Final answer:
Radiotherapy uses ionizing radiation to target and destroy rapidly reproducing cancer cells, aiming to maximize the therapeutic ratio. It involves techniques to concentrate the dose in cancerous tissue while limiting exposure to normal cells, illustrating the dual role of radiation as both a cure and a potential cause of cancer.
Step-by-step explanation:
Radiotherapy, also known as radiation therapy, is a common and effective cancer treatment method. Ionizing radiation is used during radiotherapy to damage the DNA of the cells. Since cancer cells reproduce rapidly, they are more sensitive to radiation damage compared to normal cells. This makes them more likely to be destroyed by the radiation. The main goal of radiotherapy is to maximize the damage to cancer cells while minimizing the harm to surrounding normal cells. This is achieved by using various techniques to concentrate the radiation dose in the tumor, such as directing narrow beams at the tumor from multiple angles (a geometric technique). The balance between destroying cancer cells and sparing normal cells is known as the therapeutic ratio, which is a critical concept in radiation treatment.
It's important to note that while ionizing radiation can be an effective cure for cancer, it can also cause cancer by inducing mutations when cells are exposed to it. This dual nature of ionizing radiation – being both a potential cause and treatment for cancer – is one of the complexities of cancer therapy.