Radiation Effects on the Human Brain

The effects of radiation on the brain are apparent in those who've undergone radiation therapy. This treatment is used in cases where a tumor mass is present. The purpose of this treatment is to shrink the tumor by destroying its cells. Adverse effects can occur anywhere from months to several years after the procedure is performed.

Identification

• Radiation is a form of energy made up of subatomic particles. This energy moves in waves, and is able to pass through skin, bone and clothing as well as a other types of materials. When radiation is applied to the brain, or any other cells in the body, it alters their physical make-up, leaving them unstable and unable to function normally. In the case of a brain tumor, the cancerous cells die off, however nearby healthy cell formations may be exposed in the process. Both short term, and long term side effects can result from this exposure.

Types of Radiation

• There are two types of radiation--ionizing and non-iodizing. Ionizing radiation is the type used in radiation therapy. Its effects on brain cells causes them to become unstable by adding ions, or charges to their atomic structures. Non-iodizing radiation is the type used in microwaves and cell phones. These energy waves are weaker than ionizing radiation, so no cell alterations take place. Ionizing waves alter cell structures on contact. As of yet, it is unknown whether non-ionizing waves have long term effects, as may be the case with ongoing cell phone usage.

Function

• The effects of radiation on healthy brain cells can be minimal when administered in low doses. When large doses are used, the cells must undergo a process of self-repair in order to recover from the exposure. If too much damage has occurred and they are unable to repair themselves, these cells will die off. As radiation exposure does destabilize a cell's structure and function, some cells may attempt to repair themselves even though their genetic coding has been significantly altered. When this happens, the probability that adverse effects will occur increases.

Cell Regeneration

• The nerve pathways which connect the nerve cells in the brain are coated by a substance called myelin. Myelin acts as an insulating material that promotes the fast transmission of nerve impulses. When radiation exposure damages this coating, a person may experience side effects while cells regenerate and rebuild their pathways. Common side effects experienced include nausea, vomiting, hair loss, skin irritation, possible hearing problems, fatigue and loss of appetite. The type of side effects experienced will depend on the amount of radiation used, the area it was applied to, and the total brain surface targeted.

Delayed Effects

• The effects of radiation therapy on the brain can vary depending on the individual. The onslaught of these effects fall into two categories--early delayed and late delayed. Early delayed effects can occur several weeks after treatment, and typically effect the cognitive functions of the brain. Memory problems are likely, however, this is a temporary condition that can last for up to a year. Late delayed effects happen in cases where physiological systems within the brain have been damaged. These effects are permanent, and can become progressively worse over time. Late delayed effects may include personality changes, impaired memory, decreased intellect and confusion.