Cyclotron for Cancer

Jovial young Physicist Ernest Orlando Lawrence has an 85-ton atom smasher at Berkeley, Calif. Intrigued by the Lawrence cyclotron, promoters of the Golden Gate International Exposition asked if they could borrow it to smash atoms for next year's fair. Physicist Lawrence, who was deep in experimentation, pointed to the protective wall of six-foot-high water tanks surrounding the cyclotron, explained that neutrons flying free as hail around an exhibition room might settle in the tissues of spectators, even render them sterile. The exposition officials hastily retired, and last fortnight they hatched plans to exhibit a model cyclotron with lights and noises in which imaginary projectiles would smash phantom atoms.

Main reason why Dr. Lawrence is so loath to part with his cyclotron is that he is now engaged in the most significant problem of his career: the effect of neutron rays on cancer of human beings. The cyclotron whirls ions of heavy hydrogen (deuterons) between the poles of a huge electromagnet, then hurls them into a drumlike vacuum chamber. When they are charged with nearly eight million volts of energy, the ions are shot against a target of light metal, usually beryllium. The bullets knock out streams of neutrons, tiny particles about the same weight as protons but carrying no electric charge.

Physicist Lawrence and his brother, Physician John Hundale Lawrence, soon discovered that neutron rays directed at animals act with much greater force and selectivity than X-rays, are five times more lethal for tumor tissue than X-rays but in tumor-killing doses considerably easier on normal tissue.

Last year Surgeon General Thomas Parran granted Ernest Orlando Lawrence $30,000 to use in cancer experiments. Last week Dr. Ludvig Hektoen, director of the National Advisory Cancer Council, announced that a group of cancer patients, drawn from a special list in the University of California's San Francisco teaching hospital, have been placed under the cyclotron for treatment. Wary of raising false hopes, Dr. Hektoen warned that "these treatments are purely experimental."

Added Dr. John Lawrence: "It may be months, even years, before the results are known."

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