Question: How much time do radiation treatments for cancer take?
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. 
Radiation therapy is an adjuvant treatment for most women who have undergone lumpectomy and for some women who have mastectomy surgery.
In these cases the purpose of radiation is to reduce the chance that the cancer will recur.
Radiation therapy involves using high-energy X-rays or gamma rays that target a tumor or post surgery tumor site.
This radiation is very effective in killing cancer cells that may remain after surgery or recur where the tumor was removed.
Radiation therapy can be delivered by either external beam radiotherapy or brachytherapy (internal radiotherapy).
In the case of external beam radiotherapy, X-rays are delivered from outside the body by a machine called a Linear Accelerator or Linac.
In contrast, brachytherapy involves the precise placement of radiation source(s) directly at the treatment site.
Radiation therapy for breast cancer is usually performed after surgery and is an integral component of breast-conserving therapy.
Radiation therapy eliminates the microscopic cancer cells that may remain near the area where the tumor was surgically removed.
The dose of radiation must be strong enough to ensure the elimination of cancer cells.
However, radiation affects normal cells and cancer cells alike, causing some damage to the normal tissue around where the tumor was.
Healthy tissue can repair itself, while cancer cells do not repair themselves as well as normal cells.
For this reason, radiation treatments are given over an extended period, enabling the healthy tissue to heal.
Treatments using external beam radiotherapy are typically given over a period of five to seven weeks, performed five days a week.
Recent large trials (UK START and Canadian) have confirmed that shorter treatment courses, typically over three to four weeks, result in equivalent cancer control and side effects as the more protracted treatment schedules.
Each treatment takes about 15 minutes.
A newer approach, called 'accelerated partial breast irradiation' (APBI), uses brachytherapy to deliver the radiation in a much shorter period of time.
APBI delivers radiation to only the immediate region surrounding the original tumor and can typically be completed over the course of one week. 
Surgery and radiation therapy have been the major treatments for medullary thyroid carcinoma.