ジドウ ソウサホウ ニヨル ガン チリョウヨウ 125 Ｉ シード ホウシャセン キョウド ケンテイ システム ノ カイハツ

A new scanning system using a NaI(Tl) scintillation survey meter, copper slit and drive-unit has been developed for quality control of radioactive seeds. Radioactive seed implants, also called brachytherapy, are widely used modality in the treatment of early stage prostate cancers. Seeds containing the iodine-125 are most commonly used for permanent implant prostate brachytherapy. These seeds are commercially available and delivered in a sterile environment in the form of packaged cartridge. It is impractical to re-sterilize and re-load seeds after calibration. This paper describes a new method to calibrate all seeds in the seed cartridge in a sterile package

Yeast functional assay of the p53 gene status in human cell lines maintained in our laboratory

We used a yeast functional assay (functional analysis of separated alleles in yeast: FASAY) to determine the p53 gene status of human cell lines maintained in our laboratory. This assay enables the researcher to score wild-type p53 expression on the basis of the ability of expressed p53 to transactivate the reporter gene HIS 3 via the p53-responsive GAL 1 promoter in Saccharomyces cerevisiae. The cell lines examined were ten hepatoma, two hepatoblastoma, three in vitro immortalized fibroblast, two osteosarcoma, a chondrosarcoma, an ovarian teratocarcinoma and a colon cancer cell line. Out of 20 cell lines, 11 cell lines had mutations in both alleles of the p53 gene, and another 8 cell lines had no mutation in the p53 gene. Thus, 55% of the cell lines examined had mutations in the p53. Interestingly, PA-1 cells had both the normal and the mutant p53 alleles, showing that FASAY is a useful method for detecting the wild-type and mutated p53 genes simultaneously. As for the three liver cell lines harboring HBsAg, there was no relationship between their p53 gene status and the presence of HBsAg. Two cell lines were normal for p53 status, while the other had a mutation of the p53 gene.</p

Status of 48Ca double beta decay search in CANDLES

We study a strategy to reduce veto-time in the search for neutrino-less double-beta decay (0υββ) with CANDLES-III system. We develop a new likelihood analysis and apply it to our new Run010 data. We show that we can increase the un-vetoed live-time by 11.8%. Thanks to this improvements, We expect to increase a limit on the life-time of 0υββ by a factor of three by analyzing both Run009 and Run010 data

Upgrading of shielding for rare decay search in CANDLES

In the CANDLES experiment aiming to search for the very rare neutrino-less double beta decays (0νββ) using 48Ca, we introduced a new shielding system for high energy γ-rays from neutron captures in massive materials near the detector, in addition to the background reduction for 232Th decays in the 0νββ target of CaF2 crystals. The method of background reduction and the performance of newly installed shielding system are described