Development of voltage sensitivity preamplifier to application in radioguided surgical probe

The methods of nuclear medicine are increasing used to complement standard diagnostic examinations. Some of these are radioguided detection of the sentinel lymph node (SN) and the radioguided localization of occult lesions. The SN technique is used in a small-size breast carcinoma and involves the identification, removal and immediate histological examination. Specifically, particles of colloidal human serum albumin are labelled with low activities of 99mTc and are inoculated into the breast lesion or close in the case of SN biopsy. Subsequently, a hand-held gamma-ray detecting probe with reduced dimensions is used to locate the lesion or the SN as a hot spot and guide its surgical removal. Many techniques can be used for gamma-ray probes development. Gamma photons can be either directly detected via high atomic numbers semiconductors detectors or indirect detection, as scintillator crystal converts gamma photons into light photons. In all of them, the preamplifier is used as close as possible to the detector for obtaining a good energy resolution and due to the necessary small probe dimension, the preamplifier must have reduced size. The commercial preamplifiers are not small enough to be assembled inside the probe. It was developed a not usually preamplifier configuration for high-resolution spectroscopy energy, adequate in size to be set up in gamma-ray probes. This tension preamplifier can be split between the gamma-ray probe and the read out unit. Due to this configuration the effective size required inside the probe was reduced. The results and the probe assembling are showed in this work. (author)