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. 2023 Mar 25;15(3):e36680. doi: 10.7759/cureus.36680

Figure 3. Target definition, dose distributions, and dose-volume histograms.

Figure 3

The images show CECT images for SRS planning (A-H); target definition (A, E); dose distributions for the original (B, C, F, G) and alternative plans (D, H); axial images (A-D); sagittal images (arrow in E indicating the ventral side) (E-H); representative isodoses (I); and dose-volume histograms (DVHs) (J-L). 

(A, E) The original GTV and uniform 2-mm added and reduced objects (GTV + 2 mm, GTV – 2 mm). The contours of margin-added or reduced structures generated on Monaco® (Elekta AB, Stockholm, Sweden) are not smooth but slightly jerky. (B, F) The 20 Gy isodose lines covers 95% of the original GTV (oGTV) with some over-coverage (arrows in B, F). (D, H) The dose gradients just outside and inside the oGTV boundary in the alternative plan (D, H) are steeper and more concentrically laminated than those for the original plan (C, G). (J) The DVHs for the oGTV and oGTV + 2 mm. (K) The DVHs for the corrected GTV (cGTV) and cGTV + 2 mm in addition to the oGTV and oGTV + 2 mm. (L) Comparison of the DVHs for the original and alternative plan. The wall structure is the 8-mm thickness object outside the oGTV + 2 mm boundary.

CECT: contrast-enhanced computed tomography; SRS: stereotactic radiosurgery; GTV: gross tumor volume