Neutron Radiation: Radiation Protection.

Dmitri Popov. PhD, Radiobiology.

MD (Russia)

Advanced Medical Technology and Systems Inc. Canada.

Slava Maliev, PhD, Radiobiology,

Academy of Science, Russia.

Neutron radiation: Radiation Protection.

• Neutron radiation is a kind of ionizing radiation which consists of free neutrons. A result of nuclear fission or nuclear fusion, it consists of the release of free neutrons from atoms, and these free neutrons react with nuclei of other atoms to form new isotopes, which, in turn, may produce secondary, induced radiation.

• https://en.wikipedia.org/wiki/Neutron_radiation

• http://www.slideshare.net/dlpopov/induced-radioactivity

• http://www.intechopen.com/books/current-topics-in-ionizing-radiation-research/radiation-toxins-molecular-mechanisms-of-toxicity-and-radiomimetic-properties-

Neutron radiation: Radiation Protection.

• Cosmogenic neutrons, neutrons produced from cosmic radiation in the Earth's atmosphere or surface, and those produced in particle accelerators can be significantly higher energy than those encountered in reactors.

• Most of them activate a nucleus before reaching the ground; a few react with nuclei in the air.

• The reactions with nitrogen-14 lead to the formation of carbon-14, widely used in radiocarbon dating.

• https://en.wikipedia.org/wiki/Neutron_radiation

Neutron radiation: Radiation Protection.

• In health physics neutron radiation is a type of radiation hazard. Another, sometimes more severe hazard of neutron radiation, is neutron activation, the ability of neutron radiation to induce radioactivity in most substances it encounters, including the body tissues. This occurs through the capture of neutrons by atomic nuclei, which are transformed to another nuclide, frequently a radionuclide. This process accounts for much of the radioactive material released by the detonation of a nuclear weapon. It is also a problem in nuclear fission and nuclear fusion installations as it gradually renders the equipment radioactive such that eventually it must be replaced and disposed of as low-level radioactive waste. https://en.wikipedia.org/wiki/Neutron_radiation

• http://www.slideshare.net/dlpopov/induced-radioactivity

• http://www.intechopen.com/books/current-topics-in-ionizing-radiation-research/radiation-toxins-molecular-mechanisms-of-toxicity-and-radiomimetic-properties-

Neutron radiation: Radiation Protection.

• Due to the high kinetic energy of neutrons, this radiation is considered to be the most severe and dangerous radiation to the whole body when it is exposed to external radiation sources. In comparison to conventional ionizing radiation based on photons or charged particles, neutrons are repeatedly bounced and slowed (absorbed) by light nuclei so hydrogen-rich material is more effective at shielding than iron nuclei. The light atoms serve to slow down the neutrons by elastic scattering so they can then be absorbed by nuclear reactions. However, gamma radiation is often produced in such reactions, so additional shielding has to be provided to absorb it. Care must be taken to avoid using nuclei which undergo fission or neutron capture that results in radioactive decay of nuclei that produce gamma rays.

• https://en.wikipedia.org/wiki/Neutron_radiation• http://www.slideshare.net/dlpopov/induced-radioactivity

Neutron radiation: Radiation Protection.

• Neutrons irradiation produce a unique biological effectiveness compare to different types of radiation because their ability to create a denser trail of ionized atoms in biological living tissues

• Straume 1982;

• Latif et al.2010;

• Katz 1978;

• Bogatyrev 1982.

• http://www.intechopen.com/books/current-topics-in-ionizing-radiation-research/radiation-toxins-molecular-mechanisms-of-toxicity-and-radiomimetic-properties-

Neutron radiation: Radiation Protection.

The efficacy of an Anti-Radiation Vaccine for the prophylaxis, prevention and therapy of acute radiation pathology was studied in a neutron exposure facility.

The biological effects of fast neutrons include damage of Central Nervous system and Cardiovascular system with development of Acute Cerebrovascular and Cardiovascular forms with acute radiation pathology.

http://www.intechopen.com/books/current-topics-in-ionizing-radiation-research/radiation-toxins-molecular-mechanisms-of-toxicity-and-radiomimetic-properties-

Neutron radiation: Radiation Protection.

• After irradiation by high doses of fast neutron in irradiated tissues started formation of toxins: neurotoxins, hematotoxins, cytotoxins, which are forming from cell's or tissue structures.

• High doses of Neutron Irradiation generate general and specific toxicity, inflammation reactions.

Neutron radiation: Radiation Protection.

• Current Acute Medical Management and Methods of Radiation Protection are not effective against moderate and high doses of neutron irradiation.

• Our experiments demonstrate that immunological reactions playinextraordinary role in development pathological processes and Antiradiation Vaccine is the most effective radioprotectant against high doses of neutron-radiation.

Neutron radiation: Radiation Protection.

• Radiation Toxins(biological substances – enzymes and secretory prooteins with radio-mimetic properties) isolated from central lymph of gamma-irradiated animals are working substances with specific antigenic properties for vaccination against neutron irradiation.

Neutron radiation: Radiation Protection.

• Antiradiation Vaccine preparation standard - mixture of a toxoid form of Radiation Toxins - include

• Cerebrovascular RT Neurotoxin,

• Cardiovascular RT Neurotoxin,

• Gastrointestinal RT Neurotoxin,

• Hematopoietic RT Hematotoxin.

Neutron radiation: Radiation Protection.

• Radiation Toxins were isolated from the central lymph of gamma-irradiated animals with different forms of Acute Radiation Syndromes – Cerebrovascular ARS,

• Cardiovascular ARS,

• Gastrointestinal ARS,

• Hematopoietic forms ARS.

Neutron radiation: Radiation Protection.

• Devices for Y-radiation were "Panorama", "Puma".

• Neutron exposure was accomplished at the Department of Research Institute of Nuclear Physics, Dubna, Russia.

• The neutrons irradiation generated in a canal of Research Reactor BBP-M and BBP-M.

• Mixed neutron beam contained 95% of fast neutron irradiation and 5% of gamma-irradiation. Neutron energy - 1.98 - 2.30 Me V energy. Dose - 10.7 Gy., 0.22 Gy-min.

Neutron radiation: Radiation Protection.

• Scheme of experiments:

• Rabbits from all groups were irradiated in a canal of Research Reactor together.

• Group A: control-5 rabbits;

• Group B:placebo-5 rabbits;

• Group C: Radio-protectant Cystamine (50 mg-kg)-5 rabbits, 15 minutes before irradiation

• Group D: Radio-protectant Mexamine (10 mg-kg)-5 rabbits { 15 minutes before irradiation;

• Group E: Antiradiation Vaccine: subcutaneus administration or I/M - 2 ml of active substance , 20 days before irradiation.

Neutron radiation: Radiation Protection.

• Results:

• Control Group A - 100% mortality within the next two hours after neutron irradiation with clinical symptoms of acute cerebrovascular syndrome.

• Group B - 100% mortality less than two hours following irradiation. Group C - 100% mortality within 8-10 hours after irradiation.

• Group D - 100% mortality within 8-11 hours after irradiation. In Groups A - D the development of extremely severe form of Acute Radiation Cerebrovascular Syndrome with outcome - rapid death.

• Group E - 100% mortality within 240 hours ( 9 -10 days) following neutron irradiation and animals exhibiting cardiovascular, cerebrovascular and gastrointestinal clinical symptoms.

Neutron radiation: Radiation Protection.

• Discussion:

• A pre-irradiation vaccination with Antiradiation Vaccine is effective against mild and even high doses of neutron radiation. Vaccination with antiradiation Vaccine prolonged survival time of rabbits, exposed to a high dose LD100, of neutron radiation: from two hours (control) up to 11 days. We also postulate that radiation toxins, isolated from lymph of gamma-irradiated animals are likely similar to structure of radiation toxins circulated in blood and lymph of neutron irradiated animals.

Neutron radiation: Radiation Protection.

• Toxic-kinetics and toxic-dynamics of radiation toxins of after neutron-irradiation were under research investigation and distinguished from different types of radiation.