Proximity detection system for imaging systems and method for sensing proximity

A proximity sensor array for a medical imaging system includes a flexible substrate configured to be mounted to a detector, and a plurality of sensors disposed on the substrate, the flexible substrate being deformable to contact a sensing surface of the detector. A method of fabricating a proximity sensor array and a medical imaging system are also described herein.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates generally to imaging systems, and more particularly to proximity detection system for a medical imaging system.

Diagnostic nuclear imaging is used to study radionuclide distribution in a subject, such as a patient. Typically, one or more radiopharmaceuticals or radioisotopes are injected into the patient. Gamma camera detector heads, typically including a collimator, are placed adjacent to a surface of the patient to monitor and record emitted radiation. At least some known gamma camera detector heads are rotated around the patient to monitor the emitted radiation from a plurality of directions. The monitored radiation data from the plurality of directions is reconstructed into a three dimensional image representation of the radiopharmaceutical distribution within the patient.

Generally, the resolution of a gamma camera degrades with increasing distance between the imaged organ and the detector. In operation, it is desirable to place the gamma camera as close as possible to the patient to facilitate minimizing the loss of resolution. While it is desireable to place the gamma camera as close as possible to the patient to perform an imaging operation, it is also desireable to reposition the gamma camera to avoid contact with the patient.

Accordingly, at least some known conventional gamma cameras include a proximity sensor that alerts the operator that the gamma camera may be too close to the patient. However, conventional proximity sensors typically have a flat profile and are therefore not easily adaptable to many gamma cameras, such as for example, cameras having curved scanning surfaces. Moreover, conventional proximity sensors typical protrude a distance beyond the detector surface to enable the proximity sensor to identify a potential contact prior to the gamma cameras contacting the patient or contacting each other. The conventional proximity sensors protrude a distance to interfere or prohibit the gamma cameras from being positioned in certain scanning arrangements, such as, for example, an L-mode configuration. Moreover, the conventional proximity sensors are relatively expensive, thus increasing the overall cost of an imaging system.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a proximity sensor array for a medical imaging system is provided. The proximity sensor array includes a flexible substrate configured to be mounted to a detector, and a plurality of sensors disposed on the substrate, the flexible substrate being deformable to contact a sensing surface of the detector.

In another embodiment, a method of fabricating a proximity sensor array is provided. The method includes forming a plurality of sensors on a flexible substrate, the flexible substrate being deformable to contact a sensing surface of a detector, the sensors including a plurality of transmitters and a plurality of receivers arranged in rows and columns, and electrically coupling the plurality of receivers in each row in electrical series.

In a further embodiment, a medical imaging system is provided. The medical imaging system includes a gantry, at least one gamma camera coupled to the gantry, and a proximity sensor array coupled to the gamma camera. The proximity sensor array includes a flexible substrate configured to be mounted to the gamma camera, and a plurality of sensors disposed on the substrate, the flexible substrate being deformable to contact a sensing surface of the detector.

DETAILED DESCRIPTION OF THE INVENTION

Described herein is a proximity detection system that may be utilized to determine the location of an object contacting one or more sensors in the detection system. More specifically, the output from the sensors may be utilized by the imaging system to either reposition at least one gamma camera or to provide a visual and/or audio indication that an object is contacting the gamma camera.

FIG. 1is a perspective view of an exemplary nuclear medicine imaging system10constructed in accordance with various embodiments, which in this embodiment is a single-photon emission computed tomography (SPECT) imaging system. The system10includes an integrated gantry12that further includes a rotor14oriented about a gantry central bore16. The rotor14is configured to support one or more nuclear medicine (NM) cameras18and20. The cameras18and20may be embodied as gamma cameras, Ultra-Fast Cameras (UFC), SPECT detectors, multi-layer pixelated cameras (e.g., Compton camera), and/or positron emission tomography (PET) detectors. It should be noted that when the medical imaging system10is a multi-modality system, a CT camera or an x-ray camera may be provided, such as an x-ray tube (not shown) for emitting x-ray radiation towards the detectors. The rotor14is further configured to rotate axially about an examination axis22.

A patient table24may include a bed26that is slidingly coupled to a bed support system28, which may be coupled directly to a floor or may be coupled to the gantry12through a base30coupled to the gantry12. The bed26may include a stretcher32slidingly coupled to an upper surface34of the bed26. The patient table24is configured to facilitate ingress and egress of a patient (not shown) into an examination position that is substantially aligned with the examination axis22. During an imaging scan, the patient table24may be controlled to move the bed26and/or stretcher32axially into and out of the bore16. The operation and control of the imaging system10may be performed in any manner known in the art. It should be noted that the various embodiments may be implemented in connection with imaging systems that include rotating gantries or stationary gantries.

In the exemplary embodiment, the imaging system10also includes a proximity detection system (PDS)100which may form part of an automatic body contouring system (ABS) not shown. In operation, the PDS100facilitates maintaining the gamma cameras18and20in relatively close proximity to the imaged subject, such as for example, a patient being imaged without contacting the patient or each other. Accordingly, and in the exemplary embodiment, the PDS100includes a first patient safety device or sensor array110and a second patient safety device or sensor array112. As used herein, an array is an arrangement of electronic parts that together form the sensor arrays110and/or112. The sensor array110is coupled to a scanning surface of the camera18and the sensor array112is coupled to a scanning surface of the camera20. In one embodiment, the sensor arrays110and112are coupled directly to the scanning surface of the cameras18and20, respectively. In the exemplary embodiment, the cameras18and20each include a collimator,40and42, respectively and the sensor arrays110and112are coupled to the scanning surface of the collimators40and42.

Although the following discussion describes the construction and operation of the array sensor110, it should be realized that the sensor array112is substantially similar to the sensor array110, but disposed on a different gamma camera, for example, the gamma camera20shown inFIG. 1. The sensor array110has a length120and a width122. In the exemplary embodiment, the length120and the width122are substantially the same as a length124and a width126of the scanning surface of the camera18. In another embodiment, the length120and the width122may be selected to be smaller or larger than the length124and the width126of the gamma camera18. For example, the length120and/or width122may be selected to be larger than either the length124or the width126of the gamma camera18to enable the sensor array110to cover a portion of the sides of the gamma camera18and therefore cover portions of the gamma camera18that may have beveled surfaces that may potentially contact surfaces of the gamma camera20in some modes of operation.

In the exemplary embodiment, the sensor array110is fabricated to be flexible to enable the sensor array110to be mounted flush to the surface of either the gamma camera18or the collimator40(shown inFIG. 1) when utilized. More specifically, after the sensor array110is coupled to the gamma camera18, the sensor array110has a profile that is substantially complementary to a profile of the gamma camera18such that the sensor array110is substantially flush with, and in physical contact with, the scanning surface of the gamma camera18. Accordingly, portions of the sensor array110may be fabricated using, for example, a flexible material such as, but not limited to, metal-on-polyimide, an aramid, a fluorocarbon, and a polyester.

The outputs from the sensor arrays110and112are input to a computer114. As used herein, the term “computer” or “module” may include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set computers (RISC), ASICs, logic circuits, and any other circuit or processor capable of executing the functions described herein. The above examples are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of the term “computer”.

The computer114is coupled to, and receives information from, the sensor arrays110and112. In the exemplary embodiment, the computer114may include a proximity detection system module116that is configured to utilize the information received from the sensor arrays110and112to reposition the cameras18and20and/or to generate a visual and/or audio indication to an operator that the cameras18and/or20may contact each other or the patient. In operation, the contouring module116executes a set of instructions that are stored in one or more storage elements, in order to process the data received from the sensor arrays110and112. The storage elements may also store data or other information as desired or needed. The storage element may be in the form of an information source or a physical memory element within either the computer114or the module116.

FIG. 2is a block diagram of the exemplary imaging system10shown inFIG. 1. It should be noted that the imaging system may also be a multi-modality imaging system, such as an NM/CT imaging system. The imaging system10, illustrated as a SPECT imaging system, generally includes, as discussed above, the gantry12and the rotor14that is oriented about a gantry central bore16. The rotor14is configured to support one or more NM pixelated cameras18and20.

The patient table24is configured to facilitate ingress and egress of a patient25into an examination position that is substantially aligned with the examination axis22. During an imaging scan, the patient table24may be controlled by a table controller unit800to move the patient table24axially into and out of the bore16. In the exemplary embodiment, the imaging system10also includes the proximity detection system (PDS)100. In operation, the PDS100facilitates maintaining the gamma cameras18and20in relatively close proximity to a region of interest, such as for example, a patient being imaged without contacting the patient or each other. Accordingly, and in the exemplary embodiment, the PDS100includes a first patient safety device or sensor array110and a second patient safety device or sensor array112. The outputs from the sensor arrays110and112are input to the computer114.

The gamma cameras18and20may be located at multiple positions (e.g., in an L-mode configuration) with respect to the patient25. It should be noted that although the gamma cameras18and20are configured for movable operation along (or about) the gantry12. The controller unit80may control the movement and positioning of the patient table24with respect to the gamma cameras18and20and the movement and positioning of the gamma cameras18and20with respect to the patient25to position the desired anatomy of the patient25within the fields of view (FOVs) of the gamma cameras18and20, which may be performed prior to acquiring an image of the anatomy of interest. The controller unit800includes a table controller802and a gantry motor controller804that each may be automatically commanded by the computer114, manually controlled by an operator, or a combination thereof. The table controller802may move the patient table24to position the patient25relative to the FOV of the gamma cameras18and20. The imaging data may be combined and reconstructed into an image, which may comprise 2D images, a 3D volume or a 3D volume over time (4D).

A Data Acquisition System (DAS)810receives analog and/or digital electrical signal data produced by the gamma cameras18and20and decodes the data for subsequent processing as described in more detail herein. An image reconstruction processor812receives the data from the DAS810and reconstructs an image using any reconstruction process known in the art. A data storage device814may be provided to store data from the DAS810or reconstructed image data. An input device816also may be provided to receive user inputs and a display818may be provided to display reconstructed images.

In various embodiments, the sensor arrays described herein may also include a pressure safety device (PSD), capable of deactivating motorized motion of parts of the camera when the patient makes physical contact with the PSD thus preventing injuries to the patient.FIG. 3schematically depicts a rigid-plate.

In various embodiments such PSD may optionally be combined or placed with a PDS according to embodiments of the invention. For example, a PSD500is shown inFIG. 3. The PSD500includes a rigid plate502resting on a plurality of springs504and having switches510between the plate and the detector. The PSD500may be integrated with a PDS by placing the capacitive PDS sensor on the plate502. In this embodiment, the switches continue to act as in the art, providing safety. The plate502of PSD500may be made as a rigid printed circuit board (PCB). The PCB may optionally be made rigid enough to act as the plate. In the exemplary embodiment, the PSD500includes a substantially rigid pressure sensing plate502, a plurality of springs504, and micro-switches508and510. For example, four micro-switches may be positioned at the corners of a substantially rectangular plate502. In the exemplary embodiment, the sensing plate502is substantially rectangular and includes four springs504, wherein a spring504is located at each corner of the sensing plate502. As shown inFIG. 3, the PSD500may be mounted to a surface of the gamma camera18or optionally to a surface of the collimator40.

In operation, when an object or the patient contacts the sensing plate502, the sensing plate502is depressed. Depressing the sensing plate502causes the springs504and506to depress such that at least one of the micro-switches508and/or510is activated. Activating at least one of the micro-switches508and/or510causes the micro-switch to output a signal that is utilized by the imaging system to determine the location of the object contacting the PSD500. More specifically, the output is utilized by the imaging system to halt motorized motion of camera parts that may endanger the patient. Optionally the output is utilized by the imaging system to either reposition one or both of the gamma cameras18and/or20or to provide a visual an/or audio indication that an object is contacting the gamma camera18. It should be realized that only a single pressure sensing device is illustrated inFIG. 3, the PSD500may include a plurality of sensing devices that are arranged in a grid that is coupled to the surface of the gamma camera18or the collimator40.

The PSD500may be configured to deactivate automatic control of moving parts of the imaging system10, for example the rotor14, the gamma cameras18and/or20, and/or the bed26, when the PSD500contacts a patient being scanned. After the PSD500detects contact with the patient or other object, in one embodiment, the system10stops all moving parts of system10. Thereafter, control of the moving parts may be restricted to manual control and motion that may bring either the gamma camera18or the gamma camera20nearer to the patient being scanned, even in manual control, until contact between the PSD500and the patient is corrected.

FIG. 4is side cross-sectional view of a portion of another exemplary PSD550that may be incorporated with the various sensor arrays described herein. Optionally, the PSD550may be utilized separately from the sensor arrays described herein. In the exemplary embodiment, the PSD550has a rubber structure that is glued to the detector. There is an array of contacts acting as safety switches. Moreover, a proximity sensor forming a part of the PSD550has a flexible upper layer with multiple contacts552. A lower layer554may be rigid or flexible (however, rigid lower layer may restrict the device to a flat plane, while a completely flexible configuration allows bending the device, for example to conforms to the cylindrical shape of a nuclear camera or CT bore).

For example, in one embodiment, the PSD550includes an upper flexible pressure sensing plate552, a lower pressure sensing plate554and a plurality of flexible dividers556. The flexible dividers556are utilized to form separate sensing elements, such as for example, an element560, and element562. . .n, etc. Each element, such as element560includes a pair of metallic pads. For example, each element includes a metallic pad570that is coupled to a lower surface of the sensing plate552and a metallic pad572that is coupled to an upper surface of the sensing plate554.

In operation, when an object or the patient contacts the sensing plate552, the sensing plate552is depressed. Depressing the sensing plate552causes the metallic pad570to come into physical and electrical contact with the metallic pad572to form an electrical circuit. In operation, the electrical circuit outputs a signal that is utilized by the imaging system10to determine the location of the object contacting the PSD550. More specifically, the output is utilized by the imaging system10to either reposition one or both of the gamma cameras18and/or20or to provide a visual and/or audio indication that an object is contacting the gamma camera18.

The PSD550may be configured to deactivate automatic control of moving parts of the imaging system10, for example the rotor14, the gamma cameras18and/or20, and/or the bed26, when the PSD550contacts a patient being scanned.

FIG. 5is a block diagram of an exemplary proximity sensor250formed in accordance with various embodiments. The proximity sensor250includes a sensor cell252that is connected to the electronics. The sensor cell252is deposited on an insulating substrate256. The proximity sensor250includes a transmitter electrode260, a receiver electrode262, and optionally a ground electrode266that optionally has similar dimensions to the receiver electrode262and is disposed on an opposite side of the substrate256from the receiver electrode262. The proximity sensor250also includes a signal source268that in one exemplary embodiment, is a 600 kHz, 10V sinusoidal signal source that is connected to the transmitter electrode260. In operation, there is a small equivalent capacitance280between the transmitter electrode260and the receiver electrode262. In operation, when a conductive and potentially grounded object, such as a finger282or other patient body part is near the sensor cell252it interferes with the current flow from the transmitter260to the receiver262, causing a change in that current. A possible explanation is that the electromagnetic field is disturbed and the coupling between the transmitter260and receiver262is decreased, thus the signal detected will decrease. The sensor250may include an optional capacitor288that is an AC coupler of a current follower amplifier290(having a feedback capacitor292in the loop). In operation, an AC/DC converter294is a synchronized rectifier (preferred for small signal rectification and noise rejection; however other rectification means such as Diode Bridge, a “Precision rectifier” or a “lock in amp” rectifier may be utilized. The rectified signal is optionally “low pass filtered” by an optional filter296to remove noise and ripple, and digitized by an analog/digital converter298, analyzed116and transmitted to the motion controller804shown inFIG. 2.

For example, during SPECT data acquisition the information may be used by the motion controller804to move the detectors such that the distance between them and an object282is maintain as small but safe distance in spite of the gantry rotation and possible patient motion such as breathing.

FIG. 6illustrates the proximity sensor250shown inFIG. 5coupled to an exemplary sensor array110. More specifically,FIG. 6shows the muxing of transmitter and receiver channels. It should be realized that the motion of the detectors is slow, thus, the distance to the patient is generally sampled up to few times a second. Frequent sampling, allows for reduction in the complexity, cost and energy consumption of the system by serially sampling locations (sensor cells) on the surface of the proximity sensor (PDS), one at a time. In various embodiments, muxing is optional, and there are many possible muxing strategies. To be sensitive to a small body part such as a finger or the tip of the nose, a “transmitter/receiver pair” should be of an area similar to the body part: for example ˜1×1 1×2 or 2×2 cm (but other sizes may be used), thus, on a 60×50 cm detectors there are ˜750 to 3000 such transmitter/receiver pairs. In various embodiments, each transmitter/receiver pair may be wired individually. However, the muxing allows interrogating one (or more) pairs at a time. Moreover, different frequencies may be utilized for each active transmitters, and use coherent detection.

In the exemplary embodiment, the system100includes at least the sensor array110, a transmitter multiplexer130, and a receiver multiplexer132. In the exemplary embodiment, the sensor array110includes a plurality of sensing elements that are discussed in more detail below. In operation, the transmitter multiplexer132transmits a signal to various sensing elements on the sensor array110via a plurality of input lines136. Moreover, the receiver multiplexer134receives a plurality of output signals from the sensor array110via a plurality of output lines138. In the exemplary embodiment, the transmitter multiplexer1320and the receiver multiplexer134may be mounted on a side of the gamma camera18. Optionally, the transmitter multiplexer132and the receiver multiplexer134may be located remote from the gamma camera18, within, for example, the computer114or incorporated within the proximity detection system module116. In operation, the inputs supplied to the sensor array110via the transmitter multiplexer132and the outputs received from the receiver multiplexer134may be utilized to either reposition the gamma camera18or to provide a visual and/or audio indication that the gamma camera is close to and/or contacting either the gamma camera20, the patient being imaged, or any other object detected by the sensor array110.

The sensor array110includes a plurality of transmitters and receivers that are arranged in rows and columns. For example, referring toFIG. 7, the sensor array110is shown as including five rows140,142,144,146, and148of transmitters150and four rows152,154,156, and158of receivers160. It should be realized that althoughFIG. 7illustrates only nine rows of transmitters and receivers, that in the exemplary embodiment, the sensor array110includes more than nine rows of transmitters and receivers.

The sensor array110, in one embodiment, is configured such that rows of transmitters are interleaved with rows of receivers. For example, the row142of transmitters160is disposed between a pair of rows152and154of receivers160. Accordingly, in the exemplary embodiment, each respective row of transmitters is positioned adjacent to at least one row of receivers such that no two rows of transmitters or receivers are disposed adjacent to each other. Moreover, the transmitters150and the receivers160are also arranged in columns, such as, for example, columns170,172,174, and176. As shown inFIG. 7, each respective column170,172,174, and176is arranged such that the transmitters150are interleaved with the receivers160. For example, the transmitter142ais disposed between a pair of receivers152aand154a. Accordingly, in the exemplary embodiment, each respective transmitter150is positioned adjacent to at least two receivers160such that no two transmitters or receivers are disposed adjacent to each other.

The receivers in each respective row of receivers are coupled together electrically. For example, the receivers152a,152b,152c, and152din row152are coupled together; receivers154a,154b,154c, and154din row154are coupled together; receivers156a,156b,156c, and156din row156are coupled together; and receivers158a,158b,158c, and158din row158are coupled together. Moreover, the outputs from each of the respective receivers in a single row are transmitted to the receiver multiplexer134via a single output line.

For example, in operation when an output is requested from the row152, the outputs from each of the receivers152a,152b,152c, and152din the row152are transmitted concurrently to the receiver multiplexer134via an output line152R. Additionally, the outputs from the receivers154a,154b,154c, and154din row154are transmitted concurrently to the receiver multiplexer134via an output line154R. The outputs from receivers156a,156b,156c, and156din row156are transmitted concurrently to the receiver multiplexer134via an output line156R, and the outputs from receivers158a,158b,158c, and158din row158are transmitted concurrently to the receiver multiplexer134via an output line158R.

As shown inFIG. 7, and in the exemplary embodiment, various transmitters are coupled together such that at least a portion of the transmitters, in each respective column, are coupled together electrically. More specifically, transmitters for each respective column are coupled together such that alternating transmitters, or every other transmitter, is coupled to the same input line.

Accordingly, in operation when an input signal is input to the sensor array110, via an input line170T1, the input signal is subsequently supplied to the transmitters140a,144a, and148ain column170because transmitters140a,144a, and148aare coupled together in series. Additionally, when an input signal is supplied to the sensor array110, via an input line170T2, the input signal is subsequently supplied to the transmitters142aand146a, an input signal supplied to the sensor array110, via an input line172T1provides an input to the transmitters140b,144b, and148bin column172, an input signal supplied to the sensor array110, via an input line172T2provides an input to the transmitters142band146bin column172, an input signal supplied to the sensor array110, via an input line174T1provides an input to the transmitters140c,144c, and148cin column174, an input signal supplied to the sensor array110, via an input line174T2provides an input to the transmitters142cand146cin column174, an input signal supplied to the sensor array110, via an input line176T1provides an input to the transmitters140d,144d, and148din column176, and an input signal supplied to the sensor array110, via an input line176T2provides an input to142dand146din column176. It should be realized that although the output lines136(seen inFIG. 6) are shown as being on a first side of the sensor array110and the input lines138(seen inFIG. 6) are shown on a different side of the sensor array, the output and input lines may be disposed on any side of the sensor array100or on the same side of the sensor array110.

In operation, the input and output lines136and138are activated/and or deactivated in a predetermined sequence to both supply input signals to the sensor array110and to also receive information from the sensor array110. An adjacent transmitter and receiver may form a sensing cell. A cell, as used, in various embodiments defines a single transmitter and a single transceiver on the sensor array110. Accordingly, the sensor array110includes a plurality of cells. For example, as shown inFIG. 7, the sensor array includes a cell that may be defined by the transmitter140aand the receiver152a. A cell may include the transmitter142aand the receiver154a, etc. As can be seen inFIG. 7, a cell includes a single transmitter and a single receiver in the same column. Moreover, a cell may include a transmitter and an adjacent receiver whether the receiver is above or below the transmitter in the same column. For example, a cell may include the transmitter148dand the receiver158d.

In operation, the sensor array110is iteratively scanned to determine if contact with any portion of the sensor array110has occurred. Initially an input signal is supplied via the input line170T1, to transmitters140a,144a, and146a. Accordingly, if the cell200detects an object, via a capacitance that occurs between a transmitter and a receiver, the signal from the input line170T1will be transmitted to the output line152R via the combination of the transmitter140aand the receiver152a. More specifically, although the input signal is supplied to140a,144a, and146a, only the receiver152a, which in combination with the transmitter140aforms the cell200is read via the output line152R. Thus, only a single cell is read at a time to determine if an object has come close to, and influenced the cell. Next, for example, the cell202, which includes the transmitter142aand the receiver154amay be read. To read the cell202, an input signal is supplied via the input line170T2, to transmitters142aand146a. Accordingly, if the cell202detects an object, the signal from the input line172T2will be transmitted to the output line152R via the combination of the transmitter142aand the receiver154a. More specifically, although the input signal is supplied to transmitters142aand146a, only the receiver154a, which in combination with the transmitter142awhich forms the cell204, is read via the output line154R. Thus, only a single cell is read at a time to determine if an object has come close to, and influenced the cell. It should be realized that the transmitters150and the receivers160may be arranged to form a wide variety of arrays and cells. Moreover, it should be realized that in the exemplary embodiment, only one cell is read at a time, via the operation of the input and output lines. In this arrangement a location of an object in close proximity to, or actually contacting a portion of the sensor array110, may be specifically identified by determining the exact cell indicating that a contact or touch has occurred. Reading one cell (or few cells, depending on MUXing strategy) at a time improves the Signal to Noise Ratio (SNR) and improves reliability and sensitivity of proximity detection.

More specifically, when transmitter line170T1is activated, the transmitter electrodes140a,144a, and149aare powered. If, at that time line152R is activated, currents from receiver electrodes152a,152b,152cand152dare summed and detected. Thus, only “sensor cell200” is effectively detecting presence of patient above it. On the other hand, if the transmitter line170T2is activated, then transmitter electrodes146a, and142aare powered. If at that time line152R is activated, currents from receiver electrodes152a,152b,152cand152dare summed and detected. Thus, only “sensor cell202” is effectively detecting presence of patient above it. In the exemplary embodiment, the configuration shown inFIG. 7may be implemented using a plurality of layers that include for example, two conductive layers, one on each side of the PCB, or a one-sided, two-layer PCB or a three layers PCB, or other known PCB manufacturing techniques. Not seen in this figure are the optional ground pads266′ that are positioned, each under (opposite to the direction towards the patient) a corresponding receiver pad. These will be seen in several cross sectional views and inFIG. 8a-8c.

FIGS. 8A,8B, and8C, respectively show different conductor layers in a three layers PCB that may be utilized to form the sensor array shown inFIG. 7. In the exemplary embodiment,FIG. 8Aillustrates an exemplary top layer350that may be formed to include the receiver electrodes and connecting lines360to the receiver MUX134.FIG. 8Bis a central layer352that may be formed to include the transmitter electrodes and connecting lines362to the transmitter MUX132.FIG. 8Cis an optional bottom layer354that shows the ground electrodes266′ and connecting line364grounding the ground electrodes. In an exemplary embodiment, layers350and352may be deposited on the side of the substrate that is close to the patient, while layer354may be deposited on the opposite side of the substrate (as seen in the example ofFIG. 5. The optional ground electrodes serve to reduce coupling of signals from transmitters to receivers which is not via the effective capacitance formed by the detected object (for example by isolating the receivers from signals being coupled to the conductive structures of the gamma camera such as the collimator), thus improving the SNR. It should be realized thatFIGS. 8A-8Care exemplary, and that the sensor arrays described herein may be fabricated in other manners. For example, the transmitters and the ground electrodes may be formed on the same layer, and the connecting traces routed using “vias”.

FIG. 9is a plan view of another exemplary sensor array400. The sensor array400also includes a plurality of transmitters150and receivers160that are configured to perform differential sensing. In this embodiment, the transmitters160and the receivers are arranged in columns. Moreover, each transmitter150is disposed between a pair of receivers160. Additionally, both the transmitters150and receivers160are staggered from column to column such that a transmitter410in a first column412is offset from a transmitter420in a second column422. Moreover, a transmitter430in a third column432is offset from a transmitter440in a fourth column442. Additionally, the transmitter410is disposed parallel to the transmitter430and the transmitter420is disposed parallel to the transmitter440.

In this embodiment, the transmitters in each column are coupled together and the receivers in each row are coupled together. Accordingly, in operation and similar to sensor array110described above, each row of receivers is read sequentially. More specifically, an input signal is first supplied to the column412of transmitters. Next, a single row of receivers is read, for example, row S1. As discussed above, even though a signal is supplied to each transmitter in the column412, only a single row of receivers is read. Therefore, a cell that includes, for example, a transmitter450and a receiver452is defined and read separately from the other cells, such as a cell that includes the transmitter450and a receiver454.

FIG. 10is side cross sectional view of a portion of another exemplary sensor array600that includes a proximity sensor system602that may be incorporated with the sensor array600or various other sensor arrays described herein. Specifically,FIG. 10illustrates a proximity sensor and a flexible PSD formed in one device. In the exemplary embodiment, the sensor array600includes four PCB layers610,612,614, and616. In this embodiment, a plurality of receivers620are disposed on the layer610and a plurality of transmitters622are disposed on the layer612. The sensor array600also includes a plurality of ground electrodes624, wherein each respective ground is disposed proximate to a respective receiver620. The sensor array600further includes a plurality of electrical connection lines630disposed for example on the third layer614that electrically couple each respective transmitter622to the transmitter multiplexer132described above. The sensor array600further includes a plurality of electrical connection lines631disposed for example on the first layer610that electrically couple each respective receiver620to the receiver multiplexer134described above. The fourth layer616is formed as ground plane to include a plurality of metallic pads640.

In operation, when an object is sensed by the receiver620, a capacitance is generated. The capacitance is then read by the receiver multiplexer134as described above. More specifically, assume that the transmitter144dand the receiver154dform a single cell. Accordingly, when an object is sensed, e.g. comes close to a cell formed by the receiver154dand the receiver154d, it forms a capacitance which is read when the system scans the cell that is composed of the transmitter144dand the receiver154d. It should be realized that the cells are continuously and iteratively scanned to determine when an object has contacted the sensor array. In the exemplary embodiment, the sensor array18is coupled to the gamma camera18or collimator40using an adhesive material336. Sensor array600may act for example as the upper flexible pressure sensing plate552of PSD550flexible dividers556and lower pressure sensing plate554are not seen in this figure.

FIG. 11is side cross sectional view of a portion of another exemplary sensor array650that includes a proximity sensor system652that may be incorporated with the sensor array650or various other sensor arrays described herein. Specifically,FIG. 11illustrates another embodiment of a proximity sensor and a flexible PSD formed in one device. For drawing clarity flexible dividers are not seen in this figure. In the exemplary embodiment, the sensor array652includes two PCBs660and662. In the exemplary embodiment, a plurality of receivers670are disposed on a first side672of the PCB660and a plurality of ground plates674are disposed on a second side676of the PCB660. The sensor array650further includes a plurality of transmitters680that are disposed on a first side682of the PCB662and an optional ground plate674that is disposed on a second side676of the PCB660. The sensor array650further includes a plurality of electrical connection lines690that are disposed on the first side682of the PCB662to interconnect the transmitters680. The sensor array652further includes a plurality of metallic pads692. Optionally, each metallic pad692is coupled to a respective ground plate674, and a plurality of metallic pads694, located opposite to pad692. Optionally each metallic pad694is coupled between a pair of transmitters680. Pads694and692form a PSD such as PSD550seen inFIG. 4. For drawing clarity flexible dividers are not seen in this figure. In this embodiment layer660acts as flexible pressure sensing plate552, while layer662acts as pressure sensing plate554and is closer to the patient.

In operation as a PSD, when an object contacts the plate660, the flexible PCB660flexes or bends until at least one of the metallic pads694contacts a respective metallic pad692. The metallic pad694contacting the metallic pad692causes an electrical circuit to be formed between the contacts signaling physical contact with an object. When acting as a PDS, sensor array650behaves as disclosed above.

FIG. 12is a side cross sectional view of a portion of the sensor array110shown inFIG. 1. In one embodiment, the sensor array110includes a plurality of transmitters260′ disposed on a printed circuit board (PCB)300. In the exemplary embodiment, transmitters260′a,260′b, and250′care shown. PCB300may be flexible, or a rigid PCB if array110is flat. The PCB300is formed to include the various electrical connections that are utilized to connect the transmitters260′ to the transmitter multiplexer132as described above. Referring again toFIG. 12, the sensor array also includes a plurality of lower PSD contacts310(two such contacts:310aand310bare seen) that are electrically coupled to the PCB300. Optionally, lower PSD contacts are places on, and in electrical contacts to ground electrode pads266′ (two such ground electrode pads266′aand266′bare seen inFIG. 12). The sensor array110further includes a flexible upper pressure sensing plate552′ which incorporates PSD contacts570′ and receivers262′ that is electrically separated from the PCB300using an insulating flexible dividers556′ (only one such separator is seen for drawing clarity). The flexible separator320may be fabricated for example from an insulating material, such as for example, a rubber material. The sensor array110further includes receivers262′ (two such receivers262′aand262′bare seen in this figure). As shown inFIG. 12, a metallic pad570′ is optionally coupled to each respective receiver262′.

In operation as a PSD, when an object contacts the pressure plate552′, the flexible plate552′ flexes or bends such that at least one of the metallic contacts570′ contacts a respective metallic contact310on the PCB300. In some embodiments, the direct electrical contact of the receiver to ground cased by pressure causes a strong decrease of the signal or elimination of the signal which may be interpreted as contact with the patient. In other embodiments, the PSD circuit optionally operates at a different frequency or at DC and is continuously monitored. For example, all the transmitters may be connected (via a coil or resistor) to some DC source. The DC current in the ground line (equivalent to line362inFIG. 9c) is zero as long as the PSD is not pressed and activated.

In operation as PDS, the AC signal is supplied to only one transmitters' column at a time and a signal is read from only one receivers' row at a time similarly to the way explained above. It should be realized that the cells are continuously and iteratively scanned to determine when an object has approached the sensor array. In the exemplary embodiment, the sensor array110is coupled to the gamma camera18or collimator40, for example using an adhesive material336.

The inputs and outputs to the sensor array, including the transmit multiplexer132and the receive multiplexer134may be housed within a single enclosure340. In one embodiment the enclosure340may be coupled to a side of the gamma camera18. Optionally, the enclosure340may be located remote from the gamma camera18. In the exemplary embodiment, the enclosure340is coupled to the gamma camera18via a connector342.

The above-described embodiments of a proximity detection system may provide a cost-effective and reliable means for examining a patient. In some embodiments, the imaging system includes a plurality of gamma cameras each having multiple degrees of freedom of movement, such that, during a scan, the gamma cameras may be automatically controlled, by the various sensor array described herein, to move the gamma cameras along a contour of the body of a patient to reduce the distance between the region of interest and the gamma camera sensitive face. An imaging system is also provided that may facilitate improving the resolution of the gamma cameras.

Exemplary embodiments of a proximity detection system are described above in detail. The automatic proximity detection system components illustrated are not limited to the specific embodiments described herein, but rather, components of each automatic proximity detection system may be utilized independently and separately from other components described herein. For example, the proximity detection system components described above may also be used in combination with other imaging systems.

A technical effect of the systems and methods described herein includes facilitating minimizing the distance between an organ of interest and an imaging system detector during an automatic imaging scan of a patient, and therefore facilitating reducing operator input to the scanning procedure and reducing the time necessary to perform a scan while improving the resolution of the imaging system.