Magnetic particle imaging devices and methods
View Patent ↗A magnetic particle imaging device is provided. The device includes a magnetic field source configured to produce a magnetic field having a non-saturating magnetic field region, an excitation signal source configured to produce an excitation signal in the non-saturating magnetic field region that produces a detectable signal from magnetic particles in the non-saturating magnetic field region, and a signal processor configured to convert a detected signal into an image of the magnetic particles. Aspects of the present disclosure also include methods of imaging magnetic particles in a sample, and methods of producing an image of magnetic particles in a subject. The subject devices and methods find use in a variety of applications, such as medical imaging applications.
1. A magnetic particle imaging device comprising:
a magnetic field source configured to produce a magnetic field having a non-saturating magnetic field region;
an excitation signal source configured to produce an excitation signal in the non-saturating magnetic field region that produces a detectable signal from magnetic particles in the non-saturating magnetic field region; and
a signal processor configured to recover low frequency image data and produce a native image of the magnetic particles from the detectable signal.
2. The device of claim 1 , wherein the image is a one-dimensional image, a two-dimensional image, or a three-dimensional image.
3. The device of claim 1 , wherein the image includes a plurality of images of the magnetic particles in the sample over a period of time.
4. The device of claim 1 , wherein the device further comprises two or more coaxially arranged magnetic field sources.
5. The device of claim 4 , wherein the coaxially arranged magnetic field sources are permanent magnets.
6. The device of claim 4 , wherein the magnetic field has a magnetic field gradient ranging from 0.5 Tesla/meter to 30 Tesla/meter.
7. The device of claim 1 , wherein the excitation signal comprises a RF excitation signal.
8. The device of claim 7 , wherein the excitation signal further comprises an intermodulation excitation signal.
9. The device of claim 1 , wherein the device further comprises a scanning magnetic field source configured to produce a scanning magnetic field that positions the non-saturating magnetic field region in the magnetic field.
10. The device of claim 9 , wherein the device is configured to produce a linearly varying signal with respect to the concentration of magnetic particles in the non-saturating magnetic field region.
11. The device of claim 1 , wherein the device further comprises a receiver configured to detect the signal from the magnetic particles in the non-saturating magnetic field region.
12. The device of claim 11 , wherein the receiver comprises a receiver coil with a Q factor of 100 or more.
13. The device of claim 11 , wherein the receiver is configured to have a receive bandwidth ranging from 10 kHz to 1 MHz.
14. The device of claim 1 , wherein the device is configured to have a signal to noise ratio ranging from 10 to 500,000.
15. The device of claim 1 , wherein the device is configured to have a resolution ranging from 1 mm to 100 μm.
16. The device of claim 1 , wherein the device is configured to have a sensitivity ranging from 1 μg to 0.1 ng.
17. The device of claim 1 , wherein the device is configured to have a field of view ranging from 1 cm to 50 cm.
18. The device of claim 1 , wherein the device is configured to produce images of the magnetic particles in the field free region at different resolutions.
19. The device of claim 1 , wherein the device is configured to perform a high resolution scan from sample points within an imaging region where magnetic particles were detected from a low resolution scan.
20. The device of claim 10 , wherein the device is configured to produce the linearly varying signal as the non-saturating magnetic field region is repositioned in the gradient magnetic field.
21. The device of claim 11 , wherein the receiver is configured to have a receive bandwidth ranging from 1 kHz to 100 MHz.
22. The device of claim 1 , wherein the device is configured to produce a signal that is shift invariant.
23. The device of claim 1 , wherein the non-saturating magnetic field region is a non-saturating magnetic field line.
24. A method of producing an image of magnetic particles in a sample, the method comprising:
applying a magnetic field having a non-saturating magnetic field region to a sample comprising magnetic particles;
applying an excitation signal to the magnetic particles in the non-saturating magnetic field region to produce a detectable signal from the magnetic particles in the non-saturating magnetic field region;
detecting the signal from the magnetic particles in the non-saturating magnetic field region; and
analyzing the detected signal to produce a native image of the magnetic particles in the sample by recovering low frequency image data.
25. The method of claim 24 , further comprising applying a scanning magnetic field to the magnetic field having the non-saturating magnetic field region to position the non-saturating magnetic field region in the magnetic field.
26. The method of claim 25 , further comprising:
repositioning the non-saturating magnetic field region in the magnetic field; and
repeating the detecting and repositioning to detect two or more signals from the magnetic particles in the non-saturating magnetic field region.
27. The method of claim 26 , wherein the analyzing comprises correlating the detected signal to the position of the non-saturating magnetic field region when the signal was detected.
28. The method of claim 26 , wherein the analyzing comprises converting the detected signals into partial field of view images.
29. The method of claim 28 , wherein the analyzing further comprises combining the partial field of view images to produce the image of the magnetic particles in the sample.
30. The method of claim 25 , further comprising varying the magnetic field strength of the magnetic field while applying the scanning magnetic field to produce images having different resolutions.
31. The method of claim 30 , further comprising analyzing the images having different resolutions to determine low frequency image data.
32. The method of claim 24 , wherein the applying the excitation signal comprises applying an RF excitation signal to the magnetic particles in the non-saturating magnetic field region.
33. The method of claim 32 , wherein the applying the excitation signal further comprises applying an intermodulation signal to the magnetic particles in the non-saturating magnetic field region.
34. The method of claim 24 , wherein the method comprises producing a plurality of images of magnetic particles in the sample over a period of time.
35. The method of claim 24 , further comprising acquiring a high resolution image of an imaging region containing sample points where the magnetic particles were detected from a low resolution scan.
36. The method of claim 24 , further comprising moving the sample relative to the magnetic field.
37. The method of claim 24 , further comprising reducing the bandwidth to increase the signal to noise ratio of the signal.
38. A method of producing an image of magnetic particles in a subject, the method comprising:
administering magnetic particles to a subject;
positioning the subject in a magnetic particle imaging device;
applying a magnetic field having a non-saturating magnetic field region to the subject;
applying an excitation signal to the magnetic particles in the non-saturating magnetic field region to produce a detectable signal from the magnetic particles in the non-saturating magnetic field region;
detecting the signal from the magnetic particles in the non-saturating magnetic field region; and
analyzing the detected signal to produce a native image of the magnetic particles in the subject by recovering low frequency image data.