Chinese nuclear physicists have developed a medical treatment using heavy ion beams to destroy malignant tumors more than 2.1 cm below the skin's surface.

Compared with light ion beams, such as gamma rays and X-rays used in traditional radiotherapies, heavy ion beams are considered the most effective means so far of accurately moderating the amount of radiation and minimizing the damage done to healthy cells, said Zhan Wenlong, the country's leading nuclear physicist.

He explained the new treatment uses stronger heavy ion beams that reach a maximum of 400 mega electron volts (MeV) and can travel further into the human body to kill deeper tumors.

With this medical goal achieved, China joins Germany, Japan and the United States using heavy ions in cancer therapy.

The Cooler Storage Ring, a 300 million yuan ($44 million) project by the Heavy Ion Research Facility (HIRF) in Lanzhou, the capital of the northwestern Gansu province, is playing a key role in generating the beams.

Zhan explained that in contrast to traditional light ion beam treatment, in which the amount of ions diminishes the further it travels, the amount of ions in heavy ion beam treatment peak when they get to the deep tumors, becoming strong enough to kill tumor cells and better protect healthy cells along the way.

At the Institute of Modern Physics of the Chinese Academy of Sciences, Zhan and his research team have produced a broad spectrum of heavy ion beams. They range from 80 to 400 MeV, which can be used to treat both shallow and deep-seated tumors.

Scientists are now optimizing the system software to pave the way for massive clinical testing in the near future, he added.

According to HIRF Director Yue Haikui, the method had been used on 85 cancer patients by the end of 2006, with satisfactory results. Yue's team will continue monitoring the patients to probe the effect of the treatment.

(ChinaDaily October 25, 2008)