Dynamic Tracking of Lung Deformation during Breathing by Using Particle Method

To reduce the side effects and to improve the efficiency of radiation therapy in lung cancer, a pinpoint radiation therapy system is under development. In the system, the movement of lung tumor during breathing could be estimated by employing a suitable numerical modeling technique. This paper presents a gridless numerical technique called Moving Particle Semi-implicit (MPS) method to simulate the lung deformation during breathing. The potential of the proposed method to employ in the future pinpoint radiation therapy system has been explored. Deformation of lung during breathing was dynamically tracked and compared against the experimental results at two different locations (upper lobe and lower lobe). Numerical simulations showed that the deformation of lung surface ranged from less than 4 mm to over 20 mm depending on the location at the surface of lung. The simulation showed that the lower section of lung exhibited comparatively large displacement than the upper section. Comparing with the experimental data, the lung surface displacement during inspiration process was predicted reasonably well. Comparison of numerical prediction with experimental observations showed that the root mean squared error was about 2 mm at lower lobe and less than 1 mm at upper lobe at lung surface

In vitro characterization of cells derived from chordoma cell line U-CH1 following treatment with X-rays, heavy ions and chemotherapeutic drugs

<p>Abstract</p> <p>Background</p> <p>Chordoma, a rare cancer, is usually treated with surgery and/or radiation. However, very limited characterizations of chordoma cells are available due to a minimal availability (only two lines validated by now) and the extremely long doubling time. In order to overcome this situation, we successfully derived a cell line with a shorter doubling time from the first validated chordoma line U-CH1 and obtained invaluable cell biological data.</p> <p>Method</p> <p>After isolating a subpopulation of U-CH1 cells with a short doubling time (U-CH1-N), cell growth, cell cycle distribution, DNA content, chromosome number, p53 status, and cell survival were examined after exposure to X-rays, heavy ions, camptothecin, mitomycin C, cisplatin and bleocin. These data were compared with those of HeLa (cervical cancer) and U87-MG (glioblastoma) cells.</p> <p>Results</p> <p>The cell doubling times for HeLa, U87-MG and U-CH1-N were approximately 18 h, 24 h and 3 days respectively. Heavy ion irradiation resulted in more efficient cell killing than x-rays in all three cell lines. Relative biological effectiveness (RBE) at 10% survival for U-CH1-N was about 2.45 for 70 keV/μm carbon and 3.86 for 200 keV/μm iron ions. Of the four chemicals, bleocin showed the most marked cytotoxic effect on U-CH1-N.</p> <p>Conclusion</p> <p>Our data provide the first comprehensive cellular characterization using cells of chordoma origin and furnish the biological basis for successful clinical results of chordoma treatment by heavy ions.</p

Highway PC Bridge Inspection by 3.95 MeV X-Ray/Neutron Source

We have developed portable 950 keV/3.95 MeV X-ray/neutron sources and applied them to inspection of PC concrete thicker than 200 mm within reasonable measuring time of seconds - minutes. T-girder-, Box- and slab- bridges are considered. Now we are to start X-ray transmission inspection for highway PC bridge (box) by using 3.95 MeV X-ray sources in Japan in 2020. By obtaining X-ray transmission images of no-grout-filling in PC sheath and thinning of PC wires, we plan to carry out numerical structural analysis to evaluate the degradation of strength. Finally, we are going to propose a technical guideline of nondestructive evaluation (NDE) of PC bridges by taking account of both X-ray inspection and structural analysis. Further, we are trying to detect rainwater detection in PC sheath, and asphalt and floor slab by the 3.95 MeV neutron source. This is expected to be an early degradation inspection. We have done preliminary experiments on X-ray transmission imaging of PC wires and on-grout-filling in the same height PCs in 450–750 mm thick concretes. Moreover, neutron back scattering detection of water in PC sheath is also explained

Dynamic tracking of lung deformation during breathing by using particle method,” Modelling and Simulation

Recommended by Ewa Pietka To reduce the side effects and to improve the efficiency of radiation therapy in lung cancer, a pinpoint radiation therapy system is under development. In the system, the movement of lung tumor during breathing could be estimated by employing a suitable numerical modeling technique. This paper presents a gridless numerical technique called Moving Particle Semi-implicit (MPS) method to simulate the lung deformation during breathing. The potential of the proposed method to employ in the future pinpoint radiation therapy system has been explored. Deformation of lung during breathing was dynamically tracked and compared against the experimental results at two different locations (upper lobe and lower lobe). Numerical simulations showed that the deformation of lung surface ranged from less than 4 mm to over 20 mm depending on the location at the surface of lung. The simulation showed that the lower section of lung exhibited comparatively large displacement than the upper section. Comparing with the experimental data, the lung surface displacement during inspiration process was predicted reasonably well. Comparison of numerical prediction with experimental observations showed that the root mean squared error was about 2 mm at lower lobe and less than 1 mm at upper lobe at lung surface