Radiation Therapy

Overview of Radiation Therapy in India

Radiation therapy is one of many treatments available for the treatment of cancer. You may hear radiation therapy referred to as either radiotherapy or therapeutic radiology.

Radiation therapy uses high-energy X-ray, gamma-ray, or charged particle (electron or proton) beams to kill cancer cells. There are many ways to use radiation therapy, depending on the type of cancer you have and the location of the disease.

You may use radiation therapy to treat your cancer or use radiation therapy to control the cancer and prevent it from growing or spreading. Another option is to use radiation therapy to prevent the recurrence of cancer. You may also use radiation therapy to shrink tumour masses and relieve symptoms.

For some patients, radiation therapy may be their only treatment; however, most patients receive radiation therapy as part of their cancer treatment and in conjunction with chemotherapy, surgery, or other cancer therapies.

What is Radiation Therapy?

Radiation therapy is used to treat diverse cancers through the application of high-energy particles or waves (i.e., x-rays, protons, gamma rays, and electron beams). By generating significantly smaller than normal levels of breakage in the DNA of these tumour cells, this process hampers the cancer cell's ability to multiply or grow, resulting in death to the tumour cell over time.

In contrast to chemotherapy and other treatments for cancer, radiation therapy is considered local in nature because it is a targeted delivery system that delivers a highly focused beam of high-energy particles/waves directly to the cancer that is being treated; therefore, killing only the cancer and causing minimal harm to neighbouring healthy cells in the vicinity of the tumour being destroyed.

Types of Radiation Therapy:

Two types of radiation therapy exist- external beam radiation therapy (EBRT) and internal radiation therapy. Both methods destroy the DNA of cancer cells to treat cancer. Cancer cells rely on DNA for instructions for growth and multiplication; thus, when the DNA is missing, the cancer cell will die, and the tumour will decrease in size. In addition to treating cancer, healthcare providers may also use low-dose EBRT to treat non-cancerous conditions.

External Beam Radiation Therapy

This​‍​‌‍​‍‌​‍​‌‍​‍‌ is the most prevalent method of radiation therapy used nowadays. The procedure involves a machine that emits highly penetrating radiation towards a cancerous growth. While X-ray is the predominant type, electrons or protons can also be used. The machine can move around your body, but it won't physically touch you at any point. Various forms of EBRT can be distinguished:

3D CRT: This technique relies on the use of CT images and computer programs to develop a 3D representation of the tumor. This representation is then used to steer the machine in concentrating radiation beams on the tumor.

Intensity-modulated radiation therapy (IMRT): This method modulates the intensity of the beams to deliver a very high dose to the tumor while minimising exposure to normal tissues.

Image-guided radiotherapy (IGRT): You could be given IGRT if your tumor is located within a body area that moves during treatment. In order to ensure that the treatment remains targeted on the tumor, your team will perform imaging tests both before and during the treatment.

Proton therapy: This method utilises proton particles to eradicate tumors.

Stereotactic radiosurgery: This method delivers high doses of radiation to small tumors located in the brain through one or more fractions.

Stereotactic body radiation therapy (SBRT): It is the technique by which tumors outside of the brain are treated with radiation (such as lung or kidney cancer in the initial stages).

Intraoperative radiation (IORT): You may be administered this therapy to complement the surgical resection of the tumor. If the surgery fails to remove any minute cancerous cells, 

IORT comes in handy in eliminating them.

Low-dose radiation therapy (LDRT): Radiation at a lower strength can be administered by doctors in order to treat numerous ailments such as osteoarthritis, ventricular tachycardia, and benign (noncancerous) ​‍​‌‍​‍‌​‍​‌‍​‍‌tumors.

Internal Radiation Therapy

Internal radiation therapy places radioactive materials within the body; it is typically used to treat smaller cancers located in the head, neck, breast, cervix, uterus and prostate. There are two types of internal radiation therapies:

Brachytherapy: Brachytherapy is when a solid radioactive source (seed or implant) is placed inside or next to a tumor. Some seeds or implants give off a small dose of radiation over several days or weeks, while others release larger doses of radiation over shorter periods of time.

Systemic therapy: Systemic therapy is when you receive liquid radioactive material into your bloodstream through an injection or by swallowing a pill.

Procedure:

The treatment procedure consists of many crucial stages to provide an effective and safe treatment, while at the same time offering Patient-specific customized services.

Consultation and Evaluation

A Radiation Oncologist takes medical history, performs a physical examination, and discusses treatment options with the patient. 

Treatment Planning (Simulation)

Imaging Scanning - Imaging scans, including CT, MRI, and PET scans, will be used to determine the exact location of tumor.

Immobilisation Device - The patient will have to be immobilised during treatment. The use of custom moulded devices or customised masks will keep the patient as still as possible for proper targeting of radiation beams.

Marking the Treatment Site - There will be small tattoo/skin marks on the skin where the radiation beams will be directed, to serve as the guide for the radiation treatment beams.

Calculating Radiation Doses

A group of experts, known as radiation oncologists, determines the best possible dose of radiation to kill cancerous cells, whilst doing the least amount of injury to non-cancerous tissue.

Radiation Treatment Sessions

External Beam Radiation Therapy: The patient will lie on a treatment couch, and a linear accelerator (a machine that produces external beam radiation) will be used to deliver the radiation. Each session will last several minutes and may occur five times each week over a period of several weeks.

Brachytherapy: A radioactive source of radiation can be either placed temporarily or permanently inside the patient's body, in the region/area of the tumor, depending upon the treatment plan as defined by the radiation oncologist.

Patient Monitoring and Follow-Up

Regular follow-up visits with the patient's physician will be established to evaluate the patient's response to treatment and to provide additional management for any short or long-term side effects. Follow-up visits will also help determine the efficacy of the current treatment plan and whether further treatment will be needed.