PMC8041142_01
Axial treatment planning CT scan demonstrating the isodose distribution by minimum dose limits of 12 Gy (I), 8 Gy (II), and 4 Gy (III) with corresponding color maps.
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He was treated with LINAC SRS to a dose of 12 Gy prescribed to the 89% isodose line (Fig. 1 ) with corresponding dose metrics to the brainstem of 10 Gy to 1 cc, 12 Gy to 0.5 cc, and 13 Gy to 0.03 cc (Fig. 2 ).
Dose-volume histogram of the brainstem for the patient with a vestibular schwannoma treated to 12 Gy in 1 fraction. Absolute volume of the brainstem is plotted on the y-axis and dose (cGy) is plotted on the x-axis.
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He was treated with LINAC SRS to a dose of 12 Gy prescribed to the 89% isodose line (Fig. 1 ) with corresponding dose metrics to the brainstem of 10 Gy to 1 cc, 12 Gy to 0.5 cc, and 13 Gy to 0.03 cc (Fig. 2 ).
Axial T1-post contrast MRIs of the brain before and after treatment with SRS and after infection with SARS-CoV-2.
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MRI of the brain performed approximately 1 month after treatment demonstrated stable disease without any radiographic change in tumor dimensions, cystic evolution of the tumor, or RN (Fig. 3 ). An MRI of the brain was therefore repeated, approximately 4.5 months from SRS, with significant radiographic changes on comparison to his past imaging studies: necrosis in the center of the tumor, thin peripheral enhancement, and enhancing stranding in the adjacent brainstem with new surrounding vasogenic edema consistent with RN (Fig. 3).