Oblique Surface Dose Calculation in High-Energy X-ray Therapy

During radiation therapy, incident radiation oblique to the skin surface is high and may cause severe skin damage. Understanding the dose of radiation absorbed by the skin is important for predicting skin damage due to radiation. In this study, we used a high-energy (4 MV) X-ray system and an optically stimulated luminescence dosimeter (OSLD) that was developed for personal exposure dosimetry. We determined the dose variation and angular dependence, which are the characteristics of a small OSLD required to derive the calculation formula for the oblique surface dose. The dose variation was determined using the coefficient of variation. The maximum coefficient of variation for 66 small-field OSLDs was 1.71%. The angular dependence, obtained from the dose ratio of the dosimeter in the vertical direction, had a maximum value of 1.37. We derived a new equation in which the oblique surface dose can be calculated within the error range of −7.7-5.1%

Calculus and Materials for Stirling Engines Bolter and Regenator

The performances of the Stirling engine are affected by the convection coefficient and the ldquoXrdquo factor and not only by the variation of the gas quantity from the cylinder with the medium pressure variation. The convection factor indicates that a sensibility study concerning the characteristic parameters is mandatory

地域に開かれた「大学付属博物館」紙上構想と展開の研究 : バーチャルミュージアム"産業考古学館"をめざして

学長特別研究費21世紀における都市・地域の魅力地域に開かれた大学の、開かれた大学博物館をめざいて計画された「産業考古学館(仮称)」は、建設計画の一部休止をやむなきにいたった。代わって学内に設置されたのが「産業考古学研究資料室」(研究室1206)である。本研究の目的は、上記研究資料室のメンバーが近い将来の建設計画再開に備えて、各自の視点から研究を積み上げハード(建物)よりもソフト(研究論文・データ収集など)を先行させ、"デジタルアーカイブ"・"バーチャルミュージアム"へつなげて行くためのものである

バーチャル・ミュージアム"産業考古館"の教育・展示・調査の試行、ならびに学習プログラム開発に関する研究

学長特別研究費21世紀における都市・地域の魅力都市イベントの創造1. 「はままつエリア」から起業した産業の歴史的転回(産業史の研究)2. 現在の「はままつエリア」に集積した企業群像の調査(企業史の研究)3. これからの「はままつエリア」はどうなるか。　　特に都市と産業の環境、まちづくり、ものづくりをシミュレーションする。　上記3展に関する調査研究・問題提起・解釈と解説・将来像への示唆をバーチャル・ミュージアムとして試行的に発信し、学内外の議論と認識の深化に寄与する。(平成15(2003)年2月の申請・計画書に記載した事項

Impact of patient positioning uncertainty in noncoplanar intracranial stereotactic radiotherapy

The aim of this study is to evaluate the patient positioning uncertainty in noncoplanar stereotactic radiosurgery or stereotactic radiotherapy (SRS/SRT) for intracranial lesions with the frameless 6D ExacTrac system. In all, 28 patients treated with SRS/SRT of 70 treatment plans at our institution were evaluated in this study. Two X-ray images with the frameless 6D ExacTrac system were first acquired to correct (XC) and verify (XV) the patient position at a couch angle of 0o. Subsequently, the XC and XV images were also acquired at each planned couch angle for using noncoplanar beams to detect position errors caused by rotating a couch. The translational XC and XV shift values at each couch angle were calculated for each plan. The percentages of the translational XC shift values within 1.0 mm for each planned couch angle for using noncoplanar beams were 77.86%, 72.26%, and 98.47% for the lateral, longitudinal, and vertical directions, respectively. Those within 2.0 mm were 98.22%, 97.96%, and 99.75% for the lateral, longitudinal, and vertical directions, respectively. The maximum absolute values of the translational XC shifts among all planned couch angles for using noncoplanar beams were 2.69, 2.45, and 2.17 mm for the lateral, longitudinal, and vertical directions, respectively. The overall absolute values of the translational XV shifts were less than 1.0 mm for all directions except for one case in the longitudinal direction. The patient position errors were detected after couch rotation for using noncoplanar beams, and they exceeded a planning target volume (PTV) margin of 1.0-2.0 mm used commonly in SRS/SRT treatment. These errors need to be corrected at each planned couch angle, or the PTV margin should be enlarged