Radiotherapy (treatment with ionizing radiation) is one of the most effective cu

Radiotherapy (treatment with ionizing radiation) is one of the most effective current cancer treatments. It works by damaging DNA and other cellular components.

Part A

In which ways could radiotherapy control or cure cancer?
 A. Radiotherapy is a universal treatment for tumors caused by viruses. The radiation destroys the virus and products the cell from further damage.
 B. Radiotherapy is a cancer treatment only for external treatment. It works by damaging the cancer cells' plasma membrane and killing the cell.
 C. Radiotherapy is a cancer treatment only for internal applications. It starts the process of apoptosis in cancer cells by damaging the cells' proteins.
 D. Radiotherapy is often administered externally or internally to kill cancer cells by damaging their DNA.


Part B

Why does radiotherapy often have significant side effects?
A.  In addition to killing cancer cells, radiotherapy can also kill normal cells too, causing side effects.
B.  It produces internal sources of radiation in the organism.
 C. A radiation dose that was too low to kill or slow the growth of cancer cells was used.