Types of Radiation Therapy
Irradiation may be done by a device outside the body (external radiation therapy) or by a radiation source inside the body (internal radiotherapy) or by radioactive material inside the body (systemic radiotherapy). The type of irradiation to the type of tumor, the tolerance of healthy tissues surrounding its location, the distance that radiation must travel within the body, and also the general health of the patient, the history of the disease and whether the patient will use other treatments or not, and a range of other factors. In most patients, external radiation therapy is used and in a number of patients, external, internal, systemic, combined or separate radiation therapy is used.
External Radiotherapy: Radiotherapy or external radiation therapy is commonly used in outpatient settings. Most of these patients do not need to be hospitalized. External radiotherapy is used to treat types of cancer including bladder, brain, breast, rectum, pancreas, stomach, cervix, larynx, lung, prostate and uterus. In addition, external radiation therapy may be To reduce metastatic pain or other problems caused by the spread of tumors.
Intraoperative Radiotherapy: This is a type of external radiation therapy with surgery. IIORT is used to treat concentrated tumors that can not be completely eliminated or there is a risk of recurrence. After removing all or most of the tumor tissue, a high dose of high energy is given directly to the tumor during surgery (healthy tissues around are protected by special shills). The patient is admitted to the hospital after surgery. This technique may be used to treat thyroid tumors, gynecological, colorectal, and pancreatic colon. This method is for the treatment of some types of brain tumors and pelvic sarcoma in adults.
3D Conformal Radiation Therapy 3D Radiation Therapy: Adaptive Radiation Therapy is in contrast to the three-dimensional old-fashioned treatments and uses a computer to target the tumor more precisely. Today, most oncologists use this method. 3D images of CT, MRI, PET or SPECT, and designed with special software, beams that match the shape of the tumor. Because in this technique, the healthy tissue around the tumor is far from radiated, higher doses can be used to treat the tumor. The use of this method in nasopharyngeal tumors, lung prostate, liver and brain tumors has better outcomes.
IMRT: In this method, which is a new three-dimensional adaptive radiotherapy, x-rays are often used with different intensities for transmitting different radiation doses to small tissue regions simultaneously. In this technology, high doses of the tumor and lower doses of the surrounding tissues will be around. In some techniques, the patient receives more daily doses and the total treatment time is reduced and the success of treatment is increased. IMRT may reduce the side effects of treatment. The irradiation in this method is accomplished by a linear accelerator equipped with a Multileaf colimator (the colimator helps to accurately shape the beams). By turning the device around the patient’s body, the beams enter the tumor from the best angle. The beams are as closely as possible fitted to the tumor shape. Because the IMRT device is highly specialized, the oncology centers rarely use this device. This new technology is used to treat brain tumors, head circumference, pharynx, breast, liver, lung, prostate, and uterus. This technique is not used for any patient or tumor.
Internal Radiation Therapy (Brachytherapy): In this method, the source of radiation that is wrapped in a small wrapper inside the tumor or close to it is called Implant or Implant. Implant materials may exist in different shapes such as small wires, plastic tubes (catheters), ribbans (strands), capsules or in the form of dents. Implants are inserted directly into the body. In internal radiotherapy, the patient may need to be hospitalized. Internal radiotherapy is usually done in one of the following ways, each of which is described separately. In all three methods, sealant implants are used.
Interstitial Radiotherapy: In this method, the radioactive substance is placed inside the tissue or near the tumor site. This method is used to treat head and neck tumors, prostate, cervix, ovaries, breast, pelvic and around the anus. In external radiotherapy of the breast, a higher dose (Boost) may be given to the patient, either internally or externally.
Intraocular radiotherapy: In this way, the radioactive source is inserted into the body by an applicator. This method is commonly used in treating tumors of the uterus. Researchers are studying the types of radiotherapy for treating other cancers including breast, bronchial, cervical, bladder, oral, tracheal, rectal, uterine and vaginal.
Systemic Radiation Therapy (Nuclear Medicine): In this method, radioactive substances like I131 Strontium89. Oral or injectable. This treatment is sometimes used to treat thyroid cancer and adult non-Hodgkin’s lymphoma. Researchers are reviewing materials that could be used to treat other types of cancer.
