Radiation Therapy – Zap them out
Radiation therapy (also called radiotherapy) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. At low doses, radiation is used in x-rays to see inside your body, as with x-rays of your teeth or broken bones.
The type of radiation therapy that you may have depends on many factors, including:
- The type of cancer
- The size of the tumor
- The tumor’s location in the body
- How close the tumor is to normal tissues that are sensitive to radiation
- Your general health and medical history
- Whether you will have other types of cancer treatment
- Other factors, such as your age and other medical conditions
Stereotactic body radiation therapy (SBRT) is a new approach that is being applied to some types of cancer which differs from more traditional therapy in a variety of ways. SBRT is different than traditional therapy because it uses highly focused radiation concentrated on small tumors and only low doses to surrounding tissues.
The next part of the treatment plan is to “map the tumor.” – For example how and where the radiation will be entering the patient. The preferred mapping method is called 4D-conformal radiation therapy and uses multiple imaging modalities to characterize the treatment target such as using PET-CT and MRI images. This methods provides detailed information to define the specific target of the radiation from multiple angles, thus making delivery even more precise, enabling the maximum amount of radiation to be aimed at the most active portion of the tumor. In addition, the beams come from multiple angles and the intensity can be modulated (called intensity modulated radiation therapy or IMRT) which allows the primary area of the tumor to receive the most treatment while surrounding tissues receive less radiation, creating fewer side effects and less damage to normal tissue. The skin is also less damaged because the radiation treatments are coming from multiple angles.
While lung and liver are only two examples of cancers where SBRT seems to be improving treatment strategies, there are other cancers that are also being considered and will likely be addressed in this manner in the future.
Patients sometimes hear about these treatments through advertisement by treatment centers indicating that they have a particular state of the art machine. There are many manufacturers of these machines that offer this type of treatment, such as the Novalis TX and Cyberknife. They have different names, like luxury cars such as BMW and Mercedes Benz. The most important consideration is, as with driving a car, having someone who really knows how to use the machine. Just because a treatment center has a special machine does not insure that they have well-trained and experienced physicians using them. It is an important part of the equation to have improved technology but the human variable is critical. Mistakes often happen when technology is not being appropriately used by individuals and human judgment is not emphasized.