Design and construction of a stand-alone camera system and its clinical application in nuclear medicine

This paper reports investigations into some of the improvements of the performance of 'modular' gamma-ray cameras. Each modular camera has a 10 x 10 cm NaI(Tl) scintillation crystal and four 5 x 5 cm photomultiplier tubes (PMTs). When the gamma-ray photons interact with the crystal, scintillation flashes are emitted from the crystal and detected by the PMTs. The PMTs then convert the light flashes to current pulses. A digital computing circuitry processes the PMT outputs and assigns an estimated (x, y) coordinate corresponding to the location of interaction of each gamma-ray photon in the crystal and thus an image is formed. This paper is concerned with improvements and clinical applications of the modular cameras. We do the camera characterization by measuring spatial resolution and sensitivity of the modular camera and compare these characteristics to those of a commercial gamma camera. We design and construct a stand-alone planar imaging system based on the modular camera. This imager is examined with a set of phantoms and clinical tests to demonstrate the clinical feasibility of the stand-alone system.