Recent advances in Surface Guided Radiation Therapy

Abstract

The growing acceptance and recognition of Surface Guided Radiation Therapy (SGRT) as a promising imaging technique has supported its recent spread in a large number of radiation oncology facilities. Although this technology is not new, many aspects of it have only recently been exploited. This review focuses on the latest SGRT developments, both in the field of general clinical applications and special techniques. SGRT has a wide range of applications, including patient positioning with real-time feedback, patient monitoring throughout the treatment fraction, and motion management (as beam-gating in free-breathing or deep-inspiration breath-hold). Special radiotherapy modalities such as accelerated partial breast irradiation, particle radiotherapy, and pediatrics are the most recent SGRT developments. The fact that SGRT is nowadays used at various body sites has resulted in the need to adapt SGRT workflows to each body site. Current SGRT applications range from traditional breast irradiation, to thoracic, abdominal, or pelvic tumor sites, and include intracranial localizations. Following the latest SGRT applications and their specifications/requirements, a stricter quality assurance program needs to be ensured. Recent publications highlight the need to adapt quality assurance to the radiotherapy equipment type, SGRT technology, anatomic treatment sites, and clinical workflows, which results in a complex and extensive set of tests. Moreover, this review gives an outlook on the leading research trends. In particular, the potential to use deformable surfaces as motion surrogates, to use SGRT to detect anatomical variations along the treatment course, and to help in the establishment of personalized patient treatment (optimized margins and motion management strategies) are increasingly important research topics. SGRT is also emerging in the field of patient safety and integrates measures to reduce common radiotherapeutic risk events (e.g. facial and treatment accessories recognition). This review covers the latest clinical practices of SGRT and provides an outlook on potential applications of this imaging technique. It is intended to provide guidance for new users during the implementation, while triggering experienced users to further explore SGRT applications.

Magnetic Resonance-Guided Stereotactic Body Radiotherapy of Liver Tumors: Initial Clinical Experience and Patient-Reported Outcomes

“…Traditionally, motion management includes the usage of an internal target volume (ITV) concept resulting in larger, unnecessary target volumes which might further harm OAR (24). Advanced motion management strategies comprise gating and tracking of the target lesion: surface-guided (SG) SBRT uses the body surface as a surrogate structure for image guidance including patient positioning, intra-fraction motion monitoring and respiratory gating (25)(26)(27)(28), while the Cyberknife system can track invasively implanted fiducials using frequent noncoplanar X-ray scans (29). MR-guided radiotherapy has recently become clinically available offering additional superior soft-tissue contrast for precise identification of liver lesions and adjacent OAR.…”

Split-VMAT technique to control the deep inspiration breath hold time for breast cancer radiotherapy

“…The increasing use of surface guided radiation therapy (SGRT) systems has allowed for a reduction localization uncertainty during treatment delivery. When using DIBH techniques, SGRT enables monitoring of the patient movements and respiration, optimizing position reproducibility and minimizing internal target motion, hence increasing the accuracy of the treatment of specific anatomic sites [ 19 – 21 ]. This system can be linked to the treatment machine to trigger automatic beam delivery or beam hold when respiration is within predefined respiratory phases [ 20 ].…”

In-House Developed Surface-Guided Repositioning and Monitoring System to Complement In-Room Patient Positioning System for Spine Radiosurgery

“…If a difference in location occurs, the location of the lesion is considered to have changed. The SGRT system using non-ionizing radiation integrates a projector with two or three cameras to obtain a real-time 3D surface of the patient [10]. During radiation therapy and radiosurgery, a stereo vision system or depth camera is used to optically scan the surface, thereby identifying the location of the patient and monitoring it with high spatial resolution [11].…”