Speed With a Clinical Purpose
Central to Accela is a redesigned C-arm linear accelerator incorporating a gantry capable of rotating at 2.5 RPM, a newly designed multileaf collimator, dose rates up to 40 Gy/min, and a large HyperSight cone-beam CT imaging panel. According to Siemens Healthineers, the combination is intended to shorten the time required for imaging and treatment delivery.
During the demonstration, Datta emphasized that speed is important not simply from a throughput perspective, but because reducing treatment time may also limit the opportunity for patient motion and internal organ motion. “You essentially, in that sense, freeze motion because you’re treating so fast,” Datta said.
The potential is particularly relevant for breast and lung treatments requiring breath-hold techniques. Datta explained that repeated breath-holds can become increasingly difficult for patients to reproduce over the course of imaging and treatment. Accela powered by NeoArc is designed to compress these sequences, potentially reducing the number of breath-holds required in appropriate cases. Siemens Healthineers reports that Accela with NeoArc can enable stereotactic treatment within a single breath-hold.
Introducing a New Dynamic Arc Approach
NeoArc represents another important component of the platform. DMAT dynamically coordinates gantry speed, multileaf collimator movement, and dose rate to create conformal treatment plans while shortening treatment delivery time.
During the ASTRO demonstration, Datta described how the system can vary its delivery speed as the gantry moves around the patient, slowing at selected positions according to the treatment plan rather than delivering radiation in the same manner throughout the arc.
The approach is supported by Eclipse Neo, a new planning module developed for NeoArc treatments. Existing IMRT and VMAT workflows remain supported via existing treatment planning platforms, an important consideration for centers already operating Varian treatment systems. Datta also noted that treatment plans can be transferred between Accela and other Varian platforms, although NeoArc delivery itself is specific to Accela.
Potential for More Complex Treatment
Another area of interest is multi-site disease. Siemens Healthineers reports that Accela with NeoArc can enable multi-site SBRT treatment in as little as 60 seconds.
Datta said faster delivery could make treatment of patients with multiple lesions more practical by reducing the time required to address several targets during a treatment session. The potential implications include not only patient experience, but also workflow and the ability of radiation oncology departments to accommodate increasingly complex cases.
Development of Accela and NeoArc included collaboration with an advisory group of cancer centers including Mayo Clinic, Washington University School of Medicine and Siteman Cancer Center, University Hospital Zurich, University Hospitals Cleveland Medical Center, Maastro in the Netherlands, Mass General Brigham Cancer Institute, and Memorial Sloan Kettering Cancer Center.
Because Accela remains 510(k) pending, its ultimate clinical impact will depend on regulatory clearance and subsequent clinical experience. Its ASTRO debut, however, points toward a broader direction in linear accelerator development, one in which greater treatment speed is being pursued alongside precision to reduce treatment time and make increasingly complex radiation therapy more practical to deliver.