[Result of the onsite dosimetry and questioning about quality assurance/ quality control of radiotherapy in the Hokuriku area - a comparison with past results -].

PURPOSE: To analyze temporal changes in human resources in the radiotherapy section, quality assurance/quality control (QA/QC) and dose difference for radiotherapy in the Hokuriku area based on the results of past investigations and our investigation. METHOD: We visited radiotherapy sections of 17 hospitals in the Hokuriku area (5 in Toyama, 9 in Ishikawa and 3 in Fukui) to measure the dose at the reference point of a linear accelerator (LINAC), as we asked questions to a radiotherapist about human resources, QA/QC of LINAC, etc. We compared our results with past reports (1992 to 2007) on the dose difference, human resources and frequency of dose monitor system calibration. RESULTS: The number of physicians has not changed since 1999, but the number of radiotherapists was significantly increased. Weekly dose monitor system calibration has been achieved in 80% of the institutions in our survey. This percentage was significantly higher than in the past surveys. The dose difference distribution from our onsite dosimetry did not significantly differ from that from the onsite dosimetry in 2007. 91% of the institutions have accomplished within 2% of the dose difference. CONCLUSION: We found that the number of physicians has not increased since 1999, but the number of radiotherapists has increased. We conclude that the increment of radiotherapists led to 80% achievement of the weekly dose monitor system calibration. Almost all institutions in Hokuriku area have properly performed QA of the dose monitor system.

Two Groups of Phytoplasmas from Japan Distinguished on the Basis of Amplification and Restriction Analysis of 16S rDNA.

Phytoplasmas (mycoplasmalike organisms, MLOs) associated with mitsuba (Japanese hone-wort) witches'-broom (JHW), garland chrysanthemum witches'-broom (GCW), eggplant dwarf (ED), tomato yellows (TY), marguerite yellows (MY), gentian witches'-broom (GW), and tsu-wabuki witches'-broom (TW) in Japan were investigated by polymerase chain reaction (PCR) amplification of DNA and restriction enzyme analysis of PCR products. The phytoplasmas could be separated into two groups, one containing strains JHW, GCW, ED, TY, and MY, and the other containing strains GW and TW, corresponding to two groups previously recognized on the basis of transmission by Macrosteles striifrons and Scleroracus flavopictus, respectively. The strains transmitted by M. striifrons were classified in 16S rRNA gene group 16SrI, which contains aster yellows and related phytoplasma strains. Strains GW and TW were classified in group 16SrIII, which contains phytoplasmas associated with peach X-disease, clover yellow edge, and related phytoplasmas. Digestion of amplified 16S rDNA with HpaII indicated that strains GW and TW were affiliated with subgroup 16SrIII-B, which contains clover yellow edge phytoplasma. All seven strains were distinguished from other phytoplasmas, including those associated with clover proliferation, ash yellows, elm yellows, and beet leafhopper-transmitted virescence in North America, and Malaysian periwinkle yellows and sweet potato witches'-broom in Asia.