High-tech radiotherapy – volume-modulated arc therapy (VMAT)

This is an automatically translated article.

The article was written by MSc Doan Trung Hiep - Head of Radiation Therapy Department and Engineer Tran Ba ​​Bach - Vinmec Times City Radiation Therapy Center.
Intensity-modulated radiation therapy, also known as dose-modulated radiation therapy (IMRT), is a radiotherapy technique in which the radiation beam is modulated so that the intensity at points within the field of view is not uniform. using a compensator or leaf pairs of a multileaf collimator (MLC),...

IMRT has been in clinical practice since the early 1990s. Today, IMRT has become the mainstream. a standardized protocol that allows for a more consistent delivery of radiation dose (improved tumor volume coverage and greater avoidance of healthy tissue) than 3-D (3D-compatible) radiotherapy techniques CRT) and routine radiotherapy.
Arc volume modulated radiotherapy (VMAT) is a new evolution of IMRT, which allows for more consistent delivery of radiation doses, shorter duration of treatment, and radiation dose (MU) ) emits less than the IMRT technique. During VMAT radiotherapy, the linear accelerator can both change the dose rate, change the position of the MLC leaflets and the Gantry rotates around the patient.
VMAT is a high-tech radiotherapy technique that has been applied in developed countries around the world since 2007 in the US and in Japan since 2008. In Vietnam, VMAT has been successfully deployed and become a common practice. prescribed at Vinmec for patients with head, neck, and pelvic cancers since December 2014.

1. Designated object

Applicable to any patient: All cancer patients with indications for radiation therapy. Who is contraindicated for: patients who have undergone radiation therapy, have complex systemic diseases, patients with near death, patients who cannot lie still on the table to perform the technique.

2. Advantages/disadvantages of the technique?

2.1 Advantages Provides optimal radiation dose to the target and reduces dose to healthy tissues adjacent to the tumor, reducing acute side effects of radiation therapy (less than 20% of grade 3 or more side effects with this technique). normal and less than 5% with VMAT technique) such as dry mouth, dermatitis, stiff jaw,... Therefore, VMAT technique shows outstanding advantages with tumors near important organs of the body. (Example: Head and neck cancer, pelvic cancer...). According to statistics at Vinmec Times City Radiation Therapy Center: For patients treated with VMAT technique, the overall survival rate reached 87.5% after 3 years for head and neck cancer, equivalent to the results in Japan. Reduce radiation treatment time by 1/2 to 2/3 by delivering high and precise doses to the tumor without compromising patient safety Providing patient comfort and reassurance in daily treatment 2.2 Disadvantages High cost, complicated process, expensive modern equipment and machines

3. Implementation process (implementation steps)

Step 1: Approving the indications of radiation therapy by the Multi-specialty Oncology Council: Leading experts in the fields of: Radiation Oncology, Medical Oncology, Surgery, Diagnostic Imaging, Pathology , ... will consult together to consider and make a decision whether to appoint VMAT for the patient or not.
Step 2: Simulated CT scan of radiation therapy

Step 3: Plan for VMAT
radiotherapy

Step 4: Check the quality of the plan before radiotherapy: Perform the planned irradiation on the phantom and measure the actual dose to compare with the calculated dose on the plan to check the quality of the plan before radiotherapy.

Step 5: Daily VMAT radiotherapy: Use a set of posturing and immobilization kits similar to that of a simulated CT scan. Prior to the scheduled irradiation, a verification scan was performed (daily two-dimensional x-rays and two-week CBCT holograms) to check bone landmarks and assess the accuracy of the technique.

Step 6: Monitor and evaluate patients during and after radiation therapy: Monitor and evaluate patients before, during and after VMAT radiation sessions. Then every 6 months, the patient was clinically evaluated, taking MRI/CT/PET-CT.

4. Why should this technique be done at Vinmec?

The Department of Radiation Therapy - Vinmec Times City International General Hospital is the first facility in Vietnam that has successfully, safely and effectively implemented VMAT (since December 2014). Currently, we have treated many patients with head and neck cancer, pelvic cancer, and breast cancer (esophageal, breast,...)
We have been and will continue to create breakthrough, leading the market in high-tech radiation therapy in Hanoi as well as in Vietnam. Based on well-trained human resources to ensure safe, accurate and effective implementation as well as fully equipped with modern equipment and machines.
All patients are approved by the Tumor Board (including leading experts in: surgery, radiation therapy, chemotherapy, imaging, pathology...) to decide on radiation treatment. treat.
The equipment is modern and complete, all technical standards are applied according to American and Japanese standards.

5. Some treatment pictures

The first patient with nasopharyngeal cancer stage T3N2bM0

Throat Cancer Patient T4N1M0

Vinmec International General Hospital is one of the hospitals that not only ensures professional quality with a team of leading medical doctors, modern equipment and technology, but also stands out for its examination and consultation services. comprehensive and professional medical consultation and treatment; civilized, polite, safe and sterile medical examination and treatment space. Customers when choosing to perform tests here can be completely assured of the accuracy of test results.

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