Why Do I have to be treated with IMRT?
How Long Does IMRT Last?
Simulation
What is IMRT (Intensity Modulated Radiation Therapy)?
What is IMRT Procedure?
Radiation used in IMRT
Nazoprharynx Cancer-Saliva Glands



Why Do I have to be treated with IMRT?
IMRT is the most definitive and correct radiotherapy technique available today. Apart from allowing for higher doses in the tumour and target tissues, this technique makes it possible to minimise radiation exposure in the surrounding healthy tissues to the lowest possible dose, thereby protecting the functions of the healthy tissues. Put more simply, just like one does in a paint job, the procedure is similar to taping off those areas you do not want to come into contact with paint so that you get exactly the result you intend.Top

How Long Does IMRT Last?
Depending on the part of the body and the disease, radiotherapy is applied 5 days a week over a period of 6-7 weeks. However, when applied for palliative purposes, it is applied over 2-3 weeks. Daily treatment takes approximately half an hour. The spreading over of the entire dose into daily doses and weekend radiotherapy applications allows time for healthy tissue cells to repair themselves.Top

Simulation

What is simulation?
A part of the treatment planning process is called simulation which is performed by radiation oncologist and radiotherapy technologist, in a special device called simulator is helpful to define target area precisely, locate and mark. Simulator is a machine similar to diagnostic x-ray machine can not be used for therapeutic purposes. The duration of simulation is depends on the treatment type, region, disease.Generally it could be done in one or two sessions. Your radiation oncologist and radiotherapy technologist will give you information about simulation.

How is simulation performed?
Optimal treatment position which should be convenient for the machines and comfortable for the patient, needed to repeat in each fraction of radiotherapy throughout whole treatment schedule will determined. During simulation you need to keep the position on simulator table as radiation therapy technologist asked. Radiotherapy technologist uses a special x-ray machine to define your treatment port or field as defined by your doctor. This is the exact place on your body where the radiation will be aimed. Depending on the location of your cancer, you may have more than one treatment port.
Depending on the type of treatment you will be receiving, body molds or other devices that keep you from moving during treatment (immobilization devices) may be made at this time. They will be used each time you have treatment to be sure that you are positioned correctly.
Radiotherapy technologist often will mark the treatment port on your skin with tattoos or tiny dots of colored, permanent ink. It's important that the radiation be targeted at the same area each time. If the dots appear to be fading, tell your radiation therapist who will darken them so that they can be seen easily.
Simulation may also involve CT scans or other imaging studies given below to plan how to direct the radiation better according to your disease.
CT (computed tomography) scan
An x-ray procedure that uses a computer to produce a series of detailed pictures of a cross-section of the body; also called a CAT scan. It is different than diagnostic CAT scan used only delineate target structures better. It is necessary when developed radiotherapy technology such as 3-D radiotherapy planning and IMRT (intensity modulated radiotherapy) performed.
Three-dimensional conformal radiation therapy is a radiation technique that is being used in some cancer centers. Computer simulation produces an accurate image of the tumor and surrounding organs so that multiple radiation beams can be shaped exactly to the contour of the treatment area. Because the radiation beams are precisely focused, nearby normal tissue is spared. This technique is being used to treat prostate cancer, lung cancer, and certain brain and head and neck tumors.

IMRT (Intensity Modulated Radiation Therapy)?
IMRT involves varying (or modulating) the intensity of the radiation, being used as therapy for cancer. It is a new form of radiation therapy that uses computer-generated images to plan and then deliver more tightly focused radiation beams to cancerous tumors than is possible with conventional radiotherapy. With this capability, clinicians can deliver a precise radiation dose that conforms to the shape of the tumor, while significantly reducing the amount of radiation to surrounding healthy tissues. Consequently, the technique can increase the rate of tumor control while significantly reducing adverse side effects.

Urinary Catheter: A thin, flexible, hollow tube through which fluids enter or leave placed to bladder via urethra. Radioactive materials may be placed in catheters and bladder and urinary system could be seen. It is removed after simulation.

Rectal Catheter: A flexible, hollow tube through which fluids enter or leave placed to rectum which is helpful distinguish rectum and protect from radiation side effects. It is removed after simulation.

Oral barium
Oral barium is useful to visualize pharynx, eusaphagus and stomach. Barium included fluid is taken before simulation.

Small bowel contrast:
It is useful to visualize small bowel and protect from radiation side effects taken as drink. Top


What is IMRT (Intensity Modulated Radiation Therapy)?

It is the procedure that changes and adjusts the intensity of the radiation used in the treatment of cancer. Prior to application, this new technology makes it possible to devise a treatment plan over the images produced by the computer, thus, compared to classical radiotherapy, radiation gets directed to cancerous tissues in a more selective manner. Physicians may direct high dose radiation to the tumour tissues in manner that will minimise their impact on the surrounding healthy tissues. As a result, this technique allows for increased tumour control and the side effects of the treatment are reduced.Top

What is IMRT Procedure?

Even though different hospitals may have different approaches, IMRT is basically similar to the conventional-classical radiotherapy procedure. The decision to apply IMRT is made by radiation oncologists following physical examination and reviews. In the preparation stage, it is necessary to prepare a custom-made body mould and mask for the patient. These should be worn by the patient to make sure that he receives treatment exactly in the same position every day. It may also be necessary to put some marks and lines on the patient's body in order to facilitate the set-up of the patient during radiotherapy procedure. CT images are taken to be used for treatment planning, and, in selected cases, MR and PET images. Preparation stage in treatment planning takes almost 1 hour and CT takes 15 minutes. The planning stage of IMRT is completed within a couple of days. Once planning is over, the treatment stage starts. Because final checks are performed before treatment is initiated, the first day of treatment takes longer than the following days. On the following days, treatment takes almost 15 minutes to complete. Treatment application procedure is similar to classical external radiotherapy.Top

Radiation used in IMRT

Photons currently used in linear accelerator devices are the same ones used in IMRT. Equipped with improved technology, these linear accelerator devices have the capacity to form small radiations of different intensities and direct them from different angles.Top

Nazoprharynx Cancer-Saliva Glands

Due to the proximity of its location to important nerves and blood vessels, nazopharynx cancer does not avail itself to surgical intervention and radiotherapy is the treatment method opted for. In patients receiving radiotherapy under conventional methods, the healthy tissues surrounding the tumour also get exposed to high doses of radiotherapy. Once the treatment is over, this causes serious side effects which affect their daily activities, professional lives and quality of life. For instance, the impact on saliva glands causes side effects such as swallowing and speech difficulties, nutrition problems and dental cavities. Breathing difficulties may be experienced during sleep which may be caused by dryness in the mouth; it disrupts sleep quality and the normal daily life functions of the patient.

Compared to classical radiotherapy, radiotherapy application with IMRT (intensity-modulated radiotherapy) directs higher treatment doses to the tumour and other organs of the body which need to be exposed to radiation. At the same time, it protects the function of healthy tissues by lowering the dose of radiation they get exposed to. To illustrate with an example, a nazopharynx cancer patient would have satisfactory saliva secretion following radiotherapy which would allow for satisfactory professional performance for teachers, stewardesses and speakers. IMRT makes it possible to enjoy higher quality of life following radiotherapy.

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