Radiation therapy for therapeutic purposes can be done in two different ways: External radiotherapy and brachytherapy. With the radiation generated by modern external radiotherapy devices outside the patient from high electrical energy, the areas to be treated in the body are determined beforehand and made externally. While performing these treatments, using different features of the device depending on the software, conformal radiotherapy (3D RT), intensity-modulated radiotherapy (IMRT), image-guided radiotherapy (IGRT), respiratory supported RT (4 D RT), Stereotactic radiotherapy (SBRT) can be performed. All of these techniques have been developed to deliver the highest dose that will destroy the tumor and the lowest dose in the normal tissues around the tumor.
Brachytherapy is a different form of radiation therapy used in cancer treatment. It consists of placing radioactive sources directly or through catheters in or adjacent to the tumor to be treated. The form of radioactive sources placed in the organs with spaces in the body by various applicators is called intraluminal brachytherapy, while the method performed by catheters placed directly into the tumor is called interstitial brachytherapy. Since the radius of the radioactive source is limited in these irradiations, the target tumor receives the highest dose in the organ in which it is placed, while the surrounding healthy tissues are affected at least from the radiation.
In interstitial brachytherapy, various catheters are placed in the area to be treated, mostly without the need for a device, and radioactive sources are placed in these catheters to irradiate tumor tissues directly.
Devices used in intraluminal brachytherapy; Contrary to external radiotherapy devices, they do not generate radiation by themselves. These devices are used by externally loading various radioisotopes with certain properties in terms of half-life and energy.
Iridium-192, cobalt-60, cesium-137, iodine-125, and palladium-103 are among the most commonly used radioisotopes in both types of brachytherapy.
In terms of the energies of the radioisotopes, low dose rate (LDR) or high dose rate (HDR) irradiation is performed. In LDR brachytherapy, the radioisotope irradiates at a dose rate of 0.4-2 Gy / hour, in this treatment, the treatment time takes longer than HDR, and irradiation is performed in a single session. In HDR brachytherapy, treatment takes a short time due to the dose rate of the radioisotope over 12 Gy / hour. In these, treatment is often done in several fractions.
Brachytherapy; In various cancers such as gynecological tumors, breast cancer, prostate cancer, head and neck cancers, skin cancers, lung cancers, esophageal cancer, anal cancer, and soft tissue sarcomas, it can be performed as an additional option after external irradiation depending on the stage of the disease.
The GAMMAMED PLUS device we have in our center is a brachytherapy device that performs HDR treatment using iridium-192 radioactive sources. Because of the available applicators, brachytherapy is performed in our center for cervical cancer and endometrial cancer. Depending on the stage of the gynecological tumor, it can be performed after surgery after external radiotherapy or as the only treatment option without external radiotherapy. In addition, it can be used in combination with external radiotherapy or as the only treatment option in patients who do not undergo surgery depending on the stage of the tumor.
In patients with gynecological tumors who are indicated, appropriate applicators are applied to the patient and the patients are 3D treatment planning in the computerized planning system with the CT images taken. While the appropriate tumor dose is given, radioactive sources are loaded on the applicators attached to the patients by the plan made so that the dose to be received by the surrounding healthy tissues (bladder and rectum) is the least, and treatment is applied on the device.