Surface-guided radiation therapy (SGRT) (sometimes referred to as Surface-image Guided Radiation Therapy) is the process of using 3D imaging to position and track movement of
radiation therapy
Radiation therapy or radiotherapy (RT, RTx, or XRT) is a therapy, treatment using ionizing radiation, generally provided as part of treatment of cancer, cancer therapy to either kill or control the growth of malignancy, malignant cell (biology), ...
patients during treatment.
Goals and clinical benefits
SGRT can help to improve the safety, effectiveness and efficiency of radiation therapy treatments, by offering guidance across every step of the radiation therapy workflow, including simulation, planning, treatment and dose visualisation.
Developed as an advancement to
image-guided radiation therapy
Image-guided radiation therapy (IGRT) is the process of frequent imaging, during a course of radiation treatment, used to direct the treatment, position the patient, and compare to the pre-therapy imaging from the treatment plan. Immediately prior ...
, SGRT relies on 3D imaging as opposed to an x-ray. SGRT uses cameras to feed data into a software program linked to the linear accelerator delivering the radiation. Each camera uses a projector and image sensors to create a 3D surface model of a patient, by projecting a red light containing a pseudo-random speckle pattern on their skin.
The pattern allows the SGRT system to reference thousands of points on the skin, acting as virtual
medical tattoo
A medical tattoo is a tattoo used to treat a condition, communicate medical information, or mark a body location for treatment. People may get a paramedical tattoo to conceal a condition or the effects of treatment, such as creating the appearanc ...
s. This imaging information is fed into the software to allow real-time tracking and sub-millimetric accuracy during radiotherapy treatments. Information on movements is fed back to the radiation therapist, who is alerted if the patient moves from the optimal position (as determined by their treatment plan). SGRT systems can be set to automatically stop the delivery of radiation if a patient moves outside of a certain tolerance level.
SGRT can help to reduce errors in set-up and positioning, allow the margins around
target tissue when planning to be reduced, and enable treatment to be adapted during its course, with the aim of overall improving outcomes.
Clinical applications
For breast cancer treatment, SGRT increases the patient setup information compared to laser‐based setup (LBS), by using the entire patient skin surface instead of only three skin marks. SGRT also enables clinicians to monitor a patient in real-time to replicate the same position during the CT scan for
sarcoma
A sarcoma is a rare type of cancer that arises from cells of mesenchymal origin. Originating from mesenchymal cells means that sarcomas are cancers of connective tissues such as bone, cartilage, muscle, fat, or vascular tissues.
Sarcom ...
patients.
When used with
deep inspiratory breath-hold, SGRT supports initial positioning, both in free breathing (at mid-patient reference point) and in DIBH (at treatment isocenter). This process has been found to help reduce errors in set-up, positioning and improve overall outcomes for patients. It has also been used with
Stereotactic Body Radiation Therapy to assist with the initial set-up and detect intrafraction patient motion throughout treatment.
For
stereotactic surgery
Stereotactic surgery is a minimally invasive form of surgery, surgical intervention that makes use of a three-dimensional coordinates, coordinate system to locate small targets inside the body and to perform on them some action such as ablation, ...
, SGRT allows a frameless system to be used to monitor the surface of the patient within an open-face immobilization mask.
See also
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Radiography
Radiography is an imaging technology, imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiog ...
*
Treatment of cancer
Cancer treatments are a wide range of treatments available for the many different types of cancer, with each cancer type needing its own specific treatment. Treatments can include surgery, chemotherapy, radiation therapy, hormonal therapy (oncolo ...
References
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External links
Google Scholar articles on surface-guided radiation therapy
Radiation therapy procedures
Interventional radiology