Feasibility of dose painting using volumetric modulated arc optimization and delivery

Figures & data

Figure 1. (a) The Cu-ATSM PET image for the patient, (b) the dose prescription map, (c) the substructures corresponding to five dose prescription levels, (d) an example of the optimised dose.

Table I. Mean doses (in Gy) for the target substructure sets. Used as prescription doses in the level-based approach, and as target optimization objectives in Eclipse.

	3 levels	5 levels	7 levels	9 levels	11 levels
PTV1	78.4	73.4	70.5	69.2	68.6
PTV2	92.8	82.3	77.9	75.4	73.8
PTV3	107.0	93.1	85.2	80.9	78.3
PTV4		102.9	93.1	87.1	83.1
PTV5		112.9	100.7	93.2	88.2
PTV6			108.2	99.2	93.2
PTV7			115.2	104.9	98.1
PTV8				111.2	103.1
PTV9				116.5	107.9
PTV10					113.0
PTV11					117.7

Figure 2. Quality volume histograms for: (upper left) all the number of dose prescription levels used (with default settings of the optimisation paramenters); 11 levels (solid line), 9 levels (dashed line), 7 levels (dotted line), 5 levels (dash-dot line), 3 levels (thin solid line), (lower left) 11 dose prescription levels for one (dotted line) and two (solid line) arcs, (lower right) 11 dose prescription levels for MLC width 2.5 mm (solid line) and 5 mm (dotted line), (upper right) 11 dose prescription levels for collimator rotations 45(315) (solid line), 30(330) (dashed line), 15(345) (dotted line) and 0(0) (dash-dot line).

Table II. Tabulation of Q_0.95–1.05 for combinations of physical parameters for level-based dose painting for optimisation with 11 dose levels.

	One arc		Two arcs
11 levels	2.5 mm	5 mm	2.5 mm	5 mm
45 degrees (315 for second arc)	88.9	85.6	92.8	90.5
30 degrees (330 for second arc)	88.6	85.2	91.6	90.6
15 degrees (345 for second arc)	86.6	85.8	89.7	89.6
0 degrees (both arcs)	74.0	68.8	84.6	82.0

Figure 3. Magnitudes of Q_0.95–1.05 for the default settings of optimisation parameters for all numbers of dose prescription levels for no positional shift (circles), shift of 1 mm in all directions (squares), and shift of 2 mm in all directions (diamonds).