U.S. patent application number 13/031463 was filed with the patent office on 2011-08-25 for imaging probe.
Invention is credited to Tumay O. Tumer.
Application Number | 20110208049 13/031463 |
Document ID | / |
Family ID | 26959403 |
Filed Date | 2011-08-25 |
United States Patent
Application |
20110208049 |
Kind Code |
A1 |
Tumer; Tumay O. |
August 25, 2011 |
Imaging Probe
Abstract
The design of a compact, handheld, solid-state and
high-sensitivity imaging probe and a micro imager system is
reported. These instruments can be used as a dedicated tool for
detecting and locating sentinel lymph nodes and also for detecting
and imaging radioactive material. The reported device will use
solid state pixel detectors and custom low-noise frontend/readout
integrated circuits. The detector will be designed to have
excellent image quality and high spatial resolution. The imaging
probes have two different embodiments, which are comprised of a
pixelated detector array and a highly integrated readout system,
which uses a custom multi-channel mixed signal integrated circuit.
The instrument usually includes a collimator in front of the
detector array so that the incident photons can be imaged. The data
is transferred to an intelligent display system. A hyperspectral
image can also be produced and displayed. These devices are
designed to be portable for easy use.
Inventors: |
Tumer; Tumay O.; (Beverly
Hills, CA) |
Family ID: |
26959403 |
Appl. No.: |
13/031463 |
Filed: |
February 21, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11202183 |
Aug 12, 2005 |
7894881 |
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13031463 |
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10279003 |
Oct 24, 2002 |
6940070 |
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11202183 |
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60330597 |
Oct 25, 2001 |
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Current U.S.
Class: |
600/436 |
Current CPC
Class: |
A61B 6/4258 20130101;
G01T 1/161 20130101; G01T 7/00 20130101; A61B 6/508 20130101 |
Class at
Publication: |
600/436 |
International
Class: |
A61B 6/00 20060101
A61B006/00 |
Claims
1. A portable imaging device comprising: a first position sensitive
detector mounted to a first side of the device, wherein the first
detector receives a plurality of particles from a portion of an
organism emitting particles that produce a plurality of signals; a
first readout circuit mounted to the first detector that receives
and processes the plurality of signals; a processor coupled to the
readout circuit to process at least a portion of the plurality of
signals to produce an image; and a screen mounted on a second side
of the device different from the first side of the device, wherein
the screen is coupled to the processor, and wherein the screen
displays the image of the portion of the organism.
2. The portable imaging device of claim 1, further comprising a
first collimator coupled to the first detector.
3. The portable imaging device of claim 2, further comprising a
second collimator that is interchangeable with the first
collimator.
4. The portable imaging device of claim 1, further comprising a
control button mounted on a side of the device that controls the
image displayed on the screen.
5. The portable imaging device of claim 1, further comprising a
circuit board coupled to the integrated circuit and the processor
that provides power to the portable imaging device.
6. The portable imaging device of claim 1, wherein the first
detector comprises an active area of at most 5.times.5
cm.sup.2.
7. The portable imaging device of claim 1, wherein the first
detector comprises an active area of at most 3.times.3
cm.sup.2.
8. The portable imaging device of claim 1, wherein the first
detector is selected from the group consisting of silicon pad
detectors, silicon pixel detectors, double sided silicon microstrip
detectors, double sided silicon strip detectors, CdZnTe pixel
detectors, and CdTe pixel detectors.
9. The portable imaging device of claim 1, wherein the first
detector comprises a material selected from the group consisting of
Silicon, HPGe, BGO, CdWo4, CsF, Nal(TI), CsI(Na), CsI(TI), CdTe,
CdZnTe, HgI2, GaAs, and PbI2.
10. The portable imaging device of claim 1, wherein the first
detector comprises ohmic electrodes.
11. The portable imaging device of claim 1, wherein the first
detector comprises blocking type electrodes.
12. The portable imaging device of claim 1, further comprising a
second position sensitive detector layered with the first
detector.
13. The portable imaging device of claim 1, wherein the first
readout circuit composes a circuit board that is mounted within the
device.
14. The portable imaging device of claim 1, further comprising a
pair of comparators that filters the plurality of signals by
selecting an energy window around a nuclear line.
15. The portable imaging device of claim 1, wherein the screen has
an image area that is as large as an active area of the first
detector.
16. The portable imaging device of claim 1, wherein the screen
comprises a ruler corresponding to the active dimensions of the
first detector.
17. The portable imaging device of claim 1, further comprising a
memory that stores the image.
18. The portable imaging device of claim 1, further comprising a
second readout circuit daisy-chained with the first readout
circuit.
19. The portable imaging device of claim 1, wherein the readout
circuit comprises an analog readout section and a digital readout
section.
20. The portable imaging device of claim 1, wherein the second side
of the device is opposite from the first side of the device.
21. A method of producing an imaging device, comprising: mounting a
first position sensitive detector array to a first side of an
imaging device, wherein the first detector receives a plurality of
particles from a portion of an object emitting particles that
produce a plurality of signals; mounting a first readout circuit to
the first detector wherein the first readout circuit receives and
processes the signals produced by the first detector; coupling a
processor to the circuit to convert the processed signals to an
image; and mounting a screen on a second side of the device
different from the first side of the device, wherein the screen is
coupled to the processor, and wherein the screen displays the image
of the portion of the object.
22. The method of claim 21, further comprising mounting a first
collimator coupled to the first detector.
23. The method of claim 22, further comprising mounting a second
collimator that is interchangeable with the first collimator.
24. The method of claim 21, further comprising providing a control
button mounted on a side of the device that controls the image
displayed on the screen.
25. The method of claim 21, further comprising mounting a circuit
board to the integrated circuit and the processor, wherein the
circuit board provides power to the portable imaging device.
26. The method of claim 21, wherein the first detector comprises an
active area of at most 5.times.5 cm.sup.2.
27. The method of claim 21, wherein the first detector comprises an
active area of at most 3.times.3 cm.sup.2.
28. The method of claim 21, wherein the first detector is selected
from the group consisting of silicon pad detectors, silicon pixel
detectors, double sided silicon microstrip detectors, double sided
silicon strip detectors, CdZnTe pixel detectors, and CdTe pixel
detectors.
29. The method of claim 21, wherein the first detector comprises a
material selected from the group consisting of Silicon, HPGe, BGO,
CdWo4, CsF, Nal(TI), CsI(Na), CsI(TI), CdTe, CdZnTe, HgI2, GaAs,
and PbI2.
30. The method of claim 21, wherein the first detector comprises
ohmic electrodes.
31. The method of claim 21, wherein the first detector comprises
blocking type electrodes.
32. The method of claim 21, further comprising layering a second
position sensitive detector with the first detector.
33. The method of claim 21, wherein the first readout circuit
composes a circuit board that is mounted within the device.
34. The method of claim 21, further comprising providing a pair of
comparators that filters the plurality of signals by selecting an
energy window around a nuclear line.
35. The method of claim 21, wherein the screen has an image area
that is as large as an active area of the first detector.
36. The method of claim 21, wherein the screen comprises a ruler
corresponding to the active dimensions of the first detector.
37. The method of claim 21, further comprising coupling a memory to
the processor that stores the image.
38. The method of claim 21, further comprising daisy-chaining a
second readout circuit with the first readout circuit.
39. The method of claim 21, wherein the readout circuit comprises
an analog readout section and a digital readout section.
40. The method of claim 21, wherein the second side of the device
is opposite from the first side of the device.
Description
CROSS REFERENCE TO PROVISIONAL AND PARENT PATENT APPLICATION
[0001] This application is a divisional of co-pending U.S.
Non-Provisional patent application Ser. No. 11/202183 filed Aug.
12, 2005, which is a continuation of parent U.S. patent application
Ser. No. 10/279,003 filed Oct. 24, 2002, now U.S. Pat. No.
6,940,070, which claims the benefit of the filing date of U.S.
Provisional Patent Application No. 60/330,597 filed Oct. 25, 2001,
each of which is incorporated herein by reference.
FIELD OF INVENTION
[0002] The focus of this work is to develop an enhanced portable
imaging probe for detecting and locating sentinel lymph nodes
during breast cancer surgery. It may also be used for
scintimammography: diagnosis and accurate location of breast cancer
tumors and their spread to surrounding tissue, especially axillary
lymph nodes. It is expected to improve and expedite the sentinel
node detection and locating, and enhance breast and other cancer
surgery.
[0003] The instruments described can also be used for many
different applications. In medical imaging, for example, they can
be used for many types of x-ray and gamma ray imaging such as
imaging small body organs, for molecular imaging of small animals,
especially nude and scidd mice, and as an essential surgical tool.
In security applications it can be used to scan people for
radioactive material. In military it can be used in the field in a
different portable embodiment to search and image radioactive
material and/or objects that contain radioactive materials. In NDI
and NDE it can be used as a portable tool to image objects for
defects, cracks, etc. It may also be used to detect corrosion and
cracks on aircraft and other vehicles.
BACKGROUND OF INVENTION
[0004] Single detector non-imaging probes have been in use for some
time to detect and locate the sentinel lymph node(s) during breast
cancer surgery. These probes have proven to be useful to the
surgeon in this regard. However, they are limited in use as they do
not provide an image, just a crude count rate from a 1 cm.sup.2
area detector. Therefore, locating the sentinel node is not very
accurate and it does not provide accurate information on the extent
of the tumor. Therefore, an imaging probe with an adjustable
spatial resolution by removing or exchanging the collimator will
achieve significant improvement in sentinel node detecting and
locating. It will also enable the imaging probe to be used for
other applications such as detecting and locating primary and
secondary tumors in the breast tissue and lymph nodes through
scintimammography.
[0005] Recently breast imaging studies with .sup.99mTc SestaMIBI
and .sup.201Tl have demonstrated uptake by sentinel lymph nodes and
malignant breast tumors but not by benign masses (except some
highly cellular adenomas). Most of the results give sensitivities
and specificities of about 90%, and recently equally encouraging
results have been reported for .sup.99mTc Methylene Diphosphonate
(MDP) with a sensitivity of 92% and a specificity of 95%, even
though these studies were carried out with conventional full size
gamma-ray cameras which have some inherent limitations for breast
imaging especially during surgery: [0006] 1. The large size of the
gamma camera makes it difficult to position optimally relative to
the breast. [0007] 2. Not usable during surgery due to the large
size, low sensitivity and low spatial resolution.
[0008] The reported small, compact, handheld solid-state imaging
probe is expected to achieve much better performance in all of
these categories. It will be especially useful before, during and
after surgery to locate the sentinel lymph node(s) using the
drainage of the radiopharmaceutical from the tumor site to the
sentinel node(s). It may also be used in the scintimammography mode
to locate a lesion and its metastatic components, completely remove
the cancerous tissue and verify that no cancer is left behind. Also
the cancers that are not detectable by conventional mammography
such as fibrocystic change and dense breasts especially in young
women (.apprxeq.40% between 40 and 50 year old), lack of
calcifications (about 50% of all preinvasive cancers) and
mammographically occult breast cancers. These, in many cases, will
be identifiable by the reported system, because the method of
detection relies on isotope uptake in the tumor, not on subtle
differences in its radiodensity.
[0009] The instruments described here are called SenProbe (FIG. 1)
and MicroImager (FIG. 7). While the SenPROBE and MicroImager
systems are not directly a therapeutic tool, They have the
potential to become excellent tools in monitoring the progress of
surgery. Before the surgery it can be used for detecting and
locating the sentinel lymph node(s), searching for malignancy in
the sentinel and axillary lymph nodes, the location, size and the
distribution of the tumor. During surgery the accuracy of the
position and the extent of the tumor can be determined, removal of
the cancerous tissue can be monitored and for the metastatic tumors
the lymph nodes and the surrounding tissue can be screened,
decreasing the likelihood that the physician will leave cancerous
tissue behind. After the surgery the surgeon can use the SenPROBE
or the MicroImager to check that the tumor is completely removed,
and no residual malignant tissue remains. SenPROBE or the
MicroImager may also be used in some cases before, during and/or
after chemotherapy. Monitoring the tumor size will confirm that the
chemotherapy treatment is effective.
SUMMARY OF INVENTION
[0010] A small, compact, portable solid state imaging probe with a
built in high sensitivity tiny gamma camera as shown in FIG. 1 is
discussed here as a probe to locate sentinel lymph nodes. It can
also be used as a high sensitivity tool for scintimammography. The
high sensitivity of the reported system is due to the very short
distance to the source as the probe will be used making direct
contact with the tissue, even inside a surgical cut; high Z solid
state CdZnTe detector material with high quantum efficiency; and
high energy resolution, about 5% to 10%, to discriminate against
scattered photons and other background.
[0011] FIG. 1 is showing a drawing of the SenPROBE with one
Image/Reset button and the separate LCD monitor with On/Off and
Store buttons displaying two active sentinel lymph node sites. FIG.
2. is a drawing of the SenPROBE showing the internal components;
honeycomb collimator (at the bottom) which is removable and
interchangeable for higher sensitivity or higher spatial
resolution. On top of the collimator there are the CdZnTe pixel
detectors mounted on a circuit board. On the other side of the
circuit board the new front-end chips will be mounted directly on
the circuit board without bulky packaging to achieve the small
thickness required. The data acquisition and display electronics
will be housed in the color LCD monitor. The collimator is shown
here as integrated into the probe. However, in practice the
collimator will be easily exchanged or removed in the operating
room. This will allow trade off between sensitivity and spatial
resolution.
[0012] A high sensitivity SenPROBE with excellent spatial
resolution is required to make this new method viable. The SenPROBE
will provide the following enhancements: [0013] 1. High energy
resolution, 5% to 10% at 122 keV, 3 to 5 mm thick CdZnTe pixel
detectors with pixel pitch of about 2 to 3 mm with about 5.times.5
cm2 active area will be developed. [0014] 2. Gamma rays between
about 50 and 250 keV will be detected with high quantum efficiency.
[0015] 3. Imaging probe size about 5.times.5.times.1 cm3 without
collimator. Collimator thickness will be about 0.5 to 1 cm if
needed. Most applications can be carried out at touching distance,
<1 cm to the source, and will not need a collimator. Distances
larger than about 1 cm will need coarse or fine collimation
depending on distance. [0016] 4. An integrated circuit is developed
specifically for this applications. The noise is expected to be
lower and energy resolution higher. The new chip will enable
compact and portable design of the imaging probe. [0017] 5. A
single button will control the imaging. Each pressing will reset
the image and acquire a new one. Or separate reset and image
buttons can be used. Any image can be stored using the Store button
on the monitor. [0018] 6. Excellent spatial resolution, about 1 mm
with collimator. Without a collimator image acquisition will be
fast but the image will be slightly blurred depending on the
distance to the source. [0019] 7. A radio transmission system can
be placed inside the SenProbe and/or the MicroImager. It can be
inside the handle or attached to the instrument to relay
information to the LCD monitor and eliminate connecting cable
completely. [0020] 8. More then one detectors inside the instrument
or two or more SenProbes and MicroImagers can be used to produce
three dimensional and/or stereoscopic imaging.
[0021] The invention described comprises a medical imaging system
for imaging a portion of a living organism. The living organism is
treated with a radiopharmaceutical, which emits gamma ray photons.
The detector contains two-dimensional array of pixels. It has an
entrance aperture, which is external to the living organism and
placed close or at touching distance to the portion of the living
organism. The emitted gamma ray photons enter into the detector
array and may scatter within the detector array.
[0022] A multi channel readout system is connected to the detector
pixels. A processor is connected to the multi-channel readout
system. A monitor is coupled to the processor. The monitor displays
an image of the number of photons coming from the portion of the
living organism imaged.
[0023] Most of the incident gamma ray photons undergo photoelectric
absorption in the detector. The system includes a collimator to
restrict the angle of the gamma rays incident on the detector
system to determine the direction of the photons. The collimator is
therefore helps to produce the image of the incident gamma
rays.
[0024] The radiopharmaceuticals may contain a radio isotope(s) such
as thallium-201, technetium-99m, iodine-123, iodine-131, and
fluorine-18. The medical imaging system contains many pixels
fabricated on the detector material. The detector(s) used can be
silicon pad detectors, silicon pixel detectors, double sided
silicon microstrip detectors, double sided silicon strip detectors,
CdZnTe pixel detectors and CdTe pixel detectors. The detector
material may be selected from Silicon, HPGe, BGO, CdWo4, CsF,
Nal(TI), CsI(Na), CsI(TI), CdTe, CdZnTe, HgI.sub.2, GaAs, and
PbI.sub.2.
[0025] The pixels may be fabricated on both sides of the detector.
The pixels may be fabricated as ohmic and/or blocking type
electrodes. The pixel pitch may vary from 0.01 to 10 mm. The
medical imaging system may have several layers of detector
planes.
[0026] The detector has a handle for holding the medical imaging
system. The medical imaging system is also made compact and
portable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a drawing of the SenPROBE with one Image/Reset
button and the separate LCD monitor with On/Off and Store buttons
displaying two close active sentinel lymph node sites.
[0028] FIG. 2 is a drawing of the SenPROBE showing the internal
components; honeycomb collimator (at the bottom) which is removable
and interchangeable for higher sensitivity or higher spatial
resolution. On top of the collimator there are the CdZnTe pixel
detectors mounted on a circuit board. On the other side of the
circuit board the new front-end chips will be mounted directly on
the circuit board without bulky packaging to achieve the small
thickness required. The data acquisition and display electronics
will be housed in the color LCD monitor. The collimator is shown
here as integrated into the probe. However, a removable collimator
will be used, which will be easily attached or removed in the
operating room. This will allow trade off between sensitivity and
spatial resolution.
[0029] FIG. 3 is a photograph of a solid-state gamma camera. It
consists of CdZnTe pixel detector units and RENA readout module
boards. Each readout module board can house up to four CdZnTe
detector units. In the photograph, the top module board has no
detector unit, the middle one has only one detector unit, and the
bottom one has four detector units.
[0030] FIG. 4 is a spectrum of .sup.139Ce measured using NOVA's
CdZnTe pad detectors obtained from eV Products. The detectors are
read out by the present RENA chip at or near room temperature. The
shaping time is set to 1.7 .mu.s. A Gaussian fit to the 166 keV
peak ignoring the trapping tail has a width (.sigma.) of 3.1 keV.
The two partially overlapping low-energy peaks correspond to K
lines (at 33.2 and 37.8 keV, respectively) of Lanthanum, the
product of the Cerium decay. These lines were suppressed by
shielding the source with 0.02'' of copper. b) The two nuclear
gamma lines at 122 and 136 keV are clearly visible A Gaussian fit
to the 122 keV peak has a width of 9 keV FWHM without significant
trapping tail, which is about 7% FWHM energy resolution.
[0031] FIG. 5 is a spectrum of .sup.57Co, measured with a new CdTe
PIN detector developed by another company showing practically no
charge trapping tail. Both detectors are read out by the present
RENA chip at or near room temperature. The shaping time set to 1.7
.mu.s. The two nuclear gamma lines at 122 and 136 keV are clearly
visible. A Gaussian fit to the 122 keV peak has a width of 9 keV
FWHM without significant trapping tail, which is about 7% FWHM
energy resolution.
[0032] FIG. 6 is a block diagram of the new integrated circuit
showing the analog circuits for one channel and some of the digital
circuits.
[0033] FIG. 7 is a drawing of the MicroImager showing the control
buttons, the display of an imaged tumor, and the ruler showing the
location of the tumor.
[0034] FIG. 8 is a drawing of the MicroImager showing the internal
components; honeycomb collimator (at the bottom), the CdZnTe pixel
detectors on top of the collimator and the circuit boards for the
front-end, data acquisition and display electronics,
respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] For this application, we plan to use detectors 24, 30, 82
with a thickness of 3 to 5 mm, which is well suited for photons
from .sup.99mTc, the radionuclide most commonly used in
radiopharmaceuticals. The pixel sizes will be selected from 1 to 3
mm. One side of these detectors have two-dimensional array of
pixels (electrodes) normally as anodes and the other side is a
single plane electrode, normally used as cathode. Another
embodiment would be to make the pixels as cathodes and the backside
electrode to function as anode. A bias voltage is applied between
the anode and cathode where the electrons generated by an x-ray or
a gamma ray are collected at the anode(s). In the main embodiment
the two dimensional pixelated side faces the printed circuit
board.
[0036] The energy resolution of our current CdZnTe pixel detectors
(FIG. 3) 30 with 4.times.8 pixels and 3.times.3 mm.sup.2 pixel
pitch, read out by the RENA chip, has been measured using
.sup.57Co, .sup.139Ce, and .sup.241Am sources. Sample energy
spectra are shown in FIG. 4 and FIG. 5.
[0037] FIG. 3 shows a photograph of a prototype solid-state gamma
camera. It consists of CdZnTe pixel detector units 30 and RENA chip
readout module boards 31. Each readout module board can house up to
four CdZnTe detector units 30 and RENA chips. In the photograph,
the top module board has no detector unit, the middle one has only
one detector unit, and the bottom one has all four detector units
30.
[0038] We plan to optimize the pixel size for the reported portable
gamma camera (SenProbe). The CdZnTe pixel array 30 with 3.times.3
mm.sup.2 pixel size shown in FIG. 3 is bulky. Therefore, new
technology is used to reduce the pixel size and also miniaturize
the electronics so that a compact SenProbe can be developed as
shown in FIG. 1 10 and in FIG. 2 20. We plan to design the printed
circuit boards to be parallel to the detector plane 22, as shown in
FIG. 2, compared to the perpendicular design 31 shown in FIG. 3, to
significantly reduce the SenPROBE thickness and size. Only one
multi layer circuit board will be used in the probe imaging plane
22 which will house detectors on one side and the new ASICs mounted
directly on the board on the other side to achieve high density and
small thickness. The standard PC boards are not low noise so we
will either use a ceramic carrier or a teflon board for low noise
operation. The peripheral electronics, such as the ultra low noise
voltage references and supplies are used in developing the
instrument.
[0039] The RENA (Readout Electronics for Nuclear Application) chip
22 and 83 is used for these instruments. This chip has low noise
and excellent energy resolution. Lower noise versions with more
functionality and features can also be designed and used.
[0040] RENA chip 22 and 83 is a 32-channel signal processor IC for
use with solid-state radiation detectors and other devices that
produce a charge output. Each channel consists of an analog and a
digital section; in addition, there are two isolation analog
channels, one along each side of the analog channel group. RENA is
self-triggered, with several different trigger modes that allow
flexible operation. The flexibility is further enhanced by having
eight digitally controlled shaper peaking times; this allows the
chip to accommodate different charge collection times of various
detectors. Up to sixteen RENA chips can be daisy-chained together
with common buses for analog outputs, digital address outputs and
some control signals; in this configuration the chips can be read
out as a single ASIC with up to 512 channels.
[0041] FIG. 4 shows a spectrum of .sup.139Ce measured with CdZnTe
pad detectors 30 obtained from eV Products and Both detectors are
read out by the RENA chip at or near room temperature. The shaping
time set to 1.7 .mu.s. A Gaussian fit to the 166 keV peak ignoring
the trapping tail has a width (.sigma.) of 3.1 keV. The two
partially overlapping low-energy peaks correspond to K lines (at
33.2 and 37.8 keV, respectively) of Lanthanum, the product of the
Cerium decay. These lines were suppressed by shielding the source
with 0.02'' of copper.
[0042] FIG. 5 shows a spectrum of .sup.57Co using a new CdTe PIN
detector developed by another company showing practically no charge
trapping tail. The two nuclear gamma lines at 122 and 136 keV are
clearly visible. A Gaussian fit to the 122 keV peak has a width of
9 keV FWHM without significant trapping tail, which is about 7%
FWHM energy resolution.
[0043] A block diagram of a single analog channel and some digital
section of an improved integrated circuit is shown in FIG. 6. The
first stage of the signal path is a switched-reset integrator low
noise charge sensitive amplifier. A calibration input, which is
capacitatively coupled to first amplifier allows simple testing of
analog channels using an external signal source. The second stage
of the signal path is a polarity amplifier, which amplifies the
signal from the first stage and has a control to select a positive
or negative gain. The shaper, which follows the polarity amplifier,
is a first order transconductance-C bandpass filter with
programmable bandwidths. These bandwidths are selected through
three bits in the configuration shift register. The filtered signal
is peak-detected in the following stage. The peak detector is
configured as such in typical operation, or as a voltage follower
for diagnostic and test purposes. During readout, the peak-detected
signal is isolated from the input by a switch in front of the peak
detector. Two comparators sense the output level of the peak
detector. The threshold comparator generates the trigger signal
that is then used in the channel logic. The high-level comparator
may be used, for example, to select an energy window around a
nuclear line such as the 141 keV .sup.99mTc line. The peak-detected
signals from the thirty-two channels are multiplexed onto an analog
bus that is fed to an output amplifier connected to the output pad.
The chip also has sparse readout capability where only the channels
with valid event are read out. The new ASIC also has fast trigger
output for timing applications and a hit/read shift register to
provide the number and address of the channels with valid
event.
[0044] The SenPROBE (FIG. 1 10 and FIG. 2 20) will be developed to
have an active area of about 5.times.5 cm.sup.2. The most likely
area will be about 4''.times.4''. The total thickness of the
SenPROBE will depend on the collimator 21 thickness and the number
of circuit boards 22. The collimator 21 is expected to be about 5
to 10 mm thick depending on spatial resolution required. The hole
diameter will be selectable from about 1 mm to 3 mm to allow for
fast or fine resolution imaging as required. The collimator 21 will
be designed to be interchangeable so that the operator or the
surgeon can change it as required. The CdZnTe detector 24 thickness
will be about 3 to 5 mm. The probe will have a handle 11 connected
to the display or monitor via a cable 12. The cable 12 can be
eliminated if a radio or microwave connection between the probe and
the monitor is established. The monitor 13 has a display screen 16
and it can use a microprocessor or computer to process data
obtained from the probe and display the image 17 on the display
screen 16. The display or monitor 13 has buttons to control the
instrument such as the ON/OFF button 15 and STORE button 14. Other
buttons such as RESET and IMAGE (not shown) may also be used.
[0045] Up to four circuit boards can be deployed. The first one
will house the detectors 24 on the bottom side and the RENA chips
22 on the top side so that the pixels can be connected through
short, low capacitance leads to achieve high energy resolution. The
second circuit board will house the data interface to the data
acquisition board and will be housed in the handle 25 of the probe.
The third board will contain the power supplies, the data
acquisition, and display interface circuits and it will be housed
inside the color LCD display monitor 13. The fourth circuit board
will have the onboard microprocessor and the display driver. The
entire electronics will be run by high-power rechargeable Ni-MH or
Li ion or similar batteries.
[0046] The display 16 will be made from a large size color LCD. The
display will show a contour plot of the received image 17 (counts
per pixel) from the detector in real time. The operator will decide
how long to acquire the image. The display will also have a ruler
on all sides 16 corresponding to the active dimensions of the
detector. On the sides of the SenProbe 10 and 20 there will be a
corresponding ruler. This will allow the surgeon to make marks on
the tissue corresponding to the center and size of the tumor.
[0047] In another embodiment called MicroImager 70 and 80 in FIG. 7
and FIG. 8 a small, compact, portable solid state gamma camera is
shown which is a different embodiment to SenProbe shown in FIG. 1
10. This embodiment may be used as a complementing modality to
mammography to solve the problems stated above.
[0048] MicroImager 70 contains a display 71 an several buttons to
control the instrument. These buttons can be START/STOP button 73,
IMAGE button 74 and a RESET button 75. A drawing of the MicroImager
showing a display of a tumor 72 is shown in FIG. 7. The display 71
has ruler markings allowing easy determination of the location of
the tumor 72. FIG. 8 displays a drawing of the MicroImager 80
showing the internal components; honeycomb collimator 81 at the
bottom, the CdZnTe pixel detectors 82 on top of the collimator and
the circuit boards 83, 84 and 85 for the front-end, data
acquisition and display electronics, respectively.
[0049] The MicroImager (FIG. 8) 80 will be developed to have an
active area of about 3''.times.3'' to about 5''.times.5''. The most
likely area will be about 4''.times.4''. The total thickness of the
MicroImager will depend on the collimator thickness and the number
of circuit boards. The collimator 81 is expected to be about 1 to
10 mm thick. The hole diameter will be selectable from about 2 mm
to 5 mm to allow for fast or fine resolution imaging as required.
The collimator 81 will be designed to be interchangeable so that
the operator or the surgeon can change it as required. The CdZnTe
detector thickness will be about 2 to 5 mm.
[0050] We plan to build three circuit boards (FIG. 8). The first
one will house the detectors 82 on the bottom side and the RENA
ASICs 83 on the top side so that the pixels can be connected
through short, low capacitance leads to achieve high energy
resolution. The middle circuit board 84 will house the power
supplies, the data acquisition, and interface circuits. The top
circuit board 85 will have the onboard microprocessor and the
display driver. The entire electronics will be run by high-power
rechargeable Ni-MH batteries.
[0051] The display 86 will be made from a large size LCD with
dimensions as close to the active area as allowed by the real
estate available on the top surface of the MicroImager. The display
will show a contour plot 87 of the received signal (counts per
pixel) from the detector in real time. The operator then can decide
how long to acquire the image. The display will also have a ruler
on all sides corresponding to the active dimensions of the
detector. On the sides of the MicroImager 80 there will be a
corresponding ruler. This will allow the surgeon to make marks on
the tissue corresponding to the center and size of the tumor. After
the MicroImager is removed the lines can be joined to mark the
location of the lesion so that it can be easily located and
removed.
[0052] The position resolution will depend on the collimator 81
used. The best position resolution achievable is expected to be
about 1 mm.
[0053] There are three function buttons, START/STOP 73, IMAGE 74,
and RESET 75. START/STOP will turn the detector on and off, IMAGE
button will initiate the image acquisition and the RESET button
will clear the image. The can be other buttons if needed. An image
memory will store about 32 or more images, which can be downloaded
later to a computer if needed.
* * * * *