— Vladimir Yuryevich, your research group is working on the study of scintillation crystals, which can be used in modern positron emission tomographs.

Please tell us what is the process of positron emission tomography, how does PET differ from MRI and CT, and what are the advantages of this technology?

— Methods of MRI and CT belong to the so-called transmission methods of diagnostics.

In the case of CT, a person is exposed to external X-ray radiation, which is absorbed to varying degrees by various organs and tissues, and then captured by a detector.

The process is similar to fluorography, only with volumetric resolution.

In the case of MRI, we also place the patient in a special external magnetic field, which, interacting with magnetically susceptible structural elements of human organs and tissues, allows us to get an idea of ​​his condition.

And when positron emission tomography is performed, a radiopharmaceutical is introduced into the patient's body, which contains a short-lived medical isotope and its carrier, which delivers the isotope "to its destination."

For example, for the diagnosis of oncological pathologies, a synthetic analogue of glucose, fluorodeoxyglucose, containing the short-lived isotope of fluorine-18, is widely used.

It is known that cancer cells multiply rapidly largely due to the ability to actively absorb natural glucose from the blood.

Synthetic glucose similarly quickly accumulates in pathological tissues, delivering fluorine-18 to them.

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Accordingly, in these places, the process of decay begins with the emission of positrons.

In a short time, positrons annihilate with the electrons of human tissues, and two gamma quanta are emitted, which move in strictly opposite directions.

They fly out of the patient's body and are fixed by special detectors, the main element of which is just scintillation crystals.

Based on these data, we can localize the places where the accumulation of the radiopharmaceutical has occurred, which indicates the pathological processes occurring there.

This method is based on the emission of gamma rays.

The main advantage of nuclear medical diagnostics is that it makes it possible to detect oncological or other pathology at the earliest stages, when it leads to only minor changes in physiological processes.

For comparison, computed tomography allows diagnosing oncology only when it is already possible to visualize a formed tumor to a certain extent.

— What are scintillation crystals and what functions do they perform in positron emission tomographs?

- Let me draw this analogy: a person can identify certain chemicals by smell, for example, chlorine.

But we do not have sense organs that could detect radiation.

The gamma-quantum emitted from the patient's body during PET diagnostics must not only be captured, but also its energy must be converted into secondary excitations that are capable of stimulating visible range photons in the volume of the crystal.

Then, with the help of photoelectric devices, it is possible to fix the photon fluxes and convert them into electric current pulses in the recording path of the product.

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— Is it true that now all equipment for PET, including crystals, is imported?

Why did such a situation arise?

- Look, each of us imagines what a good car is.

And even in general it is clear how such a technique works.

But for a number of reasons, it has not yet been possible to create in Russia a complete technological cycle for the production of cars comparable in characteristics to foreign models, from domestic raw materials and components.

Although work in this direction, of course, has always been and is being done.

In the case of scintillation crystals, the situation is similar: the main methods for growing crystals are known, they are described in scientific publications and are protected by patent solutions.

But as long as foreign-made scintillation crystals were relatively easily available, the development of domestic technologies was not given such close attention as it is now.

The task is not only to obtain prototypes, but a much more difficult challenge is to organize not a piece, but a mass production of materials similar in properties.

This is painstaking work on establishing and correcting technological regimes, selecting raw materials of the required purity, etc. This process requires not one-time support, but stable long-term financing.

There are examples of the creation of such industries abroad.

Certain scintillation materials are also obtained in Russia.

In Russia, the creation of a PET tomograph is carried out by JSC NIITFA, which is part of the state corporation Rosatom and has experience in developing complex high-tech medical equipment.

In 2016, the company has already presented a prototype PET scanner.

Another enterprise of Rosatom, JSC Giredmet named after V.I.

N.P.

Sazhin.

Ural Federal University, having many years of experience in the study of scintillation materials, cooperates with Giredmet precisely in terms of determining the scintillation properties of newly grown crystals.

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Recently, Giredmet has obtained experimental samples of lutetium silicate crystals with acceptable characteristics.

Now we need to replicate this technology, to achieve reproducibility of the properties of crystals.

If this problem is solved, then the way will be opened for the creation of domestic detector components for PET tomographs, including for the modernization of foreign PET tomographs already available in Russia.

— Does Russia have the raw materials necessary for the production of scintillation crystals?

- In general, yes.

Another thing is that in order to obtain a high-quality crystal, in addition to technology and the selection of growing modes, raw materials of proper purity are needed.

From my point of view, for pilot production in the laboratory, it is possible to refine the necessary amount of chemicals to the desired state.

Similar tasks in JSC "Giredmet" them.

N.P.

Sazhin successfully decide, as evidenced by the receipt of crystals of decent quality.

But the growth of crystals in significant volumes may require, in turn, scaling up the technology of purification of raw materials.

— Can we say that the creation of such a tomograph will give an additional impetus to the development of related science-intensive areas?

This effect is usually spoken of in relation to defense technologies - many of them eventually migrated to the civilian sphere.

— A PET tomograph is a product that requires a number of technologies in the field of photonics, electronics, micromechanics, etc. to be raised to the required level. From my point of view, the equipment of the class of medical tomographs combines a whole range of top-level solutions in the field of high technologies.

Undoubtedly, the task of creating a domestic PET scanner can become a driver for their development in Russia.

  • Rear of the Ural Federal University named after the first President of Russia B.N.

    Yeltsin in Yekaterinburg

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— The PET procedure is considered one of the most expensive diagnostic studies.

If Russia succeeds in setting up the production of its own positron emission tomographs, will this help make such diagnostics more accessible?

- The cost of a tomograph to a certain extent affects the price of diagnostics.

But we must not forget about the cost of the radiopharmaceutical, which is used during the procedure.

To produce it, you need a cyclotron - a charged particle accelerator.

A radiochemical complex is also needed, which allows isotopes to be combined with a carrier that determines their path in the body.

This is a rather complicated and costly production, associated with both the radiation factor and the proper culture of the production of medicines.

Therefore, it is not worth hoping that the cost of procedures will noticeably decrease.

After all, PET diagnostics is also an expensive procedure abroad.

- In what other areas are scintillation crystals used, besides medicine?

Do each area need its own types of crystals or are they interchangeable?

“Scintillation crystals are needed wherever it is necessary to determine not only the intensity of ionizing radiation, but also the composition of radiation fields — that is, to engage in spectrometry.

These are the industries that are somehow connected with radiation technologies.

Unfortunately, over the past three decades, market conditions have led to the fact that products of domestic manufacturers have been replaced by products of foreign manufacturers.

And here we will have to restore the status quo of domestically produced equipment.