Radiation therapy is a packet of energy known as photons or gamma rays. This packet of energy breaks apart water molecules inside of tumor cells. As a result, unstable and highly charged ions are formed. These ions in turn interact with the tumor cells' DNA. By attaching to the tumor cell DNA, the ions cause damage that will eventually result in breaks in the tumor cell DNA. All cells, even cancer cells, require intact DNA to reproduce. Consequently, the damaged radiated cancer cells are unable to reproduce, resulting in tumor cell death.
How does radiation affect a tumor without injuring other parts of the body?
The different types of cells in our body divide at varying rates. Rapidly dividing cells include the cells comprising hair, skin and intestinal lining. Other cells divide very slowly or not all, including the cells in muscle, bone or nervous tissue. The more rapidly a cell divides, the more sensitive it is to the effects of radiation therapy. Cancer cells are typically very rapidly dividing cells. As a result, relatively low doses of radiation therapy are required to kill a tumor cell.
These doses of radiation are typically too weak to cause significant damage to the surrounding, slower dividing normal tissues. In addition, doses of radiation therapy are usually given in small amounts (fractions), once per day for several weeks. By delivering radiation therapy in this fashion, the normal cells in the body can rest and repair much more effectively.
Ideally, radiation therapy should be delivered primarily to the tumor. The normal tissues and organs in the body should be spared as much as possible. Recent, highly technical advances in radiation therapy are allowing radiation oncologists to deliver higher doses to the tumor with less and less exposure to the normal organs. The Radiation Oncology Department at Riverside Community Hospital is the most technologically advanced center in the immediate service area, and is equipped with every modern device for sparing normal tissues and organs.
Every patient receiving radiation therapy at Riverside Community Hospital will be treated with CAT-scan planning. CAT-scan planning uses a CAT-scan image to create a 3-dimensional, highly conformal beam of radiation. As this beam enters the patient's body, the radiation is deposited in a conformal fashion in the tumor. Intensity Modulated Radiation Therapy (IMRT) is the latest, highly technical advance in radiation therapy.
IMRT further shapes and modifies the conformal radiation beam as it enters the patient's body. By so doing, even higher doses of radiation therapy can be delivered to the tumor with even greater sparing of the surrounding tissues and organs. As a result of these higher radiation therapy doses, greater control of tumor and higher cancer cure rates are possible.