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Radiation Oncology 

Radiotherapy, also called radiation therapy, is among the most innovative and modern treatment methods in curing cancer and relieving symptoms. Radiation Oncology (Radiotherapy) department is one of the important and successful treatment methods of cancer disease. Radiotherapy can be the only treatment method in cancer, or it can accompany surgery and chemotherapy. The use of modern and targeted techniques in radiotherapy gives the patient the chance to recover comfortably and in the best possible way, with the least side effects. 

What is radiotherapy?

Radiation is a special type of energy carried by waves or particles. It can be produced by special devices or released by substances called radioactive. This energy is used in medicine for imaging purposes as well as to treat cancer and some other diseases. Special devices are needed to direct the radiation to the diseased organ. In this way, the use of high-dose radiation energy for treatment is called "radiotherapy" or "radiation therapy".

How does radiotherapy affect the body?

High doses of radiation have the ability to kill cells or prevent them from dividing and multiplying. Since cancer cells divide and multiply much faster than normal cells, radiotherapy is more effective on cancer cells than normal cells. In addition, it is much easier for normal healthy cells to recover and become old than cancer cells. At the stage called "planning", the necessary drawings are made so that the diseased tissues are exposed to the maximum radiation and the normal tissues the least radiation, and the treatment is applied in a targeted way.

What are the benefits and objectives of radiotherapy?

Radiotherapy is applied in cancer type that can occur in almost any part of the body and in approximately 50% of cancer patients. For some types of cancer, radiotherapy is the only treatment. Radiotherapy is a treatment method that can be applied alone or in combination with surgery and/or drug therapy ("chemotherapy"), in which a full recovery can be achieved in many patients.

Radiotherapy is used for the objectives that are listed below:

  • for the targeted, high-dose and short-term therapy (stereotactic)

  • shrinking the tumor before surgery (neoadjuvant),

  • removing the cancer cells that may have remained at the microscope level in the body after surgery (adjuvant)

  • during surgery (intraoperative) in some types of cancer

  • without surgery, directly for treatment with chemotherapy (curative),

  • in some cases where it is not possible to completely cure the disease; Radiotherapy can be applied to reduce the patient's complaints such as pain and bleeding. This type of treatment is called "palliative therapy"

Who gives radiotherapy?

A "radiation oncologist", a physician who specializes in the treatment of diseases with radiation, determines the type and plan of treatment that the patient needs.

During the treatment, radiation oncology specialists work with a special team. 

Radiation physicist: Checks that the devices work correctly and give the appropriate dose of radiation.

Radiotherapy nurse: Provides nursing services during the treatment, helps to minimize the side effects that may occur for the patient and provides nutritional support during the treatment.

Radiotherapy technician: Prepares the patient before the treatment and applies the daily planned treatments using the treatment devices.

What are the types of radiotherapy?

Radiotherapy is applied in two ways. externally and internally. In some patients, these two forms can be applied in succession.


In most patients, radiotherapy is applied externally. It is an application that is generally performed in treatment centers and outpatient clinics, and it is performed by directing the rays to the diseased tissue by using radiotherapy devices. External treatments were carried out in 2D with devices called Cobalt-60 or linear accelerator until recent years. In two-dimensional treatments, normal tissue damage and side effects were more common, as wide margins of safety were required to deliver sufficient dose to the target volume. However, thanks to the technological changes in radiotherapy devices in recent years, three-dimensional conformal radiotherapy, IMRT (intensity-adjusted radiotherapy), stereotactic radiotherapy (linac-based, gammaknife, cyberknife) are applied to the target volume, while maximum dose is applied to the target volume, while it can be ensured that the normal tissue receives a minimum dose. Once the decision is made to administer radiation therapy, the doctor will also decide which device is more suitable for the patient.


In internally applied radiation, the radioactive material or source is placed either directly into the tumor or into a body cavity with thin wire or tubes. The method, which is often applied in gynecological tumors, can also be applied to the space left after surgery.

How does the doctor make a treatment plan for the external radiotherapy?

Radiation sources used in radiotherapy are diverse. The doctor may use an X-ray or electron beam. The choice of radiation source to be used is determined by the type of tumor, its location in the body and especially its depth. High-energy X-rays are used for the treatment of many types of cancer. Electron beams, on the other hand, can treat some skin diseases.

Before starting the treatment, a preparatory session is performed together with the computerized planning tomography. The aim is to personalize the treatment and to determine the irradiation technique that should be chosen according to the type and extent of the cancer. Details about this preparatory session and the treatment itself (especially the frequency and duration of the sessions) are informed to the patient by the radiation oncology specialist during the first examination. First of all, during the radiotherapy sessions, the position that the patient has to take inside the device is determined, and then computed tomography is taken in this position. Making the treatment plan with computed tomography allows the determination of the tumor and/or the most risky areas for the spread of the tumor, as well as the detection of normal tissues that need protection. During tomography, fixation devices, plastic masks may be used, or it may be necessary to take a film by injecting a contrast agent into the vein.

By making markings on the patient's skin, the "target volume" is irradiated under the same conditions from one radiotherapy session to the next. For this purpose, non-removable ink pens are used or tattooing can be done. It will not be a problem for you to take a daily bath, as water-resistant tapes are used. In case your marks are erased, it would be appropriate to warn the technician and not to complete it yourself.

After the target volume and normal tissue determinations are made by the doctor by the tomography sections, your doctor discusses with the radiation physicist how much radiation dose the patient needs, how this dose will be given and how many sessions it will take. As long as the planning process can be on the same day, it can take a few days.

After the treatment is started, the doctor monitors the patient's response to the treatment, the general condition and possible side effects of the treatment. You can meet with your radiation oncologist with checkups, which are usually done once a week, but the check-up may be more frequent depending on the patient's needs. It is very important to receive scheduled treatments on time. Disruptions in treatment and unnecessary breaks may reduce the expected effectiveness of treatment.

What is hyperfractional radiotherapy?

Radiotherapy is given by dividing daily doses according to tumor type and location. In hyperfractional radiotherapy, the daily dose is divided into several small parts. If several treatments are to be given to an area by dividing them into one day, the application is usually done at intervals of 4-6 hours.

What is intraoperative radiotherapy?

In intraoperative radiotherapy, surgery and radiotherapy are applied simultaneously. The surgeon removes the tumor tissue as much as possible and radiotherapy is given to the tumor bed in the operating room immediately after the surgery to clean the tumor cells that may have remained in the removed area.

What happens in a regular radiotherapy session?

Before starting the treatment, the patient takes off his clothes and puts on a gown. For this reason, it is recommended to come to treatment with clothes that can be changed easily.

The radiotherapy technician uses previously marked lines on the patient's skin to identify the treatment area. The patient should sit in a special chair or lie on the treatment table. Although an average of 15 minutes is spent in the treatment room in each session, the delivery of the radiation dose takes place in 1 to 5 minutes. External radiotherapy is as painless as an X-ray.

There is no need for the patient to hold their breath during the procedure unless there are special conditions, and only normal breathing is sufficient. In radiotherapy sessions; It is important that the defined dose is given in the most sensitive way, that the rays reach the right place in the body, that the patient's position is not deteriorated throughout the treatment, that the same position is created in each treatment, and that the environment is immobilized in order to ensure the comfort of the patient in the best way. In this process called immobilization, accessories such as head-neck masks, vacuum mattresses, under-knee stabilizers or shoulder pullers can be used depending on the treated area.

The radiotherapy technician leaves the room before the beam is delivered. The devices are controlled from a small area nearby. The patient can also watch through a monitor or window. Meanwhile, when the patient speaks, his/her voice can be heard through the loudspeaker and communication with the technician and doctor can be established. A slightly noisy environment may occur when radiotherapy devices rotate around the treatment area at different angles due to their large structures. However, it should not be forgotten that the patients are operated by the relevant technicians and their operation is regularly checked. Any questions about the treatment room or devices can be asked to the technician or doctor.

Radiation cannot be seen, heard or felt in any way. If a situation occurs during the treatment session in which the patient will feel very bad or uncomfortable, the technician should be informed immediately. When necessary, the operation of the devices can be stopped immediately.

Are there any side effects to radiotherapy?

External radiotherapy does not make the body radioactive. Therefore, there is no need to avoid contact with people receiving treatment. Even in contact situations such as hugging and kissing, there is no risk that will negatively affect other people.

The side effects of radiotherapy are usually the complaints of the treated area. The doctor and nurse advise the patient on how to manage these side effects. The doctor or nurse should be informed when there are complaints such as cough, fever, sweating or unusual pain during the treatment. Side effects usually disappear within a few weeks after the end of treatment and can be controlled with medications or diet. Side effects that may last longer can also be managed with appropriate treatments.

The effectiveness of the treatment is monitored by the doctor. After the treatment, it is felt that pain, bleeding and other similar complaints decrease, and other signs of improvement appear over time. Some tests may order blood while the doctor monitors the treatment effects.

Questions about appointments?

You'll find answers to questions about the appointments process, scheduling, referrals and more.

See Frequently Asked Questions here.

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