HHC MEDİKAL MÜHENDİSLİK

Linear Accelerator Renewal and Overhaul

With the developing technology, the treatment of many diseases can now be provided with a much more practical and easy method. Diseases such as cancer can now be treated much more quickly. It is among your greatest wishes that your loved ones and yourself can live in good health and that they get rid of their health problems as quickly as possible. It is now much more possible to treat cancer cells and cure cancer. The linear accelerator is a device in the oncology section of health institutions, used in cancer treatment and fulfilling the purpose of giving X-rays to the sick person. A linear accelerator is an external treatment machine that applies a high amount of radioactive rays to cancer cells, without causing any damage to the surrounding healthy cells, in the area to be imaged through images taken from medical imaging machines (such as MR). Radiotherapy treatment is performed with two different methods, external and internal. Linear accelerator is a method used in external radiotherapy application. The linear accelerator working principle, under high voltage, accelerates the electron fragments detached from the targeted metal in the accelerator tube, and focuses the X-rays, which occur as a result of striking the detached electrons to a target in the head region of the world, through certain collimators, to the region of the sick person to be controlled. These given X-rays start to form a reaction in the body in a very short time. Molecules that occur as a result of the reactions create breaks in the genetic code of the cells that cause cancer. In this way, genetically impaired tumor cells begin to divide, fail to grow, and die after this process. This treatment, which does not require any pain, bleeding or surgery in patients, can also be called bladeless surgery. The question of what is a linear accelerator can be briefly answered in this way.

Linear Accelerator Working Mechanism

The working mechanism of linear accelerators is the same as that of x-ray tubes. Unlike normal X-rays, however, electrons cannot travel faster than 400 kV in beam tubes. The distance between cathode and anode is greater in linear accelerators. The linear accelerator parts and their working principles are simply as follows: From the power source, the central cathode and the anode around it, forming a cylindrical shape, conducts the current to the madulator, which contains the network network and hydrogen lamp. The transmitted electrical energy is stored in the modulator and it creates vibration by using this current transmitted by the control system. High voltage impulses continuing from the modulator are delivered to the klystron or magnetron tubes and also to the electron gun. Linear accelerator parts Klystron is the system that makes the electromagnetic wave stronger. The magnetron, on the other hand, is a system that generates electromagnetic waves at the micro level. The accelerator has a cylindrical shape and has an average diameter of 10 centimeters. A large amount of vacuum is applied to this tube. The electrons gained from the electron gun are transmitted to the copper tube at a speed of two-fifths of the keV speed of light. Vibrations with a frequency of 3000 MHz are created inside chambers with a diameter of 10 centimeters. These frequencies are sent to the middle channel. Meanwhile, the electrons produced by the gun pass to the accelerator copper tube. This process starts to progress by accelerating linearly in the chamber channel. Then the electron in question is accelerated as it moves to the next chamber. When they exit the last chamber, the electron velocities will be equal to the sum of the speeds at which they accelerated in the chamber. Magnetic focusers are used to collect the electrons to a single point and then direct them to the target. Electrons generated in the linear accelerator are used to treat cancer cells located close to the skin. In addition, the electron collection is transmitted to the target, and the resulting high-energy X-rays help the treatment of deeply located cancer cells.

Linear Accelerator Usage Areas

The linear accelerator is suitable for use in radiotherapy treatments. Cancerous cells in many parts of the body can be treated using a linear accelerator. The region where the device works most effectively is cancerous cells in the body region. Problems and diseases in areas such as the chest, lungs, abdomen and hips can be cured with this method at a high rate. Because the MRI machine creates a very good image in these regions. The linear accelerator, which can be used for all cancer cells, is an extremely effective treatment method, especially in areas such as prostate, liver metastases and cancer, chest wall, prostate and lung. Since it started to be used as a medical linear accelerator treatment method, the success rate of treatments in pancreatic cancer has increased remarkably. Numerical data show that the success rate has increased from 10% to 90%. It is thought that the linear accelerator, which is considered as a treatment method beyond its age, can also be applied to different parts of the body. The dose to be sent to the tumors where the cancerous cell is located can be adjusted in this way. In this way, the treatment allows to get a much more effective result. Some diseases that can be treated with the linear accelerator device can be listed as follows;

• Abdominal tumors

• Lung cancer

• Inoperable pancreatic cancer

• Inoperable rectal cancers

• kidney cancer

• kidney tumor

• adrenal gland cancer

• adrenal gland metastasis

• adrenal cancer

• adrenal metastasis

• low risk prostate cancer

• early stage breast cancer

• early stage prostate cancer

• Fallopian tube cancer

• Hepatobiliary cancers

• liver cancer

• Liver metastases

• Abdominal masses

• Abdominal tumors

• Pancreatic cancers with limited operation

• Colon cancer

• Colorectal cancers

• breast cancer

• bladder cancers

• Gastric cancer

• pancreatic cancer

• Prostate cancer

• cervical cancer

• uterine cancer

• Uterine cancer

• rectal cancers

• Vaginal cancer

• Esophageal cancer

• soft tissue sarcoma

Linear accelerators, which are used in the treatment of many diseases today, are painless and are much more likely to be successful, especially in the trunk area.

Head of Linear Accelerator

Linear accelerator components include the head. The parts of the head are as follows;

• There is a collimator consisting of movable jaws to detect the area to be treated. A collimator is a device that collects X-rays at a certain point and prevents them from scattering, which is used to send them to a specific target.

• The collimator detects the diameter of the beam of light and has a circular first chamber.

• It contains a filter called an equalizer in a cone structure that spreads X-rays homogeneously.

• During X-ray generation, there is a tungsten target where the beam of electrons is reflected. The tungsten target creates braking X-rays by stopping all electrons at the target.

• When the tungsten target is not used, that is, when the electrons begin to irradiate, the part that creates a magnetic field, also known as the diffuser or electron sweeper, ensures an even distribution of electrons.

• There are two arc ionization chambers in order to determine the dose administered to the patient in two different ion chambers and to control the symmetry and intensity of the beam group.

The linear accelerator structure is designed in such a way that the radiation source can rotate on the horizontal axis. While the gantry (head) rotates circularly around a horizontal axis, the collimator (collimator) simultaneously rotates around the axis passing through the midpoint of the field. The intersection point of these two linear accelerator components (Gantry and collimator) rotation axes is called isocenter.  The target articles of linear accelerators are cooled by water. The highest-energy incoming X-rays have the same energy as the electron.