Overview of MX200. Device Description. Market Analysis. Subtraction Method. Social Impact. Hypersensitivity reaction to iodine (3-12% patients) Increase patient safety: reduce the amount of potent contrast agents used during angiography
Overview of MX200
Figure 2. Initial images taken with an empty phantom (left) and with saline (right).
Figure 3. Images taken with 1:256 dilution with the subtraction method (left) and differential method (right).
Coronary PhantomDesign for K-edge Angiography
John Jorgensen1, Sarah Pachtman1, Punam Patel1,Marcus Spallek1
Advisors: Paul King, Ph.D.1;Frank E. Carroll, M.D.2
1 Department of Biomedical Engineering, Vanderbilt University, Nashville, TN
2Vanderbilt University Medical Center Department of Radiology and Radiological Sciences
Coronary Phantom Design
MXISystems, Inc. in conjunction with Vanderbilt University and the Office of Naval Research has developed a laser synchrotron (Inverse Compton scattering) X-ray source for the energy region from 10 keV to 50 keV. It is capable of producing X-ray fluences sufficiently high that a single, 9-ps pulse produces a complete medical X-ray image. The device is a tunable, monochromatic x-ray (MX200) to be used in medical imaging. Current research focuses on the application for intravenous coronary angiography.
The coronary phantom consists of a hollow chamber, with a 5 mm diameter tube for saline pump attachment. The outer surface is comprised of interconnected tubes. The three vertical tubes have internal diameter of 1 mm. The horizontal tubes range in diameter from 2 to 5 mm. Two openings are directly connected to the ring grid and allow for fluid filing and emptying. The tubes do not open into the chamber. The device is one solid unit designed to be filled with fluids for imaging with the MX200.
Figure 1. Diagram of MX200’s laser paths and major elements.
Tan θ = 3/30 = 0.10
θ ~ 6°
3-D images of the empty phantom indicated that one of the walls separating the arteries from the main chamber was damaged. It was noted that when air was blown into the arterial portion of the phantom the air leaked out of all ports, indicating the presence of a hole in the wall between the inside chamber and the surface arteries. The phantom was filled with a small amount of saline and a leak was detected.
The images were taken with an iodine dilution of 1:256. A balloon filled with water was inserted in the center chamber while the contrast solution was filled in the arteries (image on left). Note the balloon and water appear very opaque and would require high dose exposures to image through the phantom. The 1:256 dilution we were able to image is still significantly lower than the dose of about 1:16 given to a CT patient. The image on the right was edited using a differential method. This method relies on logic function and provided a clear image of the contrast agent over the subtraction method.
The 3-D movie shows the phantom with rotations of 3, 6, 9, 12 degrees. The 6° is found to be the optimal stereo angle for imaging.
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This project was made possible through the help of the following contributors:
Scott Degenhardt; Robert Traeger; Dr. Frank Carroll; Philip Davis; Z-Corporation