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Figure 4 | Radiation Oncology

Figure 4

From: Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract

Figure 4

Influence of different contours on the DVH analysis. Each contour was layered over the original default plan (Soseikai General Hospital). The dose calculation was made by ShioRIS, and the DVH was calculated using ShioRIS-2. a) Pituitary adenoma:10 contours Left panel. PTV. Default D90 = 25 Gy/5 fractions. According to the applied contours, the D90 median dose was 24.68 Gy (23.34 - 24.78 Gy). Right panel. OAR (left optic nerve). Left optic nerve received 8.79 Gy in default plan (made by T. T.), median 12.41 Gy (8.78 - 23.64 Gy; 23.64 Gy = 268% of default plan) b) Meningioma: 11 contours Left panel. PTV. Default D90 = 30 Gy/5 fractions. According to the applied contours, the D90 median dose was 30.29 Gy (24.24 - 30.66 Gy). Right panel. OAR (right optic nerve). The right optic nerve received a median dose of 19.39 Gy (16.21 - 24.84 Gy; 18.9 Gy in the default plan). Therefore, some plans used 24.24 Gy as a D90 prescribed dose (19% lower dose than anticipated in widen PTV group) when using their contoured PTV. In addition, a higher maximum dose of 24.84 Gy (131% higher dose than default plan 18.9 Gy) was delivered to the right optic nerve in contours used in some institutes.

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Radiation Oncology

ISSN: 1748-717X

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