A. VMAT is an advanced type of external beam radiation therapy in which radiation is directed in a series of arcs or angles to treat different types of tumors.

A. VMAT works in the following way:
VMAT is a type of intensity-modulated radiation therapy (IMRT), in which the dose of radiation varies continuously throughout the treatment. 
A linear accelerator (LINAC) machine is used to deliver radiation for VMAT. 
The radiation beam’s shape and the dosage change automatically as the machine moves. 
Therefore, the VMAT procedure is more targeted and accurate than a single beam radiation therapy and also minimizes the risk of damage to the surrounding healthy tissue.

A. The primary differences between external beam radiation therapy and internal beam radiation therapy are:
External beam radiation therapy involves providing radiation beams to the tumor site from a machine outside the body. Internal beam radiation therapy, however, involves placing the radioactive material directly inside or close to the tumor in the form of source delivery devices like seeds, rods, or wires.
A patient undergoing internal beam radiation therapy generally emits radiation for some time after the radiation therapy session and therefore needs to stay away from visitors for some time after treatment. However, patients undergoing external beam radiation therapy do not emit any radiation after treatment.

A. VMAT is generally performed in the following cases:

• Tumors in larger areas of the body having uneven boundaries
• Tumors located close to the vital body organs
• It is generally used to treat the following different types of cancers:
• Breast cancer 
• Skin cancer
• Prostate cancer 
• Brain cancer
• Lung cancer
• Head and neck cancers
• Gastrointestinal cancer

A. VMAT procedure is generally performed by a radiation oncologist.

A. VMAT has the following advantages over other radiation therapies:
Accurately targeted radiation beams
Maximum radiation dosage provided to the cancerous tissue
Minimal or no damage to the surrounding healthy tissues 

A. The doctor suggests the following diagnostic tests before a VMAT procedure:

• Physical examination: The doctor will evaluate the physical health, symptoms, and medical history of the patient.
• Imaging tests: CT scans, MRI scans, and PET scans are the different types of imaging tests that can help the doctor obtain a clear picture of the tumor.
• Endoscopy: A tube with a camera on one end, known as an endoscope, is used by the doctor to check the suspected cancerous organ internally.
• Blood tests: Certain medical conditions can be checked using blood tests.
• Biopsy: The doctor surgically removes the suspected tissue growth and sends it to the laboratory to check if cancer cells are present and what type of cancer cells are present.

A. The following preparation is needed before a VMAT procedure:

• Inform the doctor about any pre-existing medical diseases that you may be having.
• Inform the doctor if you are having any supplements, herbs, or medications currently.
• If you have a known sensitivity or allergy to anything, inform the doctor about the same.
• The doctor checks your medical history and diagnostic test results to determine the precise location that requires treatment. This radiation planning session is known as simulation.
• The VMAT session is usually scheduled one or two weeks after simulation.
• Simulation helps the doctor in the accurate delivery of radiation to the tumor leading to minimal or no damage to the surrounding healthy tissues.
• You will have to lie still on the examination table, while imaging scans like CT scans, MRI scans, or PET scans are performed to define the treatment field or treatment port. These are the precise locations where the radiation beams are aimed during treatment.
• A special custom-fit mask, mold, or cast of a body part is made. This ensures that you will be staying in the same position for every subsequent therapy session.
• The doctor will mark the treatment field with small dots using semi-permanent ink. 

A. The following are the post-procedure steps after VMAT:
The patient can usually go home immediately following a VMAT session.
VMAT will not make the patient radioactive either during or after the session. Hence, the patient can interact with pregnant women, children, and others after therapy.
Fatigue and skin irritation may be seen in some patients after a few treatment sessions.
Regular follow-ups with the doctor are recommended after treatment. The patient is physically evaluated and certain diagnostic tests are performed during the follow-up sessions to check if cancer has been eradicated completely, or if the patient needs any additional treatment.
The patient should go to the doctor for regular follow-ups even after the cancer has been completely eliminated to check for recurrence of cancer.