If you’re treated with radiation, the kind of radiation you will likely receive is called external beam (EB) radiation. Various pieces of equipment perform the important task of delivering this type of radiation to the cancer. Radiation therapy (RT) utilizes a machine to focus rays of high energy on the cancerous mass.
EB RT emanates from equipment that focuses radiation at the cancerous location in your body. This is considered localized treatment. Local means that the treatment addresses a certain body part. EB RT is utilized to combat many kinds of cancer. Besides EB RT, there are also two other types of radiation beams, which include:
Photo beam RT. Scientific research has revealed that photon beams are the preferred type of beam for x-rays. Radiation comes out of the equipment as an energy wave. Photon beams travel into a tumor’s body, but can additionally harm healthy tissue near the tumor. These beams are produced by equipment referred to as a linear accelerator (LA). Photon beams cannot be seen by the naked eye and cause no sensation when traveling through the skin and towards the cancerous mass.
Particle beam RT. These beams are energy units like neutrons or protons. Radiation is given off from equipment as a high energy particle stream. Particle beam radiation travels into a body like photo beams, but the energy of these beams is given off at a specific distance. This means that radiation of this type can bring increased radiation to a tumor while reducing its impact on healthy tissues surrounding the tumor. The beams are produced by certain kinds of machines referred to as particle accelerators including cyclotrons or synchrotrons. Particle beams cannot be seen by the naked eye. Particle beams also do not create a sensation when traveling through the outer layers of a person’s body. Many kinds of EB RT provide high prescribed doses of radiation while saving healthy tissue surrounding the tumor. Each type depends on computers to analyze tumor imagery to determine the exact dose and best course of treatment possible.
3-D Conformal RT. This kind of RT is a popular kind of EB RT that utilizes scans like MRI and PET to cautiously map out the area being treated. A program is used to study imagery and create beams of radiation matching the shape of a tumor. This type of radiation matches a tumor’s shape by delivering beams from various directions. Shaping makes it possible to use higher radiation doses for the tumor while sparing normal tissue. This radiation method is preferable to people who want to reduce the damage from radiation and better terminate cancerous cells by focusing radiation dosage n the tumor’s specific shape and size. Most people who receive 3-D conformal Rt receive treatment at least once daily. The exact course of treatments varies between individuals based on unique elements of that person’s disease including the kind and staging of the cancer as well as the tumor’s location and size.
Intensity-modulated RT. This type of therapy is a 3-D conformal RT. Like 3-D conformal radiation, beams for this therapy focus on the tumor from a variety of angles. This therapy, however, uses a smaller beam than 3-D conformal. The strength of the beams in some locations can be switched to provide higher doses to certain tumor sections. The advantage of this type of therapy is that by changing some beam’s strength, it allows stronger doses to get to distinct points of the tumor and help reduce damage to surrounding body tissue. People receiving this type of treatment often receive treatment daily. The course of treatments varies between individuals based on unique aspects of the cancer.
Image-guided RT. This type of therapy is an intensity-modulated RT. Image-guided RT utilizes image scans not just for planning treatment before RT but also during Rt. During treatment, a person receives repeat scans. These scans are analyzed by computers to determine changes in the size and location of a tumor. Repeated imaging allows your position or radiation dose to be adjusted during treatment if required. Adjustments improve treatment accuracy and help save normal tissue. Most people receive treatment at least once a day. The specifics of the treatment that a person receives depends on specifics about that person’s cancer including its stage and size.
Tomotherapy. This is a type of Intensity-modulated RT that utilizes a machine that includes both a CT scanner and external-beam radiation equipment. Tomotherapy captures images of the cancerous region before treatment to permit precise treatment targeting the area. Tomotherapy rotates around you while you receive treatment and emanates radiation in a spiral pattern. Tomotherapy might very well perform better in sparing normal tissue than 3-D conformal RT. People routinely receive Tomotherapy once a day.
Intraoperative RT. This type of therapy is an external type of radiation given directly to the tumor or tumors during surgery. This approach is utilized if tumors cannot be completely removed or if a high risk exists that cancer will return to the same area. While a patient is under anesthesia, a medical professional will move normal tissues from the tumor and protect them with special shields. This will allow the physician to give one large radiation dose to the cancer and restrict the effects on surrounding tissue.
Stereotactic radiosurgery. This type of therapy relies on focused high energy beams to combat small tumors with easily defined edges in both the central nervous system and brain. This type of therapy might be an option if surgery is too risky because of your age, other health challenges, or if a tumor cannot be safely accessed during surgery. During this type of therapy, a person is situated in a frame for the head to ensure that you make no movements while receiving treatment. During stereotactic radiosurgery, tiny radiation beams are focused at the tumor from different angles. A single beam has little impact on the body’s tissue, but a specific dose of radiation is given to the location where all beams are united. Like nearly all other types of treatment, treatment is given daily.
Stereotactic body RT. Stereotactic body RT is close to stereotactic radiosurgery. The therapy used to be for tiny tumors situated outside the brain and spinal cord which are routinely found in the liver or lung. It may be an available choice when a person cannot receive surgery as a result of issues like age, the location of the tumor, or health problems. As in stereotactic radiosurgery, stereotactic body radiation relies on distinct equipment that a person holds during treatment to deliver a focused beam to a small area. This type of therapy is used for brain tumors as well as other tumors located inside the head. After the spot of a tumor is determined from brain scans, radiation is sent to the area from various angles. The radiation is focused to impact surrounding tissues as little as possible. This procedure is referred to as “radiosurgery” because it is so specific in regards to where it delivers radiation. Unlike surgery, however, no cutting is involved. Tumors outside the brain are disposed to move with the normal motion of the body. Radiation beams cannot be targeted as precisely as they are in stereotactic radiosurgery.
The Three Types of Electron Particles
Radiation beams utilized in external RT come from the particles:
Electrons. Particles with negative charges are called electrons. The beams of electrons cannot travel especially far through body tissues. The use of electrons is restricted to tumors either on the skin or close to the body’s surface.
Photons. Most RT equipment utilizes photon beams. Photons are utilized in x-rays, but x-rays use a low dosage. Photon beams have the potential to reach tumors found deep in a person’s body. As beams travel through a person’s body, photon beams scatter small portions of radiation along the path. Beams do not stop after they reach tumors but instead pass into normal tissues.
Protons. Protons are particles with a positive charge. Like photon beams, proton beams can also come into contact with tumors deep in the body. Proton beams do not disperse radiation as they travel through the body and stop after reaching the tumor. Medical professionals think that proton beams might lower how much normal tissue is subject to radiation exposure. Clinical trials are currently being performed to compare RT using proton beams with therapy that does not use photon beams. Some cancer centers are utilizing photon beams in RT, but the high costs and size of machines are restricting their use.
Treatment outside the brain is referred to as stereotactic body RT, which can be used for lung, spine, and live tumors. In many clinics that offer radiation, this technology is referred to by the name of the company that produces the machine. You might hear these names used at treatment locations or when speaking to cancer professionals:
- Clinac, CyberKnives, and X-Knives. This machinery moves around a person’s cancerous mass from various angles. Some other brands in this category include Novalis, Synergy-S, Edge, and TrueBeam.
- Gamma Knife utilizes around 200 radiation beams at once, which ends up creating a large dose. This dosage is often given in one treatment session. Because this process does not use a knife, there is no cutting involved.
- Another kind of machine focuses particle beams at the cancerous location from various angles. These particles release most of the radiation’s energy at the end of their trajectory, limiting damage to closeby healthy tissue or organs.
The Role of Linear Accelerators
Medical professionals routinely perform EB RT treatment with the use of an LA.
LAs customize either electronics or x-rays to the shape of a patient’s tumor and also destroy cancer cells while avoiding the surrounding tissue. LAs include several built-in safety measures. These measures ensure that the accelerator will not deliver a higher dose than prescribed. A medical professional will also perform routine checks of the equipment to ensure that it remains in adequate working order.
If you are scheduled for RT with the use of an LA, your medical professional will work with several other medical specialists to create a unique plan for your care. Your medical professional will re-check your plan before treatment commences. Your physician will also implement quality assurance measures to ensure that each treatment is delivered in the same way.
LAs are one of the most common devices utilized for EB radiation treatment. While some equipment only treats certain parts of people with cancer, LAs treat all organs of the human body. The equipment provides high energy electrons or x-rays to part of a patient’s tumor. A medical professional crafts treatments to eliminate cancer cells while saving the surrounding tissue. LAs treat all sites on a person’s body, utilizing conventional techniques including volumetric modulated arc therapy and image-guided RT.
LAs use microwave technology similar to radar to accelerate electrons in a section of the accelerator known as the “wave guide”. Then, the LA allows electrons to come into contact with a metal object to create high energy x-rays, which take on the shape of the tumor in a patient’s body as the electrons leave the machine. The uniquely-shaped beam is also focused on the patient’s tumor. The beam is often shaped by a multileaf collimator that is incorporated into the machine’s head. The patient during this time remains lying on a couch utilized for treatment. Medical professionals depend on lasers so a patient will remain in the appropriate position. Treatment couches can move in various directions. Beams extend from a part of the accelerator known as the gantry. Medical professionals can rotate the gantry around the body of a patient. Medical professionals can deliver radiation to the tumor from any angle through rotation of the gantry as well as moving the treatment couch.
A person’s radiation oncologist will prescribe the preferred treatment in regards to volume and dosage. Other medical professionals will decide how to deliver the prescribed dosage. These medical professionals also calculate how much time it will take for the accelerator to deliver the dosage. Radiation experts utilize LAs and give patients daily radiation treatments.
Patient safety is critical and assured in various ways. Before medical professionals deliver care to a person, workers create a development plan. Medical professionals will work together to approve this plan and also double-check the terms of the plan to ensure that possible care is provided. Quality assurance involving LAs is critical. Several systems exist in accelerators so they do not deliver higher doses than what is prescribed by the medical professional. Each day, before patients receive treatment, routine checks are performed on the machine. The medical professionals ensure that the radiation intensity is uniform across the beam and continues working properly. Additionally, medical workers perform monthly and annual checks on LAs as well.
How Much Radiation Patients Receive
Based on radiation simulations, tests, and the kind of cancer that you have, the oncologist will work with other team members to determine how much radiation is required, how radiation will be given, and how many treatments you require. These details are figured out based on research that reveals what the minimum and maximum radiation dosage should be for the body area receiving treatment.
If cancer has not disappeared or returns, additional treatment might still be required. In these situations, a team of radiologists will help determine whether RT is a suitable option. This decision depends on the type of cancer, where the tumor is located, and how much radiation was given to the area. If the maximum dose has been reached, radiation might not be the best strategy and additional treatment might be suggested.
How Long External Radiation Treatment Lasts
In most situations, the total amount of radiation required to terminate a tumor cannot be provided at once. This is because a big radiation dose given at one time can result in increased damage to surrounding tissues.
The entire dosage of external radiation is often separated into smaller amounts or fractions. Many patients receive treatment daily. Weekend recuperation affords time for healthy cells to heal.
The total dosage of radiation and how many times a person receives treatment depends on the cancer’s size, the cancer’s location, the type of cancer, the reason for treatment, your overall health, and whether you are receiving any other types of treatment.
Other schedules for radiation might be utilized in some cases. RT might last a mere few weeks when it is used to alleviate symptoms because the total radiation dosage needed is lower. Sometimes, a person might receive radiation as two or additional treatments daily. Or, a person might have time off in the middle of treatments so that the individual’s body heals while cancer reduces.