APPLICABILITY OF A HANDHELD LaBr3(Ce) SPECTROMETER FOR INTERNAL RADIOACTIVE CONTAMINATION EXAMINATION IN RADIOLOGICAL EMERGENCY.

In case of a nuclear or radiological emergency, there may be a very large population of individuals being affected by radiation exposure. Rapid and on-site examinations of possible internal radioactive contaminations are required for early dose assessment and large-scale screening. With the appropriate methodology, early dose information of internal exposure can be instantly obtained by a handheld spectrometer only.

Analytical formulas of surface emitted energy spectra of alpha flat source.

The analytical formulas of the surface emitted energy spectra of an alpha infinite flat source are derived, using the derived formulas of the distribution of residual range of alpha particles, considering the different thicknesses of the source and the absorbing layer. Utilizing these formulas, the typical residual range distributions and the energy spectra of alpha particles have been calculated and shown in figures. The variation tendency of the calculated spectrum is in good agreement with the measured spectrum.

An improved method of nasal swab analysis for assessing alpha internal radioactive contaminants.

When responding to nuclear and radiological emergencies, rapid and on-site detections of possible internal radioactive contaminants are required for early dose estimation and medical triage. Nasal swab analysis is an effective method to provide valuable information for early and fast estimates of alpha radionuclide inhalation intakes and resultant doses. In this study, to improve the quality of nasal swab measurements, a specialised double-detector alpha counter was designed.

Study of rat organ dose conversion coefficients for external photon irradiation based on voxel model and Monte Carlo simulation.

A newly voxel rat model was developed from Micro-CT images of a rat to study rat organ dose for external photon irradiation. The voxel model with voxel size of 0.16 × 0.

Determining organ dose conversion coefficients for external neutron irradiation by using a voxel mouse model.

A set of fluence-to-dose conversion coefficients has been calculated for neutrons with energies <20 MeV using a developed voxel mouse model and Monte Carlo N-particle code (MCNP), for the purpose of neutron radiation effect evaluation. The calculation used 37 monodirectional monoenergetic neutron beams in the energy range 10(-9) MeV to 20 MeV, under five different source irradiation configurations: left lateral, right lateral, dorsal-ventral, ventral-dorsal, and isotropic. Neutron fluence-to-dose conversion coefficients for selected organs of the body were presented in the paper, and the effect of irradiation geometry conditions, neutron energy and the organ location on the organ dose was discussed.

EXPERIMENTAL STUDY ON ASSESSING INTERNAL RADIOACTIVE CONTAMINANTS BY USE OF NASAL SWAB.

Nasal swab analysis is an effective method to provide valuable information for early and fast estimates of alpha radionuclide intakes and resultant doses. In this study, an inhalation environment was built by use of lead nitrate aerosol to simulate alpha radioactive aerosol inhalation. The result of exposure and swabbing experiments with guinea pigs shows that the lead smeared on nasal swabs represents ∼13 % of intake if samples are acquired within 90 min after exposure and declines over time with a half-time of 1.

Effects of frequency, irradiation geometry and polarisation on computation of SAR in human brain.

The power absorbed by the human brain has possible implications in the study of the central nervous system-related biological effects of electromagnetic fields. In order to determine the specific absorption rate (SAR) of radio frequency (RF) waves in the human brain, and to investigate the effects of geometry and polarisation on SAR value, the finite-difference time-domain method was applied for the SAR computation. An anatomically realistic model scaled to a height of 1.

Structural shielding design for a gamma ray stereotactic body radiotherapy system.

An OUR-QGD gamma ray stereotactic body radiotherapy system (body knife), made in China, is described. According to its structure and the principle of gamma radiation revolved on a focus, the energy distribution of scattered radiation in its treatment room is calculated. The structural shielding of the wall, roof, and door for a certain treatment room is calculated according to the local radiation protection law.