scholarly journals High-sensitive colour indicator of absorbed dose of epithermal neutrons radiation

2022 ◽  
Vol 2155 (1) ◽  
pp. 012032
Author(s):  
G A Kulabdullaev ◽  
A A Kim ◽  
G T Djuraeva ◽  
A F Nebesniy ◽  
G A Abdullaeva ◽  
...  
Keyword(s):  
Absorbed Dose ◽  
High Sensitivity ◽  
Neutron Radiation ◽  
Arsenazo Iii ◽  
Indicator Solution ◽  
Tissue Equivalent ◽  
Epithermal Neutrons ◽  
Delayed Measurement ◽  
Artificial Illumination ◽  
Error Of Measurement

Abstract In our study, the high-sensitivity colour indicator of the absorbed dose of radiation of epithermal neutrons with energy 0 to 10 keV for dosimetry of low-energy neutrons was developed. We had been developed an indicator on the basis of the dye solution of arsenazo III and gadopentetic acid, allowing precisely define of absorbed dose in the range 2 to 103 Gy. The properties of arsenazo III as metallic indicator, which changes colour after binding of free ions of metals, were used. Colour of the indicator solution before irradiation and after it is stable enough in time at storage in the dark, at artificial illumination or at scattered sunlight. The developed indicator, consisting of a solution of arsenazo III and gadopentetic acid, allows estimating the absorbed dose of epithermal neutron irradiation with good accuracy and reduces the error of measurement related to changing colour of dye under the influence of other factors (light, temperature etc.) Dosimeter is tissue-equivalent and possesses a high-sensitivity neutron radiation due to the content of gadolinium in solution, which has great neutron capture cross-section. The developed dosimeter persists spectrophotometric characteristics after irradiaion within few weeks that allows to use it for measurement of the absorbed dose, both in real time mode and with the delayed measurement within few weeks.

On Some Methodological Issues of Studying Cytogenetic Effects in Cancer Patients Treated with Neutron Therapy Using U-120 Cyclotron

2018 ◽  
Vol 63 (2) ◽  
pp. 47-54
Author(s):  
В. Лисин ◽  
V. Lisin
Keyword(s):  
Radiation Field ◽  
Chromosome Aberrations ◽  
Absorbed Dose ◽  
Neutron Radiation ◽  
The Body ◽  
Beam Intensity ◽  
Whole Body ◽  
Γ Radiation ◽  
Cytogenetic Effect ◽  
Tissue Equivalent

Purpose: To study dosimetric characteristics of neutron radiation field, to determine their role in the formation of the total cytogenetic effect in the patient’s body and to assess the cytogenetic dosimetry capabilities in improving the quality of NT. Material and methods: A therapeutic beam with the average neutron energy of ~6.3 MeV was obtained from the V-120 cyclotron. The radiation field of the beam was investigated with the help of two ionization chambers with different sensitivity to neutrons. Chamber with high and low sensitivities were made of polyethylene and graphite, respectively. To exclude the uncertainty associated with the change in beam intensity in time, a dosimeter monitor operating in the integral mode was used. Results: The dependence of the monitor factor on the irradiated area was measured. The distributions of the absorbed dose of neutrons and γ-radiation over the depth of the tissue-equivalent medium were found. The contribution of γ-radiation to the neutron dose was increased from ~10 % at the entry to the medium to ~30 % at a depth of 16 cm. Dose distributions of scattered neutron and γ-radiation in the plane of the end face of the forming device were obtained. The contribution of these radiations to the dose received by the patient’s body was estimated. This contribution was shown to be comparable with that from the therapeutic beam. The analysis of the influence of NT on the estimation of the frequency of chromosome aberrations in the blood of patients was carried out. Conclusion: The frequency of chromosome aberrations in the blood of patients was determined by the whole-body dose, including dose due to scattered radiation. When using equal focal doses, the cytogenetic effect was found to be dependent on the area of the irradiated field and the depth of the tumor in the patient’s body. The differences in the RBE of neutrons and γ-radiation as well as the instability of the therapeutic neutron beam intensity create uncertainties that do not allow for the necessary control over the doses using the cytogenetic dosimetry. Therefore, cytogenetic dosimetry should be combined with an effective instrument dosimetry method. The use of biodosimetry based on the assessment of the frequency of chromosome aberrations is promising for controlling the average whole-body dose, on which the overall radiation response of the body depends.

THE DETERMINATION OF NEUTRON FLUENCE TO ABSORBED DOSE CONVERSION COEFFICIENTS AND RELATIVE BIOLOGICAL EFFECT BASED ON MICRODOSIMETRY MEASUREMENTS

2019 ◽  
Vol 187 (2) ◽  
pp. 262-267
Author(s):  
Weihua Zhang ◽  
Chunjuan Li ◽  
Yisheng Zou ◽  
Yina Liu ◽  
Hailong Luo
Keyword(s):  
Biological Effect ◽  
Absorbed Dose ◽  
Neutron Radiation ◽  
Electron Multiplier ◽  
Lineal Energy ◽  
Radiation Fields ◽  
Empirical Procedure ◽  
Tissue Equivalent ◽  
Conversion Coefficients ◽  
Tissue Equivalent Proportional Counter

Abstract A tissue-equivalent proportional counter (TEPC) is a reference detector to measure microdosimetric quantities. A conventional spherical TEPC and a novel TEPC based on a ceramic thick gas electron multiplier (THGEM) foil were developed to carry out microdosimetric measurements of lineal energy spectra in monoenergetic and 252Cf/241Am-Be neutron radiation fields, and the absorbed dose values had been derived. In order to go further in radiobiology and therapy, the fluence to absorbed dose conversion coefficients in neutron fields were also determined. According to the dose distribution in lineal energy, the neutron relative biological effect (RBE) values were also calculated using an empirical procedure applying biological weighting functions.

scholarly journals A comparison of in-air and in-water calibration of a dosimetry system used for radiation dose assessment in cancer therapy

2010 ◽  
Vol 25 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Waheed Arshed ◽  
Khalid Mahmood ◽  
Ikramullah Qazi ◽  
Asad Ullah ◽  
Perveen Akhter ◽  
...  
Keyword(s):  
Radiation Dosimetry ◽  
Absorbed Dose ◽  
Dose Assessment ◽  
Dose Delivery ◽  
Air Kerma ◽  
Tissue Equivalent ◽  
Dosimetry System ◽  
Irradiation Geometry ◽  
Radiation Dose Assessment ◽  
Absorbed Dose To Water

An accurate calibration of the therapy level radiation dosimetry system has a pivotal role in the accuracy of dose delivery to cancer patients. The two methods used for obtaining a tissue equivalent calibration of the system: air kerma calibration and its conversion to a tissue equivalent value (absorbed dose to water) and direct calibration of the system in a water phantom, have been compared for identical irradiation geometry. It was found that the deviation between the two methods remained within a range of 0% to ?1.7% for the PTW UNIDOS dosimetry system. This means that although the recommended method is in-water calibration, under exceptional circumstances, in-air calibration may be used as well.

Low-Flux Neutron Radiation Detection Technology with High Sensitivity

2014 ◽  
Vol 668-669 ◽  
pp. 924-927
Author(s):  
Yang Liu ◽  
Zhen Ni Xing ◽  
Guo Zheng Zhu
Keyword(s):  
Energy Deposition ◽  
Plastic Scintillator ◽  
Detection Efficiency ◽  
Radiation Detection ◽  
High Sensitivity ◽  
Neutron Radiation ◽  
Fission Neutron ◽  
Deposition Flux ◽  
Low Intensity ◽  
Detection Technology

Boron-containing plastic scintillator detectors have a high detection efficiency for low-intensity thermal neutrons and fast neutrons which is currently the preferred types of neutron detector. This article is based on Monte Carlo method, studied boron-containing plastic scintillator for neutron detection performance, and analysis the energy deposition flux characteristics and detection efficiency when low intensity fission neutron incident to the boron plastic scintillator. We obtain the low-flux neutron detector performance in a variety of neutron source energy, boron-containing plastic scintillator diameter and length. Results showed that, when the boron-containing plastic scintillator lengths increase, the energy deposition flux will increase. When the length and diameter is constant, increasing source strength can increase the energy deposition flux brought by the recoil proton to a certain extent. When the source intensity over after thermal neutrons, due to the decrease of the cross section, the energy deposition fluxes brought by the react of neutrons and will decrease. The results provide help for low intensity fission neutron radiation detection technology with high sensitivity.

Absorbed-dose depth distribution in tissue-equivalent absorber for quasiisotropic incidence of 1 MeV electrons

1974 ◽  
Vol 36 (4) ◽  
pp. 377-378 ◽  
Author(s):  
R. Ya. Strakovskaya ◽  
G. N. P'yankov ◽  
I. R. Entinzon
Keyword(s):  
Depth Distribution ◽  
Absorbed Dose ◽  
Tissue Equivalent
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