CA2111284A1 - Scanning nuclear camera - Google Patents
Scanning nuclear cameraInfo
- Publication number
- CA2111284A1 CA2111284A1 CA002111284A CA2111284A CA2111284A1 CA 2111284 A1 CA2111284 A1 CA 2111284A1 CA 002111284 A CA002111284 A CA 002111284A CA 2111284 A CA2111284 A CA 2111284A CA 2111284 A1 CA2111284 A1 CA 2111284A1
- Authority
- CA
- Canada
- Prior art keywords
- energy
- gamma camera
- patient
- camera
- transmitters
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/04—Positioning of patients; Tiltable beds or the like
- A61B6/0487—Motor-assisted positioning
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/10—Application or adaptation of safety means
- A61B6/102—Protection against mechanical damage, e.g. anti-collision devices
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/42—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for detecting radiation specially adapted for radiation diagnosis
- A61B6/4208—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector
- A61B6/4258—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector for detecting non x-ray radiation, e.g. gamma radiation
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/54—Control of apparatus or devices for radiation diagnosis
- A61B6/548—Remote control of the apparatus or devices
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/58—Testing, adjusting or calibrating apparatus or devices for radiation diagnosis
- A61B6/589—Setting distance between source unit and patient
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
- G01T1/164—Scintigraphy
- G01T1/1641—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras
- G01T1/1642—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
- G01T1/164—Scintigraphy
- G01T1/1641—Static instruments for imaging the distribution of radioactivity in one or two dimensions using one or several scintillating elements; Radio-isotope cameras
- G01T1/1648—Ancillary equipment for scintillation cameras, e.g. reference markers, devices for removing motion artifacts, calibration devices
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
- A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
- A61B6/03—Computerised tomographs
- A61B6/037—Emission tomography
Abstract
Abstract of the Disclosure A system for controlling the proximity of a gamma camera to a patient during a scan of the patient by two spaced apart energy screens parallel to and spaced from the face of the gamma camera The gamma camera is moved toward the patient when neither screen is interrupted, away from the patient when both screens are interrupted and remain stationary when only the first (outermost) screen is interrupted.
Description
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Field of the Inve.ntion This invention relates to body scanning apparatus and more particularly, to gamma cameras used to scan patients either in a full body planar scannin~ mode or in an emission computerized tomographic (EGT or SPECT~ scannin~ mode.
Back~round of the Invention During a planar scan of a patlent with a gamma came~a, the gamma camera travels over the patient parallel to the cranium-caudal axis. During ECT scans the ~amma camera rotates around the re~ion of the patient to be imaged. The rotation i5 in a plane generaily orthogonal to the cranial caudal axi~ of the patient and results in the ima~in~ of a cross sectional slice of the patient's body.
In either type of scan, it is important that the camera head be maintained as closely as possible to the patient because this results in better resolution and consequently image quality is improved.
In the prior art especially for ECT studies, it is known to use various methods and systems for maintaining the camera head as clo~ely as possible to the patient. For example, U.S. Patent 4,503,331 provides a non-circular ECT scan path. The scannin~ path is elliptical and accordingly, it more closely Eollows the body contour than does a circular path.
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In U.S. Patent 4,593,18~ a camera head is provided with an optical proximity detector to urge the head to~ards the patlent while ~1 rotating around the patient. When the head gets too close to the patient, proximity detector is triggered and the head is moved away from the patient.
U.5. Patent 5,07~ 1 features an arrangement for determining the planar contour of an obiect using a plurality of light emitters and detectors positioned in a circular planar array. The array surrounds the obiect for determining the planar contour of the object, such as the pati~nt. The light emitters are ~equentially energized and resul~in~ si~nals from the li~ht detectors are used for determining the obiect' 5 planar contour. The camera i~ then directed on a path emulatin~ the contour.
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Each of the above patented sys~ems is an improvement over the original circular path used ~y gamma cameras during ECT scans.
Thus, the patent covering the elliptical orbit improves over the circular orbit, but is merely an approximation of the exact contour of the patient's body. Therefore, the distance of the camera head to the patient can be significantly decreased. The proximity detector, among other things, makes it difficult to chan~e collimators in the camera head to which it is attached. The contour determining arran~ement of Patent 5,0~7,2~1 requires a learnin~ cycle wherein the system learns the contour of the body.
This requires additional time and, therefore, reduces throughput.
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It is, therefore, an ob~ect of the present Inventlon to provide .
systems which speed up th~ scan procedure by automatically -~-positioning the scanning camera as close as possible to the patient's body, even closer than attainable with a prior art elliptical scan, durin~ the scan regimen without necessitating a ~`
learning cycle and without endan~ering the patient.
Brief DescriPtion of the Invention In accordance with a preferred aspect of the present invention, a gamma camera system is provided, said system comprisi~g:
a gamma camera gantry, mean~ for mountin~ at least one gamma camera on said gantry for :~
use in performing whole ~ody scans or emission computerized ~` ;
tomo~raphic scans of a patient, :
said camera having a radiation detectin~ side, controls for maintaining the distance between the camera and the ~ -patient at a minimum, said controls comprisin~:
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a first series of energy transmitters for transmitting energy to which the patient i5 opaque, said first series of energy transmitters each mounted to said camera at a first distance from the radiation detecting side of said camera to~ard said patient, a first series of energy reGeivers each mounted ~o said camera oppositely di~posed from said first series of said energy transmitters at said first distance away from the radiation detecting side of said camera toward said patient so that ener~y transmitted from said first series of energy transmitters impin_e on said first series of ener~y receivers after spanning the detectinP side of the camera, an in-out motor for selectively moving said camera away from or toward the patient, means for operating said motor re~ponsive to the body contour of the patient int~rrupting the transmitted energy so as to prevent the receipt of the transmitted energy by the first series of receivers to move said camera away from said patient, a second series of energy transmitters each mounted a second distance away from the radiation detectin~ side of the camera toward said patient, ~ ~
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a second series of energy receivers each mounted oppositely disposed from said second series of energy trans~itters and at said second distance away from said radiation detectin~ side of said camera toward ~aid patient so that energy transmitted from said second series of energy transmitters impinge on said second series of energy receivers after spannin~ the detecting side of the camera, said second di-~tance bein~ lar~er than said first distance, means for inhibitin~ the operation of said in-out motor responsive to interruption of the energy extending from said second series of energy trans~itters to the second series of energy receivers whereby the camera does not move in the in or out directions, and .
means for operatin~ said in-out motor to move said camera toward ~: said patient when there i5 no interruption with the energy extending from the ener~y transmitters to the energy receivers.
The gamma camera system of the invention includes means for I enabling the control of the in-out motor responsive to energy I spanning said radiation detecting side of said camera in two parallel planes, whereby when there is no interruption with the energy in either of the two planes, the in-out motor moves the camera toward th~ patient. When the patient's ~ody interrupts the energy in the plane furtherest from the radiatlon detectlng side -,~ :~ . , : ., .
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of the camera, the in-out motor is de-energized. When the patient's body interrupts both energy planes, the in-out motor is energized to move the camera away from the patient.
According to a feature of the invention, the energy planes are provided by direct transmittal and receipt of the energy at the planes parallel to the detecting side of the ~amma camera.
According to an alternative feature of the invention. the energy transmitters and/or receivers could be removed from the parallel planes ~y the use of reflecting surfaces.
Another feature of the system is a fail-safe provision for causing the in-out motor to move the camera away from the patient responsive to actuation of a pressure sensitive detector.
Still another feature of the invention provides for a dual camera system with eaGh of the cameras havin~ an individual motor for moving the camera radially irrespective of the radial motion of the other camera.
The gamma camera arrangement of the invention provides for maintaining ~aid gamma camera at a distance from the patient wherein said energy extending between ~aid second set of transmitters and ~aid second set of receivers is interrupted and ' ' ' .
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, wherèin the energy extending from sai~ first set of transmitters to said first set of receivers is not interrupted.
Another feature of the invention provides means for preventing energy cross-talk; i.e., energy transmitted from being receivad by a receiver that is not coupled to the transmitting transmitter.
Yet another feature of the invention provides a leading set of oppositely disposed energy transmitters and receivers mounted to the gamma camera so as to be responsive to longitudinal motion between the pa~ient and the camera when the patient is being positioned within the viewin~ range of the camera.
The above named and other ob~ects, features and advantages of the present invention will be more apparent from the followin~
description of a preferred embodiment of the present invention when considered along with the accompanyin~ drawings; wherein.
Brief DescriPtlon of the Drawin~s Fi~. 1 is a side view of the inventive gamma camera system for maintaining the camera proximate to the patient during scans;
~ ~ -Fig. ~ is a front Yiew of the inventive system of Fig. 1;
9 - 21 ~ 12~1 Fig. 3 is an enlarged front view of one of the gamma cameras shown in Fi~s. 1 and ~
Fig. 4 is a side view of the gamma camera shown in Fig. 3 with one of the proximity controllers removed so that details of the other proximity controller are shown;
Fi~. 5 is a block diagram showing of the controls for the inventive gamma camera system; and Fig. 6a and 6b are schematic showings of:
a) the direct generation o~ the energy planes. and : b) the ~eneration of the energy planes using reflective `4 surfaces.
General Description of the Invention Fig. 1, shows the inventive gamma camera system 11 as a dual gamma camera system which can provide either full body scans or ECT
scans. While dual camera heads are shown and the control of a single camera is described herein, it should be understood that the invention also applies to maintaining a sin~le ~amma camera or multiple cameras proximate to the patient during scans. The gamma camera system 11 of Fig. 1 comprises a ~antry assembly 12 and a .
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patient bed assembly 13. The gantry assembly 12 comprises a base 14, a stator 16 and a rotor 17. The rotor rotates in a circular fashion on the stator 16. Attached to the rotor 17 are two gamma camera heads 18 and 1~. With the rotation of the rotor, the heads ..
rotate around the body and provide data for a tomographic image.
Auxiliary to the gantry is a monitor 21 and a remote control unit 2~. The remote control unit i~ used for controlling the movement of the camera heads 18 and 19 which in addition to rotating with the rotor can move up or down as indicated by arrow 23 or can pivot around the pivot point 24 shown in camera 18. A similar point not shown is associated with camera 19.
The patient bed assembly 13 comprises a patient bed 2~ on a ba~e 27. The base i9 shown as being mounted on casters 28 and 29.
During the scanning procedure the base is locked in place and the bed ~6 i8 longitudinally movable as shown by the dashed lines 31 so that during the scan, the bed can be moved longitudinally bac~
or forth as shown by arrow 32. When the bed is mov~d and the rotor remains stationary, then a ~hole body scan is obtained. When the bed i8 moved 50 that the patient's thorax, ~or example, is beneath the camera, then the SPECT image is acquired in the thorax region of the patient. Alternatively, a helical scan is possible by rotating the rotor while the bed is movin~ longitudlnally relative to the cameras. It should ~e understood that while longitudinal movement of the bed is described, lon~itudinal movement o~ the ~ - 1 1 - 2 l ~ 1 2 ~ -1 p508 gantry would provide the same results. It is the relative movement betw~en the bed (i.e., patient) and the ~antry that i5 material.
The remote control unit 22 also controls the movement of the bed 26. The ~ed 2~ can move up or down as indicated by arrow 25, when upper base section 27a moves up or down on lower base section 27~.
In addition, the bed can swivel around axis ~3 when a swivel lock lever 34 is pres~ed to release the lock. The swivelling of the b~d makes it easier to replace the collimators on the cameras 18 and 19 .
In Fig. 2, which is the front view of the system of Fig. 1, it is seen that both of the gamma camPras 1~ and 19 have proximity controllers attached thereto. For example, ~amma camera 18 has the proximity controllers 36 and 37 spaced apart so as to provide two parallel planes of energy beams separated from and spanning across the face of the collimator. The parallel plane~ of energy beams are indicated ~y the dashed lines 3~ and 39. The dashed line 39 is closest to the collimator 41 associated with the camera 18, The camera 19 is also shown as having spaced apart proximity controllers 37a and 38a attached to the camera unit and sli~htly removed from the collimator so that energy beams traversing the space between the proximity controllers are slightly removed from the collimator.
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The camera is attached to yoke arms wlthin the box-like covers 42 and 43, respectively. The yoke arms are a~tached to a ball-screw type axles, not shown, within the rotor. When the in-out motor assi~ned to elther of the cameras is operated, the balls-screw axles are rotated to individually cause either of the cameras 18 or 19 or both to move closer to~etller or further apart. It is the control of this in-out motion that is a major object of the invention described herein.
The screen of monitor 21 is divided into two sections. The first section 46 displays the image of the patient~ the second section 47 indicates the motion of the cameras and the bed. This includes the in-out motion, the pivotin~ motion and the rotary of the cameras along with the longitudinal motion, the up and down motion and the pivoting motion around axis 33 of the bed. In addition, section 47 may relay instructions or messages for the operator.
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The yoke arms of the camera extend into the interior of the rotor.
The opening for the yoke arms are protected by dust covers such as the accordian-like dust cover indicated at 44.
A pres~ure qensitive device (PSD) 41 serves to stop any motion in the event it is actuated. Th$s is a fail-safe protective device.
The PSD could be set to actuate the individual motor to move the camera outward.
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Under normal body scannLng conditions, the camera is posl~ioned so that the outer con~our of the patient whose body is ~eing imaged is between beams 38 and 39. This position is attained because the cameras normally are caused to travel inwardly when neither beam 38 or 39 is broken. When any of beams 38 are broken there is no in-out motion since the motor is not energized. When any of the beams 39 are broken, then the motor causes the in-out motion to be outward. Just as when the pressure sensitive plate 41 i5 actuated~
the motor causes the cameras to move radially, outward away from the patient's body.
Fig. 4 ~hows details of the proximity control unit 37. It should be understood that one proximity control unit 3~ may be an energy transmitting unit whil~ the other proximity control unit such as unit ~7 may be an energy receiving unit. Alternatively, each unit could comprise energy receivers and/or transmitters. For purposes of the explanation, in Fig. 4, unit 37 is ~Qnsidered an energy transmitting unit.~ Fi~. 4 shows camera 18 mounted to the yoke arm 51 covered by yoke arm cover 43. The camera can be pivoted around pivot point 24 by a motor and controls not shown. The gamma camera 18 includes a plurality of photomultipliers, not shown, attached to a scintillating detecting crystal also not shown. When a photon of gamma energy strikes the detecting crystal, it scintillates.
Photomultiplier tu~es in the camera detect the scintillation and convert the scintillation into electrical energy. As is customary with all "Anger" ~ype gamma cameras, ~he camera compu~es the !
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location of the photon impin~ement of the crystal and the total energy. :
A collimator unit 52 is shown mounted to the detecting or crystal side of the gamma camera. Also attached to the ~amma camera iq the proximity control unit 37. A flange-like cover 53 covers the proximity control unit. Shown as part of the proximity control unit 37 are multiple rows of energy transmitters such as light emitting diodes (LEDs). These rows are shown as rows ~6, 57 and 58. The LEDs transmit energy in the Eorm of infra-red li~ht towards solid state light receivers on the oppositely di 5 posed proximity control unit 36. While LE~s and solid state li~ht receivers are indicated, the invention is sufficiently broad to cover other energy transmitters and receivers or other arran~ements of the transmitters and receivers. For example, the transmitters and receivers could be on the same side with a reflector on the opposite side. -The multiple rows of transmitters and receivers are provided inorder to accommodate different size collimators. When different ~ize collimators are used, different pairs of the multiple rows are used. Thus, either rows 56 and 57 or rows S7 and 58 are used to provide the two parallel planes of energy beams between which the camera position is maintained during scan operations. More parallel rows could be provided to accommodate even other different si~e collimators. Al50, the proximity units 36, 37 could '` ' 2:1112g~
~ - 15 -be physically extended toward the patlent when a larger ~ollimator is used.
When a larger collimator is in place and the different rows are used to accommodate the larger size collimators, then row~ 57 and 58 are energized. Then if the light emitted by the LE~ of row 58 encounter an obJect that is opaque to the light beams, such as the patient's body, the in-out motor will be de-energized and stop operating. When the light beams from LEDs in row 58 are not interrupted, then the motor is energized to bring the cameras closer togetherl that is closer to the patient's body. As soon as any of the beams from the LEDs of row 58 are interruptedl then the in-out motor is de-energized to StQp the movement of the cameras.
If the patientls body then breaks any of the beams from row 57, ~ - .
the in-out motor is actuated to separate the cameras, that is to move the cameras away from the patient. If the cameras are ~;~
positioned ~uch that the LEDs of row 57 are once again ~ transmitting uninterruptedly to the receivers of the corresponding ~ -;~; row 57 in proximity control unit 36l the motor is again -:.::. :....
de-energized. If the patient's body stops interfering with the ;:
li~ht beams from the LEDs of row 58, then the in-out motor is actuated to bring the cameras closer together. In this manner, the cameras are kept in position so that the contour of the body is between rows 58 and 57.
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- 21:L12~l The same type of operation occurs when the rows 56 and 57 are used; that is when a smaller collimator is in place. When a smaller collimator is used. the pressure sensitive device 41 is moved up higher. Then the energy transmitters of rows 56 and 57 both transmit beam~ of energy that normally impinge on energy receivers on proximity control unit 36 to control the in-out motor as explained. The transmitters and receivers are shown mounted on printed circuit boards, such as board 59 on which are mounted the rows 56, 57, 58 of energy transmitters.
An alternative mechanical arrangement for accommodating different sized collimators is also shown in Fig. 4. More particularly~
slot~ such as ~lot 60 and fastener 65 to enable radially moving the proximity control units are illustrated.
The arcuate sections in the cover 53 and in the contour of the printed circuit board 59 are clearances used when the camera pivots around pivot point 24. The printed circuit board 59 holds the LEDs or the solid state light receiver~ o~ unit 36.
.~ '"', Also mounted on the printed circuit board 59 are a set of energy transmitters and oppositely disposed receivers that provide "early warning" energy beams. The early warning energy beams are used particularly during whole body scans where the patient is moved linearly and longitudinally relative to the camera. In a preferred embodiment, the patient bed 26 is moved longitudinally until the . .
-` ` 2 1 :L 1 2 ~ l1 P5~8 en~ire patlent has gone past the camera or cameras. Then the scan is commenced by moving the camera ~oward the patlent on the bed and movin~ the bed longitudinally past the cameras back to the startin~ point while the cameras detect th~ ~amma radlation.
As the patient is moved back if an~ of the energy beams generated by any of the early warning ener~y transmitters 50, 54, or 55 is interrupted, the in-out motor is caused to move the camera or cameras away from the patient. The movement away continues until beams from row of detectors closest to the crystal are no longer lnterrupted or until a manual overide, not shown, is operated to remove power from the in-out motor.
While early warnin~ transmitters (and receivers) are shown only on one side of the camera, it should be understood ~hat within the scope of the invention they could be mounted on ~he other side of the camera or on both sides of the camera.
The block diagram of Fig. 5 show LEDs of rows 57 and 58, such as LED 58a and LED 57a. These LE~s operate to transmit energy preferably in the form of infra-red li~ht to detectors, such as detectors ~Oa and 61a in corresponding rows on a proximity control unit 36. The transmission and receipt of the light ener~y is under the control of ~he body contour controller 63.
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Means are provided to assure that the receivers operate only responsive to li~ht from a tranQmitter to which the receiver is coupl~d. This arran~ment prevents the operatiQn of the motor responsive to reflected ener~y bein~ received by a receiver not coupled to the transmitter; herein sometimes referred to as "cross-talk". More particularly~ transmitter sequencer 64 cause~
the sequenced LED of the proper row to transmi-t while the receiver encoder 66 receives information only from the receiver coupled to the transmitting transmitter of the proximity control unit 37.
The information from the body contour controller 63 is transmitted throu~h slip rings indicated by the dashed lines 67 to the motion controllin~ computer ~8. The motion controllin~ computer causes the motor driver ~9 to enerPize the in-out motor~ shown as motor 71, in the proper direction. The connection between the motor ; ~driver and the in-out motor 21 may also be through slip rings as indicated by the dashed line 67. The slip rin~s are used to couple , ~, :.
power and commands between the stator and the rotor.
In practice, single pairs of transmitters and receivers are used at any one instant under the control of the sequencer 64 and encoder 66. The pairs are in effect "scanned" at a rate that enables all the ~airs about 20 times per second. In a preferred embodiment, there are about 200 pairs. The scan time can be shortened by scannin~ two ~paced apar~ pairs at the same time.
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When the beam from an LED in row 58a to a detector in row 60a is broken, then power to the motor 71 is turned off. Prior to that, the motor is powered to cause the gamma camera to move closer to the patient. Upon breaking any of the beams extendin~ from row 58 in unit 37 to row 60 in unit 36 the in-out motor 71 is de-ener~ized and stops the movement of the gamma camera.
Similarly, when any of the beams from the LE~s of row 57 such as LED 57a is broken on its way to the receivers of corresponding row 61, such as receiver 61a in proximity control unit 36, then the motor 71 associated with the camera is powered to cause the gamma cameras to move in a direction away from the patient. If something is wrong with the operation so that breaking the beam from a LE~
of row 57 to a receiver of row ~l does not cause the cameras to move apart, then the body will press a~ainst pressure sensitive device 41 which will then stop all motion o~ the gamma cameras.
That is, the si~nal from the body contour controller ~3 to the motion control computer 68 can ~e derived from the receiver encoder ~6 or from the pressure sensitive device 41.
The schematic showing of Fig. 6a is an embodiment wherein the proximity contrQllers are mounted extending in the direction of radial movement of the camera 18 toward the patient on bed 26. The proximity controller 36 includes, for example, a plurality of rows 57 and 58 of LEDs. The LE~s in a preferred embodiment transmit beams of infra-red li~ht to similarly placed rows of infra-red o light sensors 57 and 58. Thus, parallel spaced apart energY beams are produced.
Fig. 6b ofers a variation of the embodim~nt of Fi~. 6a. The rows of transmitters 57, 58 are mounted on a plate 76 extending transverse to the direction of radial motion of the camera 18 toward or awa~ from the patient 15 on bed 26. The rows o~
receivers 57, 58 are also mounted on a plate 77 extending transverse to ~he radial motion. Reflectin~ surfaces 78 and 79 direct the ener_y beams 38 and 39 to span the front face of the camera in planes parallel to the detector face of the camera in the same manner that the energy beams 38 and 39 span ~he detecting face of the camera in Fig. 6a. It should be understood that withln ~he scope of the invention the configuration of the transmitters and receivers could be combinations of the schematic showings of Figs. 6a and 6b.
A system is thereby provided wherein ~he outer contour of the patient's body is maintained a fixed small distance away from the collimator of the gamma camera scanning the body whether the system operates when a whole body-scan is being performed or when a computerized tomo~raphic scan is being performed. In general, the system contains two well defined optical screens located iust above the detector of a gamma camera. The electronics associated with the optical screen are sensitive to any opaque disturbance of the ener~y screens. The energy screens are comprised of beams of - 21 - 2 i ' ~
ener~y such as light rays. Using the information from the optical energy screens, a command is sent to the in-out motor 71 in a way that minimizes the patient-detector distance to a few millimeters.
The system comprises two electronic proxlmity control units attached to the detector side o~ the gamma camera. One of the units has a number of energy emitters and the other at~ached unit has a number of ener~y receivers. The emitters and receivers are arran~ed eith~.r oppositely disposed in two operatin~ layers or disposed relative to reflecting surfaces with a small in~ernal distance ~etween them. In either configuration, th~ proximity controller, for example. yields light rays in parallei layers so that the system can maintain the outer contour of the patient's opaque body between the two parallel layers.
~urin~ a typical scan, the in-out motor moves the camera toward the patient when no disturbances are detected by the layered optical screens and it moves the camera away from the patient when inner layer is disturbed. The camera is not moved in an in or out direction when outer layer is disturbed and the inner layer is not disturbed. The in or out motion does not interfere with the scan motion; i.e., with the rotational motion for ECT scans and lin ar longitudinal motion for whole body scans.
Amon~ other thin~s, the uni~ue proximity controller enables the ~amma camera to be as close as possible to the patient during the entire scan. Thus, for ECT scans, for example. the cam~ra is even :
closer to the patient on the average than the proximity achieved with elliptical scans. In addition, the unique proximity controllers dramatically speed up the throughput of the system since the time consuming preliminary scan loci learning or te~ting cycles of the prior art are no longer necessary.
Having thus described the invention with particular reference to the preferred forms thereof, it will be obvious to those skilled in the art to which the invention pertains after understanding the invention that various changes and modifications may be made therein without departing from the spirit and scope of the invention as deiined by the Clai=s appended hereto.
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Back~round of the Invention During a planar scan of a patlent with a gamma came~a, the gamma camera travels over the patient parallel to the cranium-caudal axis. During ECT scans the ~amma camera rotates around the re~ion of the patient to be imaged. The rotation i5 in a plane generaily orthogonal to the cranial caudal axi~ of the patient and results in the ima~in~ of a cross sectional slice of the patient's body.
In either type of scan, it is important that the camera head be maintained as closely as possible to the patient because this results in better resolution and consequently image quality is improved.
In the prior art especially for ECT studies, it is known to use various methods and systems for maintaining the camera head as clo~ely as possible to the patient. For example, U.S. Patent 4,503,331 provides a non-circular ECT scan path. The scannin~ path is elliptical and accordingly, it more closely Eollows the body contour than does a circular path.
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In U.S. Patent 4,593,18~ a camera head is provided with an optical proximity detector to urge the head to~ards the patlent while ~1 rotating around the patient. When the head gets too close to the patient, proximity detector is triggered and the head is moved away from the patient.
U.5. Patent 5,07~ 1 features an arrangement for determining the planar contour of an obiect using a plurality of light emitters and detectors positioned in a circular planar array. The array surrounds the obiect for determining the planar contour of the object, such as the pati~nt. The light emitters are ~equentially energized and resul~in~ si~nals from the li~ht detectors are used for determining the obiect' 5 planar contour. The camera i~ then directed on a path emulatin~ the contour.
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Each of the above patented sys~ems is an improvement over the original circular path used ~y gamma cameras during ECT scans.
Thus, the patent covering the elliptical orbit improves over the circular orbit, but is merely an approximation of the exact contour of the patient's body. Therefore, the distance of the camera head to the patient can be significantly decreased. The proximity detector, among other things, makes it difficult to chan~e collimators in the camera head to which it is attached. The contour determining arran~ement of Patent 5,0~7,2~1 requires a learnin~ cycle wherein the system learns the contour of the body.
This requires additional time and, therefore, reduces throughput.
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It is, therefore, an ob~ect of the present Inventlon to provide .
systems which speed up th~ scan procedure by automatically -~-positioning the scanning camera as close as possible to the patient's body, even closer than attainable with a prior art elliptical scan, durin~ the scan regimen without necessitating a ~`
learning cycle and without endan~ering the patient.
Brief DescriPtion of the Invention In accordance with a preferred aspect of the present invention, a gamma camera system is provided, said system comprisi~g:
a gamma camera gantry, mean~ for mountin~ at least one gamma camera on said gantry for :~
use in performing whole ~ody scans or emission computerized ~` ;
tomo~raphic scans of a patient, :
said camera having a radiation detectin~ side, controls for maintaining the distance between the camera and the ~ -patient at a minimum, said controls comprisin~:
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a first series of energy transmitters for transmitting energy to which the patient i5 opaque, said first series of energy transmitters each mounted to said camera at a first distance from the radiation detecting side of said camera to~ard said patient, a first series of energy reGeivers each mounted ~o said camera oppositely di~posed from said first series of said energy transmitters at said first distance away from the radiation detecting side of said camera toward said patient so that ener~y transmitted from said first series of energy transmitters impin_e on said first series of ener~y receivers after spanning the detectinP side of the camera, an in-out motor for selectively moving said camera away from or toward the patient, means for operating said motor re~ponsive to the body contour of the patient int~rrupting the transmitted energy so as to prevent the receipt of the transmitted energy by the first series of receivers to move said camera away from said patient, a second series of energy transmitters each mounted a second distance away from the radiation detectin~ side of the camera toward said patient, ~ ~
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a second series of energy receivers each mounted oppositely disposed from said second series of energy trans~itters and at said second distance away from said radiation detectin~ side of said camera toward ~aid patient so that energy transmitted from said second series of energy transmitters impinge on said second series of energy receivers after spannin~ the detecting side of the camera, said second di-~tance bein~ lar~er than said first distance, means for inhibitin~ the operation of said in-out motor responsive to interruption of the energy extending from said second series of energy trans~itters to the second series of energy receivers whereby the camera does not move in the in or out directions, and .
means for operatin~ said in-out motor to move said camera toward ~: said patient when there i5 no interruption with the energy extending from the ener~y transmitters to the energy receivers.
The gamma camera system of the invention includes means for I enabling the control of the in-out motor responsive to energy I spanning said radiation detecting side of said camera in two parallel planes, whereby when there is no interruption with the energy in either of the two planes, the in-out motor moves the camera toward th~ patient. When the patient's ~ody interrupts the energy in the plane furtherest from the radiatlon detectlng side -,~ :~ . , : ., .
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of the camera, the in-out motor is de-energized. When the patient's body interrupts both energy planes, the in-out motor is energized to move the camera away from the patient.
According to a feature of the invention, the energy planes are provided by direct transmittal and receipt of the energy at the planes parallel to the detecting side of the ~amma camera.
According to an alternative feature of the invention. the energy transmitters and/or receivers could be removed from the parallel planes ~y the use of reflecting surfaces.
Another feature of the system is a fail-safe provision for causing the in-out motor to move the camera away from the patient responsive to actuation of a pressure sensitive detector.
Still another feature of the invention provides for a dual camera system with eaGh of the cameras havin~ an individual motor for moving the camera radially irrespective of the radial motion of the other camera.
The gamma camera arrangement of the invention provides for maintaining ~aid gamma camera at a distance from the patient wherein said energy extending between ~aid second set of transmitters and ~aid second set of receivers is interrupted and ' ' ' .
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, wherèin the energy extending from sai~ first set of transmitters to said first set of receivers is not interrupted.
Another feature of the invention provides means for preventing energy cross-talk; i.e., energy transmitted from being receivad by a receiver that is not coupled to the transmitting transmitter.
Yet another feature of the invention provides a leading set of oppositely disposed energy transmitters and receivers mounted to the gamma camera so as to be responsive to longitudinal motion between the pa~ient and the camera when the patient is being positioned within the viewin~ range of the camera.
The above named and other ob~ects, features and advantages of the present invention will be more apparent from the followin~
description of a preferred embodiment of the present invention when considered along with the accompanyin~ drawings; wherein.
Brief DescriPtlon of the Drawin~s Fi~. 1 is a side view of the inventive gamma camera system for maintaining the camera proximate to the patient during scans;
~ ~ -Fig. ~ is a front Yiew of the inventive system of Fig. 1;
9 - 21 ~ 12~1 Fig. 3 is an enlarged front view of one of the gamma cameras shown in Fi~s. 1 and ~
Fig. 4 is a side view of the gamma camera shown in Fig. 3 with one of the proximity controllers removed so that details of the other proximity controller are shown;
Fi~. 5 is a block diagram showing of the controls for the inventive gamma camera system; and Fig. 6a and 6b are schematic showings of:
a) the direct generation o~ the energy planes. and : b) the ~eneration of the energy planes using reflective `4 surfaces.
General Description of the Invention Fig. 1, shows the inventive gamma camera system 11 as a dual gamma camera system which can provide either full body scans or ECT
scans. While dual camera heads are shown and the control of a single camera is described herein, it should be understood that the invention also applies to maintaining a sin~le ~amma camera or multiple cameras proximate to the patient during scans. The gamma camera system 11 of Fig. 1 comprises a ~antry assembly 12 and a .
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patient bed assembly 13. The gantry assembly 12 comprises a base 14, a stator 16 and a rotor 17. The rotor rotates in a circular fashion on the stator 16. Attached to the rotor 17 are two gamma camera heads 18 and 1~. With the rotation of the rotor, the heads ..
rotate around the body and provide data for a tomographic image.
Auxiliary to the gantry is a monitor 21 and a remote control unit 2~. The remote control unit i~ used for controlling the movement of the camera heads 18 and 19 which in addition to rotating with the rotor can move up or down as indicated by arrow 23 or can pivot around the pivot point 24 shown in camera 18. A similar point not shown is associated with camera 19.
The patient bed assembly 13 comprises a patient bed 2~ on a ba~e 27. The base i9 shown as being mounted on casters 28 and 29.
During the scanning procedure the base is locked in place and the bed ~6 i8 longitudinally movable as shown by the dashed lines 31 so that during the scan, the bed can be moved longitudinally bac~
or forth as shown by arrow 32. When the bed is mov~d and the rotor remains stationary, then a ~hole body scan is obtained. When the bed i8 moved 50 that the patient's thorax, ~or example, is beneath the camera, then the SPECT image is acquired in the thorax region of the patient. Alternatively, a helical scan is possible by rotating the rotor while the bed is movin~ longitudlnally relative to the cameras. It should ~e understood that while longitudinal movement of the bed is described, lon~itudinal movement o~ the ~ - 1 1 - 2 l ~ 1 2 ~ -1 p508 gantry would provide the same results. It is the relative movement betw~en the bed (i.e., patient) and the ~antry that i5 material.
The remote control unit 22 also controls the movement of the bed 26. The ~ed 2~ can move up or down as indicated by arrow 25, when upper base section 27a moves up or down on lower base section 27~.
In addition, the bed can swivel around axis ~3 when a swivel lock lever 34 is pres~ed to release the lock. The swivelling of the b~d makes it easier to replace the collimators on the cameras 18 and 19 .
In Fig. 2, which is the front view of the system of Fig. 1, it is seen that both of the gamma camPras 1~ and 19 have proximity controllers attached thereto. For example, ~amma camera 18 has the proximity controllers 36 and 37 spaced apart so as to provide two parallel planes of energy beams separated from and spanning across the face of the collimator. The parallel plane~ of energy beams are indicated ~y the dashed lines 3~ and 39. The dashed line 39 is closest to the collimator 41 associated with the camera 18, The camera 19 is also shown as having spaced apart proximity controllers 37a and 38a attached to the camera unit and sli~htly removed from the collimator so that energy beams traversing the space between the proximity controllers are slightly removed from the collimator.
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The camera is attached to yoke arms wlthin the box-like covers 42 and 43, respectively. The yoke arms are a~tached to a ball-screw type axles, not shown, within the rotor. When the in-out motor assi~ned to elther of the cameras is operated, the balls-screw axles are rotated to individually cause either of the cameras 18 or 19 or both to move closer to~etller or further apart. It is the control of this in-out motion that is a major object of the invention described herein.
The screen of monitor 21 is divided into two sections. The first section 46 displays the image of the patient~ the second section 47 indicates the motion of the cameras and the bed. This includes the in-out motion, the pivotin~ motion and the rotary of the cameras along with the longitudinal motion, the up and down motion and the pivoting motion around axis 33 of the bed. In addition, section 47 may relay instructions or messages for the operator.
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The yoke arms of the camera extend into the interior of the rotor.
The opening for the yoke arms are protected by dust covers such as the accordian-like dust cover indicated at 44.
A pres~ure qensitive device (PSD) 41 serves to stop any motion in the event it is actuated. Th$s is a fail-safe protective device.
The PSD could be set to actuate the individual motor to move the camera outward.
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Under normal body scannLng conditions, the camera is posl~ioned so that the outer con~our of the patient whose body is ~eing imaged is between beams 38 and 39. This position is attained because the cameras normally are caused to travel inwardly when neither beam 38 or 39 is broken. When any of beams 38 are broken there is no in-out motion since the motor is not energized. When any of the beams 39 are broken, then the motor causes the in-out motion to be outward. Just as when the pressure sensitive plate 41 i5 actuated~
the motor causes the cameras to move radially, outward away from the patient's body.
Fig. 4 ~hows details of the proximity control unit 37. It should be understood that one proximity control unit 3~ may be an energy transmitting unit whil~ the other proximity control unit such as unit ~7 may be an energy receiving unit. Alternatively, each unit could comprise energy receivers and/or transmitters. For purposes of the explanation, in Fig. 4, unit 37 is ~Qnsidered an energy transmitting unit.~ Fi~. 4 shows camera 18 mounted to the yoke arm 51 covered by yoke arm cover 43. The camera can be pivoted around pivot point 24 by a motor and controls not shown. The gamma camera 18 includes a plurality of photomultipliers, not shown, attached to a scintillating detecting crystal also not shown. When a photon of gamma energy strikes the detecting crystal, it scintillates.
Photomultiplier tu~es in the camera detect the scintillation and convert the scintillation into electrical energy. As is customary with all "Anger" ~ype gamma cameras, ~he camera compu~es the !
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location of the photon impin~ement of the crystal and the total energy. :
A collimator unit 52 is shown mounted to the detecting or crystal side of the gamma camera. Also attached to the ~amma camera iq the proximity control unit 37. A flange-like cover 53 covers the proximity control unit. Shown as part of the proximity control unit 37 are multiple rows of energy transmitters such as light emitting diodes (LEDs). These rows are shown as rows ~6, 57 and 58. The LEDs transmit energy in the Eorm of infra-red li~ht towards solid state light receivers on the oppositely di 5 posed proximity control unit 36. While LE~s and solid state li~ht receivers are indicated, the invention is sufficiently broad to cover other energy transmitters and receivers or other arran~ements of the transmitters and receivers. For example, the transmitters and receivers could be on the same side with a reflector on the opposite side. -The multiple rows of transmitters and receivers are provided inorder to accommodate different size collimators. When different ~ize collimators are used, different pairs of the multiple rows are used. Thus, either rows 56 and 57 or rows S7 and 58 are used to provide the two parallel planes of energy beams between which the camera position is maintained during scan operations. More parallel rows could be provided to accommodate even other different si~e collimators. Al50, the proximity units 36, 37 could '` ' 2:1112g~
~ - 15 -be physically extended toward the patlent when a larger ~ollimator is used.
When a larger collimator is in place and the different rows are used to accommodate the larger size collimators, then row~ 57 and 58 are energized. Then if the light emitted by the LE~ of row 58 encounter an obJect that is opaque to the light beams, such as the patient's body, the in-out motor will be de-energized and stop operating. When the light beams from LEDs in row 58 are not interrupted, then the motor is energized to bring the cameras closer togetherl that is closer to the patient's body. As soon as any of the beams from the LEDs of row 58 are interruptedl then the in-out motor is de-energized to StQp the movement of the cameras.
If the patientls body then breaks any of the beams from row 57, ~ - .
the in-out motor is actuated to separate the cameras, that is to move the cameras away from the patient. If the cameras are ~;~
positioned ~uch that the LEDs of row 57 are once again ~ transmitting uninterruptedly to the receivers of the corresponding ~ -;~; row 57 in proximity control unit 36l the motor is again -:.::. :....
de-energized. If the patient's body stops interfering with the ;:
li~ht beams from the LEDs of row 58, then the in-out motor is actuated to bring the cameras closer together. In this manner, the cameras are kept in position so that the contour of the body is between rows 58 and 57.
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- 21:L12~l The same type of operation occurs when the rows 56 and 57 are used; that is when a smaller collimator is in place. When a smaller collimator is used. the pressure sensitive device 41 is moved up higher. Then the energy transmitters of rows 56 and 57 both transmit beam~ of energy that normally impinge on energy receivers on proximity control unit 36 to control the in-out motor as explained. The transmitters and receivers are shown mounted on printed circuit boards, such as board 59 on which are mounted the rows 56, 57, 58 of energy transmitters.
An alternative mechanical arrangement for accommodating different sized collimators is also shown in Fig. 4. More particularly~
slot~ such as ~lot 60 and fastener 65 to enable radially moving the proximity control units are illustrated.
The arcuate sections in the cover 53 and in the contour of the printed circuit board 59 are clearances used when the camera pivots around pivot point 24. The printed circuit board 59 holds the LEDs or the solid state light receiver~ o~ unit 36.
.~ '"', Also mounted on the printed circuit board 59 are a set of energy transmitters and oppositely disposed receivers that provide "early warning" energy beams. The early warning energy beams are used particularly during whole body scans where the patient is moved linearly and longitudinally relative to the camera. In a preferred embodiment, the patient bed 26 is moved longitudinally until the . .
-` ` 2 1 :L 1 2 ~ l1 P5~8 en~ire patlent has gone past the camera or cameras. Then the scan is commenced by moving the camera ~oward the patlent on the bed and movin~ the bed longitudinally past the cameras back to the startin~ point while the cameras detect th~ ~amma radlation.
As the patient is moved back if an~ of the energy beams generated by any of the early warning ener~y transmitters 50, 54, or 55 is interrupted, the in-out motor is caused to move the camera or cameras away from the patient. The movement away continues until beams from row of detectors closest to the crystal are no longer lnterrupted or until a manual overide, not shown, is operated to remove power from the in-out motor.
While early warnin~ transmitters (and receivers) are shown only on one side of the camera, it should be understood ~hat within the scope of the invention they could be mounted on ~he other side of the camera or on both sides of the camera.
The block diagram of Fig. 5 show LEDs of rows 57 and 58, such as LED 58a and LED 57a. These LE~s operate to transmit energy preferably in the form of infra-red li~ht to detectors, such as detectors ~Oa and 61a in corresponding rows on a proximity control unit 36. The transmission and receipt of the light ener~y is under the control of ~he body contour controller 63.
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Means are provided to assure that the receivers operate only responsive to li~ht from a tranQmitter to which the receiver is coupl~d. This arran~ment prevents the operatiQn of the motor responsive to reflected ener~y bein~ received by a receiver not coupled to the transmitter; herein sometimes referred to as "cross-talk". More particularly~ transmitter sequencer 64 cause~
the sequenced LED of the proper row to transmi-t while the receiver encoder 66 receives information only from the receiver coupled to the transmitting transmitter of the proximity control unit 37.
The information from the body contour controller 63 is transmitted throu~h slip rings indicated by the dashed lines 67 to the motion controllin~ computer ~8. The motion controllin~ computer causes the motor driver ~9 to enerPize the in-out motor~ shown as motor 71, in the proper direction. The connection between the motor ; ~driver and the in-out motor 21 may also be through slip rings as indicated by the dashed line 67. The slip rin~s are used to couple , ~, :.
power and commands between the stator and the rotor.
In practice, single pairs of transmitters and receivers are used at any one instant under the control of the sequencer 64 and encoder 66. The pairs are in effect "scanned" at a rate that enables all the ~airs about 20 times per second. In a preferred embodiment, there are about 200 pairs. The scan time can be shortened by scannin~ two ~paced apar~ pairs at the same time.
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When the beam from an LED in row 58a to a detector in row 60a is broken, then power to the motor 71 is turned off. Prior to that, the motor is powered to cause the gamma camera to move closer to the patient. Upon breaking any of the beams extendin~ from row 58 in unit 37 to row 60 in unit 36 the in-out motor 71 is de-ener~ized and stops the movement of the gamma camera.
Similarly, when any of the beams from the LE~s of row 57 such as LED 57a is broken on its way to the receivers of corresponding row 61, such as receiver 61a in proximity control unit 36, then the motor 71 associated with the camera is powered to cause the gamma cameras to move in a direction away from the patient. If something is wrong with the operation so that breaking the beam from a LE~
of row 57 to a receiver of row ~l does not cause the cameras to move apart, then the body will press a~ainst pressure sensitive device 41 which will then stop all motion o~ the gamma cameras.
That is, the si~nal from the body contour controller ~3 to the motion control computer 68 can ~e derived from the receiver encoder ~6 or from the pressure sensitive device 41.
The schematic showing of Fig. 6a is an embodiment wherein the proximity contrQllers are mounted extending in the direction of radial movement of the camera 18 toward the patient on bed 26. The proximity controller 36 includes, for example, a plurality of rows 57 and 58 of LEDs. The LE~s in a preferred embodiment transmit beams of infra-red li~ht to similarly placed rows of infra-red o light sensors 57 and 58. Thus, parallel spaced apart energY beams are produced.
Fig. 6b ofers a variation of the embodim~nt of Fi~. 6a. The rows of transmitters 57, 58 are mounted on a plate 76 extending transverse to the direction of radial motion of the camera 18 toward or awa~ from the patient 15 on bed 26. The rows o~
receivers 57, 58 are also mounted on a plate 77 extending transverse to ~he radial motion. Reflectin~ surfaces 78 and 79 direct the ener_y beams 38 and 39 to span the front face of the camera in planes parallel to the detector face of the camera in the same manner that the energy beams 38 and 39 span ~he detecting face of the camera in Fig. 6a. It should be understood that withln ~he scope of the invention the configuration of the transmitters and receivers could be combinations of the schematic showings of Figs. 6a and 6b.
A system is thereby provided wherein ~he outer contour of the patient's body is maintained a fixed small distance away from the collimator of the gamma camera scanning the body whether the system operates when a whole body-scan is being performed or when a computerized tomo~raphic scan is being performed. In general, the system contains two well defined optical screens located iust above the detector of a gamma camera. The electronics associated with the optical screen are sensitive to any opaque disturbance of the ener~y screens. The energy screens are comprised of beams of - 21 - 2 i ' ~
ener~y such as light rays. Using the information from the optical energy screens, a command is sent to the in-out motor 71 in a way that minimizes the patient-detector distance to a few millimeters.
The system comprises two electronic proxlmity control units attached to the detector side o~ the gamma camera. One of the units has a number of energy emitters and the other at~ached unit has a number of ener~y receivers. The emitters and receivers are arran~ed eith~.r oppositely disposed in two operatin~ layers or disposed relative to reflecting surfaces with a small in~ernal distance ~etween them. In either configuration, th~ proximity controller, for example. yields light rays in parallei layers so that the system can maintain the outer contour of the patient's opaque body between the two parallel layers.
~urin~ a typical scan, the in-out motor moves the camera toward the patient when no disturbances are detected by the layered optical screens and it moves the camera away from the patient when inner layer is disturbed. The camera is not moved in an in or out direction when outer layer is disturbed and the inner layer is not disturbed. The in or out motion does not interfere with the scan motion; i.e., with the rotational motion for ECT scans and lin ar longitudinal motion for whole body scans.
Amon~ other thin~s, the uni~ue proximity controller enables the ~amma camera to be as close as possible to the patient during the entire scan. Thus, for ECT scans, for example. the cam~ra is even :
closer to the patient on the average than the proximity achieved with elliptical scans. In addition, the unique proximity controllers dramatically speed up the throughput of the system since the time consuming preliminary scan loci learning or te~ting cycles of the prior art are no longer necessary.
Having thus described the invention with particular reference to the preferred forms thereof, it will be obvious to those skilled in the art to which the invention pertains after understanding the invention that various changes and modifications may be made therein without departing from the spirit and scope of the invention as deiined by the Clai=s appended hereto.
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Claims (25)
1. A gamma camera system comprising:
a gantry having at least one gamma camera mounted thereon for use in performing scans of a patient, controls for minimizing the distance between the patient and the gamma camera during said scans, said controls comprising a first proximity control for providing a first screen of energy beams at a first distance from the detector of the gamma camera and a second proximity control for providing a second screen of energy at a second distance from the detector of the gamma camera, said second distance being different than said first distance, and said controls minimizing the distance between the gamma camera and the patient's body by maintaining the contour of the patient's body between said first and said second energy screens.
a gantry having at least one gamma camera mounted thereon for use in performing scans of a patient, controls for minimizing the distance between the patient and the gamma camera during said scans, said controls comprising a first proximity control for providing a first screen of energy beams at a first distance from the detector of the gamma camera and a second proximity control for providing a second screen of energy at a second distance from the detector of the gamma camera, said second distance being different than said first distance, and said controls minimizing the distance between the gamma camera and the patient's body by maintaining the contour of the patient's body between said first and said second energy screens.
2. The gamma camera system of Claim 1 wherein at least one energy transmitter is provided for transmitting said energy beams, and at least one energy receiver is provided for receiving said beams.
3. The gamma camera system of Claim 1 wherein said first proximity control comprises a first energy transmitter mounted on said gamma camera toward said patient and first energy receiver also mounted on said gamma camera toward said patient to provide said first energy screen, and wherein said second proximity control comprises a second energy transmitter and a second energy receiver both mounted on said gamma camera toward said patient whereby two parallel energy screens are provided spaced apart from each other.
4. The gamma camera system of Claim 1 wherein:
said first proximity control comprises a first energy transmitter and a first energy receiver mounted on opposite sides of the gamma camera on a plane parallel to or coinciding with the front face of said gamma camera, wherein: the front face of the gamma camera is the side of the gamma camera toward the patient;
said second proximity control comprises a second energy transmitter means and a second energy receiver also mounted on opposite sides of the gamma camera on said plane parallel to or coinciding with the front face of said gamma camera, a reflector mounted at the front of said gamma camera to reflect energy from said first and second transmitter to span the front of said gamma camera, but removed therefrom at said first distance and to be reflected to said first and second energy receiver respectively on the opposite side of the front face of said gamma camera.
said first proximity control comprises a first energy transmitter and a first energy receiver mounted on opposite sides of the gamma camera on a plane parallel to or coinciding with the front face of said gamma camera, wherein: the front face of the gamma camera is the side of the gamma camera toward the patient;
said second proximity control comprises a second energy transmitter means and a second energy receiver also mounted on opposite sides of the gamma camera on said plane parallel to or coinciding with the front face of said gamma camera, a reflector mounted at the front of said gamma camera to reflect energy from said first and second transmitter to span the front of said gamma camera, but removed therefrom at said first distance and to be reflected to said first and second energy receiver respectively on the opposite side of the front face of said gamma camera.
5. The gamma camera system of Claim 1 wherein said gantry is equipped with radial drive for radially moving the gamma camera toward said patient when neither said first screen of energy nor said second screen of energy is interrupted.
6. The gamma camera system of Claim 5 wherein a radial movement brake device is provided for stopping the radial movement of the gamma camera when said first energy screen is interrupted while said second energy screen is not interrupted.
7. The gamma camera system of Claim 6 including said radial drive for moving said gamma camera radially away from said patient when said first and second energy screens are both interrupted.
8. The gamma camera system of Claim 7 wherein a plurality of gamma cameras are mounted on said gantry for use in performing scans of the patient, said radial drive comprising a motor individually associated with each of the plurality of gamma cameras for individually moving each of said gamma cameras radially relative to said patient.
9. The gamma camera system of Claim 1 wherein said gamma camera includes a collimator, and wherein the proximity control changes the minimum distance between patient and the gamma camera during said scans when different size collimators are used.
10. The gamma camera system of Claim 1 wherein the said screens of energy comprise individual beams of energy transmitted from a line of energy transmitters at once side of the front face of the gamma camera towards energy receivers at the other side of the front face gamma camera.
11. The gamma camera system of Claim 10 including a cross-talk avoidance arrangement for avoiding cross-talk between the individual beams.
12. The gamma camera system of Claim 11 wherein said cross-talk avoidance arrangement comprises circuitry for energizing the transmitters and receivers in pairs so that the energy from the transmitters are transmitted in a manner such that energy can be received by only one receiver at a time.
13. The gamma camera system of Claim 12 wherein the transmitters and corresponding receivers of the pairs are energized serially, one pair at a time.
14. The gamma camera system of Claim 10 wherein said energy transmitters comprise light emitting diodes and said energy receivers comprise light sensitive detectors.
15. The gamma camera system of Claim 10 wherein said energy transmitters comprise infra-red emitting diodes and said energy receivers comprise infra-red sensitive detectors.
16. The gamma camera system of Claim 9 wherein when different size collimators are used then multiple lines of energy transmitters at one side of camera and multiple lines of energy receivers at the other side of the gamma camera are used, and switching circuitry for causing different pairs of said multiple lines of transmitters and receivers to be used depending on the size of the collimator used.
17. The gamma camera system of Claim 9 including a mechanical actuator for mechanically moving said proximity control to accommodate said different size collimators.
18. The gamma camera system of Claim 1 including a fail-safe arrangement for ensuring that the camera does not injure the patient.
19. The gamma camera system of Claim 18 wherein said fail-safe arrangement comprises a pressure-sensitive device mounted and connected to cause said camera to move away from said patient when said pressure-sensitive device is actuated.
20. The gamma camera system of Claim 18 wherein said fail-safe arrangement comprises a pressure-sensitive device mounted and arranged to cause said camera to stop all movement when said pressure-sensitive device is actuated.
21. The gamma camera system of Claim 1 wherein an early warning system is provided to prevent said camera from moving toward said patient when said early warning system is actuated by the body of the patient as the camera is being moved laterally toward said patient.
22. The gamma camera system of Claim 21 wherein said early warning system comprises:
at least one screen of energy beams at the side of the gamma camera moving toward said patient, and a drive responsive to interruption of said screen for moving said gamma camera away from said patient.
at least one screen of energy beams at the side of the gamma camera moving toward said patient, and a drive responsive to interruption of said screen for moving said gamma camera away from said patient.
23. The gamma camera system of Claim 22 wherein said screen is provided by transmitters and receivers mounted on opposite sides of said gamma camera.
24. The gamma camera system of Claim 1 wherein the said energy screen comprises a series of energy beams.
optical controls, said camera including a radiation detecting side, said optical controls comprising:
a first series of energy transmitters each mounted a first distance away from the radiation detecting side of said gamma camera, a first series of energy receivers each mounted oppositely disposed from said first series of energy transmitters at said first distance away from the radiation detecting side of said gamma camera so that energy transmitted from said first series of energy transmitters impinge on said first series of energy receivers after spanning the detecting side of the camera, a motor, said motor operated responsive to an interruption of transmitted energy going from said first series of transmitters to said first series of receivers to move said camera away from the patient, a second series of energy transmitters each mounted a second distance away from the radiation detecting side of the camera, a second series of energy receivers mounted oppositely disposed from said second series of energy transmitters and at said second distance away from said radiation detecting side of said camera so that energy transmitted from said second series of energy transmitters impinge on said second series of energy receivers after spanning the detecting side of the camera, means for inhibiting the operation of said motor responsive to interference between the energy transmitted by the second series.
of energy transmitters and the second series of energy receivers while there is interference between the energy transmitted by the first series of energy transmitters and the first series of receivers, and controls for operating said motor to move such camera towards said patient when there is no interference with the energy extending from the first series of transmitters to the first series of receivers or with the energy extending from the second series of transmitters to the second series of receivers.
optical controls, said camera including a radiation detecting side, said optical controls comprising:
a first series of energy transmitters each mounted a first distance away from the radiation detecting side of said gamma camera, a first series of energy receivers each mounted oppositely disposed from said first series of energy transmitters at said first distance away from the radiation detecting side of said gamma camera so that energy transmitted from said first series of energy transmitters impinge on said first series of energy receivers after spanning the detecting side of the camera, a motor, said motor operated responsive to an interruption of transmitted energy going from said first series of transmitters to said first series of receivers to move said camera away from the patient, a second series of energy transmitters each mounted a second distance away from the radiation detecting side of the camera, a second series of energy receivers mounted oppositely disposed from said second series of energy transmitters and at said second distance away from said radiation detecting side of said camera so that energy transmitted from said second series of energy transmitters impinge on said second series of energy receivers after spanning the detecting side of the camera, means for inhibiting the operation of said motor responsive to interference between the energy transmitted by the second series.
of energy transmitters and the second series of energy receivers while there is interference between the energy transmitted by the first series of energy transmitters and the first series of receivers, and controls for operating said motor to move such camera towards said patient when there is no interference with the energy extending from the first series of transmitters to the first series of receivers or with the energy extending from the second series of transmitters to the second series of receivers.
25. A method of controlling the proximity of a gamma camera to a patient during a scan of the patient, said method comprising the steps of:
spanning the detector side of the gamma camera with first and second screens of energy at a first and a second distance from the detector side of the gamma camera, said first distance being smaller than said second distance, moving said gamma camera toward the patient when there is no interference with either said first or said second energy screen, moving said gamma camera away from said patient when there is interference with both said first and said second energy screens, and inhibiting movement of said gamma camera when there is no interference with said first energy screen while there is interference with the second screen.
spanning the detector side of the gamma camera with first and second screens of energy at a first and a second distance from the detector side of the gamma camera, said first distance being smaller than said second distance, moving said gamma camera toward the patient when there is no interference with either said first or said second energy screen, moving said gamma camera away from said patient when there is interference with both said first and said second energy screens, and inhibiting movement of said gamma camera when there is no interference with said first energy screen while there is interference with the second screen.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL10429292A IL104292A (en) | 1992-12-31 | 1992-12-31 | Scanning nuclear camera |
| IL104292 | 1992-12-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2111284A1 true CA2111284A1 (en) | 1994-07-01 |
Family
ID=11064378
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002111284A Abandoned CA2111284A1 (en) | 1992-12-31 | 1993-12-13 | Scanning nuclear camera |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5486700A (en) |
| JP (1) | JP3118762B2 (en) |
| CA (1) | CA2111284A1 (en) |
| DE (1) | DE4344882A1 (en) |
| FR (1) | FR2700017B1 (en) |
| IL (1) | IL104292A (en) |
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| US5625191A (en) * | 1992-10-28 | 1997-04-29 | Kabushiki Kaisha Toshiba | Scintillation camera and sensor for use therein |
| FR2719670B1 (en) * | 1994-05-03 | 1996-07-05 | Sopha Medical | Gamma camera with approach and safety plans. |
| GB2300712A (en) * | 1995-05-11 | 1996-11-13 | Elscint Ltd | Rotatable MRI magnet and patient support |
| US5651044A (en) * | 1995-10-02 | 1997-07-22 | General Electric Company | Capacitive proximity detector for radiation imager position control |
| US5805664A (en) * | 1995-10-02 | 1998-09-08 | General Electric Company | Imager control system with contact detector |
| US5654997A (en) * | 1995-10-02 | 1997-08-05 | General Electric Company | Ultrasonic ranging system for radiation imager position control |
| US5744802A (en) * | 1995-10-25 | 1998-04-28 | Adac Laboratories | Image generation from limited projections in positron emission tomography using multi-slice rebinning |
| US5650623A (en) * | 1995-12-04 | 1997-07-22 | General Electric Company | Perimeter sensing device |
| US6175116B1 (en) * | 1997-06-02 | 2001-01-16 | Picker International, Inc. | Hybrid collimation and coincidence imager for simultaneous positron and single photon imaging |
| DE19743500A1 (en) * | 1997-10-01 | 1999-04-29 | Siemens Ag | Medical apparatus with device for detecting position of object |
| EP1099123A1 (en) | 1998-04-27 | 2001-05-16 | Duke University | Transmission scanning technique for gamma camera coincidence imaging |
| US6211523B1 (en) | 1998-06-03 | 2001-04-03 | Picker International, Inc. | Autocontouring device for gamma camera using radioactive source and transverse motion |
| US8064984B2 (en) | 2003-03-18 | 2011-11-22 | Esaote S.P.A. | Magnetic resonance imaging apparatus |
| JP2005118080A (en) * | 2003-10-14 | 2005-05-12 | Ge Medical Systems Global Technology Co Llc | Radiography apparatus, collision detector, and buffer |
| FR2870428A1 (en) * | 2004-05-11 | 2005-11-18 | Gen Electric | MOBILE X-RAY MACHINE |
| US7233002B2 (en) * | 2004-11-25 | 2007-06-19 | Ultraspect Ltd. | SPECT gamma camera with a fixed detector radius of orbit |
| DE102005014188A1 (en) * | 2005-03-29 | 2006-10-12 | Siemens Ag | Device for taking projection images |
| US7723688B2 (en) * | 2006-01-19 | 2010-05-25 | General Electric Company | Methods and systems for automatic body-contouring imaging |
| US7531807B2 (en) | 2006-01-19 | 2009-05-12 | Ge Medical Systems Israel, Ltd. | Methods and systems for automatic body-contouring imaging |
| US7557352B2 (en) * | 2006-06-02 | 2009-07-07 | Ge Medical Systems Israel, Ltd. | Methods and systems for controlling medical imaging |
| JP6043280B2 (en) * | 2010-06-04 | 2016-12-14 | ニューロロジカ・コーポレーション | High resolution single photon emission computed tomography (SPECT) system |
| US9078618B2 (en) | 2010-10-29 | 2015-07-14 | General Electric Company | Methods and systems for patient alignment for nuclear medicine imaging |
| US8876377B2 (en) | 2011-12-23 | 2014-11-04 | General Electric Company | Proximity detection system for imaging systems and method for sensing proximity |
| US9995833B1 (en) | 2017-03-07 | 2018-06-12 | General Electric Company | Nuclear medicine imaging systems and methods having a secondary mechanism for controlling a detector head |
| EP3627192B1 (en) * | 2018-09-20 | 2023-08-30 | Rigaku Corporation | Protection device for an area detector |
| CN111198211B (en) * | 2018-11-16 | 2022-01-25 | 中国科学院大连化学物理研究所 | Movable imaging device based on capacitive tomography sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3805061A (en) * | 1973-04-23 | 1974-04-16 | Tyco Laboratories Inc | Object detecting apparatus |
| US3970846A (en) * | 1973-10-29 | 1976-07-20 | Xenex Corporation | Presence detecting system with self-checking |
| JPS5742873A (en) * | 1980-08-28 | 1982-03-10 | Toshiba Corp | Emission ct |
| US4593189A (en) * | 1983-11-09 | 1986-06-03 | Siemens Gammasonics, Inc. | Proximity detector for a body scanner |
| US4818866A (en) * | 1986-01-13 | 1989-04-04 | Data Instruments, Inc. | Intrusion detection system for operating industrial machines with variable sensitivity |
| US5027221A (en) * | 1990-10-10 | 1991-06-25 | Fuji Xerox Co., Ltd. | Digital image recording system with preset control for selecting output formats based on the selected amount of pixel color and density data |
| US5072121A (en) * | 1990-11-15 | 1991-12-10 | Siemens Gammasonics Inc. | Body contour determining apparatus for a rotating gamma camera |
| US5319205A (en) * | 1992-11-27 | 1994-06-07 | Trionix Research Laboratory, Inc. | Proximity sensor for gamma camera |
-
1992
- 1992-12-31 IL IL10429292A patent/IL104292A/en not_active IP Right Cessation
-
1993
- 1993-12-13 CA CA002111284A patent/CA2111284A1/en not_active Abandoned
- 1993-12-27 US US08/172,728 patent/US5486700A/en not_active Expired - Lifetime
- 1993-12-28 JP JP05335010A patent/JP3118762B2/en not_active Expired - Fee Related
- 1993-12-29 FR FR9315803A patent/FR2700017B1/en not_active Expired - Fee Related
- 1993-12-29 DE DE4344882A patent/DE4344882A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE4344882A1 (en) | 1994-07-07 |
| FR2700017B1 (en) | 1999-01-29 |
| IL104292A0 (en) | 1993-05-13 |
| IL104292A (en) | 1995-08-31 |
| US5486700A (en) | 1996-01-23 |
| JP3118762B2 (en) | 2000-12-18 |
| FR2700017A1 (en) | 1994-07-01 |
| JPH06300848A (en) | 1994-10-28 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Discontinued |