Magnetic Particle Imaging Technique Could Improve Resolution of Cancer Imaging
Nanoscale technique uses magnetic tracer particles to trace fine details of tumors.
A multi-institutional team led by Kannan Krishnan of the University of Washington has developed a method of acquiring images of cancerous tumors using a technique called magnetic particle imaging, or MPI, along with specially formulated nanoparticles.
The nanoscale technique, which works in the range of billionths of meters or in the range of some viruses, can detect the presence of magnetic tracer particles at any depth in tissue in seconds. The introduced particles flip their magnetic fields randomly, which distinguishes them from naturally occurring magnetic molecules in the body, making them easy to detect and improving resolution.
The team tested the technology by injecting mice with glioma tumor cells in their thighs. Gliomas are a type of brain tumor that includes benign and malignant tumors. Glioblastoma is a very aggressive form of a glioma, considered to be grade 4. In the mice, tumors grew at the point of injection. The researchers coated tiny particles of iron oxide with lactoferrin, a peptide that tends to collect in brain tissue, so that the iron oxide particles would be directed toward the tumors.
After injection, enough particles reached the tumors to be detected on an MPI scanner and an infrared fluorescent imager. Iron oxide is generally of low toxicity; the human body disintegrates the particles in the liver, normally saving the iron for use in hemoglobin and other molecules.
This was the first demonstration that the MPI technique could be used to image cancer cells in three dimensions in a living animal, with higher resolution than other methods. The researchers believe their method can be combined with other types of tomography and MRIs to enhance cancer diagnosis and treatment. They reported their work in the 20 October issue of Nanoscale.