1).
THE BEGINNING Almost exactly 95 years ago, a German scientist, Wilhelm Conrad Rontgen, was conducting experiments related to the nature of light in his laboratory with devices known as Crook’s Tubes and Hittorf Tubes. As he was discharging high voltage through these evacuated tubes, he was noting the various levels of fluorescence in tubes with low pressure gases present in them. He also noted another phenomenon. A Hittorf Tube that was almost totally evacuated emitted very little visible light, but seemed to emit a type of invisible radiation which caused fluorescence of various minerals at some distance from the tube. Continuing his experiments, he noted that even with the tube completely covered with an opaque cloth, the mysterious radiations still caused fluorescence at some distance. He was astounded to then note that a screen coated with crystals of barium platinocyanide would not only fluoresce, but his hand held between the evacuated discharge tube and the screen would cast shadows of internal structures such as bones. Photographic plates were quickly substituted and were exposed by this mysterious radiation. One of the earliest pictures is reported to be his wife’s hand showing her wedding ring and internal bone structures. With this amazing discovery was born the entire science of X ray with its immediate application to diagnostic X ray to observe the bony structures of the body.
CLINICAL
A flurry of publications and presentations followed this initial discovery and within 6 months Rontgen had determined most of the basic principles related to this new radiation, which he called X rays. He then moved on to other scientific work and left the new field to others. His experiments were quickly duplicated around the world. Very shortly commercial units were being constructed for
for publication
2 January
DEVELOPMENT
Scientists began to realize that these new radiations were not innocuous, but caused changes and damage to living tissues exposed to this beam for any appreciable length of time. As with any new phenomenon, a myriad of experiments were conducted worldwide in attempts to apply this new discovery to medical and scientific usage. Experimentation and observation soon documented the damaging effects on normal living tissue (Fig. 2). It was noted further that the effects on malignancies were even more dramatic than on normal tissues. Cancers appeared to shrink magically and even disappear under the influence of this new ray. Many early pieces of equipment were multipurpose machines. By simply switching the x-ray tube, you could change its use as a diagnostic or therapeutic unit. In many situations, the same tube was used for both forms of treatment. No collimation or other attempts at confining the beams or shielding the environment from scatter were present on the early units. The science of radiology made a dramatic move forward with the invention ofthe heated cathode or Coolidge tube in 19 13. Higher current, higher voltage, and far greater control of the beam were made possible by this significant improvement in the x-ray tube. A consistent stream of electrons could now be generated and controlled with ease, allowing far greater currents, hence a much greater output of x-ray energy. The voltages could now be raised, bringing the machines into a practical range for therapeutic radiology. Two hundred thousand volt units were built in the late 20’s. This energy level steadily increased to 300,000 volt and 400,000 volt units in the 30’s. Therapeutic radiology was still limited by the inability of even these high energy rays to penetrate to any appreciable depth in tissue without doing irreparable damage
THE SCIENCE
Accepted
City, OK 73 190
1990. 1171
1172
I. J. Radiation Oncology 0 Biology 0 Physics
Fia. 1. One of the very earliest commercial 1890’s.
June 199 I, Volume 20, Number 6
x-rav units. This is from an advertisement
to the surface structures. Multi-port treatment plans, sievetype beam attenuators, experimentation with fractionation and protraction all were used in an attempt to increase the effective dose of radiations into deep-seated tumors while minimizing the effects on surface tissues. In 1939, the first one million volt deep therapy unit, a resonant transformer, was constructed by General Electric (Fig. 3). In a quantum leap forward, this machine allowed the generation of highly penetrating X rays to be developed at a practical cost. This unit was soon followed by the 1.5 million volt Van de Graff generator and therapeutic radiology had finally come of age. These early units were one of a kind prototypes and were extremely expensive to construct and maintain. Consequently, they were available only in the major treatment centers. The early pioneers in therapeutic radiology used these machines to increase the knowledge of the effects of radiations on normal and abnormal tissues at a logarithmic rate. The work of Beclere, Regaud, and others was followed by Baclesse, Coutard, and Lenz, who became the founding fathers of modern radiation therapy in this exciting era of accelerated learning.
RADIUM
Shortly after the discovery of X rays by Rontgen in November of 1895, Henri Becquerel investigated the possible connection of x-ray screen fluorescence with natural mineral fluorescence. He began his experiments utilizing uranium compounds and noted that photographic plates reacted to these chemicals by being exposed. To Becquerel
that was printed
in the late
must go the honor of the discovery of radioactivity. He suggested that this was very closely allied to the recently discovered X rays. A young French scientist working in Paris with her husband realized that a very intense form of radiation was being emitted by the ore pitchblend (Fig. 4). The primary ingredient in pitchblend is an oxide of uranium which was used at that time as a pigment for paints and ceramics. Specimens of pitchblend ore left in a dark environment, but in close proximity to photographic plates, caused the exposure of these plates, creating images quite similar to those being reported with the new X ray, except that they were pictures of the emitting source. Marie Curie realized that a type of radiation was eminating from the pitchblend ore and she set about to discover the source of this radiation. Working in her laboratory in Paris, she refined and extracted many tons of pitchblend ore, eventually condensing and concentrating the leachings to a very small amount of a crystalline substance which, for its quantity, was emitting an enormous amount of high energy radiations very similar to those coming from an x-ray tube. In December 1898, her experiments with this powder identified a new element which she named polonium after her native country of Poland. Shortly thereafter she separated the crystals further and discovered the even more active element, radium. Marie Curie’s experiments were reported to the scientific world, which eagerly absorbed astonishing scientific discoveries on almost a daily basis. This was in sharp contrast to the scientific community of less than 100 years earlier, when any new phenomenon was usually discredited as
ASTRO presidential address 0 C. R. BOGARDUS JR.
Fig. 3. This is the first one million volt resonant transformer unit manufactured by General Electric in 1939. This machine opened the supervoltage era.
the laws of nature. The advent of commercial electricity, the electric light bulb, the telephone, the telegraph, the phonograph, and electric streetcars all tended to create an astonishing blur of scientific discovery where almost any announcement was accepted as being valid.
going against
DEVELOPMENT
Fig. 2. This illustration shows the long-term effects of x-ray exposure on the hands of Mihran Krikor Kassabian. These pictures were taken approximately 1904- 19 10.
OF THE
SCIENCE
Following the lead of the use of X rays, the curative effects of radium were soon applied to almost all forms of human illness. Radium baths for various skin ailments, radium stuffed pillows for the cure of arthritis, and an endless series of imaginative uses all became the fad of this new form of radiant energy. The medical era starting about 1900 and progressing for the next 30 years saw remarkable advances in the science of modern surgery and its use to excise, control, and cure cancer. Although the effects of X ray were shown to be effective against malignancy, the severe limitations of energy prevented it from developing at the same pace that surgical excision was progressing. The discovery of radium gave us the ability to encapsulate minute quantities of intensely powerful radiant energy into inert capsules of gold and platinum which could be inserted directly into a malignancy. This allowed remarkable advances to occur in the treatment of cancer of the cervix, the oral cavity, and cancers of the skin. These were often cancers far beyond the reach of surgery. Cure became a reality. Quimby, Paterson, Parker, Ernst, and others pioneered the ways of performing these applications with a science that allowed reproducibility of techniques. This provided large patient base studies to validate the claims of the cure of malignancy by the application of radium, often combined with external beam irradiation. Brachytherapy, as it was called, often performed by surgeons, and external beam irradiation, performed by radiologists, combined their sciences in the 30’s to develop
1174
1. J. Radiation Oncology 0 Biology 0 Physics
June 199I, Volume 20, Number 6
Fig. 4. Marie Curie in her laboratory
the fledgling field of therapeutic radiology or radiotherapy as it was known in those days. THE NEW ERA The science and technology of the production of high energy X rays markedly advanced with two significant outgrowths of the efforts of the defense industry in World War II. The Allis Chalmer’s Company had developed an extremely high energy machine for doing diagnostic xray work of castings for tanks, battleships and other armorment. This machine, called a Betatron, could develop electron and x-ray energies up to 22 million volts (Fig. 5). It was known that X rays generated at this level of energy could penetrate with ease through the thickest patient and
in Paris.
treat deep seated malignancies with minimal surface skin reactions. This unit could also deliver electrons directly from a special port. Rather than strike a target to create X rays, the electrons themselves could be used to treat both surface and deep lesions with remarkable effectiveness. A special electronic tube known as a magnatron was developed to produce high frequency radio waves for radar units during the war. After the war, two brothers by the name of Varian working with magnatrons and high energy radio frequency generators developed the first commercial linear accelerator in 1950. Work with atomic reactors had shown that ordinary cobalt (59Co), if left in an intense field of neutron bombardment, became radioactive “Co, which on decay emitted two high energy gamma photons
Fig. 5. An Allis Chalmer’s Betatron developed for diagnostic x-ray work of a large gun barrel casting. The same type machine was adapted for clinical use following its war duties. The Betatron was truly the first ofthe commercial supervoltage high energy machines. Although Betatrons were very cumbersome to use and had low outputs, they were capable of producing a very clean photon beam as well as an electron beam, proving conclusively the value of extremely high energy radiation therapy.
ASTRO
presidential address 0 C. R.
of 1.17 and 1.33 million volts each. Although an experimental teletherapy unit had been assembled in Europe in 1930 by Claudius Regaud utilizing most of the world’s available supply of radium (at that time 14 GM), an effective teletherapy unit could not be developed until a cheap source of high energy radioisotopes could be produced. In 195 1, three 6oCo sources of approximately 1,000 curies each were produced at the Chalk River (Ontario) Heavy Water Reactor Facility. The first source went to the Saskatoon Cancer Center and was installed in a unit that was designed by Harold Johns. The second source went to the Victoria Hospital in London, Ontario under the direction of Dr. Ivan Smith. The first patient treated with a 6oCo teletherapy unit was in London on October 27, 1951. The first Cobalt unit to deliver treatments in the United States used a source made up of 108 individual 10 curie sources from the Oakridge facility. This large source was installed in a unit at the Los Angeles Tumor Institute. The first patient was treated on April 23, 1952. The M. D. Anderson Hospital in Houston, Texas, under the direction of Dr. Gilbert Fletcher, began treating patients in July of 1952 using a 1000 curie source from the Chalk River Facility (Fig. 6). High energy x-ray units were still extremely expensive and difficult to maintain in spite of the rapid advances in technology. These machines were still limited to large institutions, primarily teaching and research centers, and were cost-prohibitive to all but the best endowed private sector. The advent of cobalt, however, heralded a new era of high energy, low cost, effective radiation treatment machines. The rapid proliferation and dissemination of cobalt units through the 1960’s and 70’s
BOCARDUS JR.
1175
brought therapeutic radiology to even small community hospitals. Paralleling the rapid growth of equipment was a rapid growth in the number of specialists trained specifically to operate this equipment to treat cancer. The field of therapeutic radiology was rapidly coming of age with the development of the equipment paralleled by the training programs of the founding giants of modern therapeutic radiology. Buschke, Cantril, de1 Regato, Fletcher Lampe, Kaplan, and their proteges swelled the ranks of those specialists doing only therapeutic radiology from a handful of pioneers in the 30’s to over 2,000 specialists in North America today. The equipment continues to improve, with linear accelerators in the 6 to 25 MeV range being commonly available and widely accepted as the state of the art today. The Betatrons have mostly been scrapped. Only one manufacturer now offers such a unit. Cobalt units, because of their low cost, convenience, and reliability are still very common and are still manufactured. New radioisotopes in practical quantities are being developed for permanent as well as temporary implantation in brachytherapy. Low, and high intensity brachytherapy sources are practical to allow remote afterloading and hence a marked improvement in the safety factor of handling these materials. 13’Cs, ‘921r 6oCo and a host of new radioisotopes are available for medical use. Exotic machines developing beams of mesons, protons, and neutrons are being studied. Cyclotrons have been adapted to purely radiation therapy purposes for the generation of these beams. Conventional linear accelerators
Fig. 6. The first Cobalt unit at the M.D. Anderson Hospital in 1952. Gilbert Fletcher, M.D. (left), Marshall Brucer, M.D. (center), and Dale Troutt, M.S. (right), physicist with the General Electric Corporation. Observing the prototype unit at Oakridge, Tennessee under going testing prior to the unit being moved to the M.D. Anderson Hospital.
1176
I. J. Radiation Oncology 0 Biology 0 Physics
are being modified to produce conformal radiation portals with varying fields, energy values, and treatment depths as well as motion of ports during treatment for any given patient treatment situation. Steriotatic radiosurgery by modified Cobalt or linear accelerators is now practiced. The advances in technology are being paralleled by advances in clinical applications with radiation treatment being used in combination with multi-modality surgery and chemotherapy to continue to improve our cure and control rate of malignancies. Surgical oncology, medical oncology, and radiation oncology are no longer looked upon as competing forms of cancer therapy, but are combined in highly innovative protocols to markedly improve the cure rate and benefit all patients. Therapeutic radiology slowly moved only to the threshold of practicality in its first 50 years. The last 40 years have seen the development of radiation oncology into a specialty that is the key to the control of cancer in our time. Therapeutic radiology grew from a scientific experiment to a philathopic sideline of diagnostic radiol-
June 199 1, Volume 20, Number 6
ogy to a full-fledged speciality standing squarely on its own in today’s medical community. We can only guess what the next 5 years will bring as radiology approaches its centennial year. While the world continues to search for “the cure for cancer”, we presently have it. Prevention, early detection, and adequate therapy will certainly be the answer well into the twenty-first century. The radiation oncologist can and must remain at the forefront of oncology, always a leader and never a follower. We started with a retrospective look at us as a speciality but we should conclude with an introspective look at us as physicians. Are we, meaning all of medicine, doing everything possible for our patients in a safe and cost effective manner, laying aside all selfish speciality interests, and thinking only of the quality of life that we alone can deliver to the patients afflicted with malignancy? The answer from radiation oncology must be “Yes” and hopefully, the rest of our medical colleagues will follow our lead.
??1990
Ph.v.\, Vol. reserved.
20, pp.
I171-1116 Copyright
0360-3016/91 $3.W i .oO RI I99 Pergamon Prew plc
I
ASTRO Special Features PRESIDENTIAL ADDRESS: THE PAST IS PROLOGUE CARL R. BOGARDUS JR., M.D.
Dept. of Radiological
Sciences,
The University
of Oklahoma
Health Sciences Ctr., P.O. Box 2690 1, Oklahoma
the purpose ofgenerating X rays, and the science of Rontgenology was born (Fig. 1).
THE BEGINNING Almost exactly 95 years ago, a German scientist, Wilhelm Conrad Rontgen, was conducting experiments related to the nature of light in his laboratory with devices known as Crook’s Tubes and Hittorf Tubes. As he was discharging high voltage through these evacuated tubes, he was noting the various levels of fluorescence in tubes with low pressure gases present in them. He also noted another phenomenon. A Hittorf Tube that was almost totally evacuated emitted very little visible light, but seemed to emit a type of invisible radiation which caused fluorescence of various minerals at some distance from the tube. Continuing his experiments, he noted that even with the tube completely covered with an opaque cloth, the mysterious radiations still caused fluorescence at some distance. He was astounded to then note that a screen coated with crystals of barium platinocyanide would not only fluoresce, but his hand held between the evacuated discharge tube and the screen would cast shadows of internal structures such as bones. Photographic plates were quickly substituted and were exposed by this mysterious radiation. One of the earliest pictures is reported to be his wife’s hand showing her wedding ring and internal bone structures. With this amazing discovery was born the entire science of X ray with its immediate application to diagnostic X ray to observe the bony structures of the body.
CLINICAL
A flurry of publications and presentations followed this initial discovery and within 6 months Rontgen had determined most of the basic principles related to this new radiation, which he called X rays. He then moved on to other scientific work and left the new field to others. His experiments were quickly duplicated around the world. Very shortly commercial units were being constructed for
for publication
2 January
DEVELOPMENT
Scientists began to realize that these new radiations were not innocuous, but caused changes and damage to living tissues exposed to this beam for any appreciable length of time. As with any new phenomenon, a myriad of experiments were conducted worldwide in attempts to apply this new discovery to medical and scientific usage. Experimentation and observation soon documented the damaging effects on normal living tissue (Fig. 2). It was noted further that the effects on malignancies were even more dramatic than on normal tissues. Cancers appeared to shrink magically and even disappear under the influence of this new ray. Many early pieces of equipment were multipurpose machines. By simply switching the x-ray tube, you could change its use as a diagnostic or therapeutic unit. In many situations, the same tube was used for both forms of treatment. No collimation or other attempts at confining the beams or shielding the environment from scatter were present on the early units. The science of radiology made a dramatic move forward with the invention ofthe heated cathode or Coolidge tube in 19 13. Higher current, higher voltage, and far greater control of the beam were made possible by this significant improvement in the x-ray tube. A consistent stream of electrons could now be generated and controlled with ease, allowing far greater currents, hence a much greater output of x-ray energy. The voltages could now be raised, bringing the machines into a practical range for therapeutic radiology. Two hundred thousand volt units were built in the late 20’s. This energy level steadily increased to 300,000 volt and 400,000 volt units in the 30’s. Therapeutic radiology was still limited by the inability of even these high energy rays to penetrate to any appreciable depth in tissue without doing irreparable damage
THE SCIENCE
Accepted
City, OK 73 190
1990. 1171
1172
I. J. Radiation Oncology 0 Biology 0 Physics
Fia. 1. One of the very earliest commercial 1890’s.
June 199 I, Volume 20, Number 6
x-rav units. This is from an advertisement
to the surface structures. Multi-port treatment plans, sievetype beam attenuators, experimentation with fractionation and protraction all were used in an attempt to increase the effective dose of radiations into deep-seated tumors while minimizing the effects on surface tissues. In 1939, the first one million volt deep therapy unit, a resonant transformer, was constructed by General Electric (Fig. 3). In a quantum leap forward, this machine allowed the generation of highly penetrating X rays to be developed at a practical cost. This unit was soon followed by the 1.5 million volt Van de Graff generator and therapeutic radiology had finally come of age. These early units were one of a kind prototypes and were extremely expensive to construct and maintain. Consequently, they were available only in the major treatment centers. The early pioneers in therapeutic radiology used these machines to increase the knowledge of the effects of radiations on normal and abnormal tissues at a logarithmic rate. The work of Beclere, Regaud, and others was followed by Baclesse, Coutard, and Lenz, who became the founding fathers of modern radiation therapy in this exciting era of accelerated learning.
RADIUM
Shortly after the discovery of X rays by Rontgen in November of 1895, Henri Becquerel investigated the possible connection of x-ray screen fluorescence with natural mineral fluorescence. He began his experiments utilizing uranium compounds and noted that photographic plates reacted to these chemicals by being exposed. To Becquerel
that was printed
in the late
must go the honor of the discovery of radioactivity. He suggested that this was very closely allied to the recently discovered X rays. A young French scientist working in Paris with her husband realized that a very intense form of radiation was being emitted by the ore pitchblend (Fig. 4). The primary ingredient in pitchblend is an oxide of uranium which was used at that time as a pigment for paints and ceramics. Specimens of pitchblend ore left in a dark environment, but in close proximity to photographic plates, caused the exposure of these plates, creating images quite similar to those being reported with the new X ray, except that they were pictures of the emitting source. Marie Curie realized that a type of radiation was eminating from the pitchblend ore and she set about to discover the source of this radiation. Working in her laboratory in Paris, she refined and extracted many tons of pitchblend ore, eventually condensing and concentrating the leachings to a very small amount of a crystalline substance which, for its quantity, was emitting an enormous amount of high energy radiations very similar to those coming from an x-ray tube. In December 1898, her experiments with this powder identified a new element which she named polonium after her native country of Poland. Shortly thereafter she separated the crystals further and discovered the even more active element, radium. Marie Curie’s experiments were reported to the scientific world, which eagerly absorbed astonishing scientific discoveries on almost a daily basis. This was in sharp contrast to the scientific community of less than 100 years earlier, when any new phenomenon was usually discredited as
ASTRO presidential address 0 C. R. BOGARDUS JR.
Fig. 3. This is the first one million volt resonant transformer unit manufactured by General Electric in 1939. This machine opened the supervoltage era.
the laws of nature. The advent of commercial electricity, the electric light bulb, the telephone, the telegraph, the phonograph, and electric streetcars all tended to create an astonishing blur of scientific discovery where almost any announcement was accepted as being valid.
going against
DEVELOPMENT
Fig. 2. This illustration shows the long-term effects of x-ray exposure on the hands of Mihran Krikor Kassabian. These pictures were taken approximately 1904- 19 10.
OF THE
SCIENCE
Following the lead of the use of X rays, the curative effects of radium were soon applied to almost all forms of human illness. Radium baths for various skin ailments, radium stuffed pillows for the cure of arthritis, and an endless series of imaginative uses all became the fad of this new form of radiant energy. The medical era starting about 1900 and progressing for the next 30 years saw remarkable advances in the science of modern surgery and its use to excise, control, and cure cancer. Although the effects of X ray were shown to be effective against malignancy, the severe limitations of energy prevented it from developing at the same pace that surgical excision was progressing. The discovery of radium gave us the ability to encapsulate minute quantities of intensely powerful radiant energy into inert capsules of gold and platinum which could be inserted directly into a malignancy. This allowed remarkable advances to occur in the treatment of cancer of the cervix, the oral cavity, and cancers of the skin. These were often cancers far beyond the reach of surgery. Cure became a reality. Quimby, Paterson, Parker, Ernst, and others pioneered the ways of performing these applications with a science that allowed reproducibility of techniques. This provided large patient base studies to validate the claims of the cure of malignancy by the application of radium, often combined with external beam irradiation. Brachytherapy, as it was called, often performed by surgeons, and external beam irradiation, performed by radiologists, combined their sciences in the 30’s to develop
1174
1. J. Radiation Oncology 0 Biology 0 Physics
June 199I, Volume 20, Number 6
Fig. 4. Marie Curie in her laboratory
the fledgling field of therapeutic radiology or radiotherapy as it was known in those days. THE NEW ERA The science and technology of the production of high energy X rays markedly advanced with two significant outgrowths of the efforts of the defense industry in World War II. The Allis Chalmer’s Company had developed an extremely high energy machine for doing diagnostic xray work of castings for tanks, battleships and other armorment. This machine, called a Betatron, could develop electron and x-ray energies up to 22 million volts (Fig. 5). It was known that X rays generated at this level of energy could penetrate with ease through the thickest patient and
in Paris.
treat deep seated malignancies with minimal surface skin reactions. This unit could also deliver electrons directly from a special port. Rather than strike a target to create X rays, the electrons themselves could be used to treat both surface and deep lesions with remarkable effectiveness. A special electronic tube known as a magnatron was developed to produce high frequency radio waves for radar units during the war. After the war, two brothers by the name of Varian working with magnatrons and high energy radio frequency generators developed the first commercial linear accelerator in 1950. Work with atomic reactors had shown that ordinary cobalt (59Co), if left in an intense field of neutron bombardment, became radioactive “Co, which on decay emitted two high energy gamma photons
Fig. 5. An Allis Chalmer’s Betatron developed for diagnostic x-ray work of a large gun barrel casting. The same type machine was adapted for clinical use following its war duties. The Betatron was truly the first ofthe commercial supervoltage high energy machines. Although Betatrons were very cumbersome to use and had low outputs, they were capable of producing a very clean photon beam as well as an electron beam, proving conclusively the value of extremely high energy radiation therapy.
ASTRO
presidential address 0 C. R.
of 1.17 and 1.33 million volts each. Although an experimental teletherapy unit had been assembled in Europe in 1930 by Claudius Regaud utilizing most of the world’s available supply of radium (at that time 14 GM), an effective teletherapy unit could not be developed until a cheap source of high energy radioisotopes could be produced. In 195 1, three 6oCo sources of approximately 1,000 curies each were produced at the Chalk River (Ontario) Heavy Water Reactor Facility. The first source went to the Saskatoon Cancer Center and was installed in a unit that was designed by Harold Johns. The second source went to the Victoria Hospital in London, Ontario under the direction of Dr. Ivan Smith. The first patient treated with a 6oCo teletherapy unit was in London on October 27, 1951. The first Cobalt unit to deliver treatments in the United States used a source made up of 108 individual 10 curie sources from the Oakridge facility. This large source was installed in a unit at the Los Angeles Tumor Institute. The first patient was treated on April 23, 1952. The M. D. Anderson Hospital in Houston, Texas, under the direction of Dr. Gilbert Fletcher, began treating patients in July of 1952 using a 1000 curie source from the Chalk River Facility (Fig. 6). High energy x-ray units were still extremely expensive and difficult to maintain in spite of the rapid advances in technology. These machines were still limited to large institutions, primarily teaching and research centers, and were cost-prohibitive to all but the best endowed private sector. The advent of cobalt, however, heralded a new era of high energy, low cost, effective radiation treatment machines. The rapid proliferation and dissemination of cobalt units through the 1960’s and 70’s
BOCARDUS JR.
1175
brought therapeutic radiology to even small community hospitals. Paralleling the rapid growth of equipment was a rapid growth in the number of specialists trained specifically to operate this equipment to treat cancer. The field of therapeutic radiology was rapidly coming of age with the development of the equipment paralleled by the training programs of the founding giants of modern therapeutic radiology. Buschke, Cantril, de1 Regato, Fletcher Lampe, Kaplan, and their proteges swelled the ranks of those specialists doing only therapeutic radiology from a handful of pioneers in the 30’s to over 2,000 specialists in North America today. The equipment continues to improve, with linear accelerators in the 6 to 25 MeV range being commonly available and widely accepted as the state of the art today. The Betatrons have mostly been scrapped. Only one manufacturer now offers such a unit. Cobalt units, because of their low cost, convenience, and reliability are still very common and are still manufactured. New radioisotopes in practical quantities are being developed for permanent as well as temporary implantation in brachytherapy. Low, and high intensity brachytherapy sources are practical to allow remote afterloading and hence a marked improvement in the safety factor of handling these materials. 13’Cs, ‘921r 6oCo and a host of new radioisotopes are available for medical use. Exotic machines developing beams of mesons, protons, and neutrons are being studied. Cyclotrons have been adapted to purely radiation therapy purposes for the generation of these beams. Conventional linear accelerators
Fig. 6. The first Cobalt unit at the M.D. Anderson Hospital in 1952. Gilbert Fletcher, M.D. (left), Marshall Brucer, M.D. (center), and Dale Troutt, M.S. (right), physicist with the General Electric Corporation. Observing the prototype unit at Oakridge, Tennessee under going testing prior to the unit being moved to the M.D. Anderson Hospital.
1176
I. J. Radiation Oncology 0 Biology 0 Physics
are being modified to produce conformal radiation portals with varying fields, energy values, and treatment depths as well as motion of ports during treatment for any given patient treatment situation. Steriotatic radiosurgery by modified Cobalt or linear accelerators is now practiced. The advances in technology are being paralleled by advances in clinical applications with radiation treatment being used in combination with multi-modality surgery and chemotherapy to continue to improve our cure and control rate of malignancies. Surgical oncology, medical oncology, and radiation oncology are no longer looked upon as competing forms of cancer therapy, but are combined in highly innovative protocols to markedly improve the cure rate and benefit all patients. Therapeutic radiology slowly moved only to the threshold of practicality in its first 50 years. The last 40 years have seen the development of radiation oncology into a specialty that is the key to the control of cancer in our time. Therapeutic radiology grew from a scientific experiment to a philathopic sideline of diagnostic radiol-
June 199 1, Volume 20, Number 6
ogy to a full-fledged speciality standing squarely on its own in today’s medical community. We can only guess what the next 5 years will bring as radiology approaches its centennial year. While the world continues to search for “the cure for cancer”, we presently have it. Prevention, early detection, and adequate therapy will certainly be the answer well into the twenty-first century. The radiation oncologist can and must remain at the forefront of oncology, always a leader and never a follower. We started with a retrospective look at us as a speciality but we should conclude with an introspective look at us as physicians. Are we, meaning all of medicine, doing everything possible for our patients in a safe and cost effective manner, laying aside all selfish speciality interests, and thinking only of the quality of life that we alone can deliver to the patients afflicted with malignancy? The answer from radiation oncology must be “Yes” and hopefully, the rest of our medical colleagues will follow our lead.
