Question: How long do traditional radiation treatments for cancer last?
About the article "Radiation therapy", section "Stereotactic radiation".

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Clinical trials, also called research studies, test new treatments in people with cancer.
The goal of this research is to find better ways to treat cancer and help cancer patients.
Clinical trials test many types of treatment such as new drugs, new approaches to surgery or radiation therapy, new combinations of treatments, or new methods such as gene therapy.
A clinical trial is one of the final stages of a long and careful cancer research process.
The search for new treatments begins in the laboratory, where scientists first develop and test new ideas.
If an approach seems promising, the next step may be testing a treatment in animals to see how it affects cancer in a living being and whether it has harmful effects.
Of course, treatments that work well in the lab or in animals do not always work well in people.
Studies are done with cancer patients to find out whether promising treatments are safe and effective.
Patients who take part may be helped personally by the treatment they receive.
They get up-to-date care from cancer experts, and they receive either a new treatment being tested or the best available standard treatment for their cancer.
At the same time, new treatments also may have unknown risks, but if a new treatment proves effective or more effective than standard treatment, study patients who receive it may be among the first to benefit.
There is no guarantee that a new treatment being tested or a standard treatment will produce good results.
In children with cancer, a survey of trials found that those enrolled in trials were on average not more likely to do better or worse than those on standard treatment; this confirms that success or failure of an experimental treatment cannot be predicted. 
Stereotactic radiation is a specialized type of external beam radiation therapy.
It uses focused radiation beams targeting a well-defined tumor using extremely detailed imaging scans.
Radiation oncologists perform stereotactic treatments, often with the help of a neurosurgeon for tumors in the brain or spine.
There are two types of stereotactic radiation.
Stereotactic radiosurgery (SRS) is when doctors use a single or several stereotactic radiation treatments of the brain or spine.
Stereotactic body radiation therapy (SBRT) refers to one or several stereotactic radiation treatments with the body, such as the lungs.
Some doctors say an advantage to stereotactic treatments are they deliver the right amount of radiation to the cancer in a shorter amount of time than traditional treatments, which can often take six to 11 weeks.
Plus treatments are given with extreme accuracy, which should limit the effect of the radiation on healthy tissues.
One problem with stereotactic treatments is that they are only suitable for certain small tumors.
Stereotactic treatments can be confusing because many hospitals call the treatments by the name of the manufacturer rather than calling it SRS or SBRT.
Brand names for these treatments include Axesse, Cyberknife, Gamma Knife, Novalis, Primatom, Synergy, X-Knife, TomoTherapy, Trilogy and Truebeam.
This list changes as equipment manufacturers continue to develop new, specialized technologies to treat cancers.
Treatment for lung cancer depends on the cancer's specific cell type, how far it has spread, and the person's performance status.
Common treatments include palliative care, surgery, chemotherapy, and radiation therapy. 
Surgery and radiation therapy have been the major treatments for medullary thyroid carcinoma. 
In optical fibers, attenuation is the rate at which the signal light decreases in intensity.
For this reason, glass fiber (which has a low attenuation) is used for long-distance fiber optic cables; plastic fiber has a higher attenuation and, hence, shorter range.
There also exist optical attenuators that decrease the signal in a fiber optic cable intentionally.
Attenuation of light is also important in physical oceanography.
This same effect is an important consideration in weather radar, as raindrops absorb a part of the emitted beam that is more or less significant, depending on the wavelength used.
Due to the damaging effects of high-energy photons, it is necessary to know how much energy is deposited in tissue during diagnostic treatments involving such radiation.
In addition, gamma radiation is used in cancer treatments where it is important to know how much energy will be deposited in healthy and in tumorous tissue.