It was noted earlier that radiation can produce biological effects. Around the turn of the century a number of experiments were carried out, which, would be characterized today as dangerous and foolhardy. It was found that ionizing radiation was capable of developing skin burns and could cause hair to fall out. In 1899, Stenbeck and Sjögren from Sweden used radiation to remove a tumor from the nose of a patient. This showed that radiation in large doses could be used to kill cancer cells. In the early years, when radium was used for treatment, the sources were made in the form of capsules or small tubes. The procedure for radium treatment was either to use a large source of radium (teletherapy) or to use a number of small sources for brachytherapy. In the latter case, paraffin wax was often used and formed to suit the part of the body to be irradiated. Small needles of radium were then sealed into the wax. This procedure gave a good dose distribution when skin ailments and tumors were treated. The general view at that time was that the radiation from radioactive sources was healthy and was a good treatment for most sufferings. Figure 10.1 (next page) shows an advertisement from 1913. Some people made good money by producing radioactive drinking water. A number of small towns in middle Europe such as Badgastein, Baden-Baden, Marienbad, and Karlovy Vary had radioactivity in their water and were considered to be healthy places. With the use of a jar and some radium salt (Figure 10.1), the water was saturated with radon when radium disintegrated. The belief was that by drinking this water you received “curative” radioactivity. In those days, like today, some
Figure 10.1. An advertisement from 1913 for radioactive drinking water. A jar with water, a cylinder and some radium salt was used. When Ra-226 disintegrates, radon is formed and is released into the water. When the tap was opened, radon was found in the water. The radiation doses were small and the whole system was rather harmless. (Reproduced with permission from R.F. Mould (1980).)
people voluntarily tried out methods that had not been tested or proved effective. In the early years, people were careless in the use of radiation and the handling of radioactive sources. The reason for this negligence was a lack of knowledge about radiation and its biological effects. Today, there is great deal of information about the effects of ionizing radiation, a great contrast to the lack of knowledge about the many chemicals in use. However, researchers in the radiation field have not been able to transmit this information to the public. The result is that the public has only an incomplete knowledge about radiation and radiation health effects. In spite of the fact that other human activities are far more hazardous than radiation, many people are unnecessarily afraid. Because large doses of radiation are known to kill cells, there is the possibilty of using radiation to treat cancer when localized to a small area of the body. Similar large whole-body doses can lead to death, which occurs in the course of days or weeks. When considering medium and small doses, the biological effect is considerably more difficult to predict. The reason for this is the time lag between the exposure and the observable biological effect. For solid cancers it may be several decades. Marie Curie, and a number of the other radiation pioneers died from cancer; thus, there are reasons to believe that their work with radiation was involved. On the other hand, recent experiments have claimed that small doses may even have a positive health effect (see Chapters 11 and 12). In all discussions on the biological effects of radiation, the radiation dose is a key issue. Without knowledge about the size of the dose it is meaningless to discuss the effects. The relationship between the dose and effect is also a hot issue in the community of research scientists. Knowledge about the dose-effect curve is a requirement when discussing mechanisms and health risks of radiation.