Radiotherapy is part of the treatment of some types of cancer. Dr. Anica Andrei, radiation therapy specialist, tells us what is radiation therapy guided by surface imaging: when it is indicated and what benefits it has.
1. What is surface imaging-guided radiation therapy?
Surface Image-Guided Radiotherapy (SGRT) is an increasingly used technique that uses stereo vision technology to track patients’ surfaces in 3D for both setup and motion management during radiotherapy. Surface imaging-guided radiation therapy can be used for many types of external beam radiation therapy, and there are now numerous publications supporting its use in the treatment of breast, brain, head and neck cancer, sarcoma, and other conditions.
2. How does surface imaging-guided radiation therapy work? How does SGRT help patient positioning and increase radiotherapy accuracy?
SGRT uses the external surface of the patient (eg: chest, abdomen, head) to ensure that the radiation dose is applied consistently according to the treatment plan. This technology uses three camera units to monitor thousands of points on the patient’s skin. SGRT is a powerful quality assurance tool that reduces patient positioning errors. This technology does not rely on radiation exposure, as do other means of patient positioning.
3. How does it detect patient movement?
An SGRT system like C-rad’s does more than check the patient’s position before treatment. In addition, it also tracks the patient’s movement during treatment. The system detects movements in six degrees of freedom. Up and down, forward and back and side to side, plus all the rotations. SGRT does this with sub-millimeter precision. This real-time positioning check also works as a safeguard during treatment. The radiation beam is activated only after the patient is correctly positioned. The beam is stopped immediately if the patient moves.
4. What happens during an SGRT-guided radiation therapy session?
The first step is the acquisition of images that will be compared with the reference ones, which are taken at the CT plan, which is done at the beginning of the treatment. If there are areas of interest that do not overlap with the initial ones, we go for the physical repositioning of the patient so that he can start the treatment in the correct position.
5. What are the benefits that SGRT offers to breast cancer patients?
For patients with breast cancer of the left breast, who are going to have radiotherapy treatment at this level, deep inspiration treatment (DIBH) is a proven method to minimize the dose delivered to the heart muscle, as well as to the lung volume, while maximizing dose time to treatment volume. Thus, at the end of the treatment, these patients end up presenting doses far below those admitted as being within the safety limit, both for the heart and for the lung, so that there are no repercussions over time at their level, which can influence in in a negative way the quality of life of these patients.
6. Which patients may need this radiation therapy?
SGRT can be used not only in patients diagnosed with non-metastatic breast cancer in order to perform radiotherapy treatment, the applications of this technology can also be extended to other locations. For example, head tumors, lung tumors or abdominal tumors, where, by monitoring the patient’s movements, the treated volume can be reduced while simultaneously protecting the organs at risk adjacent to the target volume. Thus, at the end of the treatment, we have a much lower risk of having complications following the radiotherapy treatment performed.
7. According to what criteria is the treatment plan established for a patient?
After the patient comes to the consultation and following the case analysis there is an indication to do radiotherapy, he will go to the CT department, where he will perform the CT plan, which will scan the area of interest to be treated. The patient will be explained the steps in which he must hold his breath as appropriate, so that the acquisition of images is done without movements in order not to compromise the final result, i.e. the images from the plan CT, the one after which the patient will follow to start radiotherapy treatment. This technology, SGRT, remains more reserved for elderly patients, cardiac patients or those with chronic lung diseases, which make it difficult to hold the breath for a sufficient period of time (approximately 30 seconds).
8. What is the role of the medical team in radiotherapy treatment with respiratory management?
The medical team, meaning doctor, physicist and technician, must collaborate from the CT plan to positioning the patient on the treatment table, so as to ensure that all the protocols for this case are followed, and to convey confidence to the patient that through what they do is the radiotherapy treatment is administered in a correct and professional way, and where it is necessary to make anatomical repositions of it in order to have a synchronization with the images taken initially at the plane CT and correctly treat the proposed target volume.
2023-12-19 04:04:41
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