Breakthroughs in radiation therapy—specifically, the use of heavy particles, such as protons and carbon-ions—are creating promising new possibilities for treating cancer.

First came proton therapy, a modality that uses proton beams to target tumors with greater accuracy than X-rays or gamma rays. A newer approach, carbon-ion therapy enables treatment of deeper and more sensitively located cancer cells with even higher precision. It also causes minimal disturbance to the surrounding normal tissues, making it preferable over conventional therapies and sometimes even proton therapy.

Carbon-ions, being larger than protons, require a higher acceleration to achieve the required energy for treatment, resulting in a larger equipment size. A long linear accelerator, a huge circular accelerator, a synchrotron to energize carbon-ions, and strong deflection magnets are just the beginning of what must be supported in treatment and equipment rooms to achieve effective therapy.

The basics   
Studies of existing carbon-ion therapy centers show that the utilization of a treatment room can be maximized by locating the changing, sub-waiting, and patient immobilization functions just outside. The planning of these patient spaces is based on the type of radiation beam used.

For example, the typical treatment room size for fixed-beam angles—usually 30, 45 or 90 degrees—is around 600 square feet. Unlike horizontal beams, vertical or oblique beams come from above and require ceiling heights of almost 60 feet to accommodate the bending magnets.

A gantry rotates 360 degrees to generate radiation beams at any desired angle, increasing the possibility of treating hard-to-reach tumors. The present model used for gantries is approximately 40 feet in diameter and 60 feet in length and weighs 600 tons.

It also requires a space that’s more than 60 feet high for rotations. The ceiling design of a gantry room usually includes a hatch for maintenance and replacement of machine parts, too.

These patient spaces are supported by the equipment room, which is where all the action takes place. The ion source, linear accelerator, synchrotron, and beam lines emerge from here. Even though the length of the linear accelerator varies between 16 to 33 feet, it’s not adequate for the acceleration of carbon-ions until supported by a synchrotron. A synchrotron is about 70 to 100 feet in diameter and 200 feet in circumference—huge enough to create planning constraints.

Through rigorous research, scientists have been able to generate a compact synchrotron around 65 feet in diameter and a shorter linear accelerator that’s approximately 12 feet long. The application of this model in a recently constructed carbon-ion therapy center resulted in a 33 percent reduction of the total built-up area as compared to older facilities. A smaller 42-foot-long gantry and a synchrotron that’s 33 feet in diameter are also currently under development and testing.

To address structural loading concerns, treatment and equipment rooms should be located on lower floors, either on-grade or in the basement. The challenge of flooding in basements can be avoided by adopting waterproofing measures during construction, such as physical barriers, gap walls, trenches for rise in water levels, using crystalline admixtures in concrete, etc.

The heavy carbon-ions also require greater shielding as compared to other forms of radiation. The entry to the treatment rooms is usually designed as a maze to avoid leakage of radiation. The number of turns in the maze depends on the amount of shielding required, making it either a single- or double-maze entry—both equally common in existing facilities. Utilizing the earth as a natural radiation shield in the basement areas can be more economical, as well.

Other variations for radiation shielding include lead combined with high-density concrete, steel, or borated polyethylene. Some radiation therapy experts believe that the performance and cost-effectiveness of regular concrete surpasses other materials.

The wall thickness for radiation protection is based on calculations by shielding consultants and can range between 6 to 10 feet. In fact, pre-engineered modular concrete blocks are becoming the new trend. They’re easy to construct and also reduce wall and ceiling thickness compared to regular concrete, and they allow adaptability and flexibility in design to keep up with technology upgrades.

Creating calm
The stigma and fear associated with cancer makes it imperative for designers to create calm and comforting environments for patients, especially when just the name “carbon-ion therapy” can be intimidating. The design of public spaces can play a key role in lending a human touch to balance the institutional character of such facilities.

Sights and sounds of nature, natural light, warm materials such as wood, family-friendly amenities, etc., can create a more therapeutic setting. Moving from the public to procedure spaces can cause high levels of anxiety in patients, so punctuating internal corridors with indoor gardens or pleasant artwork can provide a seamless transition from the main waiting to the treatment areas.

Within the treatment rooms, creating positive distractions through simulation of the sky or other pleasant imagery on the walls or ceilings can help alleviate patients’ stress while they’re in a seated or supine position during their procedures. This can be particularly beneficial in treatment rooms fitted with a gantry because of the intimidating equipment and the complexity of the procedure.

Apart from equipment, the facility should also be designed to create supportive environments for the care team. Staff will spend most of the day around colossal machinery with no connection to the outdoors, so providing refreshing breakout spaces for respite will be beneficial.

Working better
Even though the idea of using carbon-ions for treating cancer was conceived in the mid-1900s in the United States, the practical value of carbon-ion therapy facilities remains a big question here. The technology has long been accepted in Europe and Asia but is only now tiptoeing its way into North America.

High costs limit the growth of more centers, and due to fewer facilities offering the treatment, costs are very high. Given the current conditions, the capital cost of a carbon-ion therapy center is almost twice that of a proton therapy center, which itself is around $125 million.

Another real-world hurdle is the reimbursement model. With limited medical insurance companies providing coverage for expensive radiation therapy, it’s often afforded through private pay or out-of-pocket expenditures.

Researchers believe that an increase in the number of carbon-ion therapy facilities would result in more clinical trials that produce sufficient data to justify the cost and investment in this technology.  This would also allow the study of variables yielding returns and assessment of best practices.

One solution is to integrate these centers within existing facilities to share imaging and diagnostics services to reduce base costs compared to setting up standalone centers. Providing both proton and carbon-ion therapies under one roof may increase utilization and shorten the payback period, as well.

Physicists and scientists experimenting with heavy-ions predict that carbon-ion therapy will be an accepted technology in the coming years and will increase cancer survival rates, a trend that will drive designers to move alongside these advancements.

The target for the next 10 years should be to be make carbon-ion therapy more feasible in terms of space, budget, and effectiveness.

Humanizing complex environments that are governed by state-of-th
e-art equipment in addition to balancing the rigidity of technology with design features that signify life and hope should be the goals moving forward. Research and evidence-based design interventions to create innovative solutions will be fundamental to providing patient-centered care.


Dyutima Jha, Assoc. AIA, EDAC, is director of research and healthcare planner at Kahler Slater (Singapore). She can be reached at


Facts and figures
According to 2014 statistics published in the International Journal of Particle Therapy in July, the number of patients treated with carbon-ions from 1954 to 2014 was about 11 percent worldwide, whereas in 2014 the number of patients treated with carbon-ions increased to 17 percent.