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Neutron Therapy at the Nuclear Reactors

#1969


A Characteristics Optimization of the Neutron Beams of the Nuclear Reactors and Clinical Basis for Their Application in Neutron Therapy

Tech Area / Field

  • MED-RAD/Radiomedicine/Medicine

Status
3 Approved without Funding

Registration date
11.08.2000

Leading Institute
FEI (IPPE), Russia, Kaluga reg., Obninsk

Supporting institutes

  • Medical Radiological Scientific Center, Russia, Kaluga reg., Obninsk

Collaborators

  • University of Bremen, Germany, Bremen\nFermi National Accelerator Laboratory, USA, IL, Batavia\nGeorgia Institute of Technology, USA, GA, Atlanta

Project summary

Annual increase of the number of cases of oncological disease observed in the last decades is being accompanied by the increase in the death rate and can be considered as a ground to view the problem of the development of new, more efficient methods of tumor treatment as one of the most important tasks of the state value.

Leading place among the methods of oncological cases treatment belongs to radiotherapy; up to 70% of patients need specialized medical treatment. Further development of principally new technologies in the radiation oncology is largely determined by the level it is provided with the necessary densely ionizing radiation sources, primarily neutrons. Accelerators, cyclotrons, nuclear reactors are used as neutron radiation sources.

Radiobiological and pre-clinical studies on the reactor neutrons for the neutron-capture therapy (NCT) are being held on 13 reactors in the USA, Japan, Great Britain, Italy, Germany and Holland at present. This kind of therapy requires neutron beams with flowrate density more than 109 n/cm2×s in the energy range of 1 eV to 30 keV. Neutron spectra build-up is realized by the facilities with materials on the basis of bismuth, aluminium and its compositions with oxygen and fluorine.

In Russia the study on the neutron beam build-up for the NCT purposes was held in the RFSSC - IPPE during the design of the reactor of 200 kWt power for the radio-farmaceutical drugs production. As a result of this study another method of neutron beam build-up for the NCT purposes was developed. Original protective materials used in the process of neutron channel shield design and also filter materials – nickel isotopes, allowed to obtain epithermal neutrons flowrate density of ~ 6×109 n/cm2×s. Besides, this filter performs another necessary condition towards neutron beams for the NCT: it reduces gamma-radiation dose of the reactor.

Oncological cases treatment with the help of fast neutron remote therapy (FNRT) method on the radionuclear reactors is being held in two countries. In Munich, Germany, on the FRM reactor of the Technical University a limited clinical fast neutron usage is realized. Since 1985, 400 patients with malignant neoplasms of head and neck, breast carcinoma, bones were subjected to the FNRT treatment course accompanied by gamma-beams on the B-3 beam of the BR-10 fast neutron reactor of RFSSC - IPPE, in Obninsk, Russia. Overall survival rate of patients with advanced (T3-T4) after the treatment comprises 89%, breast carcinoma – 67%, in the control group – 65% и 44%, respectively. A new, high technology, effective method of treatment of the common radioresistant forms of tumors was developed on the BR-10 reactor of IPPE. Possibilities of the operating medical unit here allow now to perform treatment of up to 20 patients per day. Besides, studies of neutron beam of this reactor use for the NCT were begun.

Thus, the largest in the word experience on the use of reactor neutrons in the radiotherapy is accumulated at present in Obninsk, and there are all conditions for further intensive development of studies in this direction.

The Project team of RFSSC - IPPE and MRRC RAMS has been working on the problem of neutron therapy for more that 15 years now, and has got qualification for the effective fusion of knowledge and skills of the nuclear physicists, radio-biologists and radiology doctors for the realization of system tasks defined in the Project.

Objective of the project: Development of neutron beams for various types of neutron therapy on a wide range of research nuclear reactors and reasoning of their use for the clinical purposes. Realization of studies on the FNRT (and their combination) on the B-3 beam of the BR-10 fast nuclear reactor.

Tasks: Development of neutron filters and FNRT and NCT methods on the B-3 beam of the BR-10 fast neutron reactor and transfer of the obtained experience in the sphere of neutron therapy to other research reactors.

Results: Developments of scientists of two institutes, RFSSC – IPPE and MRRC RAMS will allow to find new approaches to wide clinical use of new high effective methods of radiation therapy. Neutrons of nuclear reactors will be used for treatment of patients with malignancies which can not be effectively treated by conventional techniques of treatment. Neutron therapy techniques will be possess of commercial potential.

Technical approaches and skills: The experience of RFSSC – IPPE and MRRC RAMS will be used in the treatment of oncological patients, in neutron – physical calculations, the measurements of characteristics of filtered neutron beams and in the creating of dose fields at B-3 beam of fast reactor BR-10.

The set of the forming facilities used on the B-3 beam of the BR-10 fast neutron reactor is limited and that makes the solution of the topical problem of the minimization of a damage to the healthy tissues and maximization of the neutron impact to the tumor. In order to expand methods of neutron therapy and to optimize its planning, it is necessary to transfer the available clinical experience to the other types of research nuclear reactors.

Neutron spectra of the research nuclear reactors that can be used for the development of methods of neutron therapy are different.

That is why it is necessary on the initial stage to perform calculation study to determine sensitivity of both types of therapy to neutron energy. This will provide for the more effective use of neutron beams of a wide range of research nuclear reactors for the neutron therapy purposes.

Expected results of the Project and their application:

1. Clinical experience. Experience of treatment of 400 patients by means of neutrons of the B-3 beam of the BR-10 fast neutron reactor allowed to work out methods of determining of sensitivity of each type of therapy towards neutron spectra, to work out specific neutron filters and medical collimator, to perform experimental study of characteristics of neutron beams and doses in phantom.

2. Development and manufacture of neutron filters. On the basis of design study, filters for both types of neutron therapy (or of their combination) for the specific neutron beams of the research nuclear reactor will be designed.

3. Experimental studies. Experimental work out of the methods of neutron-physical characteristics of neutron beams build-up and distribution of doses in the phantom, corresponding to each type of therapy will be realized on the B-3 beam of the BR-10 fast neutron reactor.

4. Radiobiological studies. Radiobiological study of schemes, methods and types of neutron therapy and study of the relative biological effectiveness and of the factor of therapeutic scouring will be realized on the B-3 beam of the BR-10 fast neutron reactor.

5. Clinical studies will be held on the B-3 beam of the BR-10 fast neutron reactor. Thus the expediency of use of different types of neutron therapy in accordance with the international protocols and standards will be justified.

Realization of the tasks of the project will allow to purposively affect with the help of the most effective neutron spectrum to malignant neoplasms with various morpho-hystological and clinical forms. Various constructions of these filters will be recommended for introduction to clinical practice, which allow to more effectively use FNRT and NCT separately or in combination. Working out of neutron therapy methods will be held on the B-3 beam of the BR-10 fast neutron reactor, that will be transferred during creation of therapeutic neutron beams to the other types of research nuclear reactors.

It is planned to perform activities under the Project along several interconnected lines: physical-dosimetric and radiobiological and clinical.

Tasks 1 and 2 comprise studies of neutron beam characteristics of all types of research nuclear reactors and development of filters for all kinds of neutron therapy including the B-3 beam of the BR-10 fast neutron reactor.

Tasks 3 and 4 comprise radiobiological and clinical study of neutron therapy methods with filters developed during Tasks 1 and 2.

Task 5 comprise complex analysis of neutron therapy methods developed on the B-3 beam of the BR-10 fast neutron reactor and transfer of these methods to the other types of research nuclear reactors.

Tasks 6 and 7 comprise development of a collimator, specialized mobile table for the patients and realization of a patent search of technical solutions.

Applied technical approaches and methodology will allow to:

1. Create forming facilities for the B-3 beam of the BR-10 fast neutron reactor with the increased contribution of neutrons in the energy fields sensitive to each type of therapy (FNRT and NCT), with more effective biological action.

2. Create with the help of these facilities more effective methods to affect tumors and to protect healthy tissues in FNRT on the B-3 beam of the BR-10 fast neutron reactor.

3. Principally change the existing schemes of the FNRT that will significantly increase the effectiveness of oncology cases treatment.

4. Use these neutron beams in the FNRT courses and in combination with NCT on the B-3 beam of the BR-10 fast neutron reactor.

5. Develop neutron beam forming facilities for the FNRT and NCT for any type of research nuclear reactor.

Scientists and engineers who worked earlier in the sphere of weapon production reorient their experience and knowledge for the development of new perspective high technology methods of oncological cases treatment with the use of neutrons of nuclear reactors, which is a new area of medical physics for them.

Support of the Project shall allow to increase the efficiency of the use of the operating nuclear reactors, of the high scientific and technical potential of the personnel, to provide alternative occupation of scientists and engineers in connection with the nuclear technologies from RFSSC - IPPE and to involve vast clinical possibilities of Medical Radiology Scientific Center RAMS in the interest of health of people at large.


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