Illustration of hypothetical SQUID scanner modeled in simulations. Scanner is composed of 11 planar first-order gradiometer pickup coils located to the interior of and on the same platform as the magnetic field generating coil. The value of the magnetic field is the field generated at the midpoint of a set of coils of a pickup coil. This point is defined as the scan point. End effects of the solenoid are neglected.
Computer simulated body, tumor and scan geometry. (a) Configuration of magnetic field generated by the current carrying wires in induction field solenoid. (b) Geometry of magnetization vector induced in a voxel and position with respect to a set of pickup coils in scanner. (c) Geometry of torso and tumor with respect to the scanner and direction of motion.
Magnetic properties of MACS particles. (A) The zero-field-cooled and field-cooled magnetization of of MACS solution measured in the magnetic field of . (B) The in-phase and out-of-phase components of the ac susceptibility as a function of frequency of of MACS solution.
Magnetization vs magnetic field. (A) cells MFC-7a MACS conjugated human breast cancer cells, (B) cells LNCaP MACS conjugated human prostate cancer cells.
Simulated line scans of magnetic field differential vs scan distance; tumor composed of MACS conjugated to MCF-7 cells. No contribution from torso. Tumor is located below the scanner at a scan distance of . Simulated scan performed by 11 SQUID scanner.
Simulated differential magnetic field signal maximum as a function of distance of tumor from the scanner. The magnetic induction field applied was at the scan point. The straight horizontal line reflects the limitation of the technique following from Wikswo (i.e., of applied field. For these simulations a magnetic field of was applied at the center of the pickup coils leading to a detection limit of ). Dashed line is the theoretical result for nanoparticle with twice the radius of LCDIO. Dotted line is theoretical result for nanoparticle with three times the radius of LCDIO.
Simulated differential magnetic field scan tumor plus torso, as a function of scan distance. A MCF-7 MACS targeted constructed tumor located from the end of the ellipsoid along the scan length, from the width center and located at a distance of below the central scan point at a depth of below the surface (top) of the ellipsoidal diamagnetic background (torso model). Simulated signal generated by 11 SQUID scanners scanning the width of the ellipsoid. The magnetic induction field applied was at the scan point.
Simulated line scan: Tumor plus virtual organ background plus diamagnetic background (ellipsoidal torso). Tumor is located from the end of the ellipsoid (scan distance) along the scan length, from the width (ellipsoid) center and located at a distance of below the central scan point at a depth of below the surface (top) of the ellipsoidal diamagnetic background (torso model). A virtual organ of thickness , width and length and 10% tumor concentration is centered below the scanner and from the width center and along the scan distance. Scan produced by 11 SQUID scanners.
Depth dependence of scanner signals. (a) The position of the peak in the differential magnetic field signal from the tumor as a function of tumor depth. (b) Amplitude of the maximum differential magnetic field signal from the tumor as a function of magnetic field for tumor is located and varying depth. The magnetic induction field applied was at the scan point.
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