Using SGRT for Improved SRS Accuracy

The benefits of stereotactic radiosurgery (SRS) cannot be overstated. However, the margin of error for SRS is significantly lower than that for conventional radiotherapy, which brings to the forefront patient setup and motion management during treatment delivery.

To avoid serious complications, such as radionecrosis, the clinical delivery of SRS requires the highest accuracy achievable. That level of accuracy – submillimeter – is enabled by C-RAD’s Catalyst HD surface guided radiation therapy (SGRT) solution and makes a strong case for its use in delivering SRS.

A recent study¹ in Journal of Applied Clinical Medical Physics aimed to characterize the accuracy of C-RAD’s Catalyst HD in comparison to Brainlab’s ExacTrac^®standard methods of X-ray image verification for SRS. When tested for patient set up and motion management during SRS treatment delivery, the Catalyst HD results were favorable, as evidenced by the following conclusions:

Catalyst HD achieved the required submillimeter accuracy and was comparable to ExacTrac, giving the researchers a high level of confidence in using C-RAD solutions as a method for imaging patients for SRS.
The experiments also demonstrated the submillimeter accuracy of Catalyst+ for initial setup and verification at non-coplanar couch angles using a phantom.
C-RAD’s Sentinel™ 4DCT, in combination with Catalyst HD, provides desirable features for patient setup and motion management for SRS without the addition of x-ray image radiation dose.
SGRT solutions from C-RAD don’t impact the treatment workflow, helping therapists work efficiently and improving the patient experience.

SGRT is also ideal for radiation oncology departments that face limitations. For departments that want to practice SRS but only have CBCT capability, Catalyst HD is an excellent add-on solution. And if a department can’t image at different couch angles, the addition of SGRT will increase the clinical team’s confidence in tracking accuracy throughout the course of treatment.

Highlights of the study

Two end-to-end tests evaluate the accuracy of an SGRT system (C-RAD’s Catalyst HD) for position verification in comparison to a stereoscopic x-ray imaging system (Brainlab’s Exactrac®) for single-isocenter, multiple metastases stereotactic radiosurgery (SRS) using 3D polymer gel inserts.
Dose metrics for a setup with surface imaging was found to be consistent with setup using x-ray imaging, demonstrating high accuracy and reproducibility for treatment delivery. Results indicate the feasibility of using surface imaging for position verification at noncoplanar couch angles for single-isocenter, multiple-target SRS using end-to-end quality assurance (QA) testing with 3D polymer gel dosimetry.
The results of this study demonstrate the feasibility of using SGRT for position verification at noncoplanar couch angles for mono-isocentric, multiple target SRS using end-to-end gel dosimetry. Setup with SGRT was found to be comparable to using orthogonal X-ray imaging, demonstrating high accuracy and reproducibility for treatment delivery.