Beams for the seven-field IMRT technique. Beam 1 is used in combination with an orthogonal kV beam for 3D pretreatment SGT corrections, while beams 3 and 6 are used for iSGT intrafraction corrections in the sagittal plane.
iSGT workflow. Abbreviations: AM = automated match, eth = error threshold for correction in mm; AIMS = automated identification of marker match success; M = number of detected markers; Mth = threshold for M.
Cumulative distributions of residual effective fraction set-up errors. Errors are given as lengths of 2D effective fraction error vectors in the sagittal plane, and comprise both systematic and random components.
Cumulative distributions of residual effective systematic set-up errors per patient. Errors are given as lengths of 2D effective fraction error vectors in the sagittal plane.
Performance of the AIMS test for detection of AM successes, defined as |AM − GT|< 2 mm (GT = ground truth), as a function of the parameter Mth. The data were obtained from AM for a total of 970 MV-images.
Performance of the AM algorithm in detecting true set-up errors larger than the threshold error, eth. Clinically eth = 4 mm was used. Computer simulations were used to generate data for eth = 3 mm and eth = 2 mm.
Simulated population effective setup errors for the initial group of 20 patients in SI and AP directions.
Evaluation of iSGT using images from the 100 clinical iSGT patients; the table shows measured displacements just after initial setup and as well as displacements without and with iSGT corrections for the clinical action level of 4 mm. Simulated displacements for action levels of 3 and 2 mm as well as for the NAL-based off-line protocol to correct intrafraction motion are also shown.
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