Radiotherapy is often a very important part in oncological therapy. Fortunately, in recent years the technology in this field has increasingly developed and modern brachytherapy was born. Dr. Kamen Nedev, Head of the Brachytherapy Dept. at City Clinic Oncology Center shares more details about this treatment means.
Brachytherapy is a type of internal radiation therapy where a source of radiation is inserted into the tumor itself or nearby. This leads to a number of benefits for patients in comparison to traditional external beam radiation.
The basic operating principle of radiotherapy is irradiation of tumor cells so they are damaged and gradually die. Some die at the moment of exposure, as the higher the dose, the greater their number. The remaining cells fade away within a few months. The problem is healthy cells are also subject to damage, although they are less sensitive to radiation, as they are more mature and healthier than cancer. In a very few cases however these injuries to healthy tissues may be significant and forward the patient to other specialists to treat the consequences of the administered treatment.
These adverse side effects are minimized in brachytherapy compared to external radiation since the source of radiation is inserted into the very sick organ. Thus adjacent healthy organs receive a small dose of radiation (if any) due to its steep drop the further the organ is from the source of radiation, and it suffers less. The source is usually inserted into a cavity next to the tumor; if there is none, it is inserted into the sick organ, passing through soft tissues – under anesthesia, using needles. These needles are thin and hollow, of 2 mm of diameter, and 20 cm long. The source of radiation applied is Iridium-192, the most commonly used temporary implant in brachytherapy. It is administered by a robot into each of the needles and irradiates the tumor cells. The important thing is our source has a high dose rate, allowing high dose energy released in a short period of time. Thus, exposure lasts for up to 15-20 minutes, depending on the type of tumor (prescribed dose) and the activity of the source. Post procedure, the source of radiation is retracted into the device and the patient is not radioactive, they feel completely comfortable and can be discharged a couple of hours later. Depending on the disease a patient may need three to six such procedures. Not so, however, if low dose is administered. Then sources of treatment radioactive seeds – they remain in the human body and their disintegration time is some 45-60 days. In this case, this patient has a number of issues: they must comply with measures of radiation protection and possess a special travel document.
Since it is friendlier, brachytherapy is a treatment method leading to the best quality of life thereafter. Some studies in prostate cancer show patients in greatest scale manage to retain an erection later. Fortunately, brachytherapy has a wide range of applications. Patients subject to this treatment are approximately 40% of all to undergo a radiation therapy. It can be used either as a single method of treatment or in combination with external beam radiation. The combined administration is used in patients of an increased risk of metastasis. Then brachytherapy treats the sick organ while external radiation attacks the nearest lymph nodes, where physicians expect metastases to occur. Therefore, results are always better; it is recommended to combine external sources with internal exposure.