Implementation of linearly-polarized photon scattering into the EGS4 code

Namito, Yoshihito; Ban, Syuichi; Hirayama, Hideo

doi:10.1016/0168-9002(93)90770-i

Cited by 81 publications

(42 citation statements)

References 17 publications

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“…The upgraded version of the code EGS4 (Electron Gamma Shower) for photon and electron transport (26) was used to calculate the dose distribution from interlaced MBs. This version included such details as the beam's linear polarization (27,28). The work followed similar calculations made earlier (18,19,21).…”

Section: Methodsmentioning

confidence: 99%

Interlaced x-ray microplanar beams: A radiosurgery approach with clinical potential

Dilmanian

Zhong²,

Bacarian³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

176

214

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Studies have shown that x-rays delivered as arrays of parallel microplanar beams (microbeams), 25-to 90-m thick and spaced 100 -300 m on-center, respectively, spare normal tissues including the central nervous system (CNS) and preferentially damage tumors. However, such thin microbeams can only be produced by synchrotron sources and have other practical limitations to clinical implementation. To approach this problem, we first studied CNS tolerance to much thicker beams. Three of four rats whose spinal cords were exposed transaxially to four 400-Gy, 0.68-mm microbeams, spaced 4 mm, and all four rats irradiated to their brains with large, 170-Gy arrays of such beams spaced 1.36 mm, all observed for 7 months, showed no paralysis or behavioral changes. We then used an interlacing geometry in which two such arrays at a 90°angle produced the equivalent of a contiguous beam in the target volume only. By using this approach, we produced 90-, 120-, and 150-Gy 3.4 ؋ 3.4 ؋ 3.4 mm 3 exposures in the rat brain. MRIs performed 6 months later revealed focal damage within the target volume at the 120-and 150-Gy doses but no apparent damage elsewhere at 120 Gy. Monte Carlo calculations indicated a 30-m dose falloff (80 -20%) at the edge of the target, which is much less than the 2-to 5-mm value for conventional radiotherapy and radiosurgery. These findings strongly suggest potential application of interlaced microbeams to treat tumors or to ablate nontumorous abnormalities with minimal damage to surrounding normal tissue.

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Section: Methodsmentioning

confidence: 99%

Interlaced x-ray microplanar beams: A radiosurgery approach with clinical potential

Dilmanian

Zhong²,

Bacarian³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

176

214

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“…Namito et al [116] introduced polarized Compton and Rayleigh scattering in EGS4 and made comparisons with low-energy experiments where gamma ray build-up factors and attenuation coefficients in water, iron and lead were studied in the energy range 40-250 keV [74]. The effects of binding, Doppler broadening and polarization are pronounced in the lower energy range studied 7 .…”

Section: Doppler Broadening and Linearly-polarized Photon Scatteringmentioning

confidence: 99%

The EGS5 Code System

Hirayama¹,

Namito²,

Ibaraki-ken³

et al. 2005

453

281

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“…• obtained from an EGS4 Monte Carlo simulation [25] with a low energy extension [26]. From the analysis of the simulation, the contribution to this angular resolution of the detector positional resolution is estimated to be 6.2…”

Section: B Reconstruction Of Compton Scattering Anglementioning

confidence: 99%

A prototype Si/CdTe Compton camera and the polarization measurement

Mitani

Tanaka

Nakazawa

et al. 2004

IEEE Trans. Nucl. Sci.

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Abstract-A Compton camera is the most promising approach for gamma-ray detection in the energy region from several hundred keV to MeV, especially for application in high energy astrophysics. In order to obtain good angular resolution, semiconductor detectors such as silicon, germanium and cadmium telluride(CdTe) have several advantages over scintillation detectors, which have been used so far. Based on the recent advances of high resolution CdTe and silicon imaging detectors, we are working on a Si/CdTe Compton camera. We have developed 64-pixel CdTe detectors with a pixel size of 2 mm×2 mm and double-sided Si strip detectors(DSSDs) with a position resolution of 800µm. As a prototype Si/CdTe Compton camera, we use a DSSD as a scatterer and two CdTe pixel detectors as an absorber. In order to verify its performance, we irradiate the camera with 100% linearly polarised 170 keV γ-rays and demonstrate the system works properly as a Compton camera. The resolution of the reconstructed scattering angle is 22• (FWHM). Measurement of polarization is also reported. The polarimetric modulation factor is obtained to be 43%, which is consistent with the prediction of Monte Carlo simulations.

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Implementation of linearly-polarized photon scattering into the EGS4 code

Cited by 81 publications

References 17 publications

Interlaced x-ray microplanar beams: A radiosurgery approach with clinical potential

Interlaced x-ray microplanar beams: A radiosurgery approach with clinical potential

The EGS5 Code System

A prototype Si/CdTe Compton camera and the polarization measurement

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