scholarly journals Technologies for delivery of proton and ion beams for radiotherapy

2014 ◽  
Vol 29 (14) ◽  
pp. 1441002 ◽  
Author(s):  
Hywel Owen ◽  
David Holder ◽  
Jose Alonso ◽  
Ranald Mackay

Recent developments for the delivery of proton and ion beam therapy have been significant, and a number of technological solutions now exist for the creation and utilisation of these particles for the treatment of cancer. In this paper we review the historical development of particle accelerators used for external beam radiotherapy and discuss the more recent progress towards more capable and cost-effective sources of particles.

2021 ◽  
Vol 25 (31) ◽  
pp. 1-144
Author(s):  
Douglas Adamson ◽  
Jane Blazeby ◽  
Catharine Porter ◽  
Christopher Hurt ◽  
Gareth Griffiths ◽  
...  

Background Most patients with oesophageal cancer present with incurable disease. For those with advanced disease, the mean survival is 3–5 months. Treatment emphasis is therefore on effective palliation, with the majority of patients requiring intervention for dysphagia. Insertion of a self-expanding metal stent provides rapid relief but dysphagia may recur within 3 months owing to tumour progression. Evidence reviews have called for trials of interventions combined with stenting to better maintain the ability to swallow. Objectives The Radiotherapy after Oesophageal Cancer Stenting (ROCS) study examined the effectiveness of palliative radiotherapy, combined with insertion of a stent, in maintaining the ability to swallow. The trial also examined the impact that the ability to swallow had on quality of life, bleeding events, survival and cost-effectiveness. Design A pragmatic, multicentre, randomised controlled trial with follow-up every 4 weeks for 12 months. An embedded qualitative study examined trial experiences in a participant subgroup. Setting Participants were recruited in secondary care, with all planned follow-up at home. Participants Patients who were referred for stent insertion as the primary management of dysphagia related to incurable oesophageal cancer. Interventions Following stent insertion, the external beam radiotherapy arm received palliative oesophageal radiotherapy at a dose of 20 Gy in five fractions or 30 Gy in 10 fractions. Main outcome measures The primary outcome was the difference in the proportion of participants with recurrent dysphagia, or death, at 12 weeks. Recurrent dysphagia was defined as deterioration of ≥ 11 points on the dysphagia scale of the European Organisation of Research and Treatment of Cancer Quality of Life Questionnaire oesophago-gastric module questionnaire. Secondary outcomes included quality of life, bleeding risk and survival. Results The study recruited 220 patients: 112 were randomised to the usual-care arm and 108 were randomised to the external beam radiotherapy arm. There was no evidence that radiotherapy reduced recurrence of dysphagia at 12 weeks (48.6% in the usual-care arm compared with 45.3% in the external beam radiotherapy arm; adjusted odds ratio 0.82, 95% confidence interval 0.40 to 1.68; p = 0.587) and it was less cost-effective than stent insertion alone. There was no difference in median survival or key quality-of-life outcomes. There were fewer bleeding events in the external beam radiotherapy arm. Exploration of patient experience prompted changes to trial processes. Participants in both trial arms experienced difficulty in managing the physical and psychosocial aspects of eating restriction and uncertainties of living with advanced oesophageal cancer. Limitations Change in timing of the primary outcome to 12 weeks may affect the ability to detect a true intervention effect. However, consistency of results across sensitivity analyses is robust, including secondary analysis of dysphagia deterioration-free survival. Conclusions Widely accessible palliative external beam radiotherapy in combination with stent insertion does not reduce the risk of dysphagia recurrence at 12 weeks, does not have an impact on survival and is less cost-effective than inserting a stent alone. Reductions in bleeding events should be considered in the context of patient-described trade-offs of fatigue and burdens of attending hospital. Trial design elements including at-home data capture, regular multicentre nurse meetings and qualitative enquiry improved recruitment/data capture, and should be considered for future studies. Future work Further studies are required to identify interventions that improve stent efficacy and to address the multidimensional challenges of eating and nutrition in this patient population. Trial registration Current Controlled Trials ISRCTN12376468 and Clinicaltrials.gov NCT01915693. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 31. See the NIHR Journals Library website for further project information.


2021 ◽  
pp. 20200842
Author(s):  
Susovan Banerjee ◽  
Shikha Goyal ◽  
Saumyaranjan Mishra ◽  
Deepak Gupta ◽  
Shyam Singh Bisht ◽  
...  

Artificial intelligence (AI) applications, in the form of machine learning and deep learning, are being incorporated into practice in various aspects of medicine, including radiation oncology. Ample evidence from recent publications explores its utility and future use in external beam radiotherapy. However, the discussion on its role in brachytherapy is sparse. This article summarizes available current literature and discusses potential uses of AI in brachytherapy, including future directions. AI has been applied for brachytherapy procedures during almost all steps, starting from decision-making till treatment completion. AI use has led to improvement in efficiency and accuracy by reducing the human errors and saving time in certain aspects. Apart from direct use in brachytherapy, AI also contributes to contemporary advancements in radiology and associated sciences that can affect brachytherapy decisions and treatment. There is a renewal of interest in brachytherapy as a technique in recent years, contributed largely by the understanding that contemporary advances such as intensity modulated radiotherapy and stereotactic external beam radiotherapy cannot match the geometric gains and conformality of brachytherapy, and the integrated efforts of international brachytherapy societies to promote brachytherapy training and awareness. Use of AI technologies may consolidate it further by reducing human effort and time. Prospective validation over larger studies and incorporation of AI technologies for a larger patient population would help improve the efficiency and acceptance of brachytherapy. The enthusiasm favoring AI needs to be balanced against the short duration and quantum of experience with AI in limited patient subsets, need for constant learning and re-learning to train the AI algorithms, and the inevitability of humans having to take responsibility for the correctness and safety of treatments.


2015 ◽  
Vol 31 ◽  
pp. e26-e27 ◽  
Author(s):  
T. Tessonnier ◽  
A. Mairani ◽  
S. Brons ◽  
T. Haberer ◽  
J. Debus ◽  
...  

1987 ◽  
Vol 5 (4) ◽  
pp. 609-642 ◽  
Author(s):  
K. Imasaki ◽  
S. Miyamoto ◽  
N. Yugami ◽  
T. Akiba ◽  
S. Sawada ◽  
...  

Recent progress in research on Light Ion Beams-Inertial Confinement Fusion (LIB-ICF) at ILE, Osaka University is summarized. We report on pulsed power compression using PEOS, a super high voltage source, on diode physics, on beam trajectory control for focusing, on beam-target interactions and on a conceptual reactor design (Rokko I) in this article.


2010 ◽  
Vol 49 (S 01) ◽  
pp. S59-S63 ◽  
Author(s):  
M. Gotthardt

SummaryPatient-individual dosimetric analyses are a useful tool in external beam radiotherapy (EBR) to protect patients from side effects such as radiogenic nephropathy. At this point in time, individual dosimetry is not used as a standard in patient treated with radiolabelled antibody fragments or polypeptides. The reasons are a number of problems, which make patient dosimetry more challenging than in EBR. While in EBR, the dose is distributed evenly in the organ and the organ volume can exactly be determined, in internal radiotherapy the tracer is not evenly distributed within the organ leading to a non-uniform dose distribution. In addition, the dose rate of the most commonly used radionuclides is lower than in EBR and the range of their radiation differ, so that the radiobiological effects are differing considerably in comparison to EBR. Conclusion: More complex models have to be used for clinical kidney dosimetry in internal radiotherapy.In this paper, we give a concise overview of the reasons for accumulation of radiotracers in the kidney, the most recent developments in kidney dosimetry, and approaches to reduce the kidney uptake of radiotracers in order to avoid radiogenic nephropathy.


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7617
Author(s):  
Nidal Del Valle Raydan ◽  
Leo Leroyer ◽  
Bertrand Charrier ◽  
Eduardo Robles

The industrial market depends intensely on wood-based composites for buildings, furniture, and construction, involving significant developments in wood glues since 80% of wood-based products use adhesives. Although biobased glues have been used for many years, notably proteins, they were replaced by synthetic ones at the beginning of the 20th century, mainly due to their better moisture resistance. Currently, most wood adhesives are based on petroleum-derived products, especially formaldehyde resins commonly used in the particleboard industry due to their high adhesive performance. However, formaldehyde has been subjected to strong regulation, and projections aim for further restrictions within wood-based panels from the European market, due to its harmful emissions. From this perspective, concerns about environmental footprint and the toxicity of these formulations have prompted researchers to re-investigate the utilization of biobased materials to formulate safer alternatives. In this regard, proteins have sparked a new and growing interest in the potential development of industrial adhesives for wood due to their advantages, such as lower toxicity, renewable sourcing, and reduced environmental footprint. This work presents the recent developments in the use of proteins to formulate new wood adhesives. Herein, it includes the historical development of wood adhesives, adhesion mechanism, and the current hotspots and recent progress of potential proteinaceous feedstock resources for adhesive preparation.


Author(s):  
John F. Walker ◽  
J C Reiner ◽  
C Solenthaler

The high spatial resolution available from TEM can be used with great advantage in the field of microelectronics to identify problems associated with the continually shrinking geometries of integrated circuit technology. In many cases the location of the problem can be the most problematic element of sample preparation. Focused ion beams (FIB) have previously been used to prepare TEM specimens, but not including using the ion beam imaging capabilities to locate a buried feature of interest. Here we describe how a defect has been located using the ability of a FIB to both mill a section and to search for a defect whose precise location is unknown. The defect is known from electrical leakage measurements to be a break in the gate oxide of a field effect transistor. The gate is a square of polycrystalline silicon, approximately 1μm×1μm, on a silicon dioxide barrier which is about 17nm thick. The break in the oxide can occur anywhere within that square and is expected to be less than 100nm in diameter.


Author(s):  
Mark Denker ◽  
Jennifer Wall ◽  
Mark Ray ◽  
Richard Linton

Reactive ion beams such as O2+ and Cs+ are used in Secondary Ion Mass Spectrometry (SIMS) to analyze solids for trace impurities. Primary beam properties such as energy, dose, and incidence angle can be systematically varied to optimize depth resolution versus sensitivity tradeoffs for a given SIMS depth profiling application. However, it is generally observed that the sputtering process causes surface roughening, typically represented by nanometer-sized features such as cones, pits, pyramids, and ripples. A roughened surface will degrade the depth resolution of the SIMS data. The purpose of this study is to examine the relationship of the roughness of the surface to the primary ion beam energy, dose, and incidence angle. AFM offers the ability to quantitatively probe this surface roughness. For the initial investigations, the sample chosen was <100> silicon, and the ion beam was O2+.Work to date by other researchers typically employed Scanning Tunneling Microscopy (STM) to probe the surface topography.


1991 ◽  
Vol 223 ◽  
Author(s):  
Richard B. Jackman ◽  
Glenn C. Tyrrell ◽  
Duncan Marshall ◽  
Catherine L. French ◽  
John S. Foord

ABSTRACTThis paper addresses the issue of chlorine adsorption on GaAs(100) with respect to the mechanisms of thermal and ion-enhanced etching. The use of halogenated precursors eg. dichloroethane is also discussed in regard to chemically assisted ion beam etching (CAIBE).


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