Title: 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.
Patent Number: 6,940,070 Issued on 09/06/2005 to Tumer
| Inventors:
|
Tumer; Tumay O (1525 Third St., Ste. C, Riverside, CA 92507)
|
| Appl. No.:
|
279003 |
| Filed:
|
October 24, 2002 |
| Current U.S. Class: |
250/370.09; 250/370.01 |
| Intern'l Class: |
G01T 001/24 |
| Field of Search: |
250/37009,370.01,366,367,368,369,363.03,363.04,252.1,330
378/4,37,988
|
References Cited [Referenced By]
U.S. Patent Documents
| 5821541 | Oct., 1998 | Tumer.
| |
| 6194715 | Feb., 2001 | Lingren et al.
| |
| 2003/0197128 | Oct., 2003 | Tumer.
| |
| 2004/0015075 | Jan., 2004 | Kimchy et al.
| |
Other References
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SPIE (Society of Photo-Optical Instrumentation Engineers), vol. 3445, Jul.
1998, pp. 374-382.
Kravis, Scott D., et. al., "A multichannel readout electronics for nuclear application
RENA) chip developed for position sensitive solid state detectors," Nuclear
Instruments & Methods in Physics Research, A 422, 1999, pp. 352-356.
Mainprize, James G., et al., "Image Quality of a Prototype Direct Conversion
Detector for Digital Mammography," Society of Photo-Optical Instrumentation
Engineers, 1999.
He, Z., et al., "3-D position sensitive CdZnTe gamma-ray spectrometers," Nuclear
Instruments & Methods in Physics Research, A 422, 1999, pp. 173-178.
Matteson, James L., "Position-sensitive CZT detector module," SPIE (Society
of Photo-Optical Instrumentation Engineers), vol. 3446, Jul. 1998, pp. 192-201.
Yasillo, Nicholas J., et al., "Design Considerations for a Single Tube Gamma
Camera," IEEE Transactions on Nuclear Science, vol. 37, No. 2, Apr. 1990,
pp. 609-615.
Bird, A.J., et al., "Images obtained with a compact gamma camera," Nuclear
Instruments & Methods in Physics Research, A 499, 1990, pp. 480-483.
Holl, P., et al., "A Double-sided Silicon Strip Detector with Capacitive Readout
and a New Method of Integrated Bias Coupling," IEEE Transactions on Nuclear
Science, vol. 36, No. 1, Feb. 1989, pp. 251-255.
Hall, G., "Silicon Drift Chambers," Nuclear Instruments & Methods in
Physics Research, A 273, 1988, pp. 559-564.
Aarsvold, J.N. et al., "Modular scintillation cameras: a progress report," SPIE
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II, 1988, pp. 319-325.
|
Primary Examiner: Gabor; Otilia
Attorney, Agent or Firm: Snider & Associates, Snider; Ronald R.
Parent Case Text
CROSS REFERENCE TO PROVISIONAL PATENT APPLICATION
This application claims the benefit of the filing date of U.S. Provisional Patent
Application No. 60/330,597 filed Oct. 25, 2001, the disclosure of which is incorporated
herein by reference.
Claims
1. A method of imaging a portion of a human body, the method comprising the steps of:
providing a radiopharmaceutical to said portion of said human body, said radiopharmaceutical
producing radiation;
positioning a detection system proximate to said portion of said human body,
wherein
said detection system is comprised of a compact and portable detector, wherein
said detector comprised of two dimensional plurality of pixels;
determining a direction and an energy for a portion of said radiation entering
said detection system from a plurality of pixels;
processing said direction and energy data for said portion of radiation; and
displaying an image in real time of said portion of said human body, wherein
said image is based on said processed direction and energy data.
2. The method of claim 1, wherein said portion of said human body is an organ.
3. The method of claim 1, wherein said portion of said human body is a breast.
4. The method of claim 1, further comprising using the image to determine the
position of at least one section of said portion of the said living organism which
emits gamma rays at a higher rate than the background and locating said section
using rulings on a display.
5. The method of claim 1, wherein said imaging method produces a hyperspectral image.
6. The method of claim 1, further comprising a step of detecting at least one
section of said portion of the said living organism which has higher uptake of
the said radiopharmaceutical over the rest of the said portion.
7. The method of claim 1, wherein said imaging method uses a collimator to restrict
the angle of the radiation for controlling the direction of the radiation that
enters its aperture.
8. The medical imaging system of claim 1, wherein said radiation emitted from
a radiopharmaceutical is selected from the group of particles consisting of photon,
electron, positron, proton and alpha particle.
9. A medical imaging system for imaging a portion of a living organism, said
portion treated with a radiopharmaceutical said radiopharmaceutical emitting radiation, comprising:
a detector comprised of a plurality of two-dimensional pixels, wherein an entrance
aperture of said detector is external to said living organism and proximate to
said portion of said living organism, wherein said emitted radiation enter into
said detector and are absorbed within said detector;
a multi channel readout system coupled to at least one said pixel of said detector;
a processor coupled to said multi-channel readout system; and
a monitor coupled to said processor, said monitor displaying an image of radiation
coming from the said portion of said living organism in real time.
10. The medical imaging system of claim 9; wherein a portion of said emitted
radiation enters the said detector, makes a photoelectric interaction wherein a
position of interaction is determined from energy deposited inside at least one
of the said pixels of the said detector and wherein the position of interaction
is used to determine direction of the incident radiation.
11. The medical imaging system of claim 9, further comprising a collimator to
restrict an angle of radiation incident on the said detector to determine the direction
of the incident radiation.
12. The medical imaging system of claim 9, wherein said radiopharmaceutical is
tagged with a radioactive material which is selected from the group consisting
of thallium-201, technetium-99m, iodine-123, iodine-131, and fluorine-18.
13. The medical imaging system of claim 9, further comprising a handle for holding
the said medical imaging system.
14. The medical imaging system of claim 9, wherein said detector is selected
from at least one of the detector types including pad detectors, pixel detectors,
double sided microstrip detectors, double sided strip detectors, and double sided
pixel detectors.
15. The medical imaging system of claim 9, wherein both sides of the said detector
contain said plurality of pixels.
16. The medical imaging system of claim 9, wherein said pixels are made from
ohmic type electrodes.
17. The medical imaging system of claim 9, wherein said pixels are made from
blocking type electrodes.
18. The medical imaging system of claim 9, wherein said plurality of pixels have
a pitch varying from 0.01 to 10 mm.
19. The medical imaging system of claim 9, wherein there is at least one detector plane.
20. The medical imaging system of claim 9, wherein said detector material is
selected from the group of detector materials consisting of Silicon, HPGe, BGO,
CdWo4, CsF, NaI(Tl), CsI(Na), CsI(Tl), CdTe, CdZnTe, HgI
2, GaAs, and PbI
2.
21. The medical imaging system of claim 9, wherein said imaging system is made
compact and portable.
22. The medical imaging system of claim 9, wherein said radiation emitted from
a radiopharmaceutical is selected from the group of particles consisting of photon,
electron, positron, proton and alpha particle.
Description
FIELD OF INVENTION
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.
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
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
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.
Recently breast imaging studies with
99mTc SestaMIBI and
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
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:
1. The large size of the gamma camera makes it difficult to position optimally
relative to the breast.
2. Not usable during surgery due to the large size, low sensitivity and low spatial resolution.
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 (≈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.
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
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.
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.
A high sensitivity SenPROBE with excellent spatial resolution is required to
make
this new method viable. The SenPROBE will provide the following enhancements:
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 5×5 cm2
active area will be developed.
2. Gamma rays between about 50 and 250 keV will be detected with high quantum efficiency.
3. Imaging probe size about 5×5×1 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.
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.
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.
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.
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.
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.
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.
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.
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.
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, CeF, Nal(TI), CsI(Na), CsI(TI), CdTe, CdZnTe, HgI
2, GaAs, and PbI
2.
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.
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
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.
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.
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.
FIG. 4 is a spectrum of
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 μs. A Gaussian
fit to the 166 keV peak ignoring the trapping tail has a width (σ) 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.
FIG. 5 is a spectrum of
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 μs. 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.
FIG. 6 is a block diagram of the new integrated circuit showing the analog circuits
for one channel and some of the digital circuits.
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.
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
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
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.
The energy resolution of our current CdZnTe pixel detectors (FIG. 3)
30
with 4×8 pixels and 3×3 mm
2 pixel pitch, read out by the RENA
chip, has been measured using
57Co,
139Ce, and
241Am
sources. Sample energy spectra are shown in FIG.
4 and FIG.
5.
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.
We plan to optimize the pixel size for the reported portable gamma camera (SenProbe).
The CdZnTe pixel array
30 with 3×3 mm
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.
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.
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.
FIG. 4 shows a spectrum of
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 μs. A Gaussian
fit to the 166 keV peak ignoring the trapping tail has a width (σ) 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.
FIG. 5 shows a spectrum of
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.
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
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.
The SenPROBE (FIG. 1
10 and FIG. 2
20) will be developed to have
an active area of about 5×5 cm
2. The most likely area will be about
4"×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
13.
The cable
13 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.
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.
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.
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.
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.
The MicroImager (FIG. 8)
80 will be developed to have an active area of
about 3"×3" to about 5"×5". The most likely area will be about 4"×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.
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.
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.
The position resolution will depend on the collimator
81 used. The best
position resolution achievable is expected to be about 1 mm.
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 acqusition 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.
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