Edit Proposal: Milestone-Proposal:Active shielding of superconducting magnets You do not have permission to edit this page, for the following reason: You are not currently logged in. The action you have requested is limited to users in the group: Users. Please log in or create an account. Docket ID: (admins only) Thank you for proposing a technical achievement for possible recognition as an IEEE Milestone in Electrical Engineering and Computing. Your efforts help preserve the heritage of technology. Detailed information on the Milestone application process may be found at: Milestone Guidelines and How to Propose a Milestone. At least one of the proposer(s) must be an IEEE Member (including Student Member) in good standing. To the proposer’s knowledge, is this achievement subject to litigation? If the answer is "yes", the proposal cannot proceed further. Yes No You must be able to answer "yes" to all of the following questions. If the answer to any of the following questions is "no", the proposal cannot proceed further. Contact us at firstname.lastname@example.org if you are unable to answer "yes" to all of the following and would still like to proceed. Is the achievement you are proposing more than 25 years old? Yes No Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes No Did the achievement provide a meaningful benefit for humanity? Yes No Was it of at least regional importance? Yes No Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes No Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes No Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes No Has the owner of the site given permission to place an IEEE plaque? Yes No Year or range of years in which the achievement occurred: Title of the proposed milestone. (Include date or date range in title. Example: “Alternating Current Electrification, 1886”) Please provide a plaque citation in English summarizing the achievement and its significance. Text absolutely limited by plaque dimensions to 70 words; 60 is preferable for aesthetic reasons. NOTE: The IEEE History Committee shall have final determination on the wording of the citation. Names of living persons are not normally used in citations. Exceptions to this are cases where the person's name is linked to the achievement itself (e.g. the Lempel-Ziv algorithm, Maxwell's Equations, etc.) or where the person's name is so widely recognizeable to the general public that it makes sense to use it. When used, the names should be the names of the engineers, scientists, or technologists who actually made the achievement, rather than managers or executives. For more information and suggestions about writing milestone citations, please visit Helpful Hints on Citations, Plaque Locations. At this site, the first actively shielded superconducting magnets for diagnostic Magnetic Resonance Imaging (MRI) use were conceived, designed, and produced. Active shielding reduced the size, weight, and installed cost of MRI systems, allowing them to be more easily transported and advantageously located, thereby benefiting advanced medical diagnosis worldwide. In what IEEE section(s) will the milestone plaque(s) reside? Please specify the IEEE Organizational Unit(s) which have agreed to sponsor the Milestone, and supply name and contact information for the senior officer from those OU(s). Sponsorship has three aspects: 1) Payment for the cost of the plaque(s), 2) Arranging the dedication ceremony, and 3) agreeing to monitor the plaque and to let IEEE History Center staff know in case the plaque needs to be moved, is no longer secure, etc. Number 3 must be done by the IEEE Section(s) in which the plaque(s) is located, but aspects 1 and 2 can be done by any IEEE Organizational Unit, and they need not be the same one. Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address. IEEE Organizational Unit(s) paying for milestone plaque(s) Unit: Senior Officer Name: E-mail: Unit: Senior Officer Name: E-mail: Unit: Senior Officer Name: E-mail: IEEE Organizational Unit(s) arranging the dedication ceremony Unit: Senior Officer Name: E-mail: Unit: Senior Officer Name: E-mail: IEEE section(s) monitoring the plaque IEEE Section: IEEE Section Chair name: IEEE Section Chair e-mail: IEEE Section: IEEE Section Chair name: IEEE Section Chair e-mail: Milestone proposer(s) Proposer name: Proposer email: Proposer name: Proposer email: Street address(es) and GPS coordinates of the intended milestone plaque site(s). Please include coordinates in decimal format rather than degrees. What is the intended site(s) of the milestone plaque(s) relation to the achievement? The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque. Also, please Describe briefly the intended site(s) of the milestone plaque(s). (e.g. Is it corporate buildings? Historic Site? Residential? Are there other historical markers already at the site?) Are the original buildings extant? Please provide the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. How is the intended plaque site protected/secured, and in what ways is it accessible to the public? If visitors to the plaque site will need to go through security, or make an appointment, please give details as well as the contact information visitors will need in order to arrange to visit the plaque. Who is the present owner of the site(s)? In the space below, please describe in detail: the historic significance of the achievement, its importance to the evolution of electrical and computer engineering and science, its importance to regional/national/international development, its benefits to humanity, the ways the achievement was a significant advance rather than an incremental improvement of existing technology. The material submitted here will constitute the main descriptive article on the ETHW website for readers to learn about the milestone. Space is unlimited, and detail is encouraged. Most milestones require 1000 to 1500 words of support, however there is no word limit. The article should be readable by a wide audience that includes practicing engineers, scholars of history, and the general public. Some examples of the text of good milestone articles are First Radio Astronomical Observations Using Very Long Baseline Interferometry] and G3_Facsimile International Standardization of G3 Facsimile (Do not worry about the formatting of the page, IEEE History Center Staff will do that afterwards.) What is the historical significance of the work (its technological, scientific, or social importance)? This proposed milestone concerns the development of practically realisable actively shielded superconducting magnets. This work has had huge significance by enabling the much more widespread adoption of MRI (Magnetic Resonance Imaging) by lowering overall system costs and allowing the installation of such machines without requiring hospitals to be built or re-built around them. This has significantly contributed to MRI becoming the imaging method preferred by clinicians and patients alike. MRI has revolutionised diagnosis and monitoring of many conditions and been of immense benefit to humanity (and even to the treatment of animals in certain cases). For a detailed description of MRI see: http://www.siemens.co.uk/en/about_us/index/manufacturing/about.htm The company now known as Siemens Magnet Technology has been a pioneer of the magnet technology that underpins MRI machines. The invention of the superconducting magnet (1961) and the development of a superconducting magnet large enough to allow a human body to be placed inside it (1980) were in themselves key enablers of this truly game changing medical technology. Whilst MR imaging is possible with a resistive magnet the resolution of the images is insufficient to be really useful. 1.5 and 3 Tesla magnets are now common and Siemens Magnet Systems have recently developed a 7T magnet which was runner up for the prestigious UK Royal Academy of Engineering MacRobert Award in 2016. An MRI machine based on a magnet of that size would be extremely difficult to transport, and costly and difficult to site without active shielding for the reasons set out in the section below. The original key developments have been recognised and commemorated in several ways including with a 'blue plaque' (although not an IEEE milestone plaque) at the site where they were carried out (the former Oxford Instruments site in Oxford UK); unfortunately this site now has no connection with the business and no engineering activity so a milestone plaque at that site would not get useful exposure. A subsidiary (Oxford Magnet Technology) was formed in 1982 and a new site was built at Eynsham, Oxfordshire in 1984, Siemens was a key client and acquired first a 51% share and bought the remaining 49% of the JV in 2003 and the business became Siemens Magnet Technology. Active Shielding was developed at that site and this is considered to be the best location of a Milestone Plaque as it will not only commemorate this game changing technology but will also get exposure to engineers working in the field and students visiting the site giving maximum visibility both to the achievement and to the IEEE. At the time of the development of Active Shielding the Company was known as Oxford Magnet Technology, this later became Siemens Magnet Systems. The patents are in the name 'Oxford Advanced Technology Ltd' which was the name of the OMT legal entity at that time. MRI is now one of the fundamental diagnostic tools on which modern medicine depends. Active Shielding was a key enabler to MRI becoming so widespread and important, with annual sales/installations of such machines increasing from a few units a year to over a 1000 units a year from the Eynsham site today. Truly a technology that has benefited all mankind. The key people involved in the development were: · John Woodgate (OMT Managing Director) – deceased · David Hawksworth (OMT Engineering Director and later Managing Director) – deceased · John Bird (Magnet Engineer responsible) · Frank Davis (Technical Director) Siemens Magnet Technology is believed to still be in contact with Frank Davis What obstacles (technical, political, geographic) needed to be overcome? Prior to the development of actively-shielded magnets, MRI scanners were very difficult to site in hospitals as the general exposure limit for static magnet fields is just 5 gauss. Above this level, some members of the population, such as pace-maker wearers, have to be excluded. To reduce the 5 gauss contour to an acceptable level, many Tonnes of ferrous shielding were required. The requirement for this passive shielding greatly increased the construction costs and installation lead-time and severely restricted where machines could be sited, largely restricting them to ground floors where suitable load bearing foundations could be provided. In addition, the interaction of ferrous materials in the vicinity of the scanner with the very high stray magnetic fields substantially affected parameters such as field uniformity which are important to image quality. In many cases, ferrous re-bars in the floor had to be replaced with non-magnetic reinforcement to avoid a detrimental effect on the magnet, further increasing construction costs and disruption in the case of installation in existing hospitals or clinics. Actively-shielded magnets eliminate or substantially reduce the above issues enabling lower installed cost and substantially reducing the lead-time for the installation of an MRI scanner. Without this innovation 3T and 7T magnets which enable significantly improved image resolution and thus diagnostic capability would be more expensive at the 'whole system' level and very difficult to site and install limiting their use. As a result, the Active shielding technology pioneered by OMT, has now become the industry-standard approach. The detail of why the Active shielding techniques developed by OMT were practically realisable whereas the prior art cited was not is set out in the attached patents and will not be repeated here. Suffice it to say that these actively shielded magnets combine outstanding knowledge and exploitation of materials, physical principles (including magnetics and cryogenics (-269°C (4.2 Kelvin) must be sustained just 30mm inside the room temperature exterior) as well as superconductivity), electronic controls, mechanical engineering and precision manufacturing. The internal forces involved are very large (circa 380 tonnes in a 3T magnet) and a small rise in temperature can cause the both the main and/or the shielding superconducting circuits to 'quench' dissipating enough energy to destroy the machine if not properly controlled. Large structures must be manufactured, and windings fabricated and supported all to very high degrees of accuracy (Field Uniformity is dependent on <100µm positional accuracy of the coils). Oxford Magnet Technology/Siemens Magnet Technology have also been leaders in the development of the conductors themselves which were another enabling factor. What features set this work apart from similar achievements? Early Superconducting magnets used heavy and expensive iron shielding to reduce the level of stray fields which have undesirable effects on other equipment (e.g. pacemakers) as detailed above. Whilst there was some prior art in active shielding which is cited in the patents the earlier work did not produce techniques suitable for the high field strengths needed for NMR/MRI nor would it readily accommodate changes to the bore field strength which are sometimes required. The Oxford Advanced Technology work led to techniques which could be realised in production volumes and led to stable outcomes through the ranges required. As has been said this led to machines which were lighter, cheaper, easier to transport and more flexible in terms of possible location making MRI much more widely available, benefiting huge numbers of people. Supporting texts and citations to establish the dates, location, and importance of the achievement. You must supply the texts or excerpts themselves, not just the references. Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. At least one of the references must be from a scholarly book or journal article. 'Scholarly' is defined as peer-reviewed, with references, and published. The full reference, in English, must be uploaded, not just the citation. See below section for details on uploading material to the website. All supporting materials must be in English, or accompanied by an English translation. The US and European Patents are attached: US4587504, filed Nov 7th 1984, granted 6th May 1986 [[Media:US4587504.pdf]] and EP144171B, Filed 9th Nov 1984, granted 31 Jan 1990 [[Media:EP144171B1.pdf]] Patents are public documents. Other supporting documents are: 00133510, IEEE TRANSACTIONS ON MAGNETICS, VOL. 27, NO. 2, MARCH 1991; A 2-TESLA ACTIVE SHIELD MAGNET FOR WHOLE BODY IMAGING AND SPECTROSCOPY 01065051, IEEE TRANSACTIONS ON MAGNETICS, VOL. MAG-23, NO. 2, MARCH 1987; CONSIDERATIONS IN THE DESIGN OF MRI MAGNETS WITH REDUCED STRAY FIELDS 01063856, IEEE TRANSACTIONS ON MAGNETICS, VOL. MAG-21, NO. 2, MARCH 1985; PRESENT STATUS OF MRI MAGNETS at OXFORD - useful in its description of earlier shields using Iron weighing 20T for a 1Tesla magnet 00402514, IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 5, NO. 2, JUNE 1995: Trials and triumphs of superconductivity: The making of Oxford Instruments - useful background on the overall contribution of the Oxford Instruments/Siemens team up to that date. The copyright in all of these lies with the IEEE and they are normally subject to a charge - they will therefore be submitted by email. Contemporary brochure on actively shielded magnets issues by Oxford in the mid 1980's [[Media:20180724192657.pdf ]] Slides from Siemens Magnet systems showing the position of Active Shielding within the timeline of Superconducting MRI Magnet developments and the growth in delivered volumes. The mid 1990's dip was a US market issue affecting all manufacturers [[Media:OMT developments and sales growth.pdf]] Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC) which can be made publicly available on the IEEE History Center’s website (i.e. unencumbered by copyright, or with the copyright holder’s permission). All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. Images and photographs are especially appreciated, however, it is necessary that you list the copyright owner for these and obtain the copyright owner’s permission to reuse. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to email@example.com. Please see the Milestone Program Guidelines for more information. To add attachments, first upload the file and add by adding the text: [[Media:(filename)]] For example, if the file you uploaded was named "Milestone Reference.pdf", include the text: [[Media:Milestone Reference.pdf]] in the appropriate field. Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to firstname.lastname@example.org with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s). Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished Summary: This is a minor edit Watch this page Cancel Retrieved from "http://ieeemilestones.ethw.org/Milestone-Proposal:Active_shielding_of_superconducting_magnets"