D. Kaufman

Development of a small animal PET imaging device with resolution approaching 1 mm

This paper describes progress in the design and construction of a single-plane PET tomograph having a spatial resolution approaching 1 mm. The system consists of a 12-cm diameter ring with 360 LSO (Lu/sub 2/SiO/sub 5/) detectors viewed by 30 photomultiplier tubes. Thin (5-mm) crystals and a low energy threshold are used. Crystals are identified using both position arithmetic and energy criteria. To date, the system construction has been completed, system tuning has been carried out and imaging studies have begun.

Cylindrical PET detector design

A cylindrically shaped high-resolution PET (positron-emission-tomography) detector that uses cross-plane coincidence events is being developed. A 2-D analog coded position-sensitive detector is used. It consists of a hexagonal array of photomultiplier tubes and a rectangular array of crystals, eight elements per tube. The optics has been designed to maximize the light collection and to provide uniform spatial resolution. The detector will be 60 cm in diameter by 11.5 cm wide, the crystals are 3 mm*5.7 mm*30 mm. The design, associated electronics, and results of measurements on a sector of the detector are presented. >

A Stationary Positron Emission Ring Tomograph Using Bgo Detector and Analog Readout

A single ring PET camera has been constructed to demonstrate the use of one dimensional scintillation camera techniques in positron tomographic design. A pseudo-continuous BGO detector is used. The detector is 46 cm ID, 52 cm OD, 2 cm wide and is made using 360 elements. A narrow light guide and 90 PM Tubes are used for the readout. The position of coincident events are found using unique scintillation camera logic.

A Positron Tomograph Employing a One Dimension BGO Scintillation Camera

A detector employing a pseudo-continuous ring of BGO and analog type position sensing has been constructed. It is fabricated using 360 2 × 3 × 0.4cm BGO detector elements, a light guide 1 × 1.6 × 51cm ID and 90 2cm diameter PM tubes. The position of a scintillation event is identified using logic based on a maximum likelihood estimator. A stationary high spatial resolution high detection efficiency tomograph is achieved using this approach.

One Dimensional Scintillation Cameras for Positron Ect Ring Detectors

A one-dimensional scintillation camera configured as a continuous ring with coincidence-mode collimation avoids many of the problems associated with rings formed from an array of discrete detector elements. With the goal of achieving a stationary detector exhibiting high spatial resolution and sensitivity, several detector configurations have been designed. Both analytic and Monte-Carlo simulation techniques have been used to evaluate these designs. Results of the calculations and comparative measurements on the various detector designs are discussed.

Design of a Cylindrical Shaped Scintillation Camera for Positron Tomographs

The design of a cylindrically shaped scintillation camera for volume imaging of positron emitters is discussed. The design is based on the detector concepts developed for a single ring scintillation camera, i.e., the Massachusetts General Hospital analog ring camera. Detector characteristics derived from both computer modeling and measurements are presented.

Application of a One Dimensional Scintillation Camera in a Positron Tomographic Ring Detector

The optical and position sensing properties of the array are unique. All the light from a scintillation is projected from the narrow elements through a light guide and into a ring of PM tubes yielding a narrow light spread function that is independent of the depth of an interaction. Position sensing logic based on a maximum likelihood estimator has been employed to ensure high spatial resolution. The spatial sampling has been chosen so not to impose the primary resolution limit.

A low-Z PET detector

In order to examine the potential of low-Z detector materials for PET (positron emission tomography), a small field imaging system using plastic detectors has been designed. In this system the site of a photon interaction in the detector is located using light produced by the first Compton electron. This is in contrast to high-Z detectors where multiple interactions occur. The calculated performance of the detector and supporting measurements are presented. >

Performance of small animal PET instrument with 1 mm resolution

A single-plane PET imaging instrument using LSO detectors has been constructed to demonstrate the feasibility of imaging at 1 mm spatial resolution. The performance of this instrument has been evaluated in phantoms and small animals. Measurements presented include spatial resolution, sensitivity, count-rate performance, linearity and field uniformity. Examples of several mouse imaging studies are also presented.

Design studies for a volumetric high resolution small animal PET

We have developed two LSO block detectors for single-plane small animal PET instruments which have a spatial resolution of approximately 1 mm. They have served mainly as demonstration prototypes but have also been used for numerous rat and mouse imaging studies. By extending the axial length of the detector element from these systems and adding a second ring of photomultiplier tubes, a high-resolution 2-dimensional block using analog position sensing in both the radial and axial dimensions has been implemented. It consists of ten 1.2 mm wide/spl times/7 mm deep/spl times/20 mm high LSO crystals that are discrete in the radial direction and continuous in the axial direction. An instrument based on this design results in a substantial increase in sensitivity. Experiments with this detector element have demonstrated 1.2 mm radial resolution and approximately 1.6 mm axial coincidence resolution over the central 15 mm of the 20 mm high block element. A preliminary design for an instrument based on the 2-dimensional block has been evaluated by simulation studies.