Primary brain tumors present significant challenges for surgical resection because of their location and the frequent occurrence of malignant projections extending beyond the primary
tumor. Visualization of the
tumor margins during surgery is critical for a favorable outcome. We report the use of
IRDye 800CW chlorotoxin (CLTX) as a targeted imaging agent for
brain tumors in a spontaneous mouse model of
medulloblastoma, ND2:SmoA1. Specificity and functionality of the targeted agent were confirmed in cell-based assays.
Tumors were detected by magnetic resonance imaging and
IRDye 800CW CLTX administered to individual animals for optical imaging at 1-month increments. The integrity of the blood-brain barrier (BBB) was measured by
Evan's Blue perfusion prior to sacrifice. Results show that
IRDye 800CW CLTX specifically targeted
tumor tissue. The extravasation of
Evan's Blue was observed in all
tumors, suggesting that the presence of the
tumors can introduce alterations in the permeability of the BBB. Because increased vascular permeability was observed early in the disease model, larger
dye-labeled imaging agents that exceed current BBB size restrictions may warrant renewed consideration as candidates for
tumor detection and surgical resection. Our study provides data characterizing in vitro and in vivo use of
IRDye 800CW CLTX as a broadly applicable
tumor imaging agent.