Apparatus for performing dual energy medical imaging
First Claim
1. A dual energy medical imaging system for imaging a body part through which a radio-opaque dye is flowing, said dye having a predetermined K-edge energy level, comprising:
- an electron beam target having a target surface which, when excited by a high-energy electron beam, generates a radiation output having strong K.sub.α
lines at energy levels slightly above and slightly below the K-edge energy level of the dye;
means for appling an electron beam to excite said target, said beam having sufficient energy to provide a high photon yield at the K.sub.α
line energy levels and sufficient power to obtain the photon fluence required for a medical imaging application;
filter means for selectively either filtering or passing unfiltered at least one of the K.sub.α
lines in the radiation output from the excited target surface;
an x-ray detector;
means for passing the output of said filter means with both said at least one K.sub.α
line filtered and said at least one K.sub.α
line unfiltered through the body part being imaged to said x-ray detector; and
means for processing the energy received at the detector in response to the filtered and unfiltered outputs from the filtering means to obtain an image of the body part.
2 Assignments
0 Petitions
Accused Products
Abstract
An energy substraction medical imaging system which is used for imaging a body part impregnated with a radio-opaque dye such as iodine is provided. The system includes an electron beam target having a target surface which, when excited by a high-energy electron beam, generates radiation having strong K.sub.α at energy levels slightly above and slightly below the K-edge energy level of the dye. The target surface is preferably formed of a compound containing lanthanum, such as lanthanum oxide. The target may also be formed of a compound containing a material having a K.sub.α line at an energy level slightly above the dye K-edge and a material with K.sub.α line slightly below the dye K-edge or with separate sections containing such materials which are alternately excited. The target is excited by a high-energy electron beam from a suitable source, the electron beam having sufficient energy to provide a high photon yield at the K.sub.α line energy levels and sufficient power to produce the required photon fluences at such energy lines for the medical imaging application. One of the K.sub.α lines in the radiation output from the excited target is selectively filtered and the output from the filter, both with the K.sub.α line filter and with the line unfiltered, are passed through the body part being imaged to an x-ray detector. The output from the detector in response to the filtered and unfiltered outputs is processed to obtain an image of the body part. Continuum radiation from the target is reduced by filtering the continuum radiation at frequencies above the below the K.sub.α line energy levels of the target compound, by viewing the radiation from the target in the backward direction to the beam, and by having the thickness of the target equal to a fraction of the electron range in the target compound material.
-
Citations
21 Claims
-
1. A dual energy medical imaging system for imaging a body part through which a radio-opaque dye is flowing, said dye having a predetermined K-edge energy level, comprising:
-
an electron beam target having a target surface which, when excited by a high-energy electron beam, generates a radiation output having strong K.sub.α
lines at energy levels slightly above and slightly below the K-edge energy level of the dye;means for appling an electron beam to excite said target, said beam having sufficient energy to provide a high photon yield at the K.sub.α
line energy levels and sufficient power to obtain the photon fluence required for a medical imaging application;filter means for selectively either filtering or passing unfiltered at least one of the K.sub.α
lines in the radiation output from the excited target surface;an x-ray detector; means for passing the output of said filter means with both said at least one K.sub.α
line filtered and said at least one K.sub.α
line unfiltered through the body part being imaged to said x-ray detector; andmeans for processing the energy received at the detector in response to the filtered and unfiltered outputs from the filtering means to obtain an image of the body part. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A method for performing coronary angiography on a subject comprising the steps of:
-
placing an iodine dye at an appropriate point in the bloodstream of the subject, the iodine having a predetermined K-edge energy level; exciting a target formed of a compound containing lanthanum with a high energy electron beam, the lanthanum generating strong K.sub.α
lines in response to the exciting electron beam at an energy level slightly above the iodine K-edge level and a level slightly below the iodine K-edge level;
viewing radiation from said excited target in the backward direction;selectively filtering the emitted radiation to remove energy emitted at a high K.sub.α
line of the lanthanum target radiation;successively passing the filtered and unfiltered radiation from the target through a part of the subject'"'"'s body to be imaged to a detector; and processing the detected radiation to determine the intensity in a difference image which represents the iodinated portion of the imaged body part; whereby an image of the part of the subject s body containing the iodine dye may be obtained.
-
Specification