Design and characterization of a dual modality (SPET-US) tomographic device

In the last few years, integrated dual-imaging systems have emerged as a new modality for cancer staging with the aim to offer both functional and anatomic information. At moment the prevalent dual modality devices are based on Computer Tomography and Positron Emission Tomography. In this sense, the scientific community is debating about the high effective dose to the patient, representing an indicator of the stochastic risk, especially from Computer Tomography examination. So, a new dual modality imager, based on a Ultrasound probe and a Single Photon Emission Tomography was made in order to combine functional information, from gamma camera with structural one, obtained from the Ultrasound equipment. The Ultrasound probe is the most diffuse anatomical examination device at zero-dose, using a cost-effective and reliable method with few restriction in use. The proposed Single Photon Emission Tomography detector is a compact gamma camera (10×10 cm² active area), based on LaBr₃:Ce scintillation crystal coupled to 4×4 array of Hamamatsu H8500C-MOD8 Multi Anode Photomultiplier, with high spatial and energy resolution performances, equipped with rotating slant-hole collimator. A calibration phantom, made of a Co⁵⁷ point source inside a water filled box, was utilized to acquire 3D dual modality images. The detector has shown good performances in terms of spatial resolution and localization along z-axis of object of interest. This project was developed by several Italian Universities under an INFN collaboration.