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BackgroundSeveral studies have confirmed the advantages of delivering high doses of external beam radiotherapy to achieve optimal tumor-control outcomes in patients with localized prostate cancer. We evaluated the medium-term treatment outcome after high-dose, image-guided intensity-modulated radiotherapy (IMRT) using intra-prostate fiducial markers for clinically localized prostate cancer.MethodsIn total, 141 patients with localized prostate cancer treated with image-guided IMRT (76 Gy in 13 patients and 80 Gy in 128 patients) between 2003 and 2008 were enrolled in this study. The patients were classified according to the National Comprehensive Cancer Network-defined risk groups. Thirty-six intermediate-risk patients and 105 high-risk patients were included. Androgen-deprivation therapy was performed in 124 patients (88%) for a median of 11 months (range: 2–88 months). Prostate-specific antigen (PSA) relapse was defined according to the Phoenix-definition (i.e., an absolute nadir plus 2 ng/ml dated at the call). The 5-year actuarial PSA relapse-free survival, the 5-year distant metastasis-free survival, the 5-year cause-specific survival (CSS), the 5-year overall survival (OS) outcomes and the acute and late toxicities were analyzed. The toxicity data were scored according to the Common Terminology Criteria for Adverse Events, version 4.0. The median follow-up was 60 months.ResultsThe 5-year PSA relapse-free survival rates were 100% for the intermediate-risk patients and 82.2% for the high-risk patients; the 5-year actuarial distant metastasis-free survival rates were 100% and 95% for the intermediate- and high-risk patients, respectively; the 5-year CSS rates were 100% for both patient subsets; and the 5-year OS rates were 100% and 91.7% for the intermediate- and high-risk patients, respectively. The Gleason score (<8 vs. ≥8) was significant for the 5-year PSA relapse-free survival on multivariate analysis (p = 0.044). There was no grade 3 or 4 acute toxicity. The incidence of grade 2 acute gastrointestinal (GI) and genitourinary (GU) toxicities were 1.4% and 8.5%, respectively. The 5-year actuarial likelihood of late grade 2–3 GI and GU toxicities were 6% and 6.3%, respectively. No grade 4 GI or GU late toxicity was observed.ConclusionsThese medium-term results demonstrate a good tolerance of high-dose image-guided IMRT. However, further follow-up is needed to confirm the long-term treatment outcomes.

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In the Sr–Bi–Ta–Nb–O system, three crystallographic phases are known to exist: the SrBi2(Ta1-x Nb x )O9 (SBTN) perovskite, fluorite and pyrochlore phases. It is considered that the fluorite phase is a low-temperature phase of SBT, which tends to grow in excess bismuth compositions, and the pyrochlore phase tends to grow in bismuth-deficient compositions. In conventional X-ray diffraction (XRD) characterization, the SBTN phase shows strong (115) diffraction around 29 [2θ deg]. Unfortunately, however, the other two phases also show their (111) and (222) diffractions near the same angle when the film is prepared on a platinum-coated silicon substrate. Therefore, the phase identification of the SBTN phase from the other two phases is almost impossible by the conventional technique. We employed XRD reciprocal space mapping to distinguish these phases in the present study. The three crystallographic phases were identified and distinguished from each other. It is ascertained that this technique is effective to identify crystallographic phases especially in the case in which more than two phases show similar diffraction angles.

A simple empirical formula has been found which factors out the gross target dependence of single ionization cross sections by positron and electron impact. The formula can be used to estimate cross sections for an atom if the cross section maxima for any other two atoms in the same column of the periodic table are known. Further investigation is required to understand the basic physical mechanism underlying the degree of accuracy of such a factorization.