When the designs were drawn up for a new private radiotherapy centre in Wimbledon in 2001 there were really no dedicated or specialist radiotherapy “heavy” door suppliers operating in the UK. The large US based companies that can deliver essentially “ready-made” bunkers or fast-build, high density brick-based systems were not represented and most other companies were largely radiology based usually providing shielding solutions for diagnostic imaging and so a new business opportunity presented itself.
Pic: Tennis at Wimbledon
Private Radiotherapy starts slowly in the UK
The Cromwell Hospital located on London’s Cromwell Road opened in 1981 and contained the first UK purpose built private radiotherapy centre, considered a revolution at the time and remained so until the Harley Street innovation from HCA in 1998 that provided linear accelerator-based treatments initially and uniquely installed and retrofitted under a busy London street and within listed buildings. This site had basic bunker swing doors driven by compressed air that allowed for a smaller bunker footprint and a shortened, lobby style maze with space saving critical in central London. Compressed air systems are inherently less reliable than electric motors and need to be well maintained. As a basic grade radiographer, I remember going for an interview at the Cromwell for a senior position in 1984 and was very taken by the plush hotel style reception and lounge with free coffee!
Pic: Cromwell Hospital, London
It was a widely held belief in those days that private radiotherapy would not pay nor succeed simply due to the very high capital costs of the equipment and the contentious issues in taking staff across the “divide” and into the private sector, something to this day that still concerns some managers and I for one am not sure why.
We know now that this was a very incorrect assumption and Cancer Partners (now Genesis Care) made the provision of private radiotherapy a great success with a one Linac per site business model and centres built strategically all over England over the last decade or so. Many others have now taken on the mantle with private radiotherapy on offer all over the UK in 2019 varying in complexity from Prostate seed implants right the way to Proton Beam Therapy.
Below is a link to an interesting article on private radiotherapy provision and how it stands now, well in 2016 that is and so probably needs updating again soon!
Independent sector provision of radiotherapy – eight years later (Sarah Hynd, John Pettingell, Karol Sikora – 2016 Imaging and Oncology)
In response to their article featured in Imaging & Oncology 2008, the authors review independent sector provision as it now stands eight years on and discuss whether some of the challenges outlined back then have been met. Click on this PDF link and go to page 54.
Door design can be complicated
So back to Wimbledon and the plans for two space saving, direct-entry bunkers that were designed without a maze at all. You could look straight at the Linac when standing in the door reveals and so while this saved on valuable real estate and civil engineering costs it made the door design very complex.
Not only was there no maze, the Linacs were very high energy and so also had neutron production issues that needed to be dealt with by the doors. The Head of Physics called me to ask if DHA had any contacts that could provide consultancy and design a bespoke door system that would meet all their needs and so I arranged an introductory meeting in Dijon, France with the owner of DIB Production, then the leading supplier of radiotherapy doors in Europe and the Middle East.
They were keen to work with DHA and so a UK and Ireland distribution contract was signed and consultancy provided to design a door that shielded high energy photons, neutrons and incorporated a rail system so that the doors would slide open on wheels and rails just like a fun mini-railway for kids or roller coaster in Blackpool. However, when the door was open there would be no floor in the entrance and so the design incorporated a sliding floor system that covered the access entrance and was pulled and pushed by the door back and forwards. The rails were located in a trench well below the level of the finished floor to provide sufficient shielding below the door as well as above and to the sides, the door driven by reliable electric motors. The rails were required as each door weighed over 14,000 kilos and so a unique articulated bogey system ensured even weight distribution and operational reliability. The doors contained sufficient neutron shielding too and were 40 cm thick.
I always recall the wise words of Dr Edwin Aird when contemplating bunker designs in that he would always design a new bunker with a short as possible maze and a door but when taking into account reliability issues would then change his plans to incorporate a standard long maze! I think the point he was making was that reliability of the doors may be an issue in time and that was not worth the trade-off unless absolutely essential.
DIB the manufacturer however had a great reputation for reliability that was a huge positive sales-point and they also worked with Varian, Accuray and Elekta on worldwide projects and so I was happy to associate myself with them and offer their doors to my UK clients in busy radiotherapy and physics departments.
The department in Wimbledon eventually opened in 2003.
Pic: A typical radiotherapy sliding door installation
DHA quickly established itself as the leading supplier of “heavy” radiotherapy doors and installed reliable systems all over the UK and Ireland at many hospitals working with leading NHS hospitals, radiotherapy equipment and construction companies.
Pic: A DIB swing door located at the Mount Vernon Cyberknife site
Working with construction companies then opened “doors” if you pardon the pun into other sectors such as industrial radiography as word got out as to our cost-effective solutions, bespoke designs and reliability.
These organisations initially enjoyed the one to one, hands on personal approach of myself and the DIB owner who always paid great attention to this and made every effort to visit each customer at key stages to discuss their project and provide a design that suited all their needs.
The British Museum – World Conservation and Exhibitions Centre
A grant of £10m from the Heritage Lottery Fund provided resources to enable the Museum to expand its innovative outreach and public engagement.
The World Conservation and Exhibitions Centre provides the Museum with world-class facilities for visitors and researchers taking conservation, scientific research and collection management to a new level of excellence.
Pic: The WCEC from above
The museum asked us to design a door to be installed at this new facility where a high energy industrial CT Scanner was being purchased to scan and then archive their priceless artefacts such as the Elgin marbles.
Pic: Figure of Iris from the west pediment of the Parthenon
To read more about the Elgin marbles or lesser known by their real name the Parthenon sculptures click here: www.britishmuseum.org/about_us/news_and_press/statements/parthenon_sculptures.aspx
We came up with a solution that weighed 6,000 kilos and was hung on a lintel mount above the door entrance. Unusually this door had to be installed inside the bunker and not outside, a safety hazard for operators (or patients in radiotherapy for whom we would never recommend this layout) who may be “stuck” in the room in the event of a serious failure. We designed an escape hatch above the door that had a “Mini-Me” door in it that could be removed to allow emergency access and a ladder system internally for maintenance and emergency egress.
Pic: The Museum’s door from the inside with hatch above and ladder
Diamond Light Source Synchrotron at Harwell
Diamond Light Source is the UK’s national synchrotron. It works like a giant microscope, harnessing the power of electrons to produce bright light that scientists can use to study anything from fossils to jet engines to viruses and vaccines.
Pic: The DLS facility in Oxfordshire
DLS asked us to design a door system to be located at the end of one of the beam lines that would comprise four 10,000 kilo tanks of concrete mounted on-top of each other and also a rail system similar to that described above and be fully automated. This door while weighing over 44,000 kilos in total could open in less that a minute and be manually cranked if needs be with very little effort. Concrete saved on the higher costs of steel and lead as space saving was not a huge issue.
Pic: The DLS big and very heavy door
Neutron shielding services
I also moved into providing neutron shielding for sites installing high-energy Linacs that involved Monte-Carlo based calculations to decide where in the maze the neutron absorbent linings would be fitted. The maze would be fitted out with a hardboard arch, a set distance from the concrete wall and would be filled with polyethylene style beads that changed fast neutrons into thermal ones. The thermal ones were then absorbed by a borated wall paper that lined the exterior of the wooden arch. In some cases the wood was sufficient to slow the neutrons and just the borated wall paper was required and then finished in plaster board, painted and forgotten about.
Pic: T shirt is available on Amazon!
I learned a few things about neutrons at the time, a very specialist subject that not many people in the UK were expert in but skipped the T shirt. In layman terms they bounce around the bunker like ping-pong balls and are very hard to predict. They are readily absorbed in water and so many sites would see an alarming increase in neutron dose levels in a new maze as the concrete dried out! Lime based concrete also works well as neutron absorber (as does wood above) whereas Magnetite exacerbates the problem due to its iron content and so not recommended when neutrons are an issue. I am sure the current Proton Beam Therapy sites are far more knowledgeable about neutrons now!
This business opportunity reduced considerably when the move to low energy 6MV Linacs such as Tomotherapy systems and conventional Linacs delivering IMRT and then VMAT replaced the need for high energy photons.
The door closes!
In 2018 when DHA ceased trading I sadly ended my relationship with DIB which was a great shame but the big USA based companies where now very active in the UK and Ireland, often partnering with the main Linac and Proton beam therapy manufacturers and I just couldn’t compete commercially with them. The one to one, special relationships I developed were less important to the very big civil engineering organisations and I was expected to become a combined building company and radiotherapy company where the rules, regulations and insurance issues were too big to overcome.
However, my parting gift for DIB was a big order for 10 shielding doors for a new material testing facility at UKAEA near Didcot with a call off for 5 more and so we ended on a high!
Duncan Hynd – September 2019