Radiation therapy is a critical part of cancer treatment that uses high doses of radiation to kill or damage cancer cells. This course provides an in-depth understanding of the techniques, protocols, and examples involved in radiation therapy, focusing on its use in oncological treatment.
Radiation therapy, also known as radiotherapy, is a medical treatment that uses high-energy radiation to target and destroy cancer cells. The radiation can be delivered externally, using a machine outside the body, or internally, by placing a radioactive material inside the body. The goal is to damage the DNA inside the cancer cells, preventing them from growing and dividing.
Radiation therapy is often used in combination with surgery, chemotherapy, or immunotherapy to treat various types of cancer, including brain, breast, prostate, and lung cancers.
There are two primary types of radiation therapy used in clinical practice: External Beam Radiation Therapy (EBRT) and Internal Radiation Therapy (Brachytherapy).
External Beam Radiation Therapy is the most common form of radiation treatment. In this technique, a machine called a linear accelerator directs high-energy X-rays at the cancerous area. The patient lies on a treatment table, and the machine is positioned to deliver precise radiation doses to the tumor from outside the body.
Brachytherapy involves placing a radioactive source directly inside or very close to the tumor. This method allows for higher radiation doses to be delivered to the tumor while minimizing damage to surrounding healthy tissue. Brachytherapy is commonly used to treat cancers of the prostate, cervix, and breast.
The effectiveness of radiation therapy depends on several key protocols, including accurate planning, precise dose delivery, and ongoing monitoring. Below are the essential components of a typical radiation therapy protocol:
Before starting radiation therapy, a detailed treatment plan is created. This involves the following steps:
Radiation therapy is typically delivered in daily fractions (sessions), with each fraction delivering a specific dose of radiation. The radiation dose is carefully calculated and monitored to avoid damage to healthy tissues. Depending on the tumor type, radiation therapy may be given over several weeks, with sessions lasting between 10 to 30 minutes each.
Throughout the course of radiation therapy, regular follow-up imaging and assessments are conducted to monitor the tumor’s response to treatment and to check for any side effects. If necessary, the treatment plan can be adjusted based on the patient’s progress.
Radiation therapy is generally well-tolerated, but like all cancer treatments, it can cause side effects. The side effects depend on the type of radiation therapy used, the area being treated, and the patient’s overall health. Some common side effects include:
Most side effects are temporary and can be managed with medications or lifestyle adjustments. However, it’s essential to monitor the patient’s response and adjust care as needed.
For localized prostate cancer, a common protocol involves external beam radiation therapy (EBRT) using IMRT or 3D-CRT. The treatment typically lasts for 7 to 8 weeks, with a daily session. Brachytherapy may also be used in combination, where radioactive seeds are implanted into the prostate gland.
For breast cancer patients who undergo breast-conserving surgery, radiation therapy is often delivered to the remaining breast tissue. The protocol typically involves 3D-CRT or IMRT techniques, with treatments given over 5 to 6 weeks.
Brain cancer treatment often involves stereotactic radiosurgery (SRS), which delivers a high dose of radiation precisely to the tumor while minimizing exposure to healthy brain tissue. A single treatment session is often sufficient for small, well-defined tumors.
Radiation therapy remains one of the most effective treatments for various cancers. With advancements in technology and treatment protocols, it has become a highly targeted and personalized approach, maximizing tumor destruction while minimizing harm to healthy tissues. A thorough understanding of the principles, protocols, and side effects is essential for radiologists, oncologists, and other medical professionals involved in the care of cancer patients.