The first in Russia experimental compact neutron generator NG-24 for long distance therapy of malignant tumors was put into operation at the Medical Radiology Scientific Center, the Russian Academy of Medical Sciences, in Obninsk (Kaluga Region) in March 2011. The press service of the Atommed Center, created by the Rosatom State Corporation for commercial use of research results in nuclear medicine, informed about the significance of this event. The corporation financed creation of the device. The team of scientists under Stepan Ulyanenko, Head of the Radiation Biophysics Department, in collaboration with their colleagues from N. Dukhov All-Russia Research Institute of Automation in Moscow have been working at this device for several years.

Thermal neutron bombardment of a tumor is one of the prospective radiotherapy methods. It is not too hazardous for body tissues. But if a special drug, containing, say, boron atoms, is injected into the tumor, these atoms, absorbing the neutrons, would release highly energetic radiation, destroying cancer cells. In addition, normal tissues virtually do not suffer under these conditions. It is noteworthy that this irradiation is particularly productive in cases, when other methods for the treatment of this grave disease virtually do not work. This is so for radioresistant tumors. A propos, about half a million people in Russia become cancer patients every year, and 15-20 percent of them have neglected forms of the disease. Neutron therapy for them is 3-4 times more effective than classical treatment.

For the last years of the 20th century cyclotrons were most often used for therapy. Cyclotrons are huge stationary devices with neutron-forming targets and atom reactors for research. However, high intensity of radiation, complexity of operation and exploitation limited their wide introduction into practical medicine. In addition, there are not many centers of such infrastructure in Russia. It is mainly focused in Tomsk, Chelyabinsk, Obninsk, and some other cities.

According to Ulyanenko, the future of radiotherapy is linked with the development of radiation safe generators of neutrons with sealed acceleration tubes. Due to their compactness, simple exploitation, and rather low price they can be used at all medical institutions with oncological departments--in fact, at a physician's working place.

N. Dukhov All-Russia Research Institute of Automation has been working at development of electrophysical radiation sources with wide spectra of parameters and characteristics, including specialized neutron generators for treatment of severe forms of cancer, during more than 50 years. This work is realized in collaboration with the Medical Radiology Scientific Center of the Russian Academy of Medical Sciences, where the dosimetric and biological studies, aimed at adaptation of these devices for radiotherapy, have been carried out since 2000.

Their latest joint work is NG-24 generator, including a neutron block with a sealed acceleration tube, located in a box (in the zone of exposure of the patient), a set of cables, and a biologically shielded feeding and control desk. The particles flow density on the target surface reaches 10¹⁰ neutr/cm²&b;sec. The device provides irradiation in a permanent mode during many hours. However, the specialists think that the maximum duration of a session will be no longer than 20 min.

Physical start-up of a compact generator is a tremendous step forward in medical instrument engineering.

Ulyanenko is sure that cancer control should be realized not by creating single specialized centers (their number will anyway be insufficient for a country as large as Russia), but by establishing these generators at medical institutions working now, so that the patient does not have to cross half a country to get specialized aid. Estimations show that some 100-150 devices of this kind will be needed for large regional cancer control centers. Trials of NG-24 will start from cell culture trials, similarly as trials of any other innovation device or drug. The scientists will evaluate the efficiency of exposure of tumor cells and normal tissues. The next step will be animal experiments, primarily studies on mice and rats. The specialists hope to get more information about the optimal exposure doses, so that therapeutic schemes could be created. A no less important problem is the efficiency of neutron therapy combination with exposure to gamma particles. In addition, biomedical research will provide sufficient data for improvement of the portable device. After this it will be supplemented by systems for protection of adjacent tissues from radiation and by other accessory devices, and then clinical studies will start. "Creation of a complete system is the work of a year, maybe, a year and a half, thinks Alexander Kuznetsov, Head of Atommed Center. "But we already plan a strategy of its release to Russian and foreign markets." According to the authors' estimations, the price of a serially manufactured therapeutic device would be about 40-45 mln rubles-about the same as a magnetic resonance tomograph. No doubt, these devices will be in great demand, for there are no analogs in the world.