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We have developed two prototypes of portable gamma cameras for medical applications based on a previous prototype designed and tested by our group. These cameras use a CsI(Na) continuous scintillation crystal coupled to the new flat-panel-type multianode position-sensitive photomultiplier tube, H8500 from Hamamatsu Photonics. One of the prototypes, mainly intended for intrasurgical use, has a field of view of 44 x 44 mm2, and weighs 1.2 kg. Its intrinsic resolution is better than 1.5 mm and its energy resolution is about 13% at 140 keV. The second prototype, mainly intended for osteological, renal, mammary, and endocrine (thyroid, parathyroid, and suprarenal) scintigraphies, weighs a total of 2 kg. Its average spatial resolution is 2 mm; it has a field of view of 95 x 95 mm2, with an energy resolution of about 15% at 140 keV. The main advantages of these gamma camera prototypes with respect to those previously reported in the literature are high portability and low weight, with no significant loss of sensitivity and spatial resolution. All the electronic components are packed inside the mini gamma cameras, and no external electronic devices are required. The cameras are only connected through the universal serial bus port to a portable PC. In this paper, we present the design of the cameras and describe the procedures that have led us to choose their configuration together with the most important performance features of the cameras. For one of the prototypes, clinical tests on melanoma patients are presented and images are compared with those obtained with a conventional camera.

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We have built a PET camera for small animals based on continuous block LSO crystals coupled to a PS-PMT Flat Panel. When working with continuous crystals, surface treatment is an important factor that strongly determines the main characteristics of the detector module. As a part of the work done for the development of our small animals PET camera, we have investigated the effect of the scintillator crystal surface treatment on the PET detector module performances, in order to optimize crystal configuration. We present the results for spatial resolution, image compression and energy resolution obtained when using different surface treatments in continuous LSO crystals. These results are compared with those obtained from simulations that have been carried out using DETECT2000 package.