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強度変調放射線治療を施行した胃MALT リンパ腫の1例

症例は60歳代男性で,下肢浮腫を主訴に受診.ネフローゼ症候群を認め,精査の結果,胃MALTリンパ腫および膜性腎症と診断された.Helicobacter pylori陰性であり,除菌は行なわず放射線療法の方針となり,強度変調放射線治療を用いた30.6Gy/17回の全胃照射を施行した.従来の三次元原体照射と比較し,強度変調放射線治療を用いることで,両腎の照射線量を低減できた.照射後24カ月の時点で,腫瘍は寛解を維持しており,放射線治療の副作用による腎機能の低下も認めていない.強度変調放射線治療を用いた全胃照射は,安全かつ有用な照射方法と考えられた.We present a case of gastric mucosa-associated lymphoid tissue (MALT) lymphoma in a 60s year-old male Helicobacter pylori negative patient. The patient presented with lower extremity oedema and nephrotic syndrome. Thorough examination revealed the presence of gastric MALT lymphoma and nephrotic syndrome. We chose a treatment strategy involving radiation therapy, and carried out whole stomach irradiation using intensity modulated radiation therapy (IMRT) at a total dose of 30.6 Gy delivered in 17 fractions. Using IMRT the maximum and V20 dose to the bilateral kidney was lower than using conventional 3D conformal radiation therapy. The patient has been in complete remission for 24 months after IMRT, and no further renal impairment has been detected. In conclusion, we consider that IMRT is a reliable and valuable modality for whole stomach irradiation

A Substellar Companion to Pleiades HII 3441

We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0".49 +/- 0".02 (66 +/- 2 AU) and a mass of 68 +/- 5 M_J based on three observations in the J-, H-, and K_S-band. The spectral type is estimated to be M7 (~2700 K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0 +26.1/-8.8 %. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.Comment: Main text (14 pages, 4 figures, 4 tables), and Supplementary data (8 pages, 3 tables). Accepted for Publications of Astronomical Society of Japa

Direct Imaging Explorations for Companions around Mid-Late M Stars from the Subaru/IRD Strategic Program

The Subaru telescope is currently performing a strategic program (SSP) using the high-precision near-infrared (NIR) spectrometer IRD to search for exoplanets around nearby mid/late-M~dwarfs via radial velocity (RV) monitoring. As part of the observing strategy for the exoplanet survey, signatures of massive companions such as RV trends are used to reduce the priority of those stars. However, this RV information remains useful for studying the stellar multiplicity of nearby M~dwarfs. To search for companions around such ``deprioritized" M~dwarfs, we observed 14 IRD-SSP targets using Keck/NIRC2 observations with pyramid wavefront sensing at NIR wavelengths, leading to high sensitivity to substellar-mass companions within a few arcseconds. We detected two new companions (LSPM~J1002+1459~B and LSPM~J2204+1505~B) and two new candidates that are likely companions (LSPM~J0825+6902~B and LSPM~J1645+0444~B) as well as one known companion. Including two known companions resolved by the IRD fiber injection module camera, we detected seven (four new) companions at projected separations between $\sim2-20$~au in total. A comparison of the colors with the spectral library suggests that LSPM~J2204+1505~B and LSPM~J0825+6902~B are located at the boundary between late-M and early-L spectral types. Our deep high-contrast imaging for targets where no bright companions were resolved did not reveal any additional companion candidates. The NIRC2 detection limits could constrain potential substellar-mass companions ($\sim10-75\ M_{\rm Jup}$) at 10~au or further. The failure with Keck/NIRC2 around the IRD-SSP stars having significant RV trends makes these objects promising targets for further RV monitoring or deeper imaging with JWST to search for smaller-mass companions below the NIRC2 detection limits.Comment: 16 pages, 8 figures, accepted for publication in A