Pictures of the Future    Fall 2007

Optimizing Throughput

At first blush, factories and hospitals don’t have much in common. Yet both are complex systems that must operate rapidly and efficiently. With this in mind, Siemens has tapped its expertise in simulating and optimizing automation systems, and has applied this knowledge to visualizing the configuration and workflow of—and ultimately realizing—a new heavy-ion therapy center at the University of Heidelberg Medical Center.

The center, which will open in 2008, will specialize in treating patients with tumors that are either too difficult or too risky for a surgeon to remove. The tumors will be bombarded with carbon ions—the atomic nuclei of carbon—from a particle accelerator. The particles penetrate a patient’s body and destroy growths with extraordinary precision, and without significant damage to surrounding tissue (see Pictures of the Future, Spring 2004, Particle Therapy).

Heavy ion therapy was developed and tested by the Gesellschaft für Schwerionenforschung (society for heavy ion research or GSI) in Darmstadt. GSI’s mission is basic research, not commercialization, so it sought a partner in industry—and found one in Siemens. In 2003 Siemens purchased key heavy-ion therapy patents from GSI and the German Cancer Research Center in Heidelberg and then invested a significant effort in bringing the method to market.

Siemens is supplying all the patient-related technology for the Heidelberg center, including the equipment for guiding the ion beam to the patient, patient positioning and treatment control—"everything that goes on at the business end of the accelerator," says Klaus Staab, project manager of the Heidelberg ion therapy center, who welcomes the close cooperation with Siemens. At another therapy center, the Rhön-Klinikum in Marburg, Siemens is supplying everything except the building itself, including the particle accelerator. The groundbreaking ceremony for the center took place in August 2007.

Visualizing New Terrain. GSI researchers have already proved that the new therapy works as intended. "But what’s missing is experience with regard to how the design of individual treatment steps will affect the performance of the center as a whole," says Thomas Lepel of Siemens Corporate Technology (CT). Particle therapy is an entirely new element in clinic operations. That’s why Lepel and his colleagues have developed a simultation that depicts the ion therapy center’s entire workflow. This makes it possible to analyze the effects that specific customer requirements can have on patient throughput—and on the facillity’s operational costs.

With a price tag of about €150 million—at least €100 million for the irradiation unit, plus roughly €50 million for the building, depending on how it is equipped—patient throughput is set to play a key role in the facility’s economic health. Current projections foresee about 1,300 patients per year, with treatments funded in equal parts by the state and federal governments. But a typical hospital or health care facility that relies exclusively on private funding would have to treat at least 2,000 patients per year to cover the facility’s estimated capital costs. And this equation also would have to include payments of about €20,000 per patient from health insurance providers, which corresponds to the agreement between insurers and the Heidelberg Medical Center.

By comparison, health insurers pay only €8,000 for conventional radiation therapy. Nevertheless, the ion therapy center’s higher costs seem justified, given that total cancer treatment costs, including surgery, chemotherapy, and radiation therapy, often exceed €100,000 per patient.

What’s more, clinical studies have shown that the new therapy appears to be linked to significantly fewer recurrences of some tumors. To Dr. Konstanze Gunzert-Marx, sales director at Siemens Medical Solutions (Med) in Erlangen, particle therapy has what it takes to be a success. "Extrapolating the numbers of new cancer diagnoses shows that this type of center pays off for a catchment area with between eight and ten million people," he says.

Treatment Simulation. That conclusion is confirmed by the treatment center’s business plan, which factors in its investment and operating costs, as well as the health insurance providers’ payments. To calculate cost-effectiveness, patient throughput is simulated and automatically optimized. "Essentially, we apply the know-how we’ve gained from analyzing production processes," says Lepel. "As with factories, where you have thousands of components that must be handled differently, there are a range of different processes at work in a hospital." The simulation differentiates between types of tumors, for example, and takes into account the different preparation times needed.

To define a patient who is in considerable pain as a work-process element may sound heartless, but Siemens developers have entered such classifications into their simulation to come up with a treatment control system that optimizes workflow in line with criteria that take individual patient needs into account. "One strength of our control system is that it allows physicians and medical personnel to devote more time to their patients," says Gunzert-Marx. Instead of being concerned with the ion beam in the accelerator, the physician is free to focus entirely on the patient—who is simulated as a part of the workflow, but treated as a human being.

In front of each of the three radiation rooms, for example, is a room where a patient is prepared for treatment and immobilized on a treatment table, while still another patient is undergoing radiation in the treatment area. Fed with patient data from an oncology information system, sophisticated Schedule Optimizer from Siemens optimizes the rooms’ occupancy and also the use of the ion beam to ensure as little interruption as possible. This reduces costs while shortening waiting times for patients.

If it becomes clear that the preparation of a patient will take longer than planned, another patient can be informed in time and moved ahead in the treatment schedule. Preparation and treatment are seamlessly integrated, thus shortening the entire process for each patient to an average of less than 30 minutes. As Lepel’s simulation indicates, this process—and thus patient throughput—is optimized with a configuration comprising three or four treatment rooms.

Robots at Work. A production plant can operate efficiently only if work processes are coordinated. The same holds true for hospitals. With this in mind, Siemens Med developed a high-tech treatment table made of carbon fiber, which is both strong and light. The table is as suitable for planning computer tomograph treatments as it is for ion treatment itself. Once an immobilized patient is on the table, a robot arm grasps the table and automatically moves it into the right position. The table makes it possible to prepare patients outside of the treatment room.
                                                                                                                 Bernd Müller