Milestone-Proposal talk:The Birth of the First CT Scanner

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Introduction and next steps -- John Vardalas (talk) 21:29, 22 May 2020 (UTC)

Dear Proposer:

I am a member of the IEEE History Committee and I will be the Advocate for this proposal. As Advocate, my responsibility is to facilitate the submission of this proposal to a vote by the History Committee. Before I can recommend this proposal to the Committee, at least two external expert reviews are required.

We need to put together a list of possible reviewers. If you have names to recommend, please send them on to me via my email address.

I see that you have not yet checked off the box "Site Owner Permission Letter Received". Have you not yet received this letter?

John Vardalas, Ph.D.

IEEE History Committee

Christopher James review -- ProfCJJ (talk) 21:29, 8 Sept 2020 (UTC)

I am answering the questions put to me directly below. I note the review from my colleague in the filed and I agree whole heartedly with the comments therein.

1) - "What is the historical significance of the work (its technological, scientific, or social importance)?"

The significance is profound - not only was it technologically innovative to mix X-ray radiation for imaging with this automated computed platform, but it transformed the field of engineering in healthcare, opening the door for the current state of the art in healthcare technology where healthcare is now routinely monitored using computed means. It also revolutionised the provision of healthcare and how diagnosis takes place through 2D and then 3D imaging of the body.

- "What obstacles (technical, political, geographic) needed to be overcome?"

The technological obstacles would have been great, mixing X-ray radiation with computers in this way to provide diagnostics speedily and safely. Speed and safety being the paramount concerns. The 1st generation scanners created the framework for all the future generations - each refining in speed and accuracy.

- "What features set this work apart from similar achievements?"

At the time there was nothing similar - this was quite the breakthrough.

2) Your review should include responses to the following questions.

a) Have they established clear historical significance?

I do not know the full details, only from what I have read in the text books. This looks fine to me though and I believe this is well documented in the relevant literature.

b) Are their arguments technically strong?

The arguments are 'spot on'. I don't think this is something that is up to interpretation - the technical arguments are clear and convincing.

c) Do the answers adequately support the Milestone claim:''

Yes - it s clear, concise and conveys the detail of what was achieved - it correctly states that this did indeed mark the beginning of a new era in clinical medicine. The engineer went from fixing broken auxiliary equipment to creating brand new modalities that completely revolutionised healthcare.

"On October 1st 1971 Godfrey Hounsfield produced a Computerized Tomographic (CT)T scan of a patient's brain that allowed a surgeon to remove a detected cancer. The CT scanner used in this demonstration had been invented and constructed by Hounsfield at the EMI Laboratories located on their campus at this site. It was the world's first imaging system capable of producing high resolution images of internal body structures, and marked the beginning of a new era in clinical medicine."

d) In your view, is the wording of the above claim accurate?

Yes. Concise and to the point.

e) Finally have the proposers provided adequate "Supporting texts and citations to establish the dates, location, and importance of the achievement:"


3) Please feel free to express any additional views on this proposed Milestone and make any suggestions for improvement.

Nothing other than to say that as a student just about to embark on a degree in Electronic Engineering at the University of Malta, it was seeing an article on this new computed tomography scanner in National Geographic that showed me the way to the vocation I an in now - a career in biomedical engineering - that was my "Eureka" moment :)

Review from Prof. Hawkes -- John Vardalas (talk) 05:20, 3 September 2020 (UTC)

The following, which I received on 2 Sept. 2020, is Prof. Hawkes's verbatim review of the proposal.

Professor Dave Hawkes founded the Centre for Medical Image Computing (CMIC) at University College London (UCL) in 2005 and has directed it since then. He has been co-Director of the CR-UK, EPSRC and DoH funded joint UCL/KCL Comprehensive Cancer Imaging Centre since 2011. He was Chairman of the Division of Imaging Sciences at KCL between 2002 and 2004 and Director of the £8M EPSRC and MRC funded IRC in Medical Images and Signals from 2003-2007. In 2019 Prof. Hawkes was awarded the Peter Mansfield Medal and Prize by the Institute of Physics for his lifetime contribution to medical imaging research.

"It is an honour to have the opportunity to comment on the proposal to erect a Milestone Plaque at Jupiter House, the site of the old EMI headquarters. I have read the proposal and strongly support the Milestone proposal. The invention of X-ray CT revolutionised radiology and subsequently almost every branch of medicine. There are few medical conditions that do not at some stage require a “scan”.

Early in my career I had the good fortune to work with Dr. John Perry at St. George’s Hospital in South London. John was the medical physicist tasked with checking that the newly invented “EMI-Scanner” was safe to use from a radiation safety perspective. He is the first author of the third of the three landmark papers on the new scanner, published in the British Journal of Radiology in 1973. He had a series of amusing anecdotes of the work he did with Jamie Ambrose, the neuroradiologist at Atkinson Morley Hospital, and Godfrey Hounsfield himself. The initial investment in the project arose from the large sum earned by EMI on the production of the compilation of the Beatles’ songs a year or so earlier. Godfrey Hounsfield, who’s experience was mainly in radar and defence electronics, applied internally within EMI for access to some of these funds to develop the first scanner.

John also spoke of the fortuitous link between Jamie Ambrose and Godfrey Hounsfield and their determination to create a clinically usable system. Godfrey Hounsfield had no medical experience and his early approaches to the established medical engineering industry had been rebuffed. His letter from a well-known medical engineering company, turning down his invention as “having no practical medical application”, was subsequently framed and hung in his office. Jamie Ambrose saw the potential and together they persevered with the first clinical installation at Atkinson Morley Hospital, later to become part of St. George’s Hospital.

The computer used to collect the data on the first clinical scans was not powerful enough to do the reconstructions so the data was stored on magnetic tape and driven to the EMI research labs in Hayes, West London. The reconstructed image data were sent back the next day. There was no screen capable of displaying the images at that time so the integer numerical data was printed out on large format computer paper. Attenuation numbers close to water had short numbers close to zero, bone and lesions within the skull had larger and hence longer numbers. By pinning the print out to the wall and stepping back it was possible to see the bone outline and a lesion (long numbers and appearing darker) within the brain (short numbers and appearing lighter).

I myself met Godfrey Hounsfield a few years later when I set up my lab at Guy’s Hospital. He always maintained an interest in using his CT images to guide surgery and we were developing a project at the time in augmented reality, overlaying CT and MRI renderings in a surgical operating microscope. We visited his facilities at Hayes and he regularly attended our weekly seminars. He was a shy and modest man and always crept in at the back once the talks had started, but asked probing questions at the end. The students enjoyed having him visit.

I have a couple of very minor comments:

Can I suggest inserting the words “clinical” and “X-ray” before “CT” in the title and before “Computerized Tomography” in the Milestone Claim. This distinguishes his work from earlier tomographic reconstruction methods, for example that of Cormack. Godfrey Hounsfield’s major contribution was construction of a clinically usable X-ray CT system that was installed in a hospital and used to generate images on patients. Ultrasound had also been shown to produce images of internal anatomy, but not of the head and not at the detail that X-ray CT could achieve.

I would re-phrase “..that allowed a surgeon to remove a detected cancer” as “.. that allowed a radiologist to locate a cancer and hence guide a surgeon in its removal”. While I am sure it was used by surgeons the initial published work was with a neuroradiologist, Jamie Ambrose.

In the section: “What features set this work apart from similar achievements?” I would rephrase as: “The EMI CT Scanner was the first clinical machine capable of producing high resolution images of X-ray attenuation, allowing depiction of the internal structures and organs of the human body.” MRI is a completely different imaging modality and although it does produce very high quality images, without delivering a dose of ionising radiation, X-ray CT remains the modality of choice for many investigations in for example the lung, vascular systems and the heart etc.

I think it would be appropriate to cite Godfrey Hounsfield’s landmark paper in the British Journal of Radiology. This describes the system.

Computerized transverse axial scanning (tomography): Part 1. Description of system G.N. Hounsfield, 1973, British Journal of Radiology, 46, 1016-1022"

Professor David Hawkes, FMedSci, FREng, FInstP Wellcome/EPSRC Centre for Interventional and Surgical Sciences University College London Charles Bell House 43-45 Foley Street, London, W1W 7TS

possible citation editing -- Amy Bix (talk) 02:29, 1 October 2020 (UTC)

The current citation seems a bit wordy to me and unfocused. I also wonder why choosing the 1971 "exhibit" date, rather than the 1972 patent date? (at least I see a 1972 patent date on the Nobel Prize webpage - someone should check this....)(this then raises the question of what the 1967-1975 timeframe in the title means....) Some thoughts for possible rewriting?:

At the EMI Laboratories on this site, Godfrey Hounsfield invented the world’s first clinical X-ray Computerized Tomography scanner, patented in 1972. This medical device safely and rapidly generated high-resolution images that advanced diagnostics, therapy, and research of brain tumors and other diseases. This Nobel Prize-winning breakthrough opened a new era in medical technology, advancing precision monitoring of internal health.

Re: possible citation editing -- Jason.k.hui (talk) 16:14, 4 October 2020 (UTC)

Milestones honor the achievement, rather than a place or a person. Does Sir Hounsfield need to be identified in the citation? Also, the Nobel Prize that he won in developing X-ray computer assisted tomography was shared with Allan MacLeod Cormack. The October 1971 date refers to when the first patient brain-scan was conducted on a patient at Atkinson Morley's Hospital in Wimbledon, London, UK. I agree with Amy on decoupling that event with the actual date of invention.

Re: Re: possible citation editing -- Jbart64 (talk) 00:14, 7 October 2020 (UTC)

I agree with the comments above, names are not included in Milestones unless part of a proper noun and title. I suggest modifying to drop the names and Nobel Prize reference:

A team at the EMI Laboratories on this site invented the world’s first clinical X-ray Computerized Tomography scanner, patented in 1972. This medical device safely and rapidly generated high-resolution images that advanced diagnostics, therapy, and research of brain tumors and other diseases. This breakthrough opened a new era in medical technology, advancing precision monitoring of internal health.

David Bart

History Committee proposes changes in the wording of the citation -- John Vardalas (talk) 04:46, 10 October 2020 (UTC)

The History Committee met on 7 October to discuss this proposal. A vote on it was postponed until the 3 November meeting. The merits of a Milestone for the CT Scan were never in question. However, members of the Committee did feel that revisions in the citation were needed. They suggested the following citation as a starting point towards a final version of the citation.

"EMI Laboratories on this site created the world’s first clinical X-ray Computerized Tomography scanner. This medical device safely and rapidly generated high-resolution images that advanced diagnostics, therapy, and research of brain tumors and other diseases. This breakthrough opened a new era in medical technology, advancing precision monitoring of internal health."

The 1972 patent date was left out because an ambiguity in dates arises from the title. Nowhere in the body of the proposal is there an explanation as to why "1967 - 1975". Am I correct in stating that Hounsfield came up with the idea in 1967, filed for a patent in 1968, did the first clinical test in 1971, and was granted a patent in 1972? Why then single out the 1972 date? There is also the question as to why the year 1975 appears in the title. The reference to the Nobel Prize was also dropped from the Committee's version. Reference to the Nobel Prize should be part of the body of the proposal where the evidence is presented.

If you prefer not using proposal's Discussion page, I will gladly post your comments. I believe that we are close to approval. All that remains is a mutually acceptable wording of the citation.

last phrase of the citation -- Juan Carlos (talk) 22:10, 28 November 2020 (UTC)

I think this really deserves a Milestone. I like the wordin of Amy,but what does "internal health mean? CThelps to study and diagnose Organs....

citation suggestions -- Lise Johnston (talk) 16:18, 8 January 2021 (UTC)

I suggest removing First from the citation total. If its the birth of then its obviously the first. "The Birth of the CT Scanner" is stronger.

Please remove the name of the individual as the general practice of the Milestone process is to not award a milestone that appears to be going to an individual except as needed to explain the achievement ie. "Maxwell's Equations"

I don't mind the reference to the Nobel Prize but it would be useful to say in what field it was awarded.

The Issue of the name in the citation -- John Vardalas (talk) 21:04, 18 March 2021 (UTC)

Though some valuable wordsmithing suggestions have been made, the use of the name in the citation remains the key issue. I have argued, and continue to do so, that the use of the name is appropriate for this Milestone. In its last meeting in 2020, the Committee recommended a change in the citation that, among other things, removed the name. The proposers adamantly refused to budge on the issue of the name. In light of the upcoming meeting of the History Committee, I've asked the proposers if they still hold the same position. I'm awaiting their reply.

Proposing Section reaffirms its position on the Citation wording -- John Vardalas (talk) 04:26, 22 March 2021 (UTC)

Below, in an email to me, the proposing Section reaffirms its position on the use of the name in the citation


"The UK & Ireland Section LMAG Committee's view is that the inclusion of Godfrey Hounsfield's name on the Milestone plaque is an essential part of the commemoration. There are so many examples (some quite recent, such as dedications #212, 213, 206, 204 190, etc.) where a key name has been included, that there appears to be no justification for excluding the name of a Nobel Prize winning inventor from the CT Scanner plaque.

I would also point out that the obviously inconsistent application of the History Committee's 'rule' suggests a lack of conviction within the Committee about the soundness of the policy. Perhaps the Committee should review its policy after consulting widely within other IEEE circles."


Reiterate my recommendation to approve. -- John Vardalas (talk) 04:34, 22 March 2021 (UTC)

As advocate, I still recommend that the Committee approve the Citation with Godfrey Hounsfield's name included. I also understand that one can still debate reference to to the Nobel Prize.

Reiterate my recommendation to approve. -- John Vardalas -- E.tejera (talk) 23:14, 17 April 2021 (UTC)

The inclusion of Noble Prize has the same connotations of including the person’s name since Noble Prize is related to the individual. So, we clarify the use or names, the NP issue will be solved also.

Comments: Overall, Citation, Justification and Supporting Texts -- Bberg (talk) 18:15, 21 April 2021 (UTC)

Overall comment:
The proposal is extremely terse; there should be lengthy explanations of what is certainly an interesting topic to better flesh out the important sections. Most importantly, though, the terseness provides an incomplete explanation of issues that I present below.

Citation comments:
1. 1967-1975 in the title is not at all supported by the citation; either edit the citation or the title
2. Based on the Justification section, the "world's first" claims seems best applied to the image as opposed to the scanner itself; either adjust the citation, or expand the Justification section to show that both are truly firsts
3. Since Hounsfield's and Cormack's works are described as being independent, any Nobel Prize reference should be better described
4. If Nobel Prize remains in the citation, it should be cited as the 1979 "Nobel Prize for Physiology or Medicine"

Justification comment:
Please expand on "The patents were tested in the US courts and upheld."  I would expect this to mean that they were attempted to be asserted, proved to be valid when invalidity was alleged, and used as the basis for royalties paid by one or more entities.  Is this the case?  Please explain, and include who paid royalties.

Supporting Texts comments:
1. There are supposed to be at least 5 supporting texts, but only 3 have been provided (the 3rd and 4th files are part of one document)
2. Each document is only a single page, and their quality is poor
3. Documents should be numbered, and references made to them within the proposal
4. I have emailed full OCR'ed PDFs of the 2 patents to John Vardalas, and these should replace the one-page hard-to-read documents as currently supplied

Re: Comments: Overall, Citation, Justification and Supporting Texts -- John Vardalas (talk) 20:26, 25 April 2021 (UTC)

I've been in contact with the proposer in regards to Bberg's feedback. The proposer is surprised to see certain files that he believed to be uploaded to be missing. He is in the process of getting to the bottom of the missing files as well as drafting a reply to the other comments made by bBerg.

Re: Re: Comments: Overall, Citation, Justification and Supporting Texts -- John Vardalas (talk) 18:46, 29 April 2021 (UTC)

The proposer has provided me with the following update (see below). The two journal articles have not been uploaded because of a copyright issue. I've asked the proposer to integrate the reference info for these articles in the body of the proposal text. The other documents are attached to the proposal.

I would like to thank BBerg for supplying the two Patent PDFs, now attached to the proposal.

I believe that the proposer's justification, along with the other supporting documents, makes a strong case for the use of the Hounsfield's name.

++++++++++++ ++++++++++++

++++++++++++ ++++++++++++

Dear John:

I have done some more editing and have given more details of the various attachments.

The new attachments being submitted are as follows:


- Document presenting the case for support titled 'The invention of the CT scanner', which should be positioned in the body of the text of the application.

- Journal paper by Godfrey Hounsfield 1973 (marked scan IV)

- Journal paper by Yang and Firmin 2000 (marked scan VI)

- A document listing the patents awarded to Godfrey Hounsfield, in particular, Patent number: 4052619 Abstract: In an apparatus for examining a body by means of penetrating radiation a source of the radiation and a detector are arranged to orbit about the body. Data obtained from the detector are used to provide a representation of the distribution of absorption in part of the body. To reduce patient movement artefacts in the reconstructed image some of the data are obtained for substantially the same radiation paths through the body, but at different times, and are combined after weighting by complementary factors.

Type: Grant

Filed: February 5, 1975

Date of Patent: October 4, 1977

Assignee: EMI Limited

Inventor: Godfrey Newbold Hounsfield

- A journal publication reporting the legal history concerning the EMI patents related to the CT scanner project.


In addition, there are 4 uploaded attachments listed on the application form 2 relating to the award of the Nobel Prize, and the scanned images of the two most important US patents awarded.

Evidence supporting the use of Godfrey Hounsfield's in Citation -- John Vardalas (talk) 05:53, 3 May 2021 (UTC)

There can be no doubt he the CT Scanner deserves an IEEE Milestone.

Furthermore, I firmly believe that the external reviews, the supporting documents, and the proposer's justification establish Godfrey Hounsfield as the sole hand behind the engineering achievement being proposed by this proposal. Although the Nobel Prize was shared with Alan Cormack, who independently established the theoretical framework for x-ray computed tomography, it was Hounsfield who designed and built the first functioning medical CT Scanner while at EMI's Research Laboratories.

It is my firm belief that if there is ever a case where the name of a person should be allowed in the citation, then the CT Scanner Milestone is one.

Re: Evidence supporting the use of Godfrey Hounsfield's in Citation -- Bberg (talk) 14:57, 4 May 2021 (UTC)


I don't doubt your statement about this being a deserving accomplishment for a Milestone, but most of the issues that I described in detail previously have not been addressed. You started a recent email thread about the names issue, and I responded in great detail to the shortcomings that remain in this proposal. However, none of these issues have been addressed, and thus this proposal does not meet the requirements as set forth for its consideration by the committee.

Re: Re: Evidence supporting the use of Godfrey Hounsfield's in Citation -- John Vardalas (talk) 06:01, 5 May 2021 (UTC)

As far as Brian’s concern about the phrase “the patents were tested in the U.S. courts and upheld”, there was never any question that Hounsfield did not design and build the first functioning, medical CT Scanner. Rather these actions resulted from new, and much bigger, entrants swarming into the field once they realized the great market value of Hounsfield’s CT Scanner. General Electric, for example, described the Hounsfield apparatus as a “gold mine.” (See “Dunham Celebrate 125 Years of Intellectual Property Law” in the March 2012 Issue of the International Lawyers Network)

As Amar Bhide, Srikant Datar , and Katherine Stebbins explain in their paper Case Histories of Significant Medical Advances: Computed Tomography (Harvard Business School Working Paper 20-004, 2020)

"EMI’s CT division became profitable in three years. Orders for the scanners soon exceeded EMI’s manufacturing capacity and in 1976 the company started building a plant to assemble CT scanners in the United States. Rapid CT adoption attracted fourteen other companies. EMI, which had patented its technology, sued the newcomers for patent infringement but failed to block their entry."

EMI had great difficulty maintaining its First-Mover advantages. These competitors tried to find ways around the patent by using different configurations and sized machines. New competing patents quickly followed. EMI could not generalize their head scanner patent to cover all the subsequent developments in CT Scanning technology. The history of EMI’s patent battles are well documented by A.B. Strong and R.A. Hurst in their paper “EMI patents on computed tomography: history of legal actions” (British Journal of Radiology, 67(795):315-316) .

Some firms were forced to pay royalties and other were able to elude royalties. As historically fascinating as it may be, the issue of who did, and did not, pay royalties, should not be relevant to the validity of Hounsfield's name in the citation: the first to engineer a working medical CT Scanner.

Brian may have a point about the dates. But I believe that the proposer wanted to cover the span of time from when Hounsfield's work started and to when he was finally granted the patents.

As far as further explanations as to why Alan Cormack is not included, it seems to me that the attachments are adequate. His role was the articulation of a mathematical framework for a novel medical imaging process using x-rays. The fact that Alan Cormack's name is not on the patent highlights the fact that this proposed Milestone is focusing on the engineering achievement.

Re: Re: Re: Evidence supporting the use of Godfrey Hounsfield's in Citation -- Bberg (talk) 20:47, 5 May 2021 (UTC)

This information has only become available today, the day of our meeting.

The paper on EMI’s patent battles must be purchased, and so I don't have access to it.

I don't know if the committee has a formal scheme for handling dates in the title and sync'ing them with the citation.

I never received a response re: who wrote the Word file "Invention of..." as included in the proposal.

Re: Re: Re: Re: Evidence supporting the use of Godfrey Hounsfield's in Citation -- Bberg (talk) 19:11, 4 April 2022 (UTC)

There remain numerous problems with this proposal, some of which I addressed one year ago as can be seen above. Some of these problems are again noted below, along with details of some other problems.

The number of supporting materials is required to be at last 5, but the links supplied on the proposal page do not fully meet this requirement. The statement "All 11 attachments are being sent separately" appears to indiciate that there are 11 other documents. Likely some of these were discussed above by John Vardalas on 29 April 2021, but these are not accessible via links on the main proposal webpage, and this does not appear to be all 11 of these documents. Further, the proposal should have been updated to reference and discuss these 11 documents.

One of the documents that is linked on the main page is "The Invention of the CT scanner," but its authorship is not provided, and it includes no citations to confirm its statements. Its contents, with citations, should have been integrated directly into the proposal.

I supplied full OCR'ed versions of the '614 and '619 patents. John Vardalas acknowledged that they had been submitted, and these should have replaced the one-page overviews which remain linked on the proposal page.

There is no discussion in the proposal as to how the '614 and '619 patents apply directly to the Milestone, only the words "Hounsfield's fundamental role was recognised" by their being awarded.

The Nobel Prize document has 2 single-page parts, but these really count as a single document.

The proposal should address the applicability of most if not all of the supporting materials, but this has only been given a broad brush of discussion in this all-too-brief proposal. One year ago, I noted the terseness of this proposal. Comments provided by John Vardalas on thie comments page should be integrated into the proposal, or they will be unseen if the proposal is eventually accepted.

I am a strong believer that the date(s) included in the Milestone title should be supported by the citation so that anyone reading the citation will understand and appreciate them. However, this remains an issue as only 1971 is in the citation while 1967-1975 would be included in the title.

As expert reviewer Christopher James' background and credentials are nowhere to be found, it is not possible to confirm whether he is truly an expert "in the technical field associated with the proposal" as required by the Milestone Guidelines.

rephrasing to avoid passive voice -- Amy Bix (talk) 16:47, 8 April 2022 (UTC)

for the first sentence, it would be better writing to avoid passive voice - how about "On 1 October 1971, a team at the EMI Research Laboratories located on this site produced an image of a patient’s brain, using the world’s first clinical X-ray Computerized Tomography scanner based on the patented inventions of Godfrey Hounsfield. "