The Monte Carlo model is a specialized computer program that accurately simulates the passage of every particle that passes through the radiotherapy accelerator and into the patient during therapy. Using it will enable doctors to eradicate tumors more effectively, while causing less harm to healthy tissue.

Researchers Dr. Frank Verhaegen from the National Physical Laboratory and Emiliano Spezi at Velindre Hospital, Cardiff, working on two different projects, presented their work Wednesday (23 January) on Monte Carlo simulations at the Institute of Physics' "Simulation and Modelling Applied to Medicine" conference in London.

Their programs take into account the exact anatomy of individual patients when optimizing radiotherapy treatment plans.

Current systems used to plan radiotherapy for patients with cancer are often based on clever but simplified analytical physical models. The simplification has been needed so that calculations can be carried out at a pace that is useful in clinical practice. But this means that they do not, for example, consider the individual interactions between radiation particles and the patient.

Using the more complex Monte Carlo method is widely believed to be the next step to improve radiotherapy. Readily available computing power applied to recently developed new algorithms now makes this possible.

Setting the correct dose during radiotherapy is particularly difficult when treating a tumor in the head or neck because that part of the body is made up of a complex mixture of bone, soft tissues and air passages, and the particles behave differently in each material.

Dr. Verhaegen presented work from a pioneering project that involved a research group at the Royal Marsden Hospital, London. The work led to a highly successful prototype Monte Carlo treatment planning system. He says that the simulation work has progressed so well that the next stage should be a full-scale clinical trial.

Working in the department of medical physics at Velindre Hospital, Cardiff, Emiliano Spezi is using the Monte Carlo technique to improve predictions of the treatment delivered by the particular machines they have in the hospital. He is also developing Monte Carlo programs that verify the exact dose received by individual patients.

"So far, the large amount of computing time required for Monte Carlo techniques has limited their use in clinical practice. But I think that the computers and the algorithms are so much better, that within a year or so Monte Carlo will become the standard method of calculation, at least for electron-based radiotherapy," says Spezi.

Related website:

Institute of Physics

[Contact: Dr. Frank Verhaegen, Emiliano Spezi, Alice Bows]

25-Jan-2002