The most frequent form of radiation therapy used for cancer treatment is external radiation (also known as external beam radiation). High-energy rays (or beams) from outside the body are aimed towards the tumour using a machine. External beam radiation treatment may now be delivered with extreme precision because of advances in radiation technology. These devices direct the radiation to the exact spot where it is needed, ensuring that normal tissues are spared as much as possible.
External radiation is most commonly administered during outpatient visits to a hospital or treatment facility. The majority of patients get external radiation treatment over a period of weeks. They usually go to the treatment clinic for a specific number of weeks every workday (Monday through Friday).
However, other people may just need to visit the treatment facility twice a day for a shorter period of time. Your cancer care team will work with you to determine how much radiation you’ll need and how often you’ll need it.
Three-dimensional conformal radiation therapy or three-dimensional By concentrating the radiation dosage on the tumor’s specific form and size, this helps to limit radiation harm to normal tissues while also killing the cancer more effectively.
Types of external beam therapy:
Image guided radiation therapy (IGRT) is a kind of 3D-CRT in which patients undergo imaging scans (such as a CT scan) prior to each treatment. This permits the radiation oncologist to change the patient’s posture or refocus the radiation as needed to ensure that the radiation beams are precisely focused on the tumor and that normal tissue exposure is minimized.
Like 3D-CRT, intensity-modulated radiation treatment (IMRT) alters the power of certain beams in specific regions. This enables higher dosages to reach specific areas of the tumor while also reducing harm to adjacent healthy tissues.
Helical-tomotherapy is a kind of IMRT in which the radiation is delivered in a unique method. The radiation machine releases several tiny beams of radiation to the tumor from various angles around the body for this treatment. This might allow for even more accurate radiation targeting.
External beam radiation treatment, also known as photon beam radiation therapy, is a type of external beam radiation therapy. It employs photon beams to reach the tumor, but it can also harm healthy tissue nearby. Photons are utilized in treatments administered using a linear accelerator unit. When photon beams travel through the skin to the tumor, they are invisible and cannot be felt.
Instead of photons or electrons, proton beam radiation treatment employs proton beams. Protons are atom components that cause little damage to the tissues they travel through while destroying cells after their journey. This implies proton beam radiation may be able to deliver more radiation to the tumor while having fewer adverse effects on healthy tissues. Only specific equipment known as a cyclotron or synchrotron can produce protons. When proton beams travel through the skin to the tumor, they are invisible and cannot be felt.
Stereotactic radiosurgery is a form of radiation treatment that delivers a significant dosage of radiation to a tiny tumor region in a single session, rather than surgery. It’s used to treat brain tumors and other head tumors. Radiation is delivered to the tumor from a variety of angles once the exact location of the tumor has been determined via brain imaging. The radiation is precisely targeted to do as minimal damage to surrounding tissues as possible. It’s termed “radiosurgery” because the radiation beams are delivered with such precision, almost like surgery. However, there is no cutting or incision at all.
Stereotactic body radiation therapy is a treatment that takes place outside of the brain (SBRT). SBRT may be used to treat malignancies in the lungs, spine, and liver.
In many radiation treatment facilities, this technique is referred to by the brand name of the machine’s manufacturer. These names may come up in conversations with your cancer care team or other patients at the treatment center.
These machines, such as the X-Knife, CyberKnife, and Clinic, move about to target the tumor from various angles. Synergy-S, Edge, Novalis, and TrueBeam are some of the other brands in this category.
Although most patients having stereotactic radiosurgery will get the complete radiation dosage in one session, it may be repeated if necessary. To administer the same or somewhat greater dose, physicians may divide the radiation into numerous smaller doses. Fractionated radiosurgery or fractionated stereotactic radiotherapy are two terms for the same thing.
External radiation is delivered directly to the tumors or tumors during surgery, known as intraoperative radiation treatment (IORT). It may be used if the tumors cannot be fully removed or if there is a significant danger of cancer returning in the same location.
The surgeon pulls normal tissues away from the tumor and protects them with special shields while you are unconscious (under anesthesia). This allows the clinician to deliver cancer a single big dosage of radiation while limiting the impact on surrounding tissues. IORT is administered in a separate operating room.
What is your doctor’s strategy for planning your radiation treatment?
A team of skilled health care experts plans and administers radiation. A radiation oncologist is a doctor who uses radiation to treat cancer and oversees the treatment of each patient who receives radiation. The radiation therapist, in collaboration with the radiation oncologist, administers daily radiation treatments and positions patients for each session.
Medical physicists and dosimetrists are two other experts who plan and calculate radiation dosages.
Your radiation oncologist will evaluate you, analyze your medical history and test findings, and determine the exact region to be treated before beginning radiation treatment. Simulation is the name given to this planning session. This is sometimes referred to as the sim. You’ll be requested to lie motionless on a table while the radiation therapist defines your treatment field using imaging scans (such as a CT scan or an MRI) (also called the treatment port). The radiation beams will be directed at these precise locations on your body.
The simulation is crucial and will likely take some time. It’s used to map out the exact location of the therapy on or in your body. The radiation can then be given as close to the tumor as feasible while causing as little damage to normal, healthy tissues as possible.
Radiation beams are carefully targeted. To ensure that you are in the same posture for each treatment and to help you keep still throughout treatment, a customized mold, mask, or cast of a body part may be produced. The radiation therapist may use freckle-sized dots of semi-permanent ink to indicate the treatment field. The markings will most likely diminish with time, but they are required until your therapy is completed.
Do not scrape or apply soap on these markings. Permanent dots, similar to tattoos, may be used to designate the region. (Lasers can be used to eliminate them afterward.)
What is the dose of radiation given?
The radiation oncologist will collaborate with the other members of his team to determine how much radiation is required, how it will be delivered, and how many treatments you should have based on the simulation, other tests, and your cancer kind. They determine this based on studies that indicate what the minimum and maximum radiation doses should be for the kind of cancer and body part being treated.
More therapy may be required if cancer has not fully disappeared or if it returns. In these instances, the radiation team will assist you in determining if radiation therapy is the appropriate treatment choice. This choice is based on the kind of cancer, the location of the tumor, and the amount of radiation administered to the region before. If the maximum dosage has been achieved, radiation may not be the best option, and another treatment option may be available. Re-irradiation is the process of delivering radiation to the same region again.
How long does it take to get external radiation treatment?
The complete dosage of radiation required to destroy a tumor can seldom be delivered all at once.
This is because a big dosage administered all at once might cause more harm to normal tissues nearby. This can result in more adverse effects than providing the same dose across many treatments spaced out over days or weeks.
External radiation treatment is generally separated into fractions, which are lower dosages. For 5 to 8 weeks, most patients get radiation treatments five days a week (Monday through Friday). Weekend rest periods provide normal cells time to recuperate. The total dosage of radiation and the number of treatments is calculated using the following formula:
- Cancer’s size and location
- Cancer’s kind
- The rationale for the therapy
- Your overall well-being
What other therapies are you undergoing?
In some instances, different radiation regimens may be employed. When used to alleviate symptoms, for example, radiation treatment may last only a few weeks (or less) due to the reduced overall dosage of radiation required. Radiation may be delivered in two or more sessions per day in some instances. Alternatively, you may take a few weeks off in the middle of your therapy to allow your body to recuperate as the cancer shrinks. Your doctor will discuss the best course of action for you.
What occurs at each therapy appointment?
External radiation is similar to receiving an x-ray. The procedure is painless and just takes a few minutes. However, because of the time, it takes to set up the equipment and get you in the proper posture, each session can last 15 to 30 minutes.
A linear accelerator is a machine that provides a beam (or several beams) of radiation during external radiation treatment. The equipment features a long, swiveling arm that reaches out above the treatment table. This arm is the source of the radiation. If necessary, the machine may move around the table to adjust the angle of the radiation, but it will not contact you. You will not feel anything because the radiation beams are invisible, but the equipment will produce noise.
Depending on the treatment area, you may require clothing that is simple to take off and put on in case you need to undress. You’ll be instructed to lie down close to the radiation equipment on the treatment table.
To safeguard normal tissues and organs, the radiation therapist may place special heavy shields between the equipment and portions of your body that aren’t being treated.
The radiation therapist will walk into a neighboring room to run the machine while watching you on a TV screen after you’re in the proper posture. The therapist is not exposed to radiation since the room is insulated or protected from it. An intercom allows you to communicate with the therapist. During the treatment, you will be requested to lie motionless, but you will not be required to hold your breath.
As it travels to focus the radiation beam from various angles, the machine may produce clicking and whirring noises, and it may sound like a vacuum cleaner at times. The radiation therapist monitors and regulates the movement to ensure it is functioning properly. Ask the therapist to clarify anything that happens in the therapy room if you have any concerns. Tell the therapist immediately away if you feel unwell or uncomfortable throughout the therapy. At any point, the machine can be turned off.
Will I be radioactive during or after treatment with external radiation?
External radiation treatment has a brief effect on your body’s cells. You are not radioactive since there is no radiation source in your body.