The Comparison Study on Dose Distribution of $^{6}$He and $^{4}$He Ion Beams

There is a clear basis in physics for the clinical use of proton and carbon beams in radiation therapy, namely, the finite range of the particle beam. The range is dependent on the beam initial energy, density and atomic composition of tissues along the beam path. Beams can be designed that penetrate to the required depth and deliver a uniform biologically effective dose across the depth of interest. The yield is a superior dose distribution relative to photon beams. There is a potential clinical advantage from the high linear energy transfer (LET) characteristics of carbon beams. This is based on a lower oxygen enhancement ratio (OER) and a flatter age response function. However, due to uncertainties relating OER with relative biological effectiveness (RBE), there is no clinical evidence to date that carbon ion beams have an advantage over proton beams. We strongly support performance Phase III clinical trials of protons vs carbon ion beams designed to feature a single variable, LET. Dose fractionation would be identical in both arms and dose distribution would be similar for the sites to be tested. For sites for which the carbon beam has a demonstrated important advantage in comparative treatment planning due to the narrower penumbra would not be selected for the clinical trials.

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Whole Three-Dimensional Dosimetry of Carbon Ion Beams with an MRI-Based Nanocomposite Fricke Gel Dosimeter Using Rapid T1 Mapping Method

Gels ◽

10.3390/gels7040233 ◽

2021 ◽

Vol 7 (4) ◽

pp. 233

Author(s):

Shinya Mizukami ◽

Yusuke Watanabe ◽

Takahiro Mizoguchi ◽

Tsutomu Gomi ◽

Hidetake Hara ◽

...

Keyword(s):

Dose Distribution ◽

Three Dimensional ◽

Heavy Ion ◽

Mapping Method ◽

Ion Beams ◽

Volume Data ◽

Gel Dosimeter ◽

Scanning Time ◽

Contrast Reduction

MRI-based gel dosimeters are attractive systems for the evaluation of complex dose distributions in radiotherapy. In particular, the nanocomposite Fricke gel dosimeter is one among a few dosimeters capable of accurately evaluating the dose distribution of heavy ion beams. In contrast, reduction of the scanning time is a challenging issue for the acquisition of three-dimensional volume data. In this study, we investigated a three-dimensional dose distribution measurement method for heavy ion beams using variable flip angle (VFA), which is expected to significantly reduce the MRI scanning time. Our findings clarified that the whole three-dimensional dose distribution could be evaluated within the conventional imaging time (20 min) and quality of one cross-section.

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Comparison of beam optics for normal conducting and superconducting gantry beamlines applied to proton therapy

International Journal of Modern Physics A ◽

10.1142/s0217751x19420156 ◽

2019 ◽

Vol 34 (36) ◽

pp. 1942015 ◽

Cited By ~ 3

Author(s):

Bin Qin ◽

Runxiao Zhao ◽

Xu Liu ◽

Qushan Chen ◽

Heming Chen ◽

...

Keyword(s):

Proton Therapy ◽

Dose Distribution ◽

Bragg Peak ◽

Distribution Characteristics ◽

Comparison Study ◽

Beam Optics ◽

Design Considerations ◽

Peak Dose ◽

Multiple Field ◽

Related Design

Due to the unique “Bragg peak” dose-distribution characteristics of proton beams, the proton therapy (PT) is recognized as one of the most precise and effective radiotherapy methods for tumors. A gantry is required to project the beam onto a tumor at various angles for multiple-field irradiation, and a superconducting beamline can significantly reduce the size and weight of the gantry. A PT system is under development at Huazhong University of Science and Technology (HUST), and this paper presents a comparison study of the beam optics and related design considerations for normal conducting and superconducting gantry beamlines.

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Axial Observation of X-Ray Spectra from a Beam-Foil Source

International Astronomical Union Colloquium ◽

10.1017/s0252921100108048 ◽

1988 ◽

Vol 102 ◽

pp. 339-342

Author(s):

J.M. Laming ◽

J.D. Silver ◽

R. Barnsley ◽

J. Dunn ◽

K.D. Evans ◽

...

Keyword(s):

Spectral Resolution ◽

Heavy Ion ◽

Ion Beams ◽

Beam Axis ◽

Doppler Broadening ◽

X Ray ◽

Beam Foil

AbstractNew observations of x-ray spectra from foil-excited heavy ion beams are reported. By observing the target in a direction along the beam axis, an improvement in spectral resolution, δλ/λ, by about a factor of two is achieved, due to the reduced Doppler broadening in this geometry.

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Preparation of TEM samples by focused ion beams

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138968 ◽

1995 ◽

Vol 53 ◽

pp. 518-519

Author(s):

John F. Walker ◽

J C Reiner ◽

C Solenthaler

Keyword(s):

Integrated Circuit ◽

Polycrystalline Silicon ◽

Field Effect Transistor ◽

High Spatial Resolution ◽

Ion Beam ◽

Ion Beams ◽

Focused Ion Beams ◽

Precise Location ◽

Effect Transistor ◽

Circuit Technology

The high spatial resolution available from TEM can be used with great advantage in the field of microelectronics to identify problems associated with the continually shrinking geometries of integrated circuit technology. In many cases the location of the problem can be the most problematic element of sample preparation. Focused ion beams (FIB) have previously been used to prepare TEM specimens, but not including using the ion beam imaging capabilities to locate a buried feature of interest. Here we describe how a defect has been located using the ability of a FIB to both mill a section and to search for a defect whose precise location is unknown. The defect is known from electrical leakage measurements to be a break in the gate oxide of a field effect transistor. The gate is a square of polycrystalline silicon, approximately 1μm×1μm, on a silicon dioxide barrier which is about 17nm thick. The break in the oxide can occur anywhere within that square and is expected to be less than 100nm in diameter.

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Atomic force microscopy (AFM) of the topography of silicon surfaces exposed to ion beams

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130298 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1132-1133

Author(s):

Mark Denker ◽

Jennifer Wall ◽

Mark Ray ◽

Richard Linton

Keyword(s):

Secondary Ion Mass Spectrometry ◽

Incidence Angle ◽

Ion Beam ◽

Depth Profiling ◽

Depth Resolution ◽

Ion Beams ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Trace Impurities ◽

Energy Dose

Reactive ion beams such as O2+ and Cs+ are used in Secondary Ion Mass Spectrometry (SIMS) to analyze solids for trace impurities. Primary beam properties such as energy, dose, and incidence angle can be systematically varied to optimize depth resolution versus sensitivity tradeoffs for a given SIMS depth profiling application. However, it is generally observed that the sputtering process causes surface roughening, typically represented by nanometer-sized features such as cones, pits, pyramids, and ripples. A roughened surface will degrade the depth resolution of the SIMS data. The purpose of this study is to examine the relationship of the roughness of the surface to the primary ion beam energy, dose, and incidence angle. AFM offers the ability to quantitatively probe this surface roughness. For the initial investigations, the sample chosen was <100> silicon, and the ion beam was O2+.Work to date by other researchers typically employed Scanning Tunneling Microscopy (STM) to probe the surface topography.

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