How the Study of Radiation Biology Began
Radiation biology, or more commonly known as radiobiology, is a field of clinical and basic medical sciences that studies the action of ionizing radiation on living things. Radiobiology is particularly interested in the health effects of radiation. Generally, ionizing radiation is harmful, or even lethal, to living things. Nevertheless, it can also provide health benefits in the form of radiotherapy when treating cancer and thyrotoxicosis, as well as for radiography.
How Radiobiology Began
Despite its widespread usage and effectiveness today, there is very little written about the history of radiobiology. Nevertheless, we do know that the science slowly began to be recognized as a field of study after the discovery of ionizing radiation in 1895 by Wilhelm Roentgen, a German engineer, and physicist.
After only several months of his presentation, x-rays were used on patients with cancer. It’s important to note that there was a lack of understanding of what x-rays were and its interaction with matter. Similarly, the long-term effects were virtually unknown. In those early years, radiotherapy was believed to help treat a wide range of conditions such as rheumatism, syphilis, Hodgkin disease, laryngeal cancer, Graves disease, tuberculosis, eczema, acne, or hypertrichosis (excessive hair), among many others. Thousands of patients, including children, were exposed.
Still, there were some notable aspects of patient care being developed, such as shielding the device so that x-rays were only delivered to the desired direction, as well as not placing the device too close to the patient’s skin. Jean Alban Bergonié and Louis Tribondeau, two French medical doctors, formulated the “Law of Bergonie & Tribondeau” in 1906 which theorized that tissue radiosensitivity depended on maturation and metabolism. This theory is still reasonably applicable to the radiosensitivity of tissues and cancer today.
By the mid-1910s, however, epithelial radio-reactions began being documented. By 1930, it was understood that these reactions only occurred after a specific time and that the administered dose played a role. A treatment to tolerance method was employed, knowing that radiotherapy affected both cancer and healthy cells. For best results, a high enough dose that healthy tissues could tolerate was used as it gave the best chances of eradicating disease while still preserving normal tissue function.
Curing with Fractionated Treatment
From 1919, French doctor Henri Coutard began using a fractionated treatment method on treating head and neck carcinomas, previously believed to be incurable. Treatment was delivered in twice-a-day fractions with a low-dose machine. When large tumors were targeted, however, the low dose rate was thought to be unnecessary as the total dose was reduced. Known as simple fragmentation; the delivery was a small dose/high dose rate method and quickly replaced the single dose radiotherapy technique used by hospitals.
In 1937, François Baclesse took over from Coutard and further extended treatment time to avoid the severe reactions noticed up until that point. He limited the daily doses to 2 Gray units (2 Gy) and prolonging treatment to over 6 or 7 weeks. Data from 1919 to 1947 show that this time frame generated the best results. It was also around this time when this “Paris” technique imported into the United States.
A different method was used in Britain and the greater Commonwealth, known as the “Manchester” technique where treatment times were shortened to three weeks, with a drop of total dose to compensate for larger fraction sizes. This method was used mainly because of Britain’s lack of hospital beds and equipment.