Simulated performance characteristics of an external Compton probe for prostate imaging

We have previously described an endorectal gamma imaging probe based on the Compton camera principle that promises simultaneous high sensitivity and high resolution. In this paper, we investigate an external probe that is noninvasive and does not require the high density packaging imposed by the size constraint of the endorectal probe. We analyze the performance of the external probe using Monte Carlo simulations. In particular, we evaluate the detection efficiency, spatial resolution, and lesion visibility of the proposed system. The preliminary simulation results show that our technique achieves an average detection efficiency of 2.4/spl times/10/sup -3/ for the two photon energies of In/sup 111/ labelled ProstaScint. In addition, it improves detection efficiency by nearly 2 orders of magnitude over a conventional SPECT system with a high resolution collimator, and achieves up to 26% higher efficiency than the endorectal probe. The average FWHM resolution of the proposed probe is 3.4 mm for both emission gamma-rays of In/sup 111/, which is 2 times better than that of a SPECT system and 39% larger than the endorectal probe.