Abstract. Gene therapy and virotherapy are among the approaches currently used to treat malignant tumors. Gene therapy and virotherapy use a specific therapeutic gene that causes death in cancer cells. In early attempts at gene therapy, therapeutic genes were driven by ubiquitous promoters such as the CMV promoter, which induce non-specific toxicity to normal cells and tissues in addition to the cancer cells. Recently, novel cancer-and/or tissue-specific promoter systems have been developed to target cancer cells but not normal cells including stem cells. In this review, we describe cancer and/or tissue-specific gene therapy systems for the treatment of cancer. In particular, we will discuss three systems for gene therapy and virotherapy: i) tissue-specific promoter systems, ii) cancer-specific promoter systems, and iii) oncolytic virotherapy. We will also discuss the major challenges of cancer-targeting vector systems and future directions in this area.

Abstract-We are developing a Compton camera based on Si and CdTe semiconductor imaging devices with high energy resolution. In this paper, results from the most recent prototype are reported. The Compton camera consists of six layered doublesided Si Strip detectors and CdTe pixel detectors, which are read out with low noise analog ASICs, VA32TAs. We obtained Compton reconstructed images and spectra of line gamma-rays from 122 keV to 662 keV. The energy resolution is 9.1 keV and 14 keV at 356 keV and 511 keV, respectively.

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