8. Radiation Therapy

Repeated surveys have shown that those physicians who have the most contact with radiation (radiologists) have a significantly higher incidence of leukemia—at least nine times greater than that among all other males of the same age and at least four times greater than that for other physicians.

8.1 Radiation Destroys Cells

As atomic radiation permeates living tissues, highly-organized units of living matter in the cell are disrupted. Fundamentally, the cell is composed of atoms and molecules which are split by radiation into electrically-charged fragments. This ionization process is completed in less than a trillionth of a second, yet it triggers off a chain reaction of subtle events within the cell leading to its damage or eventual death. Since cells are not inert blobs of matter but living, reproducing, organisms, they react to the radiation-induced injury by repair processes which lead to apparent recovery. If the radiation dose is overwhelming, immediate or only slightly delayed death of the cell ensues when the cell attempts to divide.

Radiation also harms cells by producing changes in the environment. Cells are bathed by solutions from which radiation-produced activated products can reach and damage them. Also, cells can be damaged by interference with their blood supply and the action of poisonous products released by radiation-killed cells themselves.

8.2 Tissue Damage

Since tissues are a specialized population of cells, their exposure to radiation causes damage as a consequence of injury and death of the component cells. The overall effect involves not only the direct action of the radiation on the individual cells but changes in the surroundings of the tissues.

One tissue may give an immediate response to radiation and another no apparent or detectable response. However, the seemingly unresponsive tissue may show injury at a much later date. The recovery of tissues from immediate radiation injury depends on the specific cell types, or the size of the radiation dose, and on the time between repeated irradiations. These factors have been summarized by Doctors E. G. Williams and S. C. Ingraham II in a United States Health report for 1956 (Jack Schubert, Radiation NY: Viking Press, 1957):

"The blood-forming organs, the skin, the membranes lining body cavities, and the secreting glands may regenerate completely and resume their normal functions. Muscle, brain, and portions of the kidney and eye cannot regenerate; their repair results only in scar formation. Even those tissues that can regenerate may fail to respond after repeated ionization and cause conditions such as nonhealing ulcers or aplastic anemia (bone marrow destruction). Also, repeated regeneration may produce cancerous conditions ... These changes have all been observed in animals following radiation exposures at levels corresponding to doses only slightly above the accepted safe limits for man. There are no constant clinical symptoms which can be relied upon to warn of latent radiation injury before life-threatening changes become manifest."

8.3 Effects on Genes

No cell fully recovers from a dose of radiation. While a cell may seem to recover, there is an irreversible effect on the chromosomes and genes. According to Drs. Williams and Ingraham: "Ionizing radiation can alter the genes in the body (somatic) cells and in the reproductive (sexual) cells and cause them to grow or reproduce abnormally. If a gene change occurs in a sexual cell, a mutation will occur in later generations provided that the cell is used in reproduction. If a gene change occurs in a cell of growing or regenerating somatic tissue like skin, liver, or bone marrow, it may cause cancerous or other harmful changes in the exposed individual."

8.4 Hormonal Disturbances

The late effects of radiation are often produced in cooperation with disturbances in body function in general. One of these disturbances in particular—hormonal imbalance —can in itself aid and abet the cancer-producing effects of radiation or even delay years the appearance of the cancer. Consequently, in evaluating the changes wrought by radiation in the body we must also take into account the complex inter-relationship existing between the various organs and the hormones released by the different endocrine glands.

Dr. Schubert theorizes that since hormones influence the regeneration and growth of almost all the cells in the body, it is reasonable to assume that many of the late changes and cancers developed in the body after radiation are related to the impairment of the endocrine glands such as the pituitary, thyroid, gonads, and adrenals, either as a result of the radiation directly on the endocrine organ or, indirectly, because of damage to a distant organ which then brings forth a response from the endocrines.

Since a female child possesses at birth all the ova she will ever use, it is very important to note that exposure of the ovaries to radiation affects eggs which are to be fertilized in the future. Thus, radiation damage is preserved by the ova and may result in defective children. Even if the children appear normal, they may carry defects in their heredity (the genes) which will be manifest in later generations.

8.5 Depression of Cells

A single dose of 50 r to the whole body causes the number of lymphocytes to drop by one-half in about "two to three days. It takes about a week for it to return to the preradiation level. After higher but nonlethal doses of radiation, the lymphocyte drop is abrupt and little or no evidence of recovery may be apparent for several months. In fact, it may take years before the number of white cells returns to normal. Another significant observation is the fact that individuals previously exposed to radiation show a greater depression of cell numbers upon subsequent radiation exposure.

8.6 Brain Damage

The brain is considered to be relatively insensitive to small radiation doses, but this does not mean there is no damage—it means rather that there exists no suitable means of detecting damage, or that it has not beer, looked for, or that no cases have been followed for a long enough time. One must be suspicious of all tissues to which radiation has been given.

Relatively small doses of radiation to localized regions of the brain give immediate effects. In 1953, two volunteers were given 100 r to a localized region of the brain (diencephalon). About one and one-half hour; later they complained of ringing in the ears, generalized numbness, and apathy. Shortly thereafter they felt mentally stimulated. Sleep that night was very deep. The next morning they were very active and "high." Then they became unusually quiet. The disturbances lasted about seven to ten days. These effects were confirmed in another experiment involving 120 persons.

There have also been several reports of brain damage in persons given heavy doses of radiation for brain tumors or for scalp lesions.