Radiation therapy- An Overview

Radiation therapy is a type of cancer treatment that uses beams of high energy to kill cancer cells. Radiation therapy mostly uses X-rays, but protons or other types of energy also used.

By Rajia Javeed

How radiation therapy works against cancer:

At high doses, radiation therapy kills cancer cells or slows their growth by damaging their DNA. Cancer cells whose DNA is damaged beyond repair stop dividing or die. When the damaged cells dead. They are broken down and removed by the body.

Radiation therapy does not kill cancer cells. It takes weeks of treatment before DNA is damaged enough for cancer cells to die. Cancer cells keep dying for weeks or months after radiation therapy Complete.

The type of radiotherapy is depend on the following factors:

  1. the type of cancer
  2. the size of the tumor
  3. the tumor’s location in the body
  4. how close the tumor is to normal tissues that are sensitive to radiation

Types of radiotherapy:

There are two types of radiotherapy:

  1. Internal radiotherapy
  2. External radiotherapy.

External Radiotherapy:

External radiation therapy comes from a machine that purpose of radiation at your cancer. The machine is large and may be noisy. This machine is only move around the patient and not touch him. The radiation is given  to a part of your body from many directions.

It is a local treatment, which means it treats a specific part of your body. For example, if you have cancer in your lung, you will have radiation only to your chest, not to your whole body.

 Types of beams used in radiotherapy:

1.electrons  2.protons  3.photons

Electrons:

These particles are the negative charge particles Electron beams cannot travel very far through body tissues. Their use is limited to or near the surface of the body.

Photons:

Protons are particles with a positive charge. Like photon beams, proton beams can also reach tumors deep in the body. Proton beams do not scatter radiation on their path through the body and they stop once they reach the tumor.

Internal Radiotherapy:

This is a treatment in which a source of radiation is put inside your body. Source of radiation is form of liquid or solid.

Internal radiation therapy with a solid object is called brachytherapy. In this type of treatment seeds, ribbons, or capsules that contain a radiation source are placed in your body, in or near the tumor. It is also a local treatment. Internal radiation therapy with a liquid source is called systemic therapy. Systemic means that the treatment travels in the blood to tissues throughout your body search out and killing cancer cells. You receive systemic radiation therapy by swallowing or through an injection With systemic radiation, your body fluids, such as urine, sweat, and saliva, will give off radiation for a while.

  Radiotherapy is treated the cancer: Radiation therapy is used to treat cancer and initial cancer symptoms. It is used to treat cancer, radiotherapy can cure cancer, prevent it from returning, or slow its growth.

 Palliative treatment:

The symptoms that are ease by the radiotherapy is called palliative treatment.

 Radiopharmaceuticals:

External beam radiation may shrink tumors to treat pain and other problems origin by the tumor, such as trouble breathing or loss of bowel and bladder control. Pain from cancer which  has spread to the bone can be treated with systemic radio therapy drugs.                                                                                                                                   

Types of the radiation used for the cancer treatment:                                   

It is normal type of cancer treatment. It uses high-energy X-rays destroy cancer cells. Radiation damages the cancer cells causing them to slow and  stop multiplying.  Some radiation therapies is used to treat cancer near the sensitive organs.

Four type of radiotherapy is used to treat the sensitive organs. some type of cancer treatment improved from including brain cancer, liver cancer head cancer etc.

 Image guided radiation therapy (IGRT)                                                                          

Tracks the tumor or fixed markers during radiation. This type of radiation treats tumors in areas of the body that shift. This includes cancers of the lungs, liver, pancreas and prostate gland, tumors located close to sensitive organs and tissues.

 

  Volumetric modulated arc therapy (VMAT):                                                                                                         

uses of multiple radiation beams of different intensities. As the treatment machine rotates, radiation is delivered at every angle. This focuses the highest dose of radiation on the tumor, while reducing radiation to healthy organs. VMAT can be used to treat other types of solid tumors, including prostate cancer, liver cancer and pancreatic cancer.

Radiation therapy is used with other cancer treatment:

1.Surgery                                                                                                                                                        

 2.chemotherapy                                                                                                     

3. immunotherapy.                                                                                                                     

Radiation therapy given before, during, or after these other treatments to improve the chances that treatment  will work. The timing of when radiation therapy is given depends on the type of cancer being treated and whether the purpose of radiation therapy is to treat the cancer or relive symptoms.                                                               

When the cancer treated with the surgery:

  1. Before surgery, to shrink the size of the cancer so it can be removed by surgery and be less to return.
  2. During surgery, it goes straight to the cancer without passing through the skin. Radiation therapy used this way is called intraoperative radiation. With this technique, doctors can more easily defend nearby normal tissues from radiation.
  3. After surgery to kill any cancer cells that remain.

Radiotherapy cause the side effects:

Radiation not only kills or slows the growth of cancer cells, it  also affect nearby healthy cells. Destroy the healthy cells can cause side effects.

Lifetime dose limits:                                                                                    

  There is a edge to the amount of radiation an area of your body can safely receive over the track of your lifetime. Depending on how much radiation an area has already been treated with, you may not be able to have radiation therapy to that area a second time.  if one area of the body has already taken the safe lifetime dose of radiation, another area might still be treated if the distance between the two areas is large sufficient.