External Beam Radiation Therapy

External beam radiation therapy is the most common type of radiation therapy that is used for the treatment of cancer. In this procedure, a machine is used for aiming high-energy rays or particles from outside the body into the tumor. External beam radiation therapy is mostly provided in the form of photon or x-ray beams, and less often in the form of particles like protons and neutrons, or electron beams.

Purpose-

• Cancer Treatment
• Elimination of a tumor or prevention of a tumor from returning / Cancer Recurrence
• Before surgery for reducation of tumor size
• Post cancer surgery- to remove any remaining cancer cells
• To treat symptoms in case of metastasis of cancer

 

Types of beams used- 

1. Photon beam radiation therapy: 
Uses very high energy waves, same as x-rays, photons travel deep into the body and kill the tumor cells, also they can damage the surrounding healthy tissues, 
The photons are emitted by a machine known as a linear accelerator.

2. Particle beam radiation therapy:
Particle beams are separate energy units, like a proton or neutrons. The radiation is released from the machine in the form of a stream of high-energy particles. This type of radiation is given by a special type of machine, known as a particle accelerator, like a synchrotron or cyclotron.

3. Electron beam radiation therapy:
Electron beams are separate units of energy and may act as particle beams or may be converted into photon beam radiation. Electrons usually do not travel too far and are mostly used to treat cancers on the skin or near the surface of the body. Electron beams can be emitted from a linear accelerator or a particle accelerator.

Symptoms

Types of Cancer where external beam radiation therapy is used- 

• Breast cancer
• Bowel cancer
• Esophageal cancer
• Head and neck cancer
• Lung cancer 
• Prostate cancer
• Colorectal cancer
• Melanoma
• Uterine cancer
• Brain tumor 

Diagnosis

Diagnostic tests used for the external beam radiation therapy are-

• Physical examination
• Imaging tests
• Endoscopy
• Blood tests
• Biopsy

 

Treatment

1. You will then be positioned using the dots on your skin and body mild or face mask to help you stay in the right position.
2. Colored lights may be seen pointed at your skin marks. These are harmless lights that help the doctor position you for treatment.
3. The doctor’s team leaves the room just before radiation is given. They will most likely be in an adjacent room where they can see and hear you, and they can also control the radiation machine.
4. You need to stay still so that the radiation reaches the exact same place every time.
5. You will hear a buzzing sound of the radiation machine moving around, but you will not be able to hear, see, feel, or smell the radiation.
6. You will receive radiation for about one to five minutes.
7. A single external beam radiation therapy session lasts for approximately half an hour to one hour, with most of the time being spent on placing you in the appropriate position.
8. Most patients get external beam radiation therapy daily, five times a week, for five to eight weeks.
9. The number of treatment sessions and the total radiation dose depends on the type of cancer present, the location and size of cancer, the reason for treatment, the general health of the patient, and any other cancer treatments that you may be getting.

 

Risks

• Loss of hair
• Skin changes
• Nausea
• Fatigue
• Difficulty in swallowing
• Tenderness
• Inflammation