Cancer Hospital Design & Radiation Bunker Structural Engineering in Pakistan

A cancer hospital brings together outpatient clinics, surgery, chemotherapy, imaging and radiotherapy. The radiotherapy bunker that houses a linear accelerator is one of the most demanding structures in any healthcare project: a heavily reinforced concrete vault whose walls and roof must stop high-energy radiation while still allowing cables, ventilation and people to pass through safely. This guide to cancer hospital design in Pakistan explains how oncology departments are planned, how radiation bunkers are engineered and built, and which approvals apply, so owners can avoid the costly mistakes that are hard to fix once concrete is poured.

Planning a Cancer Hospital

Cancer care is mostly outpatient. Many patients visit daily for weeks of radiotherapy, or every few weeks for chemotherapy. Design should make these repeated visits as easy, private and comfortable as possible, while keeping radiation and hazardous drugs safely contained.

For the wider service mix, including surgical oncology and inpatient wards, see our guide to oncology and cancer hospital design in Pakistan.

Where to Place the Radiotherapy Department

Bunkers are extremely heavy, so they are almost always built at ground level or in a basement, on their own foundations, outside the footprint of multi-storey wards. This keeps the structure simple and allows the earth to provide some shielding. Good locations also:

• Allow future bunkers to be added alongside, since demand for radiotherapy usually grows
• Keep occupied spaces, such as offices and wards, away from bunker walls and roofs
• Provide a route for delivering and eventually replacing machines
• Give patients a short, dignified route from a dedicated entrance and waiting area

How a LINAC Bunker Works

A linear accelerator rotates around the patient, so the beam can point at the walls, floor and roof. The bunker is designed with different zones of protection.

Primary barriers

The parts of the walls and roof that the main beam can strike. They are the thickest sections and are often visible as thicker bands on the plan and roof.

Secondary barriers

The remaining walls and roof, which protect against radiation scattered from the patient and leakage from the machine head. They are thinner than primary barriers but still substantial.

Maze and door

Most bunkers use a maze, an L-shaped entry corridor that makes radiation scatter several times before reaching the door, allowing a lighter door. Higher-energy machines can produce neutrons, so the door may need materials such as borated polyethylene as well as lead. Bunkers without a maze need a very heavy shielded door.

Exact thicknesses depend on machine energy, workload, beam directions and the use of neighbouring spaces. They are calculated by a qualified medical physicist and approved through the PNRA licensing process. Architects and structural engineers must not reduce them to save space or cost.

Ordinary vs High-Density Concrete

Building the Bunker: Structural and Site Engineering

Mass concrete and heat

Very thick concrete generates heat as cement hydrates. If the core gets much hotter than the surface, the concrete can crack, creating paths for radiation and water. Control measures include low-heat mix designs with cement replacement materials, cool mixing water or ice in hot weather, planned pour sizes and sequences, insulation of surfaces, and temperature sensors embedded in the pour. Lahore and Karachi summers make this especially important.

Density and quality control

Shielding depends on density as well as thickness. Trial mixes, density testing of cubes and cores, careful compaction and close supervision avoid honeycombing and voids. A physicist’s radiation survey after installation confirms performance.

Construction joints

Joints between pours should be stepped or keyed rather than running straight through the wall, so there is no direct path for radiation.

Service penetrations

Electrical conduits, dosimetry cables, ventilation ducts and water pipes must pass through the walls. They are routed at angles, through the maze, or with additional shielding, as specified by the physicist. Penetrations are fixed before concrete is poured; drilling later is difficult and risky.

Foundations and waterproofing

A bunker’s weight needs a proper geotechnical investigation and foundation design. Basement bunkers need reliable waterproofing, because leaks near high-voltage medical equipment are dangerous.

Building Services for Radiotherapy

• Ventilation: controlled air changes in the treatment room, with ducts entering through the maze or shielded routes.
• Cooling: the machine needs chilled water or dedicated cooling, often with redundancy.
• Power: stable supply with UPS and generator backup; voltage fluctuations can stop treatment.
• Safety systems: door interlocks, warning lights, emergency-off buttons and CCTV and intercom to the control area.

Designing Radiotherapy Around the Patient

A course of radiotherapy can mean visiting the hospital every weekday for several weeks. Small design decisions add up to a large difference in how patients cope.

Arrival and waiting

A separate radiotherapy entrance close to parking or drop-off spares patients a long walk through the main hospital. The waiting area should have daylight, comfortable seating, washrooms and drinking water, with a separate quieter area for patients who are very unwell. Separate seating for women and families is expected in most Pakistani communities.

Changing and dignity

Patients often change for treatment. Private changing cubicles with lockers, located between the sub-waiting area and the bunker, preserve dignity and keep throughput steady. A short sub-waiting area outside each bunker lets the next patient be ready while the current treatment finishes.

Inside the bunker

Bunkers have no windows, which can feel oppressive. Warm lighting, ceiling panels with nature images, music and a clean, uncluttered finish help patients relax and stay still during treatment.

Staff areas

Radiographers spend their day at control consoles. Control areas need space for planning screens, good acoustics, views of the maze entrance and quick access to staff rest areas.

Chemotherapy and Hazardous Drug Safety

Cytotoxic drugs must be prepared in a dedicated pharmacy clean room with appropriate safety cabinets, negative or controlled pressure and gowning areas. Waste from chemotherapy is hazardous and needs a secure, separate store. Infusion areas should be calm and daylit, with toilets close by and space for a family member.

Project Steps for a Radiotherapy Department

Common Mistakes

• Designing the bunker before the machine type and energy are decided
• No space reserved for a second or third bunker
• Uncontrolled mass pours in summer, leading to cracking
• Late service penetrations cut through finished walls
• Offices or wards placed directly above or beside bunkers without assessment

Frequently Asked Questions

Conclusion

Cancer hospital design in Pakistan succeeds when radiotherapy is planned from the start: the right location, physicist-led shielding, careful mass concrete construction and early PNRA engagement. Around the bunker, calm and dignified spaces for chemotherapy and daily treatment matter just as much to patients. ACCO designs and builds healthcare facilities, including radiotherapy structures, through its hospital construction services, with every project priced through an itemised BOQ.