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Interactions of Uncharged Particles with Matter
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
David R. Dance, J.-C. Rosenwald, Gudrun Alm Carlsson
The penetration power of a photon beam in a given medium is commonly expressed by means of the mean free path. This is defined as the average distance, , travelled by the photon before it interacts. For monoenergetic photons, it is given by:
X-Ray Interactions and Energy Deposition
Published in Jerry J. Battista, Introduction to Megavoltage X-Ray Dose Computation Algorithms, 2019
Jerry J. Battista, George Hajdok
Recall that μ is energy-dependent so that mean free paths change as photon energy progressively degrades through successive scattering events. The dimensionless product μ L = L/mfp is the radiological thickness of an absorber expressed in units of mean free paths. For example, if μ = 0.05 cm−1, the mean free path is 20 cm. For a physical thickness of 10 cm, μL equals of a mean free path (mfp). Figure 2.10 displays the mean free path lengths re-scaled by the natural density of elements
Light Propagation and Interaction in Highly Scattering Media for Deep Tissue Imaging
Published in Lingyan Shi, Robert R. Alfano, Deep Imaging in Tissue and Biomedical Materials, 2017
W. B. Wang, Shi Lingyan, Lu Luyao, Laura A. Sordillo, L. Wang, S.K. Gayen, R.R. Alfanoa
The ltr values for adipose (fat) tissue listed in Table 5.3 are different from values in Table 5.2 [53, 54]. The main reason of the discrepancy is that samples used by Peters et al. were compressed homogenized tissues, which no longer possessed any natural structure [52]. The values in Table 5.2 were obtained from in vitro samples. It can be seen from Table 5.3 that the transport mean free path of the normal glandular tissue strongly depends on wavelength and decreases with the increase of the wavelength.
Investigation of radiation protective features of azadispiro derivatives and their genotoxic potential with Ames/Salmonella test system
Published in International Journal of Radiation Biology, 2023
Burak Alaylar, Bünyamin Aygün, Kadir Turhan, Mehmet Karadayı, Esra Cinan, Zuhal Turgut, Gökçe Karadayı, Mohammed Ibrahim Abu Al-Sayyed, Medine Güllüce, Abdulhalik Karabulut
Currently, there are numerous radiation studies interested in an investigation of radiation protective properties of novel materials (glass, concrete, steel, etc.). Therefore, radiation research has been the center of attraction by scientists in various disciplines, such as agriculture, archeology, defense of military, nuclear energy and medicine, etc. because of its beneficial effects. In this regard, the present study aimed to study synthesized azadispiro derivatives have been analyzed of radiation absorption capacity and determined their potential to be exploited as substances for a drug be developed against radiation has been investigated. Neutron attenuation parameters, such as effective removal cross-section ΣR (cm−1), MFP, HVL, and transmission number were theoretically determined by using the Monte Carlo simulation Geant4 code. The fact that a material has a high ΣR (cm−1) value indicates that the material has a high rate of neutron-stopping ability (Singh et al. 2014). The low HVL and mean free path (λ) values show the neutron-stopping capacity of any material. These values show that new azadispiro derivatives have good neutron stopping power (Aygün et al. 2020a; Alaylar et al. 2021). Again, when the results are examined carefully, it can be clearly understood that the absorption parameters of azadispiro derivatives are not very low compared to the reference samples.
Numerical modeling of nanoparticle deposition in realistic monkey airway and human airway models: a comparative study
Published in Inhalation Toxicology, 2020
Nguyen Dang Khoa, Nguyen Lu Phuong, Kazuhide Ito
Particle trajectories were calculated using the discrete phase model in the Ansys-Fluent software, in order to solve the Lagrangian equation. This method has been utilized by previous studies to predict the deposition of nanoparticles ranging from 1 to 100 nm in size, in realistic human airway models (Wang et al. 2009; Dong et al. 2018). Several acting forces were employed to predict the nanoparticle transport and deposition characteristics of the airway models. The Eulerian continuous phase (airflow field) was solved first, subsequently, the Lagrangian discrete phase for particle trajectories was computed, as shown in Equation (2): p refers to the particle phase; is the Equation (3): µ is the air viscosity, da is the physical particle diameter (and is consistent with an aerodynamic diameter in this analysis), ρp is the particle density, and the Cc is the Cunningham correction factor to Stokes’ drag law, which is calculated from Equation (4) as follows: λ is the mean free path of air molecules.
Malignant cell characterization via mathematical analysis of bio impedance and optical properties
Published in Electromagnetic Biology and Medicine, 2021
Wang et.al confirmed that prostate tumors had relatively higher refractive index than its healthier regions that is accounted through alteration in tissue organization (Wang et al. 2011). The experiments identified that shorter scattering mean free path is correlated to darker staining with H&E and its association with tumor. The results confirmed that malignant cells have higher anisotropy factor, g which is a measure of the degree of anisotropy. This 2D measurement of refractive index of the cell complimented the application of refractive index as an intrinsic tool for malignant cell diagnosis.