PURPOSE: This work reports the clinical implementation of a real-time motion tracking and correction system using dynamic multileaf collimator (MLC) and jaws during helical tomotherapy delivery (Synchrony on Radixact, Accuray Inc). MATERIALS AND METHODS: The first clinical Synchrony on Radixact system was recently installed and tested at our institution. Various clinical workflows, including fiducial implantation, CT simulation, treatment planning, delivery quality assurance (DQA), treatment simulation, and delivery, for both fiducial-free and fiducial-based motion tracking methods were developed. Treatment planning and delivery data from initial patients, including dosimetric benefits, real-time target detection, model building, motion tracking accuracy, delivery smoothness, and extra dose from real-time radiographic imaging, were analyzed. RESULTS: The Synchrony on Radixact system was tested to be within its performance specifications and has been used to treat 10 lung (fiducial-free) and 5 prostate (fiducial-based) cancer patients so far in our clinic. The success of these treatments, especially for fiducial-free tracking, depends on multiple factors including careful selection of the patient, appropriate setting of system parameters, appropriate positioning of the patient and skin markers, and use of treatment simulation. For the lung tumor cases, the difficulties in model building due primarily to the changes of target detectability and/or respiration patterns, were observed, which led to important system upgrades including the addition of a treatment delivery simulation capability. Motion tracking metrics for all treated patients were within specifications, e.g., (1) DQA passing rates >95%, (2) extra dose from radiograph < 0.5% of the prescription dose, (3) average Potential Diff, Measured Δ, Rigid Body within 6.5, 2.9 and 3.9 mm, respectively. CONCLUSIONS: Practical workflows for the use of the first clinical motion tracking and correction system in helical tomotherapy delivery have been developed and the system has now been successfully implemented in our clinic for treating lung and prostate cancer patients.
PURPOSE: This work reports the clinical implementation of a real-time motion tracking and correction system using dynamic multileaf collimator (MLC) and jaws during helical tomotherapy delivery (Synchrony on Radixact, Accuray Inc). MATERIALS AND METHODS: The first clinical Synchrony on Radixact system was recently installed and tested at our institution. Various clinical workflows, including fiducial implantation, CT simulation, treatment planning, delivery quality assurance (DQA), treatment simulation, and delivery, for both fiducial-free and fiducial-based motion tracking methods were developed. Treatment planning and delivery data from initial patients, including dosimetric benefits, real-time target detection, model building, motion tracking accuracy, delivery smoothness, and extra dose from real-time radiographic imaging, were analyzed. RESULTS: The Synchrony on Radixact system was tested to be within its performance specifications and has been used to treat 10 lung (fiducial-free) and 5 prostate (fiducial-based) cancerpatients so far in our clinic. The success of these treatments, especially for fiducial-free tracking, depends on multiple factors including careful selection of the patient, appropriate setting of system parameters, appropriate positioning of the patient and skin markers, and use of treatment simulation. For the lung tumor cases, the difficulties in model building due primarily to the changes of target detectability and/or respiration patterns, were observed, which led to important system upgrades including the addition of a treatment delivery simulation capability. Motion tracking metrics for all treated patients were within specifications, e.g., (1) DQA passing rates >95%, (2) extra dose from radiograph < 0.5% of the prescription dose, (3) average Potential Diff, Measured Δ, Rigid Body within 6.5, 2.9 and 3.9 mm, respectively. CONCLUSIONS: Practical workflows for the use of the first clinical motion tracking and correction system in helical tomotherapy delivery have been developed and the system has now been successfully implemented in our clinic for treating lung and prostate cancerpatients.
Authors: William S Ferris; Wesley S Culberson; Jennifer B Smilowitz; John E Bayouth Journal: J Appl Clin Med Phys Date: 2021-03-29 Impact factor: 2.102
Authors: William S Ferris; Edward H Chao; Jennifer B Smilowitz; Randall J Kimple; John E Bayouth; Wesley S Culberson Journal: J Appl Clin Med Phys Date: 2022-04-29 Impact factor: 2.243