High-tech radiotherapy - body positioning radiosurgery (SBRT)

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.

SBRT is a high-tech radiotherapy technique that uses multiple beams to deliver a very high radiation dose to the target tissue and rapidly reduce the dose to adjacent tissues. This is a very high precision radiotherapy technique from positioning and immobilization of the patient, mechanics to dose delivery. High doses of radiation (the “surgical” dose is usually ≥ 5Gy/partition) will be delivered to the patient externally from the irradiator into the body. The duration of treatment is shortened using less therapeutic doses, usually only 1 to 5 therapeutic doses.

SBRT technique requires high precision, down to millimeters so it also requires the use of daily verification images just before irradiation (2D X-ray images and CBCT 3-D images). SBRT also requires the use of specialized patient immobilization tools and devices.
The success of SBRT depends greatly on patient immobilization, localization and management of tumor mobility during treatment, ensuring accurate and effective dosing. Some commonly used tumor mobility management techniques include: abdominal compressions, breath holding after maximal inhalation/exhalation, breathing synchronization, 4D-CT, and real-time tumor monitoring. . The choice of tumor mobility management method depends on the existing facilities of each hospital.
Breath Hold is a technique for managing tumor mobility using systems that control patient breathing. Patients are trained to be able to resume holding their breath for a certain amount of time after each maximal inhalation or exhalation. During this period of breathlessness, the motile tumor is very small and can be considered non-motile.
From August 2017 until now, Vinmec Times City General Hospital has applied Breath Hold technique in SBRT body positioning radiosurgery on Clinac iX accelerator system, SBRT fixation kit and system RPM breathing control system.

1. Designated object

SBRT body position radiosurgery can be indicated for patients with extracranial tumors (lung, liver, pancreas, prostate, paraspinal tumor,...). At Vinmec Times City: we successfully, safely and effectively apply SBRT to lung, liver and solitary metastatic tumors with multiple sites. Applied according to the treatment guidelines of the countries with the most SBRT experience in the world such as: JCOG 0403, RTOG 1112; RTOG 0813, 0915,...

2. Advantages/disadvantages of the technique?

2.1 Advantages Non-surgical, non-invasive, painless An ideal treatment for hard-to-reach tumors and near vital organs Increases tumor destruction (~90% chance for multiple sites) disease) Outpatient treatment Shorter treatment duration (1-2 weeks) than conventional radiation therapy (3-7 weeks) 2.2 Disadvantages Immobilize the patient and manage the movement of the treatment target with movement body (respiration). Requires highly qualified and experienced radiotherapy personnel, modern equipment and tools.

3. Implementation process

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 assign SBRT to the patient or not.
Step 2: Assess tumor mobility and simulate radiotherapy
CT scan

Depending on the patient's condition, tumor location, tumor mobility amplitude, ability to cooperate in breathing management, the doctor will choose a simulation CT scan and appropriate radiation technique.

Step 3: Plan SBRT and evaluate the plan

Step 4: Check the quality of the plan before radiotherapy: Carry out 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 radiation therapy.

Step 5: Daily SBRT irradiation: Use the same set of posturing and immobilization kits as during a simulated CT scan. Before the planned irradiation, a verification scan was performed: to check the bone landmarks and to 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 SBRT radiation sessions. Then every month, the patient is clinically evaluated, MRI/CT scan.
4. Why should this technique be done at Vinmec? The Department of Radiation Therapy - Vinmec Times City International General Hospital is one of the very few first facilities in Vietnam that has successfully, safely and effectively implemented SBRT technology. Currently, we have treated many patients with early stage small cell lung cancer, liver cancer, brain tumor, brain metastasis and isolated metastatic tumors in many locations.
We have been and will continue to create breakthroughs, 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.
Early clinical response: All patients achieved partial response, overall condition improved and pain relief immediately after radiation, decreased tumor volume after 6-8 weeks of radiation.
Early side effects: Only seen in 01 patient with grade 2 liver enzyme elevation and 01 other patient with grade 2 skin side effects, no case of > grade 2 side effects related to radiation therapy.
5. Some images respond to treatment

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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