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Objective To construct a voxel mouse model combining with Monte Carlo method used for radiation dose calculation.Methods A set of slice images obtained from a nude male mouse (28 g) was utilized, all slice images were registered,some organs or tissues were identified, segmented and filled with specific color, and finally the physical property was defined by MCNP application.Results A mouse model with a voxel size of 0.2 mm×0.2 mm×0.2 mm, consisting of 14 organs or tissues,was constructed, which could satisfy the requirement of precision for radiation dose distribution calculation and moderate computing time.Conclusion The voxel mouse model can be used to calculate the quantity of ionization radiation dosimetry in related areas including radiological medicine, nuclear medicine and space radiation medicine.
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<p><b>OBJECTIVE</b>To investigate the expression of aquaporin 4 (AQP4) after microwave exposure and the correlation with the brain injury by radiation.</p><p><b>METHODS</b>70 male rats were exposed to microwave whose average power density was 0, 10, 30 and 100 mW/cm(2) respectively. Rats were sacrificed at 6 h, 1 d, 3 d and 7 d after exposure. Immunohistochemistry and Western blot were used to detect the expression of AQP4 in protein level in rat hippocampus, and the expression of AQP4 in gene level was measured by in situ hybridization and RT-PCR.</p><p><b>RESULTS</b>The expression of AQP4 in rat hippocampus was abnormal after 10, 30, 100 mW/cm(2) microwave exposure. The protein level showed increased at first and then recovered at 10 and 30 mW/cm(2) groups, while increased progressively in 100 mW/cm(2) group within 14 d (P < 0.01). The gene expression of AQP4 was increased (0.51 +/- 0.02) at the beginning (6 h) and then regained after 10 mW/cm(2) microwave exposure, while in 30 and 100 mW/cm(2) groups, it rose to the peak at 7 d (0.46 +/- 0.02 and 0.43 +/- 0.08) and didn't get back (P = 0.004; P = 0.012).</p><p><b>CONCLUSION</b>Microwave radiation can increase the expression of AQP4 in rat hippocampus. The change might participate in the process of increasing permeability of blood-brain barrier and lead to the brain edema after microwave radiation.</p>
Subject(s)
Animals , Male , Rats , Aquaporin 4 , Genetics , Metabolism , Hippocampus , Metabolism , Radiation Effects , Microwaves , Rats, WistarABSTRACT
Probability of causation (PC) was used to facilitate the adjudication of compensation claims for cancers diagnosed following exposure to ionizing radiation. In this article, the excess cancer risk assessment models used for PC calculation are reviewed. Cancer risk transfer models between different populations, dependence of cancer risk on dose and dose rate, modification by epidemiological risk factors and application of PC are also discussed in brief.
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<p><b>OBJECTIVE</b>To investigate the effect of high power microwave (HPM) radiation on the expression of beta(1)-adrenergic receptor (beta(1)-AR) and M(2)-muscarinic acetylcholine receptor (M(2)-AchR) in cardiomyocytes.</p><p><b>METHODS</b>S-band HPM device of mean power density 2 approximately 90 mW/cm(2) was used to irradiate 150 healthy Wistar male rats. Immunohistochemistry and image analysis were used to study the pathological characteristics of heart tissue and the expression of beta(1)-AR and M(2)-AchR.</p><p><b>RESULTS</b>Radiation of over 10 mW/cm(2) made myocardial fibers disordered in arrangement, degeneration even sarcoplasm condensation, Pace cells necrosis, and Purkinje cells lysis in a dose-dependent manner (r = 0.968, P < 0.05). beta(1)-AR expression in endocardium, membrane and cytoplasm of myocardium of left ventricle was increased on d1 after radiation, peaked on d3 (P < 0.05) and recovered on d14. M(2)-AchR expression was peaked on d1 (P < 0.01) and recovered on d14.</p><p><b>CONCLUSION</b>Certain degree intensity of HPM radiation may cause heart injury, and increased expressions of beta(1)-AR and M(2)-AchR, which may play an important role in the pathophysiology of heart injury induced by HPM.</p>
Subject(s)
Animals , Male , Rats , Dose-Response Relationship, Radiation , Heart , Radiation Effects , Microwaves , Myocytes, Cardiac , Metabolism , Radiation Effects , Rats, Wistar , Receptor, Muscarinic M2 , Receptors, Adrenergic, beta-1ABSTRACT
<p><b>OBJECTIVE</b>To study the changes of morphology and function in rat hippocampus induced by high power microwave (HPM) radiation.</p><p><b>METHODS</b>Fifty male Wistar rats were radiated by HPM. Then their learning and memory abilities were tested with Y maze and were sacrificed 6 h, 1 d, 3 d and 7 d after radiation. The hippocampus was taken out to study the basic pathologic changes, apoptosis and the expressions of neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) by means of HE staining, Nissel body staining, in situ terminal end labeling and immunohistochemistry.</p><p><b>RESULTS</b>The learning and memory abilities of rats reduced significantly after HPM radiation. HPM also resulted in rarefaction, edema and hemangiectasia of hippocampus, nervous cells degeneration and necrosis, decrease or disappearance of Nissel bodies. The injuries were more serious in field CA4 and dentate gyrus, which showed dose-effect relationship, and were progressively aggravated within 7 days. The apoptosis cells were significantly increased. NSE was increased in neurons. The NSE positive areas were also seen in the interstitial matrix and blood vessels. GFAP was increased in astrocytes, which became shorter and thicker.</p><p><b>CONCLUSION</b>HPM can damage the abilities of learning and memory and results in morphologic changes in hippocampus. The major pathologic changes are degeneration, apoptosis and necrosis of neurons and edema in interstitium. NSE and GFAP play an important role in the pathologic process.</p>