A new method of treating oncological diseases – tumor removal in millionths of a second – is being studied by scientists at the Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS) in Troitsk. Finding a new way of ultra-flash therapy, on which specialists have high hopes, was possible thanks to the unique powerful proton accelerator available here, which has been operating since the 80s of the last century. The MK correspondent visited the accelerator complex and got acquainted with the developments for the destruction of tumors using a proton beam.
I did not think that the largest and most powerful accelerator on the entire Eurasian continent could be located in an inconspicuous-looking room. This is another proof of the derived formula for the life of modern Russian science – it lives and steps into the future largely thanks to the developments from its … progressive past. The accelerator, built more than 30 years ago, has not yet been able to create anyone on the whole continent (they say that now they are just starting to build something similar in Sweden).
The accelerator can’t be stopped
“Of course, installations of this kind should not be operated for so long, usually they are dismantled and new ones are built after 20-25 years,” Sergey Gavrilov, the head of the beam laboratory of the INR RAS accelerator complex, introduces me. – But in the current conditions, we have to work with what we have. Our accelerator of protons and negative hydrogen ions is used for applied and fundamental experiments, for obtaining radioactive isotopes used in medicine, science and industry. Some medical isotopes are used for diagnostics in tomographs, others for the treatment of oncological diseases.
Boris Zhuikov, Head of the Radioisotope Complex at INR RAS, Doctor of Chemistry, told us that thanks to the accelerated proton beam (the particle speed in it is measured in tenths of the speed of light), it is possible to obtain some isotopes with such a high yield that is not achieved in the USA , neither in Canada nor in France. For example, strontium-82 is produced here for positron emission tomography, which is in demand all over the world (a radionuclide tomographic method for studying the internal organs of a person or animals) or actinium-225. The latter, using targeted therapy methods, can be delivered to a diseased cell, where it destroys it by emitting heavy alpha particles. This is a new and very effective direction of nuclear medicine. But there is one more thing.
Destroy cancer in millionths of a second
Sergey Akulinichev, Head of the Laboratory of Medical Physics at the INR RAS, Doctor of Physical and Mathematical Sciences, Head of the Proton Beam Therapy Complex at the INR RAS, tells about ultra-flash therapy:
– I will start by explaining the method of proton therapy for oncological diseases, which was discovered quite a long time ago. This is a very complex and expensive type of therapy. Heavy particles – protons formed at the accelerator differ from other light particles in that they emit a radioactive dose not on the surface of the body, but at a given depth. The depth of maximum dose release depends on the velocity of protons. This speed can be changed and thus, by combining the proton beam with the target, one can achieve that the maximum dose is released precisely in the tumor and not in the surrounding normal tissues.
Several years ago, it was found that if the same dose in Grays is applied to a tumor not in a few minutes, as was done before (this method is called conventional), but in half a second, then the tumor cells die, and the normal, adjacent ones, are damaged. two times less than with the old method. This method of irradiating the tumor with high intensity is called flash therapy. It came in handy for those cases when the tumor is located in the brain or near critical organs – the bladder, heart, etc.
According to Sergei Vsevolodovich, for some time in his laboratory the intensity of the powerful proton beam produced at the Troitsk accelerator was underestimated so that it would be possible to work in the same mode with Western colleagues. But then they decided to check what would happen if this intensity was not reduced, and the entire therapeutic dose – 10 to the 13th degree of protons – was applied to the tumor in 100 microseconds, that is, in millionths of a second, in one pulse?
“This amount of protons was enough to instantly carry out the complete destruction of the tumor,” the researcher says. – And at the same time, the effect of irradiation on healthy cells located next to the tumor turned out to be even less, about 5-6 times compared to the flash method.
Currently, scientists have tested a new method on living cells. Ahead – research on live quail eggs, then – on animals with a tumor. Only after it becomes clear to researchers that the method is effective and absolutely safe, it is adapted for human treatment.
– It is clear that sooner or later our accelerator will be stopped, and not everyone is suitable for ultra-flash therapy, – says Akulinichev. “But our experience will at least show everyone what dose rates we should strive for when building new ones. Some installations in other cities can already be reconfigured to bring them almost up to our capacity.