Table 1.
Tumor characteristics with and without gating.
Fig 1.
Development process for a dose rate modulated arc therapy (DrMAT) plan via intermediate stages of a static conformal therapy (sCOT) plan and a dynamic conformal arc therapy (dCAT) plan.
Abbreviations: AAA, anisotropic analytical algorithm; MU, monitor unit.
Fig 2.
Virtual PTV, a pseudo target for an optimal field aperture: a) the PTV (red) and the isodose volume (blue) that covered 95% of PTV when each field aperture was set such that MLC (yellow) was tightly fitted to the PTV in its beam’s-eye view; b) the isodose volume (blue) that covered 95% of PTV after MLC (yellow) of each field was readjusted to fit the shape of the virtual PTV in its beam’s-eye view. Abbreviations: PTV, planning target volume; MLC, multileaf collimator.
Fig 3.
Schematic illustration of the procedure to transform (a) a static conformal therapy (sCOT) plan into (b) a dynamic conformal arc therapy (dCAT) plan. Abbreviations: PTV, planning target volume; MLC, multileaf collimator.
Fig 4.
Example of dose distributions for Case no. 9: a) static conformal therapy (sCOT) plan, b) dynamic conformal arc therapy (dCAT) plan, c) dose–rate modulated arc therapy (DrMAT) plan, and d) volumetric arc therapy (VMAT) plan.
Fig 5.
Comparison of dose-volume histograms between DrMAT (▲) and VMAT (■) plans for the same Case no. 9.
Abbreviations: GTV, gross tumor volume; PTV, planning target volume.
Table 2.
Dosimetric characteristics of the VMAT and DrMAT plans.
Table 3.
Comparison of critical structure doses between the VAMT and DrMAT plans.
Fig 6.
Variations of dose rate and gantry speed as a function of gantry angle, which are executed using a total of 166 control points for a DrMAT plan.
Note that every 5 control points at 2.2° intervals have the same values because an 11° sub-arc of the dCAT is equally divided by them.
Fig 7.
Comparison between the planned and delivered dose distribution for DrMAT and VMAT plans of Case no. 6: a) VMAT plan for static delivery, b) DrMAT plan for static delivery, c) VMAT plan for gating delivery, d) DrMAT plan for gating delivery. The thick and thin lines represent the plan and delivered isodose levels normalized to the prescribed dose, respectively. Note that apparent difference in the dose distributions (e.g., the 100% area) is because they are recalculated ones on a motion phantom, which is different with the patient in the whole size, isocenter location, and density distribution.
Table 4.
Gamma evaluation passing rates for VMAT and DrMAT plans.
Fig 8.
Scatter plots of gamma passing rate between the DrMAT and VMAT plans: a) 2%/2mm and b) 2%/1mm.