Combined I-124 positron emission tomography/computed tomography imaging of NIS gene expression in animal models of stably transfected and intravenously transfected tumor.
OBJECTIVE
With the advent of replication competent viruses for cancer gene therapy, it has become imperative to monitor the biodistribution, expression and replication of these vectors in living organisms. We evaluated the potential of I-124 positron emission tomography (PET)/computed tomography (CT) imaging in gene therapy animal models utilizing the sodium iodide symporter (NIS) and compared the findings to I-123 gamma camera imaging.


METHODS
CB17 SCID mice were implanted with myeloma cell lines expressing NIS or infected by MV-NIS given systemically. Mice were imaged by both gamma camera (I-123) and PET/CT (I-124 ) and image quality assessed.


RESULTS
NIS expressing tumors concentrated 7.1% of the injected activity while tumors infected with the control virus had only 0.3% of the activity injected.


CONCLUSIONS
I-124 PET/CT in combination with NIS allows the tracking of stably transfected tumors or intravenously transfected tumors. Combined modality imaging using PET/CT allows accurate and non-invasive imaging of the distribution and gene expression of a replicating viral vector in living systems.
Dingli
David
D
Molecular Medicine Program, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Kemp
Brad J
BJ
O'Connor
Michael K
MK
Morris
John C
JC
Russell
Stephen J
SJ
Lowe
Val J
VJ
D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D051379:Mice; D016513:Mice, SCID; D023421:Models, Animal; D009368:Neoplasm Transplantation; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D027981:Symporters / Q000235:genetics / Q000378:metabolism*; D014057:Tomography, X-Ray Computed; D014162:Transfection / Q000379:methods; D014183:Transplantation, Heterologous; D000099209:Sodium-Iodide Symporters
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D027981:Symporters; D000099209:Sodium-Iodide Symporters