Radiant energy – Invisible radiant energy responsive electric signalling – With or including a luminophor
Reexamination Certificate
1998-04-24
2001-01-16
Ham, Seungsook (Department: 2878)
Radiant energy
Invisible radiant energy responsive electric signalling
With or including a luminophor
C250S363040, C250S363020, C250S362000, C250S363100, C378S004000
Reexamination Certificate
active
06175116
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the art of diagnostic imaging. It finds particular application in conjunction with nuclear or gamma cameras and will be described with particular reference thereto. It is to be appreciated, however, that the present invention will also find application in other non-invasive investigation techniques and imaging systems such as single photon planar imaging, whole body nuclear scans, positron emission tomography (PET) and other diagnostic modes.
Positron emission tomography (PET) scanners are known as coincidence imaging devices. In planar coincidence imaging, two radiation detectors oppose each other with a subject disposed between the detectors. Typically, one or more radiopharmaceuticals or radioisotopes capable of generating positron emission radiation are injected into the subject. The radioisotope preferably travels to an organ of interest whose image is to be produced. The detectors scan the subject along a longitudinal axis without rotation, otherwise known as limited angle tomography. Radiation events are detected on each detector and a coincidence circuitry compares and matches the events on each detector. Events on one detector which have a coincident event on the other detector are treated as valid data and may be used in image reconstruction.
Typically, the detector includes a scintillation crystal that is viewed by an array of photo multiplier tubes. The relative outputs of the photo multiplier tubes are processed and corrected, as is conventional in the art, to generate an output signal indicative of (1) a position coordinate on the detector head at which each radiation event is received, and (2) an energy of each event. The energy is used to differentiate between various types of radiation such as multiple emission radiation sources and to eliminate noise, or stray and secondary emission radiation. A two dimensional image representation is defined by the number of coincidence radiation events or counts received at each coordinate. However during a scan, only a fraction of the events detected are coincidence events. As such, scan times are increased in an effort to obtain a sufficient data sampling for image reconstruction which poses additional inconveniences to the subject and an increase in scanning costs.
The present invention provides a new and improved diagnostic imaging system and method which provides simultaneous positron and single photon imaging which overcomes the above-referenced problems and others.
SUMMARY OF THE INVENTION
In accordance with the present invention, a new and improved diagnostic imaging system and method for diagnostic imaging is provided. A nuclear camera system includes a gantry which defines an examination region for receiving a subject. The subject is injected with a substance which emits positron radiation, positron radiation and single photon radiation, positron radiation and radiation suitable to obtain information on attenuation, or any combination thereof. First and second radiation detectors are oppositely disposed on the gantry and have the examination region therebetween. The first and second radiation detectors simultaneously detect radiation from the examination region. A coincidence circuitry connects the first and second radiation detectors and determines the likelihood of that received radiation events come from a positron emitter. Subsystems are connected to the coincidence circuitry which determine the likelihood of a single event having a particular energy band, including an energy window appropriate to define a single gamma of a pair of gamma from a positron emitter, or any other isotopes present in the examination region, including radiation from the positron emitter. An event determiner is connected to the first and second radiation detectors which direct radiation events to a proper reconstruction processor according to characteristics of the radiation events such as timing (or coincidence), energy, location on the detector, or any combination thereof.
In accordance with another aspect of the present invention, a diagnostic imaging method is provided for imaging a subject which includes injecting the subject with first and second isotopes where the first isotope generates positron radiation and the second isotope generates single photon radiation. Selected energy values of radiation are collimated. The positron radiation and the single photon radiation are simultaneously detected and a type of radiation detected is determined. Coincidence data based on the positron radiation detected is generated and single photon data based on the single photon radiation detected is generated. An image representation of the subject is reconstructed from the coincidence data and from the single photon data.
One advantage of the present invention is that positron radiation and single photon radiation arc simultaneously collected by the same radiation detectors.
Another advantage of the present invention is that dual isotope imaging is performed which provides more clinically useful information.
It is a further advantage of the present invention that the image representation of the positron emitter is obtained by selecting events that are in coincidence, events that are in coincidence and with a proper energy, or simply events that have the proper energy, thus increasing the number of events in the final image. Events coming from a different selection path are either immediately combined or separated and analyzed independently.
It is still another advantage of the present invention that an image representation of a single photon emitter (if present in the examination region) is obtained simultaneously with the image representation of the positron emitter.
It is yet another advantage of the present invention that coincidence event image representations that are best when placed in the center of the examination region, can be combined, or analyzed separately with collimated events of the same radiation known to be best at the periphery of the examination region, and to be less affected by the non-uniform nature of attenuation material in the examination region.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
REFERENCES:
patent: 5479021 (1995-12-01), Morgan et al.
patent: 5481115 (1996-01-01), Hsieh et al.
patent: 5486700 (1996-01-01), Silberklang et al.
patent: 5489782 (1996-02-01), Wernikoff
patent: 5552605 (1996-09-01), Arata
patent: 5638817 (1997-06-01), Morgan et al.
patent: 5717212 (1998-02-01), Fulton et al.
patent: 5760401 (1998-06-01), Nelleman et al.
patent: 5834780 (1998-11-01), Morgan et al.
patent: 5838009 (1998-11-01), Plummer et al.
patent: 5923038 (1999-07-01), DiFilippo et al.
patent: 5929446 (1999-07-01), Plummer et al.
patent: 5965891 (1999-10-01), Weinberg
patent: 5969358 (1999-10-01), DiFilippo et al.
patent: 5998792 (1999-12-01), DiFilippo et al.
DiFilippo Frank P.
Gagnon Daniel
Clair Eugene E.
Fry John J.
Gurin Timothy B.
Ham Seungsook
Patti John
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