penumbra
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(pĕ-nŭm′bră)

[L. paene, almost + L. umbra, shadow, shade]
1. Healthy tissue that surrounds an ischemic or infarcted part.
2. A shadow, e.g., around a radiographic image or at the margin of tissue treated with radiation therapy.
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(pĕ-nŭm′bră)

[L. paene, almost + L. umbra, shadow, shade]
1. Healthy tissue that surrounds an ischemic or infarcted part.
2. A shadow, e.g., around a radiographic image or at the margin of tissue treated with radiation therapy.
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