Abstract: A method for calibrating photomultiplier tubes in a scintillation camera having a plurality of light sources includes the steps of: pulsing all light sources simultaneously; reading the output of each photomultiplier tube; comparing the output of each photomultiplier tube with an expected value; determining whether the output of each photomultiplier tube is within a first specified tolerance; and adjusting each photomultiplier tube if the output of the photomultiplier tube is not within the first specified tolerance.

Abstract: A scintillation camera using the dual scintillation detector head is disclosed. The scintillation camera can include two dual scintillation detector heads, which are fixed in opposition to each other. The camera can include a dual scintillation detector head and a single scintillation detector head, which are also fixed in opposed relation to each other. The dual scintillation detector head has two scintillation detectors, which are fixed relative to each other, preferably fixed substantially at 90 degrees to each other. Each scintillation detector has a plurality of photomultiplier tubes, a collimator, and a scintillation medium.

Abstract: A method and apparatus for determining the centre photodetector in a planar array of photodetectors of a gamma scintillation camera is provided. The analog signals generated by a plurality of photomultiplier tubes (PMT) following a scintillation event, are digitized, integrated, and stored in a first memory. A first comparison means is used to divide the set of PMT logical signals into groups. Each group comprises an arbitrary number of PMTs. The PMT logical signals within a group are combined into pairs and compared to select the highest intensity value for each individual group. Subsets of local PMT highest intensity values are created. A second comparison means is used to receive the subsets of local PMT highest values, combine them into pairs, compare the paired signals, and record the selected signals in a second memory, until a PMT with the maximum intensity value or a centre PMT is obtained.

Abstract: A support structure for medical diagnostic equipment provides entirely independent motions on all axes of the detector and very precise and reproducible motions while allowing for static, linear and rotational imaging such as by a rotatable scintillation detector. The support structure includes a rotor or ring on which there are two arms on which the detector is mounted and a counterweight attached by links to the opposite end of the arms and on the opposite side of the rotor. The arms, on which the detector is rotatably mounted, are attached to the rotor by means of short, double pivoted links which allow the arms to move towards or away from the rotor and pivot with respect to the rotor. Two secondary arms are connected to the pivot point of the detector and to a track mounted on the rotor.

Abstract: A method and apparatus for improving the image quality of positron emission tomography is disclosed. This is achieved by analysing individual photomultiplier tubes for true events. The apparatus includes a photomultiplier tube for generating a photomultiplier tube signal. A series of pull up resistors generates a code signal identifying the photomultiplier tube. A clock generates a time stamp to the photomultiplier tube signal. A bus buffer generates an encoded signal. A position computing device calculates the position of the photomultiplier tube. An image computer generates an image from a plurality of encoded signals. A display displays the image. Analysing data from individual photomultiplier tubes results in smaller areas and smaller amounts of data to be processed. This then permits smaller time franm windows to be used. The use of time stamps also permits data before and after an event to be recorded.

Abstract: A positioner for a scintillation camera detector head is designed for use with a detector head of the type having a center of gravity dependent upon the weight of a removable collimator plate and being supported between a pair of substantially parallel support arms such that the detector head is rotatable relative to the support arms about an axis of rotation passing through the support arms. The positioner includes a pair of rigid detector head links for aligning the center of gravity of the detector head relative to the support arms. Each detector head link includes an arm end rotatably attached to the adjacent support arm by way of an arm axle, and a head end rotatably attached to the detector head by way of a head axle. The positioner also includes a lock for selectively securing the relative positions of the detector head and the detector head links.

Abstract: A photomultiplier tube identifier is designed to identify a malfunctioning photomultiplier tube in a scintillation camera having an array of photomultiplier tubes. The photomultiplier tube identifier includes a photomultiplier tube for generating a photomultiplier tube signal. An amplifier/integrator generates an amplified/integrated signal from the photomultiplier tube signal. An analog to digital converter generates a digitized signal from the amplified/integrated signal. A series of pull up resistors generates a code signal identifying the photomultiplier tube. A bus buffer generates an encoded signal comprising the amplified/integrated signal followed by the code signal. A position computing device calculates the position of the photomultiplier tube. An image computer generates an image from a plurality of encoded signals. A display displays the image.

Abstract: A patient support is designed for use with a scintillation camera that includes a vertically oriented annular rotating support having an axis, and an elongate support extending from the rotating support for supporting a detector head, the rotating support including a coaxial inner surface defining an orifice. The patient support includes a patient stretcher for supporting a patient in a horizontal position substantially parallel to the axis of the rotating support. The patient support also includes a detached support for horizontally supporting the patient stretcher on a ground surface. The detached support includes a first stretcher support for supporting the patient stretcher and for positioning the patient stretcher relative to the rotating support. The patient support also includes an engaged support for horizontally supporting the patient stretcher on the inner surface of the cylindrical support such that the patient stretcher remains unaffected by the rotation of the rotating support.

Abstract: A scintillation data collecting apparatus and method are provided for a scintillation camera and a data processor. The apparatus comprises a scintillation detector including an adder and an analyzer for detecting the valid scintillations, a plurality of conversion units each including an analog-to-digital converter for converting intensity signals derived from the valid scintillations into high, accuracy digital values, and controllers for controlling operation of each of the analog-to-digital converters of the conversion units. The method comprises steps of adding the intensity signals generated by the scintillation camera and which are indicative of the scintillations, and analyzing the sum of the intensity signals to determine if the detected scintillations are valid.

Abstract: The discriminator comprises a summing circuit for producing a sum signal from light detectors of a scintillation camera; a slope analysis circuit for analyzing a slope of the sum signal to produce a slope analysis result indicative of a given characteristic change in the slope; a first event characteristic evaluation circuit for producing in response to the slope analysis result and the sum signal a first event characteristic signal representative of an energy of the first event; a second event characteristic evaluation circuit for producing in response to the slope analysis result and the sum signal a second event characteristic signal representative of an energy of the second event; and a validity analyzer circuit for producing a valid event indicator signal in response to the slope analysis result, the first event characteristic signal and the second event characteristic signal. A method of pulsepile discrimination is also disclosed.

Abstract: A positioner apparatus for a scintillation camera comprises a rotating frame unit, a camera fork mounting provided on the unit for totatably mounting and rotating a camera fork about a first axis, and an eccentric mounting for rotatably mounting the camera to ends of the fork, and for rotating the camera about a second axis extending between the fork ends and at an offset distance with respect to the first axis. By rotating the camera 180.degree. about the second axis and the fork 180.degree. about the first axis, an aperture of the camera faces in the same direction, but at a different radial position for CAT scans.

Abstract: The scintillation camera includes a plurality of individually pulsible light emitting devices associated with a number of the photomultiplier tubes. By pulsing the light emitting device, certain ones of the photomultiplier tubes of the camera receive substantial amounts of light. Values from the certain photomultiplier tubes are compared to one another for carrying out an effective gain adjustment of at least one of the certain tubes. The gain calibration is independent of the amount of light emitted from the light emitting devices. There is also provided a method of adjusting the effective gain of the camera by using the readings resulting from a gamma ray induced scintillation instead of the pulsible light emitting devices.