Imaging, dosimetric, and oncolytic activity of VSV(Δ51)-NIS. (A) Representative planar images of VSV(Δ51)-NIS–infected, tumor-bearing mice obtained 3 hours after intraperitoneal injection of 123I 1 day after mock (PBS, intratumoral) or VSV(Δ51)-NIS injections (5 × 107 TCID50/dose, 2 doses given days −1 and 0). Radioisotope uptake is seen in the salivary glands, thyroid gland (Thy), and stomach (St), with excreted radioisotope visible in the bladder (Bd). No increased uptake is seen in the subcutaneous flank tumor of (i) control mouse, whereas increased intratumoral radioisotope uptake is demonstrated in mice treated (ii) intratumorally or (iii) intravenously with VSV(Δ51)-NIS. Arrows indicate tumor locations. The color bar (image intensity scale) demonstrates the range of uptake intensities, with 100% representing the strongest signal in the image. Planar images were acquired using a Gamma Medica X-SPECT imaging system (Gamma Medica, Northridge, CA). Images were analyzed and processed using PMOD Biomedical Image Quantification and Kinetic Modeling software version 2.75 (PMOD Technologies) and Adobe Photoshop version 7.0 (Adobe Systems, San Jose, CA). (B) Serial planar images of subcutaneous myeloma tumors were acquired on days 1 and 4 after administration of VSV(Δ51)-NIS and %ID taken up by the tumor was calculated (n = 4/group). (C) The growth of subcutaneous myeloma tumors was tested by measuring tumor volumes on days 1 and 4 (n = 4/group). Bars indicate SE.
