1. Damage to the DNA of normal cells
The potential adverse effects of radiotherapy to the DNA of normal cells may result in tissue/organ damage and potentially secondary cancer. This is mainly due to (1) the direct exposure of normal cells to radiation, and (2) the indirect effect from the free radicals generated by radiation, which might result in the modification of certain genes generally referred to mutation. As a result, there is a possibility that certain cancer might be induced in the future, also known as secondary cancer, especially if high radiation dose is used often.
In
recent years, significant technical improvements have been made to greatly
reduce this type of potential side effect. Examples of the newer radiotherapy
technologies are described in the following chapter.
