Single-slice contrasted with multiple-slice positron tomographs.
Explore the source record for details and available documents.
Costs and Cost Analysis↗
Biomedical subjects
N A Mullani
Publications and source records attributed to N A Mullani.
Design considerations for a positron emission transverse tomograph (PETT V) for imaging of the brain.
Imaging of the brain by positron emission tomography can be optimized for sensitivity by dedicating the design of the tomograph to this application. We have designed a multislice positron emission tomograph (PETT V) for imaging the human brain and the whole body of small experimental animals. The detector system of PETT V consists of a circular array of 48 NaI(Tl) scintillation detectors, each fitted with two photomultiplier tubes, with one dimensional positioning capability. Suitable sampling is achieved by rotation of the circular array of detectors and by a wobbling motion of the detector circle. The proposed system is capable of providing seven slices simultaneously, with a spatial resolution in the plane of the slice from 7 to 15 mm and with slice thicknesses of 7 and 14 mm. The minimum scanning time is 1 sec. The estimated overall sensitivity of PETT V is 350,000 counts/sec/mCi in a 20 cm diameter phantom for a resolution of approximately 1.5 x 1.5 cm. The system is under construction.
Animals↗
A multislice positron emission computed tomograph (PETT IV) yielding transverse and longitudinal images.
We designed, built, and tested a positron emission tomograph (PETT IV) capable of providing seven slices of the human body simultaneously. PETT IV utilizes a moving hexagonal array of 48 scintillation detectors placed around the subject. Each detector consists of a cylindrical activated sodium iodide crystal optically coupled to two photomultiplier tubes. The multislice capability is achieved by comparing the light outputs of the two photomultiplier tubes in each detector. The images are displayed either as transverse or as longitudinal tomographic sections. This system provides high sensitivity and resolution, and permits rapid and accurate three-dimensional imaging of the head and body.
Electrons↗
Design and performance characteristics of a whole-body positron transaxial tomograph.
A whole-body positron-emission transaxial tomograph (PETT III) is described in detail and evaluated in terms of resolution, accuracy, and efficiency. The PETT III utilizes annihilation coincidence detection to provide spatial resolution; high sensitivity is achieved by using 48 Nal(tl) detectors set in a hexagonal array with a multiple-coincidence logic. The assumptions and approximations made in the reconstruction and their effect on image quality are discussed. Phantom studies shows the depth-independent resolution and response of PETT III, as well as its ability to recover activity distribution quantitatively in the cross section measured. Images obtained with patients and normal volunteers show the potential clinical utility of PETT III.
Evaluation Studies as Topic↗
A positron-emission transaxial tomograph for nuclear imaging (PETT).
An apparatus was developed for obtaining emission transaxial images of sections of organs containing positron-emitting radiopharmaceuticals. The detection system is a hexagonal array of 24 NaI(T1) detectors connected to coincidence circuits to achieve the "electronic" collimation of annihilation photons. The image is formed by a computer-applied algorithm which provides quantitative reconstruction of the distribution of activity. Computer simulations, phantom and animal studies show that this approach is capable of providing images of better contrast and resolution than are obtained with scintillation cameras. Advantages of positron vs. single photon reconstruction tomography are discussed.
Animals↗
Application of annihilation coincidence detection to transaxial reconstruction tomography.
A study was carried out to investigate the use of annihilation coincidence detection (ACD) in emmision transaxial reconstruction tomography. The ACD was evaluated in terms of spatial resolution and sensitivity with depth, detection efficiency, effect of pulse-height analysis on resolution and efficiency, correction for attenuation, and cold spot contrast. A prototype positron emission transaxial tomograph (PETT) consisting of a hexagonal array of 24 Nal (Tl) detectors employing ACD was constructed. A fast Fourier transform algorithm was employed to generate the reconstructed image. Computer simulations and phantom and animal studies were carried out to demonstrate that this approach yields tomographic radionuclide images that have high resolution and contrast (hot and cold spot) and that are independent of activity above and below the plane examined. The ACD yields a quantitative nuclear medicine imaging device with high detection efficiency. Comparisons are presented between the ACD and the scintillation camera and scanner. Discussion of the possible applications of the PETT in nuclear medicine is included.
Animals↗
Positron emission tomography instrumentation: a review and update.
Positron Emission Tomography (PET) has evolved into a powerful modality for in vivo functional imaging of the brain and the heart. Developments in PET technology and instrumentation have occurred rapidly during the last 20 years and have been driven by the requirements for improved resolution and image quality necessary for clinical and research applications. Clinical applications of PET have now been validated for the heart and the brain, and new research in the mapping of receptor density in the brain is being explored. PET cameras have developed into sophisticated imaging devices capable of both clinical and research applications. This review article updates the previous overview on PET instrumentation written by the authors with an added emphasis on performance evaluation of PET cameras. A short summary of current PET cameras available commercially is included for the purpose of comparing some important specifications between different systems.
Brain↗
Utilization statistics and diagnostic accuracy of a nonhospital-based positron emission tomography center for the detection of coronary artery disease using rubidium-82.
A retrospective analysis has been carried out to determine utilization and diagnostic accuracy of positron emission tomography of the heart with rubidium-82 at a nonhospital-based center. Utilization statistics were derived for the first 27 months of operation of the center from a total of 1,670 patients scanned. Diagnostic accuracy for detection of coronary artery disease was assessed using three readers, blinded to the clinical information, who read 225 rest and dipyridamole-stress scans of patients that had a coronary angiogram. Utilization statistics show that the center averaged 64 patients per month, 66% were males, 38% of the patients scanned had a coronary angiogram, 25% had a history of myocardial infarction, 12% had coronary artery bypass graft surgery, and 18% had percutaneous transluminal coronary angioplasty. Sensitivity was 82%, 96%, and 100% for myocardial regions perfused with greater than 67%, 84%, and 100% diameter stenosis, respectively. Specificity was 91% for all normal regions of the heart. Accuracy was 89%, 93%, and 93% for regions with greater than 67%, 84%, and 100% diameter stenosis, respectively. These results compare well with published results from major hospital based centers.
Ambulatory Care Facilities↗