Illustrating the IMAT planning. Typically, is set to 5°–10°.
Illustrating the IMAT maximum leaf motion constraint, where and are the positions of the tip of the left leaf, is the time when the gantry arrives at angle , and is the time when the gantry arrives at angle .
Illustrating our IMAT sequencing algorithm. (a) A set of optimized intensity patterns. For simplicity of illustration, we assume that the MLC has two pairs of leaves and the IMAT uses two adjacent beam angles. (b) Segmenting the intensity patterns in (a) into intensity profiles for each pair of MLC leaves. (c) The intensity profiles for an MLC leaf pair are sequenced into a set of 1D IMAT arcs of MLC leaf openings. Here each leaf opening is represented by a rectangle whose left and right edges indicate the leaf positions and whose height indicates the beam-on time. (d) The 1D IMAT arcs are combined to form IMAT treatment arcs of MLC apertures. Each MLC aperture is represented by a 0-1 matrix in which the 1’s indicate the entries being exposed and 0’s indicate the entries being blocked by the MLC leaves.
Illustrating our algorithm for converting an intensity profile into MLC leaf openings with the minimum error.
Illustrating the adjustment of a 1D IMAT arc using the shortest path algorithm.
Comparisons between the IMAT, gantry-fixed IMRT, and tomotherapy plans for an endometrial cancer case.
The comparison of the 90%, 80%, and 60% isodose lines for a head-and-neck case. CTV2 is the shaded region to the left, and CTV3 is the shaded region to the right. The 90%, 80%, and 60% isodose lines are shown from inside out. (a) IMAT plan. (b) IMRT plan.
The DVH comparison between a nine-arc IMAT plan and a gantry-fixed IMRT plan for the head and neck case in Fig. 7. The solid lines are for the IMAT plan and the dashed lines are for the IMRT plan.
DVH comparisons of the IMAT, gantry-fixed IMRT, and tomotherapy plans for a prostate case.
Isodose comparisons of the IMAT (a), gantry-fixed IMRT (b), and tomotherapy (c) plans for a lung cancer case. Isodose lines of 95%, 85%, 65%, 30%, and 12.6% are shown from the inside out. (d) shows the DVH comparison.
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