Saul Hertz

Saul Hertz was born on April 20, 1905, to father Aaron Daniel (A.D.) Hertz and mother Bertha Hertz in Cleveland, Ohio. His parents were Jewish immigrants from what is currently Golub-Dobrzyń in Poland. A.D. Hertz was a successful real estate developer. The Hertzs raised their seven sons according to Orthodox traditions. Saul Hertz attended public school and went on to graduate from the University of Michigan. He received his medical degree from Harvard Medical School in 1929, at a time when there were strict quotas for non-legacy students. Hertz completed his internship and residency at Cleveland's Mount Sinai Hospital, which had been established to serve Cleveland's East side Jewish population.[2]

Hertz joined the Thyroid Clinic and Metabolism Laboratories at Massachusetts General Hospital in 1931.[3] Although initially a volunteer, shortly thereafter, Hertz became Chief of the Thyroid Clinic, serving in this capacity from 1931-1943.[4]

Hertz was aware that iodine was readily taken up by the thyroid gland, and he knew that certain elements could be artificially made radioactive. In 1936, Karl Compton, then president of the Massachusetts Institute of Technology, gave a presentation at Massachusetts General Hospital on possible applications of physics to medicine. Hertz, having attended Compton's presentation, asked Compton if radioactive iodine could be artificially produced. Compton responded in a letter to Hertz on December 15, 1936, describing radioactive iodine.[5] An alternative account of this encounter is that J. Howard Means posed the question to Compton about radioactive isotopes of iodine. At the time, Means was head of the Department of Medicine at Massachusetts General Hospital. Means also asked Compton if the Massachusetts Institute of Technology could produce a radioactive isotope of iodine. Compton's response was based on his consultation with physicist Robley Evans.[6]

In 1937, Hertz began a collaboration with the physicist Arthur Roberts of the Massachusetts Institute of Technology (MIT). The purpose of the collaboration was to explore possible applications of iodine radioisotopes for diagnosis and treatment of thyroid diseases. Robley D. Evans of MIT and J. Howard Means of the Massachusetts General Hospital also had roles in the collaboration.[7] Initially, Hertz and Roberts evaluated the effect of the isotope iodine-128 on thyroid function in rabbits. Roberts produced the iodine-128 by means of neutron bombardment, building on previous studies by physicist Enrico Fermi.[8] Roberts also devised a Geiger-Müller detector for quantifying the amount of the radioisotope of iodine present in the biological specimens produced in the experiment.[6]

Hertz's experiment with Roberts involved studies of 48 rabbits. They determined in the study that the hyperplastic thyroid gland absorbed more of the radioactive substance than the normal gland.[9] This proved that radioactive iodine could serve as a radioactive tracer in thyroid function.[10] The tracer procedure was critical for determining the amount of iodine the human thyroid took up so that the dosage of radioactive iodine could be established for therapeutic purposes.[11]

Shortly after his 1937 rabbit studies, Hertz predicted the therapeutic use of radioactive iodine for treating thyroid carcinoma in a scholarly journal.[12] Hertz also recognized at that time that prior administration of non-radioactive isotopes of iodine could inhibit uptake of the radioactive isotopes, based on his experimentation with rabbits.[6]

Saul Hertz demonstrates a detection device used in nuclear medicine, with colleague Doris Darby

Hertz's initial studies were conducted with iodine-128. However, this isotope has a half-life of only 25 minutes, rendering it impractical as a therapeutic or diagnostic agent. Human application of the iodine radioisotopes required a more suitable radioisotope of iodine.[7]

In 1938, Glenn Seaborg and John Livingood had artificially prepared I-131 using the University of California Berkeley's cyclotron. With a half-life of 8 days, this isotope was better suited to practical medical applications than I-128. The building of the cyclotron at MIT for producing suitable isotopes was funded for $30,000 by the Mary Markle Foundation of New York City in 1938. The construction project was completed two years later in 1940. During those two years, the experiments with rabbits continued.[3]

In early 1941, Hertz administered to the first human patient a therapeutic dose of cyclotron-produced radioiodine (RAI), the patient suffering from Graves Disease, a form of hyperthyroidism. This clinical trial was at the Massachusetts General Hospital.[13] This administration was the first successful treatment of humans with an artificially produced radioactive material.[14]

Subsequently, a series of 29 patients were treated in this way, and their outcomes were documented. The Journal of the American Medical Association published “Radioactive Iodine in the Study of Thyroid Physiology" with Hertz as lead author in its May 1946 issue. This article was a five-year follow-up study of the 29 patients, and it documented the successful treatment and safety of radioactive iodine for the treatment of hyperthyroidism. The follow-up study established the use of radioactive iodine therapy as a standard treatment for Graves’ disease.[3]

In 1943, Hertz joined the United States Navy Medical Corps. He served as an adjunct to the Manhattan Project, working in an aspect of the project related to biology and medicine for furthering medical uses of atomic energy. After his return from military duty, Hertz learned that MGH's Earl Chapman (who had taken over Hertz's clinical trials) and MIT's Robley Evans, had submitted a scientific publication to the Journal of American Medicine claiming priority for the development of the use of RAI to threat Graves' Disease. Hertz, with his collaborator Roberts, submitted their own scientific manuscript. As a result, two scientific publications appeared side by side in the May, 1946, issue of the Journal of the American Medical Association, with the Hertz publication with Roberts appearing first in the issue of the journal.[15][16]

Interest in atomic energy for peaceful purposes was heightened as the Atomic Age commenced following the atomic bombings of Hiroshima and Nagasaki.[17] Hertz envisioned broader applications of radioisotopes in cancer treatment stating, “My new research project is in cancer of the thyroid which I believe holds the key to the larger problem of cancer in general".[18]

Hertz established the Radioactive Isotope Research Institute in Boston, Massachusetts, in September 1946, with Samuel Seidlin of New York City as the associate director. Its purpose was to develop the applications of nuclear fission products to the treatment of thyroid cancer, goiter, and other malignant growths. After WWII, Hertz joined the newly expanding Boston's Beth Israel Hospital. There, Hertz directed the successful use of RAI in the diagnosis and treatment of thyroid carcinoma.[1]

Hertz worked with the government to centralize an agency to handle the distribution of radioactive isotopes for use by private enterprises working on approved projects. He advocated for the Atomic Energy Commission to produce iodine-131 in the government’s atomic piles (nuclear reactors) at Oak Ridge National Laboratory, which lowered the cost and increased radioiodine's distribution.[19] He made extensive studies of radioactive iodine in the treatment of thyroid cancer as well as in the production of total thyroidectomy in the treatment of certain cases of heart disease.[8] In 1949, Hertz established the first nuclear medicine department at the Massachusetts Women's Hospital where he expanded his research to use radionuclides to diagnose and treat other forms of cancer. Hertz studied the application of radioactive phosphorus and the influences of hormones on cancer as displayed by isotope studies.[19][20]

Hertz's research was seminal in the emergence of the field of nuclear medicine. His research continued with his appointments as instructor at Harvard Medical School from 1946 to 1950 and as an attachment to the Nuclear Physics Department at the Massachusetts Institute of Technology from 1939 to 1950.[21]

The application of radioactive iodine in the diagnosis and treatment of thyroid disease is the cornerstone of nuclear medicine.[3] Barbara Bush, who was successfully treated with radioiodine, wrote to Vitta Hertz, his widow, “It is comforting to know that so many people are well because of the scientific expertise of people like Dr. Hertz.” [22]

In the 21st century, there is a significant rise in the use of radioisotopes to diagnose and treat cancer, in a field of nuclear medicine referred to as theranostics.[23] Yttrium 90 (Y-90) and Lutetium-177 are being used to diagnose and treat neuroendocrine tumors. The use of dosimetry has its origin in Hertz's work. Alpha targeted therapy is a therapy for patients with neuroblastomas (brain tumors). The use of the protein called NIS, that is needed for the thyroid to take up the RAI in the treatment of thyroid carcinoma, is being explored to treat breast cancer. Additionally I-131 is being utilized in the treatment of stem cell replacement for leukemia patients. These are all modern extensions of nuclear medicine.

Hertz died on July 28, 1950, at age 45 of a heart attack.[24]

• Dalton Scholar - Massachusetts General Hospital - 1931 - 1933
• Henry Pickering Wolcott Fellow - Harvard Medical School - 1935 - 1937
• Key to Science/Sigma XI - Massachusetts Institute of Technology (Scientific Society) - 1940

• Nuclear Medicine
• Radioactive iodine
• Hyperthyroidism