Shepherd constructs state-of-the-art radiotherapy centre in London

Constructing one of the most advanced treatment centres in Europe, Shepherd is working in a deep basement with bunkers surrounded by the densest blocks available to control radiation.  James Stagg  reports.

The new building (pictured) could be no taller than the original five-storey structure so the building had to go deeper rather than higher.

When dealing with technology that delivers state-of-the-art radiotherapy for the treatment of tumours, construction quality and safety has to be of the highest order.

So when it won the contract to construct one of the most advanced cancer treatment facilities in Europe, Shepherd Construction had to come up with a way of containing radiation without compromising valuable treatment floor space.

In order to maximise space and minimise time on site the firm is employing super-dense Ledite blocks as an alternative to concrete alongside extensive prefabrication of services to simplify installation.

London Clinic's new cancer centre is being built in an extremely tight London site between three roads and Georgian buildings in Marylebone. When completed, the £35m building will be one of the most advanced cancer clinics in Europe, featuring a CyberKnife Robotic Radiosurgery system and two 100-tonne Linac linear accelerators.

"This is effectively an enabling works scheme to free up space in the London Clinic's main building so that the main scheme can go ahead," explains Shepherd Construction project director Mick Bodecott. "It will include 48 private rooms and a 20-bed day-care ward as well as three treatment rooms."

The work is the second phase of the London Clinic's project, which includes redeveloping the main clinic in nearby Devonshire Place and its Harley Street clinic.

The first phase, an £11.5m refurbishment of a smaller site on Devonshire Place, has been completed by Bovis Lend Lease. But it doesn't provide the most promising template. Bovis overran by 40 weeks citing complications with the design and is now involved in a £4.2m legal battle with the trustees of the London Clinic to recover funds awarded by the adjudicator.

No such trouble exists with phase two, however, and Bodecott is confident that work is on course. "The 84-week project finishes in November. We've been here for a year and work is on programme."

Planning requirements dictated that the new building could be no higher than the original five-storey structure, which was demolished by Squibb & Davies. So in order to realise 7,500m2 of floor space, the building had to go deeper rather than higher.

Three storeys below ground have already been constructed by McGee, along with a tunnel which runs across the road to the main site at Devonshire place so that patients don't have to go outside between the two. Shepherd took over from the ground floor slab to fit out the basement and build the five storeys above.

The basement

The basement, 6m from which runs the Metropolitan line, will contain all radiotherapy and plant rooms, while in the five storeys above ground there will be 47 individual rooms, 22 day-care pods and further plant equipment.

At 16m down, it is one of the deepest basement's in London. This actually suits the nature of the equipment being installed, as the high doses of radiation being delivered needs to be shielded from other areas of the building.

"They had to put the radiotherapy bunkers in the basement, which from a safety point of view is good because they're well below ground," says Bodecott.

In order to contain the radiation without eating into floor space Shepherd is employing Ledite blocks. These radiation-shielding blocks imported from the US are twice as dense as concrete and less expensive than lead. They encase all three treatment rooms and will cope with the particles being fired at tumours by the CyberKnife, which is one of only two such machines in Europe.

Door frames in the basement are 1m thick, while the wall thickness in the treatment rooms is even more substantial. The ceiling of these bunkers is steel, on top of which are six courses of interlocking Ledite as well as additional lead and steel protection. Where services exit even more lead shielding is required.

Space is at a premium here, so Ledite blocks mean you can have walls half as thick as a concrete wall would be," adds Bodecote. "They're not as thin as they could be with lead, but it's more economical and better structurally."

As with any technology on this scale, an enormous amount of mechanical and electrical services and controls are required.

Alongside the radiation hardware and three generators - one to supply the hospital, one as spare capacity and a third in case both of the others fail - there are lasers to guide the equipment, cameras that monitor patients and a host of associated equipment and technology in the high-specification patient rooms.

The building is also heavily serviced, particularly in the basement treatment rooms, where when the door is locked it's effectively an airtight vault.

This means that throughout the building there are incredible amounts of wiring and pipework serving the special equipment both in the treatment areas and patient rooms. It is being installed by sister company Shepherd Engineering Services.

Prefabrication

The main risers and service modules are all put together in factory conditions before being transported to site and craned into place. "What's different with this project is the amount of prefabrication," explains Bodecott. "The main risers are some of the biggest prefabrication units in the country."

All services are contained within 3m-long modules which are bolted to the ceiling slab. The next corridor box is then simply plugged to the last.

"This way of working means we have less labour on site which makes it easier to manage," says Bodecott. "It's an investment but you need to have the vision that it will save labour and time.

"There's also better quality control. Rather than standing on a mobile tower with sometimes poor lighting, the team are working with it on a bench in front of them. The modules are pre-tested in the factory, then when they're all plugged together we re-test the lot."

The equipment being served in the patient rooms is as state-of-the-art as that in the treatment bunkers. Shepherd has already fitted out one of the £1,000-a-night rooms, which will serve as a showroom. All lessons learned in this room, which features a tablet controlling the television, lighting, windows and temperature, will be repeated throughout all other patient rooms in the building.

"It's more or less a turnkey operation," explains Bodecott. "Apart from the drugs and toilet rolls in the holders, we supply everything. We hand over on 9 November and the first patient moves in on 6 December. The clinic has just a month to stock it up and get it working."

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Handling radiation shielding blocks

The Ledite radiation shielding blocks are 32kg in weight and twice the density of their concrete equivalent. This is a benefit in terms of radiation resistance and space saving, but not so much of an advantage when it comes to logistics.

Ledite is heavier than concrete blocks, so there are manual handing issues with it you have to address," says Shepherd's Mick Bodecott. "You can use a combination of manual systems but you can't eliminate manual handling so you have to have a very robust method statement."

Tower cranes place the 2.5t pallets of blocks straight down the basement's light well. Strict guidelines are then observed for their manual handling. "We made sure there are shorter lifts on scaffold," says Bodecott. "Also, nobody is allowed to lift below knee level and they all must use back supports, work shorter hours and take frequent breaks."

Deliveries are accepted in a loading bay on Marylebone high street. But as it's a wide road vehicles can remain in place without affecting two-way traffic. Bodecott says: "The site has a small footprint so the logistics are challenging. All deliveries come on a just in time basis. If anything arrives unannounced it gets turned away."

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Factfile

• Scheme: The London Clinic Cancer Centre, Marylebone, London
• Value: £35.5m
• Client: The London Clinic
• Main Contractor: Shepherd Construction
• M&E subcontractor: Shepherd Engineering Services
• Radiation shielding supplier: Ledite
• Structural Engineer: Alan Baxter
• Start date: February 2008
• End date: November 2009