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. Author manuscript; available in PMC: 2011 Jun 1.
Published in final edited form as: Int J Radiat Oncol Biol Phys. 2009 Aug 5;77(2):357–366. doi: 10.1016/j.ijrobp.2009.04.028

Fig. 3.

Fig. 3

Comparison of IMPT with PSPT in treating an NSCLC lesion close to the spinal cord. (a) Beam arrangements for a typical PSPT plan. (b) Beam-eye view of the aperture block, CTV (green contour), PTV (blue contour), and spinal cord (red contour) for the right lateral beam. The aperture had to be edited for this beam to avoid the cord. (c) The hot region resulting from the overlap of the two beams for the PSPT plan. CTV: yellow contour. (d) Avoidance of the hot region by intensity modulation for the IMPT plan with the use of the same two beams.