Comparative evaluation of treatment plan quality for a prototype biology-guided radiotherapy system in the treatment of nasopharyngeal carcinoma

IMRT and SBRT Treatment Planning Study for the First Clinical Biology-Guided Radiotherapy System

“…Furthermore, these studies used un-validated, prototype X1 planning systems, whereas the results reported in this work are from an X1 system that has been commissioned for clinical use. Han et al 1 compared the plan quality between prototype X1 IMRT plans, Helical Tomotherapy (HT) plans, and VMAT plans for ten nasopharyngeal carcinoma patients. The prototype X1 and the HT plans used jaw settings of 20 and 25 mm, respectively.…”

“…The RefleXion TM X1 (RefleXion Medical, Inc., Hayward, CA) is a novel radiotherapy delivery system that consists of a 6 MV flattening-filter-free (FFF) linear accelerator mounted on a ring gantry equipped with near-diagnostic-quality on-board kilovoltage fan-beam CT for IGRT and on-board PET imaging to facilitate real-time beamlet delivery guidance based on the tumor uptake of PET tracers (ie, the so-called "biology-guided radiotherapy or BgRT") 1 . Incorporating PET imaging with radiotherapy delivery systems represents the next evolutionary step in radiation therapy where the PET-avid tumor becomes its own fiducial for real-time guidance during radiotherapy delivery 2 .…”

Positron Emission Tomography (PET)/Computed Tomography (CT) Imaging in Radiation Therapy Treatment Planning: A Review of PET Imaging Tracers and Methods to Incorporate PET/CT

“…This treatment modality combines a PET-CT and a 6 MV linear accelerator into a single machine capable of real-time delivery of beamlets of radiation from the linear accelerator according to the outgoing number of PET emissions with only subsecond latency. 113 , 114 , 115 , 116 , 117 These machines essentially transform PET-avid tumors into their own fiducials and allow for real-time tumor tracking and treatment with a high accuracy. For mobile tumors, this technology has the potential to reduce the need for large margins traditionally used to account for intrafraction motion as well as help overcome some of the limitations of motion experienced with more traditional registration-based PET-guided treatments.…”