Statistics and analysis on the troubles of linear accelarator.

放射線治療の成否は厳密に設定されたTarget Volumeに如何に正確な線量を照射するかによって決まる。治療術式の過程において、最も大きな誤差を生む要因は照射機器である。誤差の少ない治療を目指す第一歩は機器を正確に作動させることであり、日常からの保守点検および整備が必要である。今回、岡山大学附属病院で1976年から1991年までに使用されたリニアックについて、その故障状況を集計し、部位別故障件数、管球の寿命、稼動率などを分析検討した。その結果、故障件数では設置され稼動を始めた1976年、装置の老朽化が進んだ1990、1991年に多かった。部位別集計では加速部に圧倒的に多く、次いで照射口、高圧部の順であった。稼動率は設置年および1987年を除いてはいずれも96％以上とよい結果であった。この結果は全国に稼動している同型の装置の保守点検に役立つものと考える。The Accuracy of radiation dose exposed the rigidly selected target volume is one of significant factors that have an influence upon the efficiency of treatment in the radiotherapy techniques. Therefore, it is necessary to daily maintain and check irradiation equipment for the radiotherapy. For the radiotherapy, the electron linear accelerator, Toshiba LMR-15A, had worked from 1976 to 1991 in Okayama University Hospital. On this study, all records regarding the operating condition were analyzed concerning parts of trouble, life of a tube and operating efficiency for these sixteen years. In a high frequency of trouble, an accelerating structure ranked first, followed by a collimator and a high voltage generator. The operating efficiency was 95% or greater. This report should be helpful to maintain and check a same model in other hosptals

Dosimetry in Radiography

Utilization of radiation in medical treatment is increasing more and more ; consequently, It becomes more important to estimate exposure dose correctly. Altough there are many reports about exposue dose for patients, most of them merely describe the results of the measurements by parts of the body. Exposure dose differs with equipment, instruments, screen-firm system, contition of radiography, and so on. This paper describes the relation between skin dose and contitions of radiography, and also shows the result of measurement of "TPR" which needs to know the absorbed dose of each organ

Relationship between X-ray Exposure and Patient Dose on the Radiological Diagnosis

Patient dose is important consideration in the radiological examination and our environment regarding radiation. Many studies have been published about patient dose, but those data were classified by each organ or tissue. Actuarially, patient dose should be checked by each examined part of patient and each exposure equipment. In this paper, we measured absorbed dose at the depth of 0-200mm with the Mix-DP phantom. The phantom is made by tissue equivalent meterial and is designed to similitude abdominal part. Percentage Depth Dose (PDD) was calculated from these doses. Three single-phase generators and three three-phases generators were used in this measurement. These measurements were analyzed by each equipment, and consequently the clear difference of PDD between the exposure equipments was not found. As the result, we can estimate patient dose at a random depth by using PDD. Furthermore, we can easily know patient dose from the tube-voltage and current time product by the calculation including PDD.These data are very useful to manager patient dose on radiological diagnosis

Influence of the Bone for Electron-beam Therapy

電子線治療は,体表面またはその近傍に発生する悪性腫瘍の治療にしばしば用いられる治療法である｡電子線はエネルギーに対応した飛程を持っており,飛程を越えると急激に線量は減少する。この性質は腫瘍に一定の線量を照射し,腫瘍後方に存在する決定臓器を保護することができるので,病巣を選択的 に治療するのに好都合である｡しかし,照射野内に人体軌部組織より密度の違う物質が存在する場合,散乱,吸収の影響が大きく,電子線線量分布は乱れたものとなる｡今回,人体内にある骨を想定してVolumeの違う骨Phantomを使 用して影響を調べたところ,骨幅によって骨後方および断端に線量の乱れが生じることがわかった｡すなわち,骨の中央ではある程度後方に距離が離れると,線量は大きく減少する現象が見られた。また,横方向の線量分布は骨断端近くで一旦線量の減少が見られ,断端を離れると急激に増加する｡したがって,実際の臨床において,Target Volume近くに骨が存在する場合は総線量の決定に際して注意が必要である｡The Electron-beam therapy is often used for the treatment to malignant tumors on the surface or its neighborhood of the body. An electron-beam has the range depended on its energy, and its dose is rapidly decreased at the points beyond the range. This property is available to irradiating a tumor with leaving the critical organs unexposed. However, we should take notice that the dose-distributions are disordered if materials of various densities are in the irradiation field. In this paper, we examined how the dose-distribution are disordered by using the phantom made from human bones of various volumes. As a result, the peculiar disorders of the dose-distribution due to the difference of the bone width were found at the back and edge of a bone. Moreover, the dose at the edge of a bone was decreased, but the dose at the side of a bone was rapidly increased in the distance position from the bone. It is necessary to take account of that the above peculiar phenomenon affect the total dose for the treatment when bones exist near the target volume in the irradiation field

The ASTRO-H X-ray Observatory

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

“Latent Gastric Cancer” after Eradicating Helicobacter pylori

Background/AimsEndoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is useful for obtaining pancreatic mass samples. The combination of modified techniques (i.e., slow-pull technique and fanning technique) may improve the quality of the sample obtained by EUS-FNA. We investigated the effectiveness of a combined slow-pull fanning technique in EUS-FNA for pancreatic mass.Methods : This prospective comparative study investigated EUS-FNA performed for pancreatic solid masses between August 2015 and July 2016. Pairwise specimens were alternately obtained using the following two techniques for targeted pancreatic lesions: standard suction or slow-pull with fanning. We compared the specimen quality, blood contamination, and diagnostic accuracy of these techniques.Results : Forty-eight consecutive patients were included (29 men; mean age, 68.1±11.9 years), and 96 pancreatic mass specimens were obtained. The slow-pull with fanning technique had a significantly superior diagnostic accuracy than the suction technique (88% vs 71%, p=0.044). Furthermore, blood contamination was significantly reduced using the slow-pull with fanning technique (ratio of no or slight contamination, 77% vs 56%, p=0.041). No difference was observed in the acquisition of adequate cellularity between the groups. In the subgroup analysis, the tumor size and sampling technique were related to the EUS-FNA diagnostic accuracy.Conclusion : sThe slow-pull with needle fanning technique showed a good diagnostic yield for EUS-FNA for pancreatic mass. This technique can be useful for performing EUS-guided sampling for diagnosing pancreatic disease

Camostat mesilate therapy for COVID-19

The role of the renin-angiotensin signaling (RAS) pathway in COVID-19 has received much attention. A central mechanism for COVID-19 pathophysiology has been proposed: imbalance of angiotensin converting enzymes (ACE)1 and ACE2 (ACE2 being the severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] virus "receptor") that results in tissue injury from angiotensin II (Ang II)-mediated signaling. This mechanism provides a rationale for multiple therapeutic approaches. In parallel, clinical data from retrospective analysis of COVID-19 cohorts has revealed that ACE inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) may be beneficial in COVID-19. These findings have led to the initiation of clinical trials using approved drugs that target the generation (ACEIs) and actions (ARBs) of Ang II. However, treatment of COVID-19 with ACEIs/ARBs poses several challenges. These include choosing appropriate inclusion and exclusion criteria, dose optimization, risk of adverse effects and drug interactions, and verification of target engagement. Other approaches related to the RAS pathway might be considered, for example, inhalational administration of ACEIs/ARBs (to deliver drugs directly to the lungs) and use of compounds with other actions (e.g., activation of ACE2, agonism of MAS1 receptors, β-arrestin-based Angiotensin receptor agonists, and administration of soluble ACE2 or ACE2 peptides). Studies with animal models could test such approaches and assess therapeutic benefit. This Perspective highlights questions whose answers could advance RAS-targeting agents as mechanism-driven ways to blunt tissue injury, morbidity, and mortality of COVID-19

The Japanese low Fodmap diet manual

Before World War II, Japanese people ate an abundance of rice and fish. Now, however, many of them are eating wheat instead of rice. Most Japanese are lactose intolerant, but they consume milk and yoghurt every day. Furthermore, fructose in fruits has been increased by breeding improvement, and oligosaccharides and sorbitol have been added to processed food made in Japan. Do these high-FODMAPs cause disease? Specifically, have they contributed to the rapid rise of irritable bowel syndrome (IBS) and inflammatory bowel disease in Japan?This book is the English version of a Japanese publication f.Intro; Contents; Acknowledgement; Preface; Purpose of the English Version Publication; Introduction by the Second Author; Chapter I; Chapter II; Chapter III; List of Food and Ingredients; References1 online resourc