The MediPROBE CdTe Based Compact Gamma Camera

摘要

We assembled a compact, hand-held gamma-ray imaging probe (MediPROBE) which could be utilized for different medical imaging tasks, including sentinel lymph node localization and scintigraphy of difficult to reach anatomical sites. Here, we report on the first images obtained with this device. The imaging system is based on a room temperature semiconductor pixel detector (1 mm-thick CdTe) with 256x256 square pixels arranged with a 55 μm pitch (sensitive area D×D = 14.08×14.08 mm~2), coupled pixel-by-pixel via bump-bonding to the Medipix2 photon counting readout CMOS Application Specific Integrated Circuit (ASIC). A set of interchangeable knife-edge pinhole collimators (1.1, 1.9 and 2.1 mm effective diameter at 140 keV) has been realized to obtain different spatial resolutions, and a set of plastic spacers (3 cm or 6 cm total length) can be placed in front of the camera in order to set the skin-to-collimator distance and, hence, to fix the field of view (FOV), working in demagnification. The probe is con-nected directly to a notebook using a dedicated USB interface and is powered via the USB port. The high voltage (-100 V @ 1 μA) necessary to bias the CdTe detector is provided either from an external power supply or from a pack of eleven bat-teries. This compact probe weights 1.5 kg without shield and 3.2 kg with a lead shield; it can be mounted on an articulated arm for bed-side operation. MediPROBE provides live-time photon counting gamma-ray imaging at a rate < 1 fps.