U.S. patent application number 15/237402 was filed with the patent office on 2016-12-01 for wearable/man-portable electromagnetic tomographic imaging.
This patent application is currently assigned to EMTensor GmbH. The applicant listed for this patent is EMTensor GmbH. Invention is credited to Serguei Y. SEMENOV.
Application Number | 20160345856 15/237402 |
Document ID | / |
Family ID | 51530434 |
Filed Date | 2016-12-01 |
United States Patent
Application |
20160345856 |
Kind Code |
A1 |
SEMENOV; Serguei Y. |
December 1, 2016 |
WEARABLE/MAN-PORTABLE ELECTROMAGNETIC TOMOGRAPHIC IMAGING
Abstract
A system for wearable/man-portable electromagnetic tomographic
imaging includes wearable headgear adapted to receive a human head
within, a position determination system, electromagnetic
transmitting/receiving hardware, and a computer system. The
electromagnetic transmitting/receiving hardware collectively
generates an electromagnetic field that passes into the headgear
and receives the electromagnetic field after being
scattered/interferenced by the human head within. The computer
system performs electromagnetic tomographic imaging based on the
received electromagnetic field.
Inventors: |
SEMENOV; Serguei Y.;
(Vienna, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EMTensor GmbH |
Vienna |
|
AT |
|
|
Assignee: |
EMTensor GmbH
Vienna
AT
|
Family ID: |
51530434 |
Appl. No.: |
15/237402 |
Filed: |
August 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14727688 |
Jun 1, 2015 |
9414764 |
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15237402 |
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13894395 |
May 14, 2013 |
9072449 |
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14727688 |
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61801965 |
Mar 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/0507 20130101;
A61B 2562/143 20130101; A61B 5/742 20130101; A61B 2562/0228
20130101; A61B 2560/0431 20130101; A61B 5/0042 20130101; A61B
5/4312 20130101; A61B 5/065 20130101; A61B 5/6802 20130101; A61B
5/6814 20130101; A61B 2576/00 20130101 |
International
Class: |
A61B 5/05 20060101
A61B005/05; A61B 5/06 20060101 A61B005/06; A61B 5/00 20060101
A61B005/00 |
Claims
1. A system for wearable/man-portable electromagnetic tomographic
imaging, comprising: wearable headgear, adapted to receive a human
head within walls that are made at least partly of a material that
is non-transparent with respect to the generated electromagnetic
field and that include a plurality of electromagnetic windows that
are each independently opened or closed via a respective microgate;
electromagnetic transmitting/receiving hardware collectively
configured to generate an electromagnetic field that passes into
the headgear through at least one open electromagnetic window and
receives the electromagnetic field passing out of at least one open
electromagnetic window after being scattered/interferenced by the
human head within; a position determination system configured to
determine position information pertaining to the wearable headgear
with respect to an external frame of reference, wherein the
external frame of reference includes a location of the
transmitting/receiving hardware or the location of the
transmitting/receiving hardware is established relative to the
external frame of reference; a computer system configured to
perform electromagnetic tomographic imaging based upon the
generated and received electromagnetic field, upon position
information from the position determination system, and upon
spatial location information for each of the open electromagnetic
windows; wherein the spatial location information for each of the
electromagnetic windows is defined with respect to the headgear,
the external frame of reference, and/or the transmitting/receiving
hardware.
2. The system of claim 1, wherein the plurality of electromagnetic
windows are distributed in the walls so as to surround the imaging
domain.
3. The system of claim 2, wherein the microgates are controlled
such that the electromagnetic field enters into the headgear
through only one electromagnetic window at a time.
4. The system of claim 2, wherein the microgates are controlled
such that the electromagnetic field enters into the headgear
through a plurality of electromagnetic windows at a time.
5. The system of claim 2, wherein the microgates are controlled
such that the electromagnetic field leaves the headgear through
only one electromagnetic window at a time.
6. The system of claim 2, wherein the microgates are controlled
such that the electromagnetic field leaves the headgear through a
plurality of electromagnetic windows at a time.
7. The system of claim 2, wherein each microgate is individually
coded.
8. The system of claim 7, wherein, as the electromagnetic field
enters the headgear through an open electromagnetic window, the
coding of the microgate for the open electromagnetic window is
applied to the electromagnetic field.
9. The system of claim 1, wherein the headgear is in the form of a
deformable hat.
10. The system of claim 1, wherein the headgear is in the form of a
non-deformable helmet.
11. A system for wearable/man-portable electromagnetic tomographic
imaging, comprising: wearable headgear, adapted to receive a human
head within walls that are made at least partly of a material that
is non-transparent with respect to the generated electromagnetic
field and that include a plurality of electromagnetic windows;
electromagnetic transmitting/receiving hardware, located outside
of, physically separate from, and spaced apart from, the headgear,
collectively configured to generate an electromagnetic field that
passes into the headgear through the electromagnetic windows and
receives the electromagnetic field passing out of the
electromagnetic windows after being scattered/interferenced by the
human head within; a position determination system configured to
determine position information pertaining to the wearable headgear
with respect to an external frame of reference, wherein the
external frame of reference includes a location of the
transmitting/receiving hardware or the location of the
transmitting/receiving hardware is established relative to the
external frame of reference; and a computer system configured to
perform electromagnetic tomographic imaging based upon the
generated and received electromagnetic field, upon position
information from the position determination system, and upon
spatial location information for each of the electromagnetic
windows; wherein the spatial information for each of the open
electromagnetic windows is defined with respect to the headgear,
the external frame of reference, and/or the transmitting/receiving
hardware.
12. The system of claim 11, wherein the plurality of
electromagnetic windows are distributed in the walls so as to
surround the imaging domain.
13. The system of claim 12, wherein the plurality of
electromagnetic windows have known spatial locations, wherein the
spatial locations for each of the electromagnetic windows is
defined with respect to the headgear, the external frame of
reference, and/or the transmitting/receiving hardware.
14. The system of claim 13, wherein knowledge of the spatial
locations of the plurality of electromagnetic windows is determined
via the position determination system.
15. The system of claim 13, wherein knowledge of the spatial
locations of the plurality of electromagnetic windows is
established independently of the position determination system.
16. The system of claim 11, wherein the position determination
system determines information about the position of the headgear,
and wherein the computer system performs magnetic tomographic
imaging based upon the received electromagnetic field and upon the
headgear position information from the position determination
system.
17. The system of claim 11, wherein the position determination
system determines information about the positions of the
electromagnetic windows, and wherein the computer system performs
magnetic tomographic imaging based upon the received
electromagnetic field and upon the electromagnetic windows position
information from the position determination system.
18. The system of claim 1, wherein the position determination
system includes a first position determination system that
determines information about the position of the headgear, wherein
the position determination system includes a second position
determination system that determines information about the
positions of the electromagnetic windows, and wherein the computer
system performs magnetic tomographic imaging based upon the
received electromagnetic field and upon the headgear position
information and electromagnetic windows position information from
the position determination system.
19. The system of claim 1, wherein the headgear is in the form of a
deformable hat.
20. The system of claim 1, wherein the headgear is in the form of a
non-deformable helmet.
21. The system of claim 1, wherein the electromagnetic
transmitting/receiving hardware includes transmitting hardware
and/or receiving hardware that is man-portable.
22. The system of claim 1, wherein the electromagnetic
transmitting/receiving hardware is a small cellular base
station.
23. The system of claim 1, wherein the electromagnetic
transmitting/receiving hardware is physically separate from the
headgear.
24. Wearable headgear, for use in electromagnetic tomographic
imaging, comprising: a hollow structure having walls made at least
partially of a material that is non-transparent with respect to an
electromagnetic field generated by electromagnetic
transmitting/receiving hardware that is physically separate from
the wearable headgear; a plurality of electromagnetic windows
distributed in the walls so as to surround the imaging domain; and
a plurality of microgates that are configured to open and close the
electromagnetic windows so as to control whether the
electromagnetic field generated by the electromagnetic
transmitting/receiving hardware enters and/or leaves
therethrough.
25. The wearable headgear of claim 24, wherein each microgate is
individually coded.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a U.S. continuation patent
application of, and claims priority under 35 U.S.C. .sctn.120 to,
U.S. nonprovisional patent application Ser. No. 14/727,688, filed
Jun. 1, 2015 (the "'688 application"), which '688 application
published on Sep. 17, 2015 as U.S. Patent Application Publication
No. 2015/0257649 and issued on Aug. 16, 2016 as U.S. Pat. No.
9,414,764, and which '688 application is a U.S. continuation patent
application of, and claims priority under 35 U.S.C. .sctn.120 to,
U.S. nonprovisional patent application Ser. No. 13/894,395, filed
May 14, 2013 (the "'395 application"), which '395 application
published on Sep. 18, 2014 as U.S. Patent Application Publication
No. 2014/0276012 and issued on Jul. 7, 2015 as U.S. Pat. No.
9,072,449, and which '395 application is a U.S. nonprovisional
patent application of, and claims priority under 35 U.S.C.
.sctn.119(e) to, U.S. provisional patent application Ser. No.
61/801,965, filed Mar. 15, 2013. The foregoing nonprovisional
applications, publications, and patents, as well as the provisional
patent application, are all incorporated by reference herein.
[0002] In addition, the entirety of U.S. Pat. No. 7,239,731 to
Semenov et al., issued Jul. 3, 2007 and entitled "SYSTEM AND METHOD
FOR NON-DESTRUCTIVE FUNCTIONAL IMAGING AND MAPPING OF ELECTRICAL
EXCITATION OF BIOLOGICAL TISSUES USING ELECTROMAGNETIC FIELD
TOMOGRAPHY AND SPECTROSCOPY," is incorporated herein by reference.
The disclosure of this particular patent may provide background and
technical information with regard to the systems and environments
of the inventions described herein.
[0003] Also, the entirety of U.S. Patent Application Publication
No. 2012/0010493 A1, which was published Jan. 12, 2012 based on
U.S. patent application Ser. No. 13/173,078 to Semenov, filed Jun.
30, 2011 and entitled "SYSTEMS AND METHODS OF 4D ELECTROMAGNETIC
TOMOGRAPHIC (EMT) DIFFERENTIAL (DYNAMIC) FUSED IMAGING," is
incorporated herein by reference. The disclosure of this particular
patent publication may provide explanation of the use of "4D"
technology in EMT systems, including with regard to inventions
described herein.
COPYRIGHT STATEMENT
[0004] All of the material in this patent document is subject to
copyright protection under the copyright laws of the United States
and other countries. The copyright owner has no objection to the
facsimile reproduction by anyone of the patent document or the
patent disclosure, as it appears in official governmental records
but, otherwise, all other copyright rights whatsoever are
reserved.
BACKGROUND OF THE PRESENT INVENTION
[0005] Field of the Present Invention
[0006] The present invention relates generally to electromagnetic
tomography, and, in particular but not exclusively, to
electromagnetic tomographic imaging with man-portable components,
including methods, devices, and systems.
[0007] Background
[0008] Electromagnetic tomography (EMT) is a relatively recent
imaging modality with great potential for biomedical applications,
including a non-invasive assessment of functional and pathological
conditions of biological tissues. Using EMT, biological tissues are
differentiated and, consequentially, can be imaged based on the
differences in tissue dielectric properties. The dependence of
tissue dielectric properties from its various functional and
pathological conditions, such as blood and oxygen contents,
ischemia and infarction malignancies has been demonstrated.
[0009] Two-dimensional (2D), three-dimensional (3D) and even
"four-dimensional" (4D) EMT systems and methods of image
reconstruction have been developed over the last decade or more.
Feasibility of the technology for various biomedical applications
has been demonstrated, for example, for cardiac imaging and
extremities imaging.
[0010] As in any biomedical imaging, the classical EMT imaging
scenario consists of cycles of measurements of complex signals, as
scattered or "interferenced" by a biologic object under study,
obtained from a plurality of transmitters located at various points
around the object and measured on a plurality of receivers located
at various points around the object. This is illustrated in FIG. 1.
As recounted elsewhere herein, the measured matrix of scattered EM
signals may then be used in image reconstruction methods in order
to reconstruct a 2D or 3D distribution of dielectric properties of
the object, i.e., to construct a 2D or 3D image of the object.
Still further, 4D imaging may be achieved by reconstructing 3D
images at different time points.
[0011] Generally, it is very important for image reconstruction to
precisely describe a distribution of EM field with an imaging
domain 21. The distribution of EM field with an imaging chamber is
a very complex phenomenon, even when there is no object of interest
inside.
[0012] FIG. 2 is a schematic view of one possible embodiment of a
prior art EM field tomographic spectroscopic system 10. Such a
system 10 could carry out functional imaging of biological tissues
and could also be used for a non-invasive mapping of electrical
excitation of biological tissues 19 using a sensitive (contrast)
material (solution or nanoparticles) injected into the biological
tissue 19 or in circulation system, characterized by having
dielectric properties that are a function of electrical field,
generated by biological excited tissue 19. As illustrated in FIG.
2, the system 10 included a working or imaging chamber 12, a
plurality of "EM field source-detector" clusters 26, an equal
number of intermediate frequency ("IF") detector clusters 28, and a
control system (not shown). Although only two EM field
source-detector clusters 26 and two IF detector clusters 28 are
shown, a much larger number of each are actually used.
[0013] The imaging chamber 12 was a closed domain, such as a
watertight vessel, of sufficient size to accommodate a human body
or one or more parts of a human body. For example, the imaging
chamber 12 may be a helmet-like imaging chamber to image brain
disorders (for example acute and chronic stroke), ii) a cylindrical
type chamber for extremities imaging, or iii) a specifically shaped
imaging chamber for detection of breast cancer. As a result, the
imaging chamber may have different shapes and sizes.
[0014] The imaging chamber 12 and its EM field clusters 26, as well
as the IF detector clusters 28, have sometimes been mounted on
carts in order to permit the respective components to be moved if
necessary, and the carts may then be locked in place to provide
stability.
[0015] Oversimplified, the system 10 operates as follows. An object
of interest (e.g., biological tissue) is placed in the imaging
domain 21. The transmitting hardware generates electromagnetic (EM)
radiation and directs it to one of antennas. This antenna transmits
electromagnetic waves into imaging domain 21, and all of the other
antennas receive electromagnetic waves that have passed through
some portion of the imaging domain 21. The receiving hardware
detects the resulting signal(s), and then the same cycle is
repeated for the next antenna and the next one until all antennas
have served as a transmitter. As described, for example, in the
aforementioned U.S. Pat. No. 7,239,731, code-division technology
can be utilized such that the transmitting hardware generates EM
radiation and directs it to a plurality of simultaneously
transmitting antennas that are specifically coded by a unique
"antenna specific code," so that the source of the resulting EM
radiation received at a particular receiving antenna can be
"recognized" on the basis of the codes. The end result is a matrix
of complex data which is transmitted to one or more computers in
the control system that process the data to produce an image of the
object 19 in the imaging domain 21. An algorithm called an
"inversion" algorithm is utilized in this process.
[0016] FIG. 4 is a schematic illustration of a three-dimensional
setting for the system of FIG. 2.
[0017] Unfortunately, traditional EMT technologies, while producing
very useful results, have required equipment that is physically
cumbersome and difficult to use. This can be true both for the
technician, diagnostician, or the like as well as the person or
animal who is being studied. With regard to latter, the discomfort
caused by the imaging chamber can also be significant. The size and
weight of the equipment also makes it very difficult to use the
equipment in the place where it is assembled; disassembling and
moving the equipment is not very feasible. Finally, the use of
arrays of antenna and other equipment creates significant
complexity and cost. Thus, a need exists for technology that
produces similar results but in a cheaper, more convenient, and
more comfortable physical form.
[0018] Moreover, a need exists for the imaging and diagnostic
capabilities offered by EMT technologies to be available in
settings beyond the traditional clinic setting. In particular, a
need exists for EMT technologies to be available in everyday human
life, providing safe, on-demand, on-line (real time) screening and
diagnosis.
SUMMARY OF THE PRESENT INVENTION
[0019] Broadly defined, the present invention according to one
aspect is a system for wearable/man-portable electromagnetic
tomographic imaging, including: a wearable/man-portable boundary
apparatus adapted to receive a biological object within; a position
determination system; electromagnetic transmitting/receiving
hardware that collectively generates an electromagnetic field that
passes into the boundary apparatus and receives the electromagnetic
field after being scattered/interferenced by the biological object
within; and a hub computer system for performing electromagnetic
tomographic imaging based upon the generated and received
electromagnetic field and upon position information from the
position determination system.
[0020] In a feature of this aspect, the wearable/man-portable
boundary apparatus is a hollow structure whose walls include a
plurality of electromagnetic windows through which the
electromagnetic field enters and leaves.
[0021] In a further feature of this aspect, the walls of the hollow
structure define the boundaries of an imaging domain and are made
at least partly of a material that is non-transparent with respect
to the electromagnetic field generated by the electromagnetic
transmitting/receiving hardware, and wherein the plurality of
electromagnetic windows are distributed in the walls so as to
surround the imaging domain.
[0022] In another further feature of this aspect, the plurality of
electromagnetic windows have known spatial locations. In further
features, each electromagnetic window may be independently opened
and closed to control whether the electromagnetic field enters
and/or leaves therethrough; each electromagnetic window may be
independently opened and closed via a respective microgate; the
microgates are controlled such that the electromagnetic field
enters into the boundary apparatus through only one electromagnetic
window at a time; the microgates are controlled such that the
electromagnetic field enters into the boundary apparatus through a
plurality of electromagnetic windows at a time; the microgates are
controlled such that the electromagnetic field leaves the boundary
apparatus through only one electromagnetic window at a time; the
microgates are controlled such that the electromagnetic field
leaves the boundary apparatus through a plurality of
electromagnetic windows at a time; each microgate is individually
coded; and/or as the electromagnetic field enters the boundary
apparatus through an open electromagnetic window, the coding of the
microgate for the open electromagnetic window is applied to the
electromagnetic field. Knowledge of the spatial locations of the
plurality of electromagnetic windows may be determined via the
position determination system; and/or knowledge of the spatial
locations of the plurality of electromagnetic windows may be
established independently of the position determination system.
[0023] In another further feature of this aspect, the position
determination system determines information about the position of
the boundary apparatus, and the hub computer system performs
magnetic tomographic imaging based upon the received
electromagnetic field and upon the boundary apparatus position
information from the position determination system.
[0024] In another further feature of this aspect, the position
determination system determines information about the positions of
the electromagnetic windows, and the hub computer system performs
magnetic tomographic imaging based upon the received
electromagnetic field and upon the electromagnetic windows position
information from the position determination system.
[0025] In another further feature of this aspect, the position
determination system includes a first position determination system
that determines information about the position of the boundary
apparatus, the position determination system includes a second
position determination system that determines information about the
positions of the electromagnetic windows, and the hub computer
system performs magnetic tomographic imaging based upon the
received electromagnetic field and upon the boundary apparatus
position information and electromagnetic windows position
information from the position determination system.
[0026] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable hat.
[0027] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable shirt.
[0028] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable vest.
[0029] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable sleeve.
[0030] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable undergarment. In a further
feature, the wearable undergarment is a wearable bra.
[0031] In another feature of this aspect, the electromagnetic
transmitting/receiving hardware is man-portable.
[0032] In another feature of this aspect, the electromagnetic
transmitting/receiving hardware is a small cellular base
station.
[0033] In another feature of this aspect, the electromagnetic
transmitting/receiving hardware includes transmitting hardware that
is man-portable.
[0034] In another feature of this aspect, the electromagnetic
transmitting/receiving hardware includes receiving hardware that is
man-portable.
[0035] In another feature of this aspect, the electromagnetic
transmitting/receiving hardware is physically separate from the
boundary apparatus.
[0036] Broadly defined, the present invention according to another
aspect is a wearable boundary apparatus, for use in electromagnetic
tomographic imaging, including: a hollow structure having walls
defining the boundaries of an imaging domain and made at least
partially of a material that is non-transparent with respect to an
electromagnetic field generated by separate electromagnetic
transmitting/receiving hardware; a plurality of electromagnetic
windows distributed in the walls so as to surround the imaging
domain; and a plurality microgates that open and close the
electromagnetic windows so as to control whether the
electromagnetic field enters and/or leaves therethrough.
[0037] In a feature of this aspect, the wearable boundary apparatus
is adapted to receive a biological object therein for a purpose of
performing electromagnetic tomographic imaging on the object via
the electromagnetic windows and the microgates.
[0038] In a further feature of this aspect, the plurality of
electromagnetic windows have known spatial locations. In further
features, each electromagnetic window may be independently opened
and closed to control whether the electromagnetic field enters
and/or leaves therethrough; each electromagnetic window may be
independently opened and closed via a respective microgate; the
microgates may be controlled such that the electromagnetic field
enters into the boundary apparatus through only one electromagnetic
window at a time; the microgates may be controlled such that the
electromagnetic field enters into the boundary apparatus through a
plurality of electromagnetic windows at a time; the microgates may
be controlled such that the electromagnetic field leaves the
boundary apparatus through only one electromagnetic window at a
time; the microgates may be controlled such that the
electromagnetic field leaves the boundary apparatus through a
plurality of electromagnetic windows at a time; each microgate is
individually coded; and/or as the electromagnetic field enters the
boundary apparatus through an open electromagnetic window, the
coding of the microgate for the open electromagnetic window is
applied to the electromagnetic field.
[0039] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable hat.
[0040] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable shirt.
[0041] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable vest.
[0042] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable sleeve.
[0043] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable undergarment. In a further
feature, the wearable undergarment is a wearable bra.
[0044] Broadly defined, the present invention according to another
aspect is a method of electromagnetic tomographically imaging a
live human body part using a wearable boundary apparatus,
including: installing a wearable and portable boundary apparatus
such that it is worn around a body part by a live human while the
human moves from once place to another; determining position
information pertaining to the wearable boundary apparatus;
generating an electromagnetic field that passes into and out of the
wearable boundary apparatus; receiving the electromagnetic field
after being scattered/interferenced by the live human body part;
and performing electromagnetic tomographic imaging based upon the
generated and received electromagnetic field and upon the
determined position information.
[0045] In a feature of this aspect, the step of installing a
wearable and portable boundary apparatus includes installing a
wearable and portable boundary apparatus that is a hollow structure
whose walls include a plurality of electromagnetic windows through
which the electromagnetic field passes in the generating step.
[0046] In a further feature of this aspect, the walls of the hollow
structure define the boundaries of an imaging domain and are made
at least partly of a material that is non-transparent with respect
to the electromagnetic field generated by the electromagnetic
transmitting/receiving hardware, and wherein the plurality of
electromagnetic windows are distributed in the walls so as to
surround the imaging domain.
[0047] In another further feature of this aspect, the method
further includes a step of incorporating information about the
spatial location of each of the plurality of electromagnetic
windows. In further features, the method further includes a step of
independently opening or closing the electromagnetic windows to
control whether the electromagnetic field passes therethrough; the
step of independently opening or closing the electromagnetic
windows is carried out via a respective microgate for each
electromagnetic window; the step of independently opening or
closing the electromagnetic windows includes controlling the
microgates such that the electromagnetic field passes into the
boundary apparatus through only one electromagnetic window at a
time; the step of independently opening or closing the
electromagnetic windows includes controlling the microgates such
that the electromagnetic field passes into the boundary apparatus
through a plurality of electromagnetic windows at a time; the step
of independently opening or closing the electromagnetic windows
includes controlling the microgates such that the electromagnetic
field passes out of the boundary apparatus through only one
electromagnetic window at a time; the step of independently opening
or closing the electromagnetic windows includes controlling the
microgates such that the electromagnetic field passes out of the
boundary apparatus through a plurality of electromagnetic windows
at a time; each microgate is individually coded; the method further
includes a step, as the electromagnetic field enters the boundary
apparatus through an open electromagnetic window, of applying the
coding of the microgate for the open electromagnetic window to the
electromagnetic field; the method further includes a step of
determining, via the position determination system, the information
incorporated about the spatial location of each of the plurality of
electromagnetic windows; and/or the method further includes a step
of establishing, independently of the position determination
system, the information incorporated about the spatial location of
each of the plurality of electromagnetic windows.
[0048] In another further feature of this aspect, the method
further includes a step of determining, via the position
determination system, information about the position of the
boundary apparatus, and wherein the step of performing
electromagnetic tomographic imaging is performed by a hub computer
system based upon the received electromagnetic field and upon the
boundary apparatus position information from the position
determination system.
[0049] In another further feature of this aspect, the method
further includes a step of determining, via the position
determination system, information about the positions of the
electromagnetic windows, and wherein the step of performing
electromagnetic tomographic imaging is performed by a hub computer
system based upon the received electromagnetic field and upon the
electromagnetic windows position information from the position
determination system.
[0050] In another further feature of this aspect, the step of
determining position information pertaining to the wearable
boundary apparatus includes determining information, via a first
position determination system, about the position of the boundary
apparatus, the step of determining position information pertaining
to the wearable boundary apparatus further includes determining
information, via a second position determination system, about the
positions of the electromagnetic windows, and the step of
performing electromagnetic tomographic imaging is performed by a
hub computer system based upon the received electromagnetic field
and upon the boundary apparatus position information and
electromagnetic windows position information from the position
determination system.
[0051] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable hat, and wherein the step of
installing a wearable and portable boundary apparatus includes
wearing the hat on the head of the live human.
[0052] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable shirt, and wherein the step
of installing a wearable and portable boundary apparatus includes
wearing the shirt on the torso of the live human.
[0053] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable vest, and wherein the step
of installing a wearable and portable boundary apparatus includes
wearing the vest on the torso of the live human.
[0054] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable sleeve, and wherein the step
of installing a wearable and portable boundary apparatus includes
wearing the shirt on an arm of the live human.
[0055] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable undergarment. In a further
feature, the wearable undergarment is a wearable bra, and wherein
the step of installing a wearable and portable boundary apparatus
includes wearing the bra around the breasts of the live human.
[0056] In another feature of this aspect, the steps of generating
and receiving the electromagnetic field are carried out by
electromagnetic transmitting/receiving hardware, and wherein the
electromagnetic transmitting/receiving hardware is
man-portable.
[0057] In another feature of this aspect, the steps of generating
and receiving the electromagnetic field are carried out by
electromagnetic transmitting/receiving hardware, and wherein the
electromagnetic transmitting/receiving hardware is a small cellular
base station.
[0058] In another feature of this aspect, the steps of generating
and receiving the electromagnetic field are carried out by
electromagnetic transmitting/receiving hardware, and wherein the
electromagnetic transmitting/receiving hardware includes
transmitting hardware that is man-portable.
[0059] In another feature of this aspect, the steps of generating
and receiving the electromagnetic field are carried out by
electromagnetic transmitting/receiving hardware, and wherein the
electromagnetic transmitting/receiving hardware includes receiving
hardware that is man-portable.
[0060] In another feature of this aspect, the steps of generating
and receiving the electromagnetic field are carried out by
electromagnetic transmitting/receiving hardware, and wherein the
electromagnetic transmitting/receiving hardware is physically
separate from the boundary apparatus.
[0061] In another feature of this aspect, the step of performing
electromagnetic tomographic imaging is carried out by a hub
computer system.
[0062] Broadly defined, the present invention according to another
aspect is a method of electromagnetic tomographically imaging a
biological object using a boundary apparatus, including: providing
a boundary apparatus comprising a hollow structure, wherein the
hollow structure includes walls defining the boundaries of an
imaging domain, is made at least partially of a material that is
non-transparent with respect to an electromagnetic field generated
by electromagnetic transmitting/receiving hardware, and has a
plurality of electromagnetic windows distributed in the walls so as
to surround the imaging domain; opening one or more of the
plurality of electromagnetic windows so as to control whether an
electromagnetic field can enter and/or leave therethrough;
generating an electromagnetic field that passes into the wearable
boundary apparatus through the opened electromagnetic windows;
receiving the electromagnetic field after being
scattered/interferenced by the biological object; and performing
electromagnetic tomographic imaging based upon the generated and
received electromagnetic field.
[0063] In a feature of this aspect, the wearable boundary apparatus
is adapted to receive a biological object therein for a purpose of
performing the electromagnetic tomographic imaging step.
[0064] In a further feature of this aspect, the method further
includes a step of incorporating information about the spatial
location of each of the plurality of electromagnetic windows. In
further features, the method further includes a step of
independently opening or closing the electromagnetic windows to
control whether the electromagnetic field passes therethrough; the
step of independently opening or closing the electromagnetic
windows includes controlling the microgates such that the
electromagnetic field enters into the boundary apparatus through
only one electromagnetic window at a time; the step of
independently opening or closing the electromagnetic windows
includes controlling the microgates such that the electromagnetic
field enters into the boundary apparatus through only one
electromagnetic window at a time; the step of independently opening
or closing the electromagnetic windows includes controlling the
microgates such that the electromagnetic field enters into the
boundary apparatus through a plurality of electromagnetic windows
at a time; the step of independently opening or closing the
electromagnetic windows includes controlling the microgates such
that the electromagnetic field passes out of the boundary apparatus
through only one electromagnetic window at a time; the step of
independently opening or closing the electromagnetic windows
includes controlling the microgates such that the electromagnetic
field passes out of the boundary apparatus through a plurality of
electromagnetic windows at a time; each microgate is individually
coded; and/or the method further includes a step, as the
electromagnetic field enters the boundary apparatus through an open
electromagnetic window, of applying the coding of the microgate for
the open electromagnetic window to the electromagnetic field.
[0065] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable hat, and wherein the step of
installing a wearable and portable boundary apparatus includes
wearing the hat on the head of the live human.
[0066] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable shirt, and wherein the step
of installing a wearable and portable boundary apparatus includes
wearing the shirt on the torso of the live human.
[0067] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable vest, and wherein the step
of installing a wearable and portable boundary apparatus includes
wearing the vest on the torso of the live human.
[0068] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable sleeve, and wherein the step
of installing a wearable and portable boundary apparatus includes
wearing the shirt on an arm of the live human.
[0069] In another further feature of this aspect, the boundary
apparatus is in the form of a wearable undergarment. In a further
feature, the wearable undergarment is a wearable bra, and wherein
the step of installing a wearable and portable boundary apparatus
includes wearing the bra around the breasts of the live human.
[0070] Broadly defined, the present invention according to another
aspect is a system for wearable/man-portable electromagnetic
tomographic imaging that includes a wearable/man-portable boundary
apparatus adapted to receive a biological object within, a position
determination system, electromagnetic transmitting/receiving
hardware, and a hub computer system. The electromagnetic
transmitting/receiving hardware collectively generates an
electromagnetic field that passes into the boundary apparatus and
receives the electromagnetic field after being
scattered/interferenced by the biological object within. The hub
computer system for performs electromagnetic tomographic imaging
based on the received electromagnetic field.
[0071] In features of this aspect, the wearable/man-portable
boundary apparatus is a hollow structure whose walls include a
plurality of electromagnetic holes through which the
electromagnetic field enters and leaves; the plurality of
electromagnetic holes have known spatial locations; and/or each
electromagnetic hole may be independently opened and closed via a
respective microgate.
[0072] In other features of this aspect, the microgates are
controlled such that the electromagnetic field enters passes into
the boundary apparatus through only one electromagnetic hole at a
time; each microgate is individually coded; the boundary apparatus
is in the form of a wearable hat; the boundary apparatus is in the
form of a wearable shirt; the boundary apparatus is in the form of
a wearable vest; the boundary apparatus is in the form of a
wearable sleeve; and/or the boundary apparatus is in the form of a
wearable bra.
[0073] In still other features of this aspect, the electromagnetic
transmitting/receiving hardware is man-portable; and/or the
electromagnetic transmitting/receiving hardware is a small cellular
base station.
[0074] Broadly defined, the present invention according to another
aspect includes a system for wearable/man-portable electromagnetic
tomographic imaging as shown and described.
[0075] Broadly defined, the present invention according to still
another aspect includes a wearable boundary apparatus for use in
electromagnetic tomographic imaging, as shown and described.
[0076] Broadly defined, the present invention according to still
another aspect includes a method of wearable/man-portable
electromagnetic tomographic imaging as shown and described.
[0077] Further areas of applicability of the present invention will
become apparent from the detailed description provided hereinafter.
It should be understood that the detailed description and specific
examples, while indicating the preferred embodiment of the
invention, are intended for purposes of illustration only and are
not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0078] Further features, embodiments, and advantages of the present
invention will become apparent from the following detailed
description with reference to the drawings, wherein:
[0079] FIG. 1 is a graphical illustration of the principle of
electromagnetic tomography (EMT);
[0080] FIG. 2 is a schematic view of a prior art EM field
tomographic spectroscopic system;
[0081] FIG. 3 is a schematic diagram illustrating the operation of
the system of FIG. 1 in a two-dimensional context;
[0082] FIG. 4 is a schematic illustration of a three-dimensional
setting for the system of FIG. 2;
[0083] FIG. 5 is a block diagram of a system for
wearable/man-portable electromagnetic tomographic imaging in
accordance with a preferred embodiment of the present
invention;
[0084] FIG. 6 is a schematic diagram illustrating the operation of
the system of FIG. 5 in a two-dimensional context;
[0085] FIG. 7 is a side perspective view of a cap serving as
wearable boundary apparatus in accordance with one or more
preferred embodiments of the present invention;
[0086] FIGS. 8A and 8B are graphical illustrations of exemplary
codes for gates of the boundary apparatus of FIG. 6;
[0087] FIG. 9A is a block diagram illustrating use of the EMWindows
coding concept;
[0088] FIG. 9B is a block diagram illustrating use of EMWindows
frequency shift keying;
[0089] FIG. 10 is a block diagram illustrating use of EMWindows
coding together with frequency conversion;
[0090] FIG. 11 is a flow diagram illustrating the operation of the
hub computer system of FIG. 5;
[0091] FIG. 12A is a flow diagram of an exemplary direct problem
solver method for optional use in an image reconstruction
process;
[0092] FIG. 12B is a flow diagram of an exemplary inverse problem
solver method for optional use in an image reconstruction
process;
[0093] FIG. 12C is a flow diagram of an exemplary gradient
calculation method for optional use in an image reconstruction
process;
[0094] FIG. 13 is a pictorial illustration of a timeline for use of
an EMT system, including the cap of FIG. 7, for imaging a human
head in response to the onset of stroke symptoms in a patient;
and
[0095] FIG. 14 is a schematic diagram illustrating the use of the
system and methods of FIGS. 5-12C in an exemplary 4D EMT
differential (dynamic) fused imaging system.
DETAILED DESCRIPTION
[0096] As a preliminary matter, it will readily be understood by
one having ordinary skill in the relevant art ("Ordinary Artisan")
that the present invention has broad utility and application.
Furthermore, any embodiment discussed and identified as being
"preferred" is considered to be part of a best mode contemplated
for carrying out the present invention. Other embodiments also may
be discussed for additional illustrative purposes in providing a
full and enabling disclosure of the present invention. As should be
understood, any embodiment may incorporate only one or a plurality
of the above-disclosed aspects of the invention and may further
incorporate only one or a plurality of the above-disclosed
features. Moreover, many embodiments, such as adaptations,
variations, modifications, and equivalent arrangements, will be
implicitly disclosed by the embodiments described herein and fall
within the scope of the present invention.
[0097] Accordingly, while the present invention is described herein
in detail in relation to one or more embodiments, it is to be
understood that this disclosure is illustrative and exemplary of
the present invention, and is made merely for the purposes of
providing a full and enabling disclosure of the present invention.
The detailed disclosure herein of one or more embodiments is not
intended, nor is to be construed, to limit the scope of patent
protection afforded the present invention, which scope is to be
defined by the claims and the equivalents thereof. It is not
intended that the scope of patent protection afforded the present
invention be defined by reading into any claim a limitation found
herein that does not explicitly appear in the claim itself.
[0098] Thus, for example, any sequence(s) and/or temporal order of
steps of various processes or methods that are described herein are
illustrative and not restrictive. Accordingly, it should be
understood that, although steps of various processes or methods may
be shown and described as being in a sequence or temporal order,
the steps of any such processes or methods are not limited to being
carried out in any particular sequence or order, absent an
indication otherwise. Indeed, the steps in such processes or
methods generally may be carried out in various different sequences
and orders while still falling within the scope of the present
invention. Accordingly, it is intended that the scope of patent
protection afforded the present invention is to be defined by the
appended claims rather than the description set forth herein.
[0099] Additionally, it is important to note that each term used
herein refers to that which the Ordinary Artisan would understand
such term to mean based on the contextual use of such term herein.
To the extent that the meaning of a term used herein--as understood
by the Ordinary Artisan based on the contextual use of such
term--differs in any way from any particular dictionary definition
of such term, it is intended that the meaning of the term as
understood by the Ordinary Artisan should prevail.
[0100] Regarding applicability of 35 U.S.C. .sctn.112, 6, no claim
element is intended to be read in accordance with this statutory
provision unless the explicit phrase "means for" or "step for" is
actually used in such claim element, whereupon this statutory
provision is intended to apply in the interpretation of such claim
element.
[0101] Furthermore, it is important to note that, as used herein,
"a" and "an" each generally denotes "at least one," but does not
exclude a plurality unless the contextual use dictates otherwise.
Thus, reference to "a picnic basket having an apple" describes "a
picnic basket having at least one apple" as well as "a picnic
basket having apples." In contrast, reference to "a picnic basket
having a single apple" describes "a picnic basket having only one
apple."
[0102] When used herein to join a list of items, "or" denotes "at
least one of the items," but does not exclude a plurality of items
of the list. Thus, reference to "a picnic basket having cheese or
crackers" describes "a picnic basket having cheese without
crackers," "a picnic basket having crackers without cheese," and "a
picnic basket having both cheese and crackers." Finally, when used
herein to join a list of items, "and" denotes "all of the items of
the list." Thus, reference to "a picnic basket having cheese and
crackers" describes "a picnic basket having cheese, wherein the
picnic basket further has crackers," as well as describes "a picnic
basket having crackers, wherein the picnic basket further has
cheese."
[0103] Referring now to the drawings, in which like numerals
represent like components throughout the several views, the
preferred embodiments of the present invention are next described.
The following description of one or more preferred embodiment(s) is
merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses.
[0104] FIG. 5 is a block diagram of a system 110 for
wearable/man-portable electromagnetic tomographic imaging in
accordance with a preferred embodiment of the present invention.
The system 110 includes a boundary apparatus 112, a position
determination system 180, transmitting/receiving hardware 126,
which includes a transmitter and a receiver, and a hub computer
system 128. Each of these will be described in greater detail
hereinbelow.
[0105] FIG. 6 is a schematic diagram illustrating the operation of
the boundary apparatus 112 and transmitting/receiving hardware 126
of FIG. 5 in a two-dimensional context. Unlike prior art systems,
the transmitting/receiving hardware 126 is not physically connected
with the imaging domain 21. In at least some embodiments, the
transmitting/receiving hardware 126 is man-portable. As used
herein, "man-portable" means capable of being carried or borne by
one human. In some embodiments, the transmitting/receiving hardware
126 may be provided in the form of a small cellular base station or
"small cell," such as, for example, a femtocell unit. In some
embodiments, the transmitter and the receiver are separate devices,
while in others the transmitter and receiver are combined in a
single unit.
[0106] The boundary apparatus 112 is a man-portable hollow
structure whose walls are made of material or materials that is or
are non-transparent (opaque) with respect to EM waves and thereby
defines the boundaries of the imaging domain 21 for the system 110.
The boundary apparatus 112 itself may take any of a variety of
shapes, forms and the like. In at least some embodiments, the
boundary apparatus 112 is in the form of a garment or other
wearable object. For example, the apparatus 112 may be a
specially-designed shirt, vest, sleeve, bra or other undergarment,
cap, or the like. In this regard, FIG. 7 is a side perspective view
of a cap serving as wearable boundary apparatus 112 in accordance
with one or more preferred embodiments of the present
invention.
[0107] Regardless of its form, the walls of the boundary apparatus
112 include a pattern of N EM-controlled "transparent" holes or
windows 148 (i.e., entry/exit points) distributed so as to surround
the imaging domain 21. In some embodiments, the pattern of holes or
windows 148 may be a repeating pattern. In other embodiments, the
pattern of holes or windows 148 may be a non-repeating pattern. The
condition ("open" or "closed") of each entry/exit hole or window
148 may be controlled by a microchip device 132. In at least some
embodiments, the open or closed condition of each entry/exit hole
or window 148 is individually coded. The combination of the
entry/exit holes or windows 148 with their microchip devices 132
are sometimes referred to herein as "EMWindows" 150. In operation,
the boundary apparatus 112 is placed around the object under study
19, or the object 19 is placed within the boundary apparatus 112,
and the system 110 is activated. During operation of the system 10,
the transmitter of the transmitting/receiving hardware 126 is used
to generate an EM field that passes through one or more of the
entry points 148 and into the imaging domain 21. After interacting
with the object 19 of interest, each "interferenced" or scattered
EM interrogation field (E.sub.set) passes through one or more of
the exit points 148, where it is then received at the
transmitting/receiving hardware 126. By determining the radiation
component corresponding to the traversal from each entry point
(hole_i, where 0<i.ltoreq.N) to each exit point (hole_j, where
0<j.ltoreq.N) and incorporating location information about the
respective entry and exit points 148, as described below, an
accurate image of the object 19 within the imaging domain 21 may be
determined and reconstructed.
[0108] In order to facilitate the use of the interferenced or
scattered EM interrogation field (E.sub.set) information to
properly determine a 2D or 3D spatial distribution of dielectric
properties within the object 19, and to thereby reconstruct a 2D or
3D image of the object 19, the microchip devices 132 may be used to
control operational aspects of the EMWindows 150. In at least some
embodiments, each EMWindow 150 includes a "smart" gate, sometimes
referred to as a "microswitch" or "microgate," that may be used by
the microchip devices 132 to open or close the entry/exit points.
The gates may include the use of PIN diodes. Using these gates, the
number of entry and exit holes windows 148 that are open or active
at any one time may be varied. In particular, the specific entry
and exit holes or windows 148 that are open and closed at any given
time may be controlled or determined using control technology, as
generally described below, and this information may be coordinated
with corresponding measurements of E.sub.set.
[0109] In at least some of these embodiments, determining the
radiation for each unique entry/exit hole pair (i,j) may be
achieved by coding the corresponding gates and then applying the
coding to the electromagnetic (EM) radiation/waves/field. This may
be accomplished, for example, using code-division technology; such
technology is described, for example, in the aforementioned U.S.
Pat. No. 7,239,731. FIGS. 8A and 8B are graphical illustrations of
exemplary codes for gates I and J of the boundary apparatus of FIG.
6, and FIG. 9A is a block diagram illustrating use of the EMWindows
coding concept. As shown in FIG. 9A, the transmitter of the
transmitting/receiving hardware 126 generates electromagnetic (EM)
radiation/waves/field, represented by complex signal E. As the EM
waves enter into the imaging domain 21 through one of the
NEMWindows (EMWindow_i) 150, the signal E is coded as E(Ci). The
coded signal E(Ci) passes through the imaging domain 21,
interacting with the tissue at a multitude of spatial points
(x,y,z) and thereby acquiring information about the spatial
distribution of dielectric properties of the tissue .di-elect
cons.(x,y,z) to produce E(Ci, .di-elect cons.(x,y,z)). The EM waves
then exit the imaging domain 21 through any EMWindow (EMWindow_j)
150 (which could even be the window EMWindow_j through which it
entered, although this information may be of little benefit) where
the signal is coded again to produce E(Ci, .di-elect cons.(x,y,z),
Cj). When finally received by the receiving hardware, the EM
radiation has thus been coded with the unique signatures of the
particular entry/exit pair. Decoding the signatures allows a matrix
of complex raw data to be recovered in relation to the particular
entry/exit hole pair (i,j). This data is further combined with
information regarding the spatial location of i and j (such
information being determined, for example, at the EMWindow position
block 310 of FIG. 11, described below). Together, this data set
(i.e., the complex matrix of raw data combined with spatial
locations of "virtual transmitters" or "transmitting windows"
(EMWindow_i in this example) and "virtual receivers" or "receiving
windows" (EMWindow_j in this example)) is analogous to the data set
generated and processed in previous EMT systems (i.e., the complex
matrix of raw data combined with spatial locations of actual
transmitters and windows). The data set is transmitted to one or
more computers in the hub computer system 128 that process the data
to produce an image of the object 19 in the imaging domain 21. As
with prior art systems, an algorithm called an "inversion"
algorithm is utilized in this process.
[0110] Additionally or alternatively to the use of gate
"open/close" coding, in at least some embodiments, determining the
radiation for each unique entry/exit hole pair (i,j) may be
achieved through the use of frequency shifting using
frequency-shift keying (FSK) or the like. FIG. 9B is a block
diagram illustrating use of EMWindows frequency shift keying. As
shown therein, a frequency shift is applied at each EM entry
opening (EMWindow_i), to shift the frequency by some amount
.DELTA.Freq_i, and at each EM exit opening (EMWindow_j) to shift
the frequency by some amount .DELTA.Freq_j.
[0111] In some embodiments, entry and exit holes or windows 148 are
opened one at a time, such that only one entry hole or window 148
and one exit hole or window 148 are open during any given
measurement. In other embodiments, more than one entry hole or
window 148 is open during at least some of the measurements, more
than one exit hole or window 148 is open during at least some of
the measurements, or both. In some of these embodiments, all of the
holes or windows 148 are open during at least some or all of the
measurements.
[0112] If the specific EMWindows 150 that are open at the time of
each E.sub.set measurement are known, and the positions of the open
holes or windows 148 at the time of such measurements are known,
then the measurements may be used to derive an accurate image of
the object 19 within the imaging domain 21. With regard to the
positions of the open holes or windows 148, the locations of the
holes or windows 148 must either be known ahead of time or must be
determinable at the time of measurement. In some embodiments, the
boundary apparatus 112 is a generally rigid structure, and the
locations of the holes or windows 148 are fixed, relative to each
other, by the rigid nature of the boundary apparatus 112. In other
embodiments, the boundary apparatus 112 is a flexible structure,
and the locations of the holes or windows 148 are not fixed
relative to each other and thus must be determined. In either case,
because the boundary apparatus 112 is preferably man-portable, and
in many embodiments may be frequently moved from place to place, it
may be useful to determine the location of the boundary apparatus
112 and to determine the locations of the holes or windows 148
based on their location relative to the boundary apparatus 112.
Determining the location of the boundary apparatus 112 and/or the
locations of the holes or windows 148 is described in greater
detail hereinbelow.
Power Considerations
[0113] Consideration must be given to the power requirements of the
transmitting/receiving hardware 126. In an exemplary embodiment,
the transmitter provides irradiating power on the biological object
through the EMWindows 150 in an amount similar to that produced by
a conventional mobile phone. Using current technology, a maximal
such power level may be between +33 dBm (2 W) and +36 dBm (4 W),
which represents the approved power level for maximum output from a
GSM850/900 mobile phone (+33 dBm) and for maximum output from a
UMTS/3G mobile phone (power class 1 mobile).
[0114] Assuming the attenuation at the EMWindows varies from 0 to
20 dB, the attenuation within the biological object (which may be a
complete organism, but more likely is merely a part of an organism,
such as a human arm or leg) is expected to be within -60 dB to -100
dB. This leads to a power level, after passing through a biological
object, of from -24 dBm to -87 dBm. Furthermore, assuming that the
signal is attenuated approximately 20 dBm to 30 dBm when it passes
from the object to the receiver, the estimated level of the signal
on Rx (without any amplification by the boundary apparatus 112) is
within a range of -44 dBm to -117 dBm.
[0115] By way of comparison, the typical power level of
wirelessly-received signals received wirelessly over variants of
802.11 networks, using commercial devices, is within -60 dBm to -80
dBm. The typical received signal power from a GPS satellite is -127
dBm, and the thermal noise floor for 1 Hz bandwidth at room
temperature is -174 dBm.
[0116] Because the estimated minimal level of the signal is about
-117 dBm and the estimated dynamic range for a static position of
the object is about 53 dB, the level of the signal and dynamic
range are believed to be within performance characteristics of
modern telecommunication technologies and may not require any
amplification of the signals at the boundary apparatus 112.
However, if amplification is desired or preferred, it may be
included in or on the microchip device 132. For example, small
low-noise amplifiers (LNAs) are readily available commercially. A
series of amplifiers suitable for use in preferred embodiments of
the present invention is the MAX2686/MAX2688 low-noise amplifier,
designed for GPS L1, Galileo, and GLONASS applications and having
dimensions 0.86 mm.times.0.86 mm.times.0.65 mm, available from
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, Calif.
94086.
Frequency Considerations
[0117] Signal interference or parasitic cross coupling between
EMWindows 150 can occur both inside the boundary apparatus 112 and
outside.
[0118] Inside the boundary apparatus 112, direct, mutual coupling
or interference may occur between EMWindows 150. More particularly,
the signal E or E(Ci) entering the imaging domain 21 may, in at
least some situations, pass around (rather than through) the body
of interest 19 and thus interfere with the signal of interest,
i.e., the signal E(.di-elect cons.(x,y,z)) or E(Ci,.di-elect
cons.(x,y,z)) that passes through the body of interest 19. In at
least some embodiments, this may be addressed using a
"matching/decoupling" media (not shown). Such a media may decouple
direct, mutual interference caused by a signal E or E(Ci) passing
around the body of interest 19. One example of such a media is a
gel with a high concentration of salt.
[0119] Outside the boundary apparatus 112, the signal E being
transmitted by the transmitting hardware may, in at least some
situations, be powerful and parasitic relative to the signal
E(.di-elect cons.(x,y,z)) or E(Ci,.di-elect cons.(x,y,z)) that
passes through the imaging domain 21, and thus may interfere with
reception thereof by the receiving hardware. Thus, in at least some
embodiments, a frequency converter may be utilized at each of the
entry EMWindows 150 to create separation between the transmitter
frequency and the receiver frequency, thereby avoiding interference
with the transmitter signal. For example, a transmitter signal at a
frequency of 0.5 GHz may be passed through a frequency doubler to
produce an interrogation signal at a frequency of 1.0 GHz. The EM
radiation thus passes through the imaging domain 21 at the
interrogation frequency and likewise through one or more EMWindows
150 before being received at that frequency as well.
[0120] Frequency conversion may be used in conjunction with gate
coding described previously. FIG. 10 is a block diagram
illustrating use of EMWindows coding together with frequency
conversion. As with the EMWindows coding shown in FIG. 9A, the
transmitter of the transmitting/receiving hardware 126 generates
electromagnetic (EM) radiation/waves/field, represented by complex
signal E. The transmission frequency is designated as Freq_Tx. As
the EM waves enter into the imaging domain 21 through one of the
EMWindows (EMWindow_i) 150, the signal E is coded as E(Ci), and the
frequency is shifted by some amount .DELTA.Freq_i. The coded signal
E(Ci) passes through the imaging domain 21, interacting with the
tissue at a multitude of spatial points (x,y,z) and thereby
acquiring information about spatial distribution of dielectric
properties of the tissue .di-elect cons.(x,y,z) to produce E(Ci,
.di-elect cons.(x,y,z)), at frequency Freq_Tx+.DELTA.Freq_i. The EM
waves then exit the imaging domain 21 through another EMWindow
(EMWindow_j) 150, where the signal is coded again to produce E(Ci,
.di-elect cons.(x,y,z), Cj). When finally received by the receiving
hardware, still at frequency Freq_Tx+.DELTA.Freq_i, the EM
radiation has thus been coded with the unique signatures of the
particular entry/exit pair but has also been shifted in frequency
by the amount .DELTA.Freq_i.
[0121] In one example, the transmission frequency (Freq_Tx) is 0.5
GHz, and a frequency shift is applied at each EM entry point
(EMWindow_i) to shift the imaging frequency (Freq_imaging) upward
to 1 GHz. In this regard, it will be appreciated that the frequency
may be shifted higher, at least up to 2.5 GHz.
[0122] It will also be appreciated that, in accordance with the
reciprocity principal:
{right arrow over (E)}(Ci,.di-elect cons.(x,y,z),Cj)={right arrow
over (E)}(Cj,.di-elect cons.(x,y,z),Ci)
Therefore, the uniqueness of the coding of each EMWindows pair
(Ci,Cj) is independent from the way the EM wave enters the imaging
domain 21 assuming the "absolute" similarity of EM and geometrical
properties of windows and that plane EM wave is irradiating the
object.
[0123] The frequency converter may be active or passive. One
passive, commercially available frequency doubler suitable for use
in the present invention is the miniature Hittite HMC156AC8. Others
may likewise be available, and it will be appreciated that the
frequency converter may be any suitable frequency multiplier,
up-converter, down-converter, or the like.
[0124] Other interference issues may exist outside the boundary
apparatus 112 as well. In some embodiments, the transmitting
hardware may be able to transmit at multiple transmission
frequencies. In at least some of these embodiments, a user may
select or adjust the transmission frequency so as to avoid
interference with other signals that may be present. Similarly, in
some embodiments, multiple frequency converters, or frequency
converters capable of shifting by a variety of different amounts,
may be provided, and in at least some of these embodiments, a user
may select or adjust the amount of shift so as to avoid
interference.
Boundary Apparatus
[0125] In order to determine the data properly and to properly
reconstruct an image, it is important to be able to know or
determine the position of the boundary apparatus 112 accurately,
and ultimately, to be able to know or determine the position of the
entry and exit holes or windows 148 accurately. In at least some
embodiments, the position of the boundary apparatus 112 within a
given operational domain, such as a room, may be determined, and
the positions of the entry and exit holes or windows 148 on or in
the boundary apparatus 112 are applied thereto in order to
determine the position of the entry and exit holes or windows 148
within the operational domain. Additionally or alternatively, the
position of the boundary apparatus 112 relative to the
transmitting/receiving hardware 126 may be determined, and the
positions of the entry and exit holes or windows 148 on or in the
boundary apparatus 112 are applied thereto in order to determine
the position of the entry and exit holes or windows 148 relative to
the transmitting/receiving hardware 126.
[0126] The position determination system 180 may be utilized to
determine the exact position of the apparatus 112. In this regard,
the position determination system 180 may use processes and
technology akin to those employed by GPS systems but in a localized
setting, with the positional data being directly available, either
online or otherwise. The spatial accuracy necessary to produce
meaningful results can vary significantly, with significant
correlation between the spatial accuracy and the accuracy of the
resulting data and image. Table 1 illustrates the required spatial
accuracy for the position of the boundary apparatus 112 for several
different exemplary transmitting frequencies.
TABLE-US-00001 TABLE 1 10 deg accuracy 1 deg accuracy Frequency
[GHz] .lamda. air[cm] [mm] [mm] 0.5 60 17 1.7 1 30 8 0.8 2.5 12 3
0.3
[0127] Similarly, data and image accuracy is also affected by the
accuracy of information about the shape and dimensions of the EM
holes or windows 148. Table 2 illustrates the accuracy for the
shape and location of the EM holes or windows 148 relative to the
boundary apparatus 112 for different exemplary transmitting
frequencies.
TABLE-US-00002 TABLE 2 .lamda. muscle or Frequency myocardial 10
deg accuracy 1 deg accuracy [GHz] .lamda. air[cm] tissues[cm] [mm]
[mm] 1 30 3.8 1 0.1 2.5 12 1.6 0.4 0.04
[0128] The complexity of the problem of accuracy with regard to
information about the positions of the entry and exit holes or
windows 148 depends, at least in part, on the type of boundary
apparatus 112 utilized. For example, the boundary apparatus 112 may
be deformable or non-deformable. Examples of non-deformable
apparatuses may include a helmet, a sleeve, a bra, a waistcoat, or
the like. Notably, non-deformable apparatuses are not necessarily
inflexible, but are generally non-elastic. One advantage of
non-deformable boundary apparatuses 112 is that the exact 3D
location of each EM hole or window 148, relative to the boundary
apparatus 112 as a whole, is known ahead of time. However, a
non-deformable boundary apparatus 112 may require a larger or
thicker "matching/de-coupling" layer.
[0129] Examples of deformable boundary apparatuses may include a
cap, an "elastic" sleeve, an "elastic" bra, an "elastic" waistcoat,
or the like. In contrast to non-deformable apparatuses, deformable
boundary apparatuses 112 may advantageously require a smaller or
thinner "de-coupling" layer. (Notably, in at least some embodiment,
a decoupling layer is utilized even when there is a perfect fit of
the boundary apparatus 112 to the biological object of interest,
because as stated previously, a significant function of a
"de-coupling" media is to decouple direct (around the body 19)
mutual interference between EMWindows 150 inside the boundary
apparatus 112.) Another advantage is that deformable boundary
apparatuses 112 may be worn more comfortably, thereby perhaps
better enabling the wearer to work, run, sleep and the like while
wearing them. On the other hand, a major disadvantage of deformable
boundary apparatuses 112 is that the exact 3D location of each of
the EM holes or windows 148, relative to the boundary apparatus 112
as a whole, is not known and has to be located/positioned every
time measurements are conducted.
[0130] In one approach that may be particularly useful with regard
to deformable boundary apparatuses, and may have applicability with
non-deformable boundary apparatuses as well, a process of
determining EM opening spatial information may be carried out in
two stages. First, the exact 3D location for each of the EM holes
or windows 148 of the boundary apparatus 112 is determined for a
theoretical state wherein the boundary apparatus 112 is in place on
or around a "standard" sized object 19. This data is stored in
memory in the system 110. Once the boundary apparatus 112 is on a
real object 19, the actual locations of the EM holes or windows 148
will vary slightly from the theoretical, "standard" locations, but
the theoretical locations may be used as a starting point for
subsequent spatial fine-tuning, thereby enhancing and accelerating
the process considerably. Spatial fine tuning is preferably within
a 3D area of the size of an EM hole or window 148. The position
determination system 180 may utilize a localized (e.g., in-room)
GPS-type system, a honeycomb algorithm wherein once the position of
one cell is determined the position of cells next to it can be
determined, or any other suitable system or approach.
[0131] Software may be used for fast determination of 3D (x,y,z)
position as well as phase-shift correction for the path
EMWindow_i-to-receiver and amplitude and phase correction at the
entry EMWindows 150 when frequency is changed. In at least some
embodiments, it is assumed that amplitude is similar for all
EMWindow_i's (i=1 . . . N).
Processing of the Data
[0132] The hub computer system 128 (sometimes referred to as the
"hub") is the processing center where initial data is pre-processed
and images are reconstructed and post-processed. In at least some
embodiments, all data processing and imaging software is located in
the hub computer system 128 and is controlled by a single entity
for commercial, research or other purposes.
[0133] Data may be transferred from the transmitting/receiving
hardware 126 to the hub computer system 128 in a variety of ways.
In various embodiments, the data may be transferred through one or
more conventional technologies, including mobile phone
communication technology, other wireless communication technology
(e.g., Wi-Fi), and/or high speed wired connections.
[0134] In at least one embodiment, data is processed directly in
the transmitter/receiver hardware 126 or a device communicatively
connected directly thereto. If the transmitter/receiver hardware
126 or other device includes a display, it may be possible to
prepare and present an image directly on the device without use of
a hub computer system. However, the processing resources of such
devices may not be sufficient to produce an image quickly or
accurately enough to achieve the desired usefulness. Additionally,
because central control is not effectuated in such an arrangement,
such an arrangement may be disadvantageous from a commercial
perspective and/or for other reasons. Thus, if the
transmitter/receiver hardware 126 or other device is to be utilized
to display an image to a user or to a patient, it may be preferable
to send data to the hub control system 128, reconstruct the image
at the hub as described below, and then send the image back if
needed. The hub 128 provides the desired efficiency, accuracy and
control to overcome the foregoing shortcomings.
Image Reconstruction at the Hub Computer System
[0135] FIG. 11 is a flow diagram illustrating the operation of the
hub computer system 128 of FIG. 5 in accordance with one or more
preferred embodiments of the present invention. As shown therein,
input parameters, including frequency and permittivity (E) of the
coupling media, are provided to an EMWindow electromagnetic model
that is developed at block 305. The EMWindow model is further
provided with the position of the opening of each EMWindow (n=1 . .
. N) (EMW.sub.n(x,y,z)) within the boundary apparatus 112, which in
FIG. 11 is referred to as the "boundary of imaging domain" ("BID").
This information is developed at block 310. For a non-deformable
boundary apparatus, the initial EMWindow positions
(EMW_init.sub.n(i,x,y,z)), shown at block 315 may be sufficient,
but for a deformable boundary apparatus position correction, shown
at block 320, may need to be applied as described above. The
EMWindow model also incorporates the position of the boundary
apparatus 112 itself (BID(x,y,z)) within a global domain as
developed at block 325.
[0136] The EMWindow position information, the EMWindow
electromagnetic model, and the other input parameters are all used
in a process at block 330 of calculating an "empty" field
E_empty(i,j) (i.e., the field when the imaging domain 21 is empty)
for each particular pair (i,j) of EMWindows (where i and j are each
selected from the N total windows). Meanwhile, corrections are
developed for EM field transforms at block 335, including
transforms for both transmitter-to-boundary apparatus (BID) and
boundary apparatus-to-receiver, using the relative EMWindow
position information and the absolute BID position information
developed at blocks 310 and 325.
[0137] The flow of raw measured complex EM data into the processing
unit is shown at block 340, with keying for each pair of EMWindows
occurring at block 345. Calculation of scattered experimental
fields in the imaging domain 21 for each pair of EMWindows i,j
(E_sct_exp(i,j)) occurs at block 350 and utilizes the calculated
"empty" field data (E_empty(i,j)) from block 330 and corrections
from block 335. The calculated data is provided to an iterative
inverse problem solver, shown at block 355. The inverse problem
solver works in conjunction with a direct problem solver, shown at
block 360, that in turn utilizes EMWindow positional information
from block 310 to produce a resulting for each point (x,y,z). A
convergence check is performed at block 365 after each iteration of
the inverse problem solver and the direct problem solver is
utilized to improve the results until convergence conditions are
reached, at which point the results are finalized at block 370 for
use in forming an EM image of the object of interest.
[0138] In part, the operation of the hub computer system 128 may
rely on a process or processes previously described in U.S. Pat.
No. 7,239,731 to solve an inverse problem of electromagnetic field
tomography. The solver might be or include, for example, a
non-simplified three-dimensional ("3D") vector solver using
Maxwell's equations or a simplified 3D scalar solver or a further
simplified 2D scalar solver. FIGS. 12A, 12B and 12C are flowcharts
of such optional processes. Use is made of an iterative procedure
based on either a gradient or a Newton calculation approach or it
may use a simplified approach using a Born or Rytov approximation.
If a non-approximation approach is used it preferably has one or
more of the following features, among others: (i) the method is
based on minimization of the difference between model scattered
fields and measured scattered fields; (ii) the method uses a
regularization method, such as Tikhonov regularization, one of its
variants, or the like; (iii) one type of the calculation mesh is
used in the method; (iv) one step of the iterative procedure is
performed as solving of the two sets of direct problems of the same
dimension: modeling of the so-called direct wave and modeling of
the inverse wave; (v) both the direct wave and the inverse wave are
calculated using nonreflecting or metallic boundary conditions;
(vi) both the direct wave and the inverse wave are calculated on
the same rectangular mesh; (vii) in order to solve the direct
problem a conjugate gradient method ("CGM") might be used; (viii)
one step of the CGM uses the sine Fourier transform; (ix) the wave
equation for non-uniform media is used to solve the direct
problem.
[0139] From a mathematical point of view, the methodology utilized
in EM field tomography is an inverse problem. It may be formulated
in terms of complex dielectric properties .di-elect cons. and/or
magnetic properties .mu. and electric and magnetic fields -E, H.
The basis is a set of the Maxwell's equations as shown in U.S. Pat.
No. 7,239,731 equation (1), where E and H represent electrical and
magnetic fields, respectively, and all other notations are
standard.
[0140] It is more practical to rewrite these equations in a form of
non-uniform wave equations such as that shown at U.S. Pat. No.
7,239,731 equation (2), where
k.sup.2=(2.pi./.lamda.).sup.2.di-elect cons..mu.
and .lamda. is a wavelength in vacuum. The EM field tomographic
system could be schematically represented as a chamber with the set
of EM openings on the surface of the chamber. As described
previously, the EM holes or windows 148 sometimes function as EM
field entry points while at other times functioning as EM field
exit points. It is useful to divide electric field E into incident
E.sub.0 field and scattered field E.sub.s as shown at U.S. Pat. No.
7,239,731 equation (3) where j is the number of a particular entry
EM opening or exit EM opening. The equation (2) can be rewritten in
the form shown in U.S. Pat. No. 7,239,731 equation (4) where
k.sub.0.sup.2 is a wave number for homogeneous matter and E.sub.0j
is the field produced by the EMWindow number j.
[0141] An object 19 may be described as a distribution of
dielectric permittivity in the imaging domain 21.
[0142] The receiver records the signal, which reflects both
incident and scattered fields.
[0143] In order to solve equation (4) we need to use some boundary
conditions on the bound of a calculation domain. Both nonreflecting
and reflecting (metallic) boundary conditions may be used on the
domain bounds. EMWindows in the current invention play similar
roles as transmitting or receiving antennas in classical EM
tomographic settings. For this reason: i) the spatial location of
EMWindows has to be known (see FIG. 11) and ii) the mathematical
model of an EMWindow as an antenna has to be provided. A simple
point source or electric or magnetic dipole or Kirchoff type source
or final elements model may be used to simulate the function of
EMWindows in both transmitting and receiving modes.
Direct Problem Solver
[0144] There are various approaches to solving the direct problem.
In some embodiments, a conjugate gradient method may be used with a
preconditioner. In order to do that, equation (4) may be rewritten
in the form shown in U.S. Pat. No. 7,239,731 equation (8), where
k.sub.av is an average value of k. The preconditioner operator can
be constructed as a first step of the iterative process shown at
U.S. Pat. No. 7,239,731 equation (9). Taking into account the fact
that the left side of equation (8) is an expression with constant
coefficient, equation (9) can be solved at step 1575 using
sine-type Fourier transform for the case with zero boundary
conditions on the bound of calculation domain. Then R. A. James's
method (originally invented for static problems, but subsequently
developed for electromagnetic problems) is applied to make boundary
conditions nonreflected. This technique creates a very robust and
effective method. Computational experiments show that the iterative
process appears to work with any reasonable contrasts and provides
nonreflecting conditions with very high accuracy. Using a sine-type
Fourier transform at step 1575 can make calculations 8 times faster
than with the regular Fourier approach.
[0145] FIG. 12A is a flow diagram of an exemplary direct problem
solver method 1535 for optional use in an image reconstruction
process. It will be appreciated, however, that other approaches may
be used. Furthermore, in at least some embodiments, the direct
solver 1535 is used only for inverse problem solving. The input
data in this case is the dielectric properties distribution in the
form of a 2D or 3D array, which is received at step 1560. For the
first step of the iteration, this input data may be received from
external input, which in some embodiments may be a homogeneous
distribution of dielectric properties of a background (or matching)
media, while in other embodiments may be merely an initial "guess"
distribution. In subsequent iterations, the input data is received
from the previous iteration. Next to occur, at step 1565, is the
preparation of the parameters and arrays, which do not change
during the direct problem solving process: the wave number, the
computational grids, and the Green function for the uniform space.
After that, the iterative procedure of the conjugate gradients
takes place at steps 1570 1580. First, the source member of
equation (4) is calculated at step 1570. Then, every step of the
conjugate gradient method requires fast Fourier transforms of the
source functions, as shown at step 1575. In order to stop
iterations the convergence of the process is checked at step 1580.
Once the iterative procedure is finished, the non-reflecting or
reflecting boundary conditions have to be implemented at step 1585.
Finally, the output of the process 1535 is created at step 1590.
The output comprises arrays containing the electric fields inside
of the computational domain and signals on the receivers for all
transmitter positions.
Inverse Problem Solver
[0146] In at least some embodiments, a gradient method may be used
to solve the inverse problem in electromagnetic tomography. In the
case of a three-dimensional vector in cylindrical geometry this
method needs significant modifications when compared with two
dimensional and scalar cases. In general the inverse problem in EM
field tomography can be formulated as a minimization problem as
shown at U.S. Pat. No. 7,239,731 equation (10), where
S.sub.ij.sup.theor are the theoretical values of the signal,
S.sub.ij.sup.exper are experimental values of the signal, and the
last term is the Tikhonov regularization functional.
[0147] An important point of any minimization procedure is the
method of a gradient calculation. It was proven that the gradient
of functional in our case is set forth at U.S. Pat. No. 7,239,731
equation (11) where E.sub.j and G.sub.ij are solutions of U.S. Pat.
No. 7,239,731 equations (12) and (13). Functions F.sub.j and
P.sub.ij describe the field patterns for EMWindows 150 being used
as entry holes or windows 148 and exit holes or windows 148,
respectively.
[0148] Direct computation using the equation (11) is very time
consuming even in the 2D case and cannot be effectively applied in
the 3D case. The reason is that every step requires N.times.M
number of direct problems to be solved, where N is the number of
transmitters, and M is the number of receivers. In at least some
embodiments, the function shown at U.S. Pat. No. 7,239,731 equation
(14) can be the solution of U.S. Pat. No. 7,239,731 equation (15).
This makes it necessary to solve only two direct problems on each
iterative step.
[0149] The calculation of the sum in the right side of equation
(15) continues to be a difficult problem, because it requires
summation on all receivers for all cells of the computational mesh.
In order to overcome this obstacle, a two-step procedure may be
applied. First, U.S. Pat. No. 7,239,731 equation (16) may be
calculated on the surface of the computational domain. This needs
significantly less computational effort compared to the calculation
of the right part of equation (15). Second, U.S. Pat. No. 7,239,731
equation (17) may be solved with those boundary conditions.
Equation (17) is the equation with constant coefficients and can be
easily solved using sine-type FFT.
[0150] Finally, one step of the gradient method procedure requires
solving two direct problems (equations (12) and (15)) plus one
equation (equation (17)) with constant coefficients.
[0151] One step of the iterative procedure can be implemented as
shown at U.S. Pat. No. 7,239,731 equation (18), where an iterative
step is chosen in a trial method. The limitations on the upper and
lower bounds of the values of the dielectric properties and the
values of the dielectric properties on the bound of the object are
applied in this step.
[0152] FIG. 12B is a flow diagram of an exemplary inverse problem
solver method 1500 for optional use in an image reconstruction
process. At step 1505, the input data is received. The input data
for the inverse problem solver 1500 includes physical and
geometrical parameters of the computational process: the sixes of
the computational domain, the working frequency, the maximum number
of iterations and the signals from the EM holes or windows 148.
Next to occur, at step 1510, is the preparation of the parameters
and arrays, which do not change during the inverse problem solving
iteration process: the wave number, the computational grids, and
the Green function for the uniform space. After that, the iterative
procedure of calculating the gradient of the residual function
(equation (11)) itself takes place at steps 1515,1520, including
the gradient calculation process itself at step 1515. In order to
stop iterations the convergence of the process is checked at step
1520. This involves comparing the value of the residual error with
the estimated experimental error. Once the iterative procedure is
finished, the boundary conditions have to be implemented at step
1525. Finally, the output of the process 1500 is created at step
1530. The output comprises the dielectric properties distribution
in the form of a 2D or 3D array.
[0153] FIG. 12C is a flow diagram of an exemplary gradient
calculation method 1515 for optional use in an image reconstruction
process. The direct wave is calculated at step 1535 according to
equation (12), followed at step 1540 by the calculation according
to equation (16) of the source for back-propagating wave on the
bounds of the computational domain. Then, at step 1545, the source
of the back-propagating wave is calculated in the volume of the
computational domain according to equation (17), and the
back-propagating wave is calculated by solving equation (13) at
step 1550. Finally, the gradient is calculated according to
equation (11) at step 1555.
[0154] The image reconstruction algorithm of this invention
includes a number of benefits. For example, using the nonreflecting
boundary conditions plus sine-type FFT makes the direct problem
solver of the invention the most effective one. Further, the
proposed way to calculate the so-called back wave (equations (15),
(16), (17)) allows working in real 3D multi-point configuration. In
addition, the method of signal calculation (equation (7)) is
distinguished from any others and allows simulating the work of
each EMWindow with high precision, and the mathematical algorithm
itself is essentially parallel, which is particularly advantageous
for parallel computing.
Application Example
Stroke Diagnosis
[0155] At least some embodiments of the EMT systems presented
herein, including without limitation the mobile embodiments such as
those presented in FIGS. 12A, 12B and 13, may be utilized
advantageously outside of the clinical setting. FIG. 13 is a
pictorial illustration of a timeline for use of an EMT system,
including the cap 112 of FIG. 7, for imaging a human head in
response to the onset of stroke symptoms in a patient. As shown
therein, at 8:00 pm, a patient may be resting at home when he
experiences the onset of stroke-like symptoms, such as
disorientation and weakness in the face and arms. In response, he
or a family member or friend contacts a medical provider, and an
ambulance is dispatched. Meanwhile, a doctor or other medical
practitioner is contacted and updated on the situation. A wearable
boundary apparatus 112, such as the cap of FIG. 7, is placed on or
around the patient's head, and scanning begins as shown around 8:25
pm. Resulting data may be provided to the doctor, ambulance staff,
imaging specialists, and other personnel. Some of the data may be
used directly for diagnosis, treatment, or the like, while complex
image-related data may be processed according to the systems and
methods of the present invention to reconstruct images from which
further diagnosis, treatment, or the like may be triggered. In at
least some embodiments, such processing may generate an automatic
alert that the data indicates that a potential stroke is likely.
Notably, in at least some embodiments, such processing is carried
out by a third party service provider who specializes in
reconstruction of images according to the systems and methods of
the present invention. During transport, from approximately 8:45 pm
to 9:00 pm, the cap 112 continues to provide data regarding the
patient's condition, and the local hospital staff is further
updated and arranges and prepares for further treatment. Once the
patient arrives at the hospital or other treatment center, the
images and data may be used in providing timely, accurate
information about the status of the stroke injury, and appropriate
treatment and follow-up may be administered. Such a system could be
utilized to provide the desired "under 3 hour" treatment that can
make a major difference in the final outcome of the stroke injury
and its effect on the patient.
Substitution or Other Use in Known EMT Systems
[0156] It will be appreciated that various elements of the present
invention may be further utilized in various systems that may have
heretofore utilized conventional EMT technology. For example, FIG.
14 is a schematic diagram illustrating the use of the system 110
and methods of FIGS. 5-12C in a 4D EMT differential (dynamic) fused
imaging system 200. At least in part, the operation of such a
system 200 may be carried out using components, and according to a
process or processes, previously described in U.S. Patent
Application Publication No. 2012/0010493 A1. As used herein,
.di-elect cons.* means a complex number, unless otherwise
indicated. The system includes a "know-how block" 202, an
"attenuation vs. boundary problems assessment block" 204, "an EMT
system set-up and test block" 206, an "images reconstruction block"
208, a "differential image formation block" 210, a "motion
correction block" 212, and a "fused images formation block"
214.
[0157] As shown in the lower right-hand corner, two important
inputs into the method and system are the type of imaging study and
the time duration of the study (T_study). The type of imaging study
may, for example, be i) a dynamic study of normal physiological
activity within soft tissue of extremity or myocardial tissue or
brain tissue, ii) a controlled stress study to assess a functional
viability of tissues (for example myocardium or muscle tissue)
during physical stress (exercise) or pharmacologically induced
stress (for example using dobutamine as per already approved
clinical procedure), iii) an injection of electromagnetic contrast
agent(s) (e.g., synthesized composite functional nanoparticles), or
the like, or a combination of the foregoing. The time duration of
the study (T_study) may be input, for example, in units of seconds
or a number of cycles of physiological activity (for example,
cardiac cycles).
[0158] Based on the input, the system calculates, as represented by
the "know-how" block 202, various desired system parameters. These
preferably include the required timely resolution (timely intervals
between each EMT acquisition cycle (frame)), the number of frames
to be acquired by the system, the required accuracy of measurements
in amplitude, the required accuracy of measurements in phase, and
the required accuracy of measurements in polarization (if
needed).
[0159] Using this information, the "attenuation vs. boundary
problems assessment block" 204 may calculate i) optimal dielectric
properties (.di-elect cons.*.sub.0=.di-elect
cons.'.sub.0+j.di-elect cons.''.sub.0) of matching media (to be
filled around the object 19 in the boundary apparatus 112), mainly
by optimizing an attenuation component (.di-elect cons.''.sub.0),
and ii) IFBW of the system based on required timely resolution and
number of channels of the system to be acquired. Then a
matching/decoupling media is prepared by mixing water, alcohol,
salt, glycerol and/or other components at an appropriate
concentration to match desired dielectric properties (.di-elect
cons.*.sub.0=.di-elect cons.'.sub.0+j .di-elect cons.''.sub.0). The
boundary apparatus 112 may then be fully or partially filled (for
making "empty" measurements or for making actual "in use"
measurements, respectively) with such media, which in at least some
embodiments is in gel-type form. In particular, as represented by
the "EMT system set-up and test block" 206, the system 200,
including the EMT system 110, is first set up and initialized and,
with the boundary apparatus 112 fully filled with matching media, a
test is conducted on this "empty" boundary apparatus--i.e., with
the boundary apparatus 112 filled with matching/decoupling media
but with no object 19 inside. This allows for assurance that the
desired system parameters are met. Then, when the system 200 is
ready, the object 19 under study is placed into the boundary
apparatus 112, along with the matching/decoupling media. In at
least some embodiments, the matching media is spread on the inner
surfaces of the apparatus 112 before placing the object 19 into the
apparatus 112.
[0160] With the object and the matching/decoupling media in place,
and full set EMT data (frames) are acquired as described above at
each time T0, T1 . . . T_study. The raw EMT data at each time frame
comes into an image reconstruction block 208 to calculate an
absolute anatomical image at each time frame T0, T1 . . . T_study.
The absolute anatomical image that is determined at time T0, which
may sometimes be referred to herein as a "BaseLine image," is used
to calculate a differential image and fused images at all further
frames T1 . . . T_study. For frame T0, the starting point (initial
distribution of dielectric properties within an imaging domain) for
an iterative image reconstruction procedure may be a homogeneous
distribution of matching media .di-elect cons.*.sub.0=.di-elect
cons.'.sub.0+j .di-elect cons.''.sub.0 within an imaging domain.
For all other frames (T1 . . . T_study), the starting point may be
a homogeneous distribution of matching media .di-elect
cons.*.sub.0=.di-elect cons.'.sub.0+j .di-elect cons.''.sub.0
within an imaging domain (a BaseLine image (.di-elect
cons.*.sub.frame T0)), or alternatively, the starting point may be
a reconstructed image from previous frame. In other words, a
BaseLine image (.di-elect cons.*.sub.frame T0), which is a
reconstructed distribution of dielectric properties at time T0, can
be used as a starting point for image reconstruction at other time
points (frames) T1 . . . T_study, or alternatively an image
reconstructed at time Tt (.di-elect cons.*.sub.frame Tt) can be
used as a starting point for image reconstruction at frames t+1,
t+2 etc. This significantly accelerates an image reconstruction
procedure by decreasing a required number of iterations.
[0161] The "differential image formation block" 210 calculates
differential images between the initial frame T0 and the current
frame Tt as follows:
.di-elect cons.*.sub.diff=(.di-elect cons.*.sub.frame Tt-.di-elect
cons.*.sub.frame T0)/.di-elect cons.*.sub.frame T0.times.100[%]
It is strongly preferred that the reconstructed images at time T0
and Tt are to be motion free. In spite of a very short acquisition
time (preferably on the order of a dozen milliseconds or less),
motion correction might be required. This may be conducted in the
"motion correction block" 212.
[0162] A fused image at each time frame Tt may be obtained via the
"fused images formation block" 214. In one exemplary
implementation, a background image, representing the absolute
anatomical image of the biological object 19, is produced using a
gray palette, and a time-differential image, produced using a color
palette, is superimposed over the background image. In this
example, bony areas having low dielectric properties may be
rendered in the absolute anatomical image using darker shades of
gray while soft tissue areas may be rendered in the absolute
anatomical image using lighter shades of gray. Also in this
example, the degree of changes may be rendered in the
time-differential image, which reflects physiological activity or
interventions during the study, along a color spectrum such that
each particular color represents a percentile of change. Simple
examples of such fused images, obtained during preliminary
experiments using the foregoing systems and methods described
above, are provided in the aforementioned U.S. Patent Application
Publication No. 2012/0010493 A1.
[0163] Based on the foregoing information, it will be readily
understood by those persons skilled in the art that the present
invention is susceptible of broad utility and application. Many
embodiments and adaptations of the present invention other than
those specifically described herein, as well as many variations,
modifications, and equivalent arrangements, will be apparent from
or reasonably suggested by the present invention and the foregoing
descriptions thereof, without departing from the substance or scope
of the present invention.
[0164] Accordingly, while the present invention has been described
herein in detail in relation to one or more preferred embodiments,
it is to be understood that this disclosure is only illustrative
and exemplary of the present invention and is made merely for the
purpose of providing a full and enabling disclosure of the
invention. The foregoing disclosure is not intended to be construed
to limit the present invention or otherwise exclude any such other
embodiments, adaptations, variations, modifications or equivalent
arrangements; the present invention being limited only by the
claims appended hereto and the equivalents thereof.
* * * * *