Tissue current-to-dose conversion factors for neutrons with energies from 0.5 to 60 MeV

Irving, D.C.; Alsmiller, R.G.; Moran, H.S.

doi:10.1016/0029-554x(67)90373-4

Cited by 18 publications

(4 citation statements)

References 5 publications

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“…The neutron transport code MCNP4B (Briesmeister 1991) was utilized to calculate the spectral fluence ⌽ E (E) and the neutron-induced photon kerma K ␥ at 14 penetration depths between 0.1 and 19.9 cm in the tissue equivalent slab. The standard soft tissue composition indicated by ICRU report 33 (1980) was used (mass fractions 0.101 H, 0.111 C, 0.026 N, and 0.762 O), and this presents a nitrogen content lower than in previous calculations (Snyder and Neufeld 1957;Irving et al 1967). ENDF/VI cross sections and light water data for thermal neutrons with hydrogen binding corrections at thermal energies were used for neutrons; standard MCNP4B cross sections were used for photons.…”

Section: Monte Carlo Calculationsmentioning

confidence: 99%

Depth Dose-Equivalent and Effective Energies of Photoneutrons Generated by 6–18 Mv X-Ray Beams for Radiotherapy

D’Errico¹,

Luszik-Bhadra²,

Nath³

et al. 2001

Health Physics

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Photoneutron production was investigated on Siemens KD 2 and Varian Clinac accelerators operating in the 6-18 MV range. Neutron dose equivalent rates were measured on the surface of a water phantom at the isocenter of the accelerators and also inside the phantom at depths of 1, 5, and 10 cm and off-axis distances of 0, 20, and 50 cm. Superheated drop detectors based on dichlorofluoromethane and etched-track detectors with boronated converters were employed in this study. The energy response of these detectors permits a direct measurement of dose equivalent without prior knowledge of the neutron energy spectra. Dose equivalent rates were assessed using the Q(L) relationship from ICRP publication 60, as well as using earlier data from ICRP publication 21. This permitted both a comparison with previously published data and an assessment of the impact of the recent ICRP recommendations--which were found to increase the dose equivalent levels by about 30%. In addition, the depth corresponding to 50% of maximum dose equivalent, dH50, was determined along the central axis of the beams and at 50 cm off-axis. Monte Carlo neutron transport calculations were performed to determine the depth-dose equivalent distributions in a phantom irradiated with monoenergetic neutrons. Effective energies of the photoneutron spectra were then estimated by comparing our measured dH50 values to those calculated for monoenergetic neutrons. It was found that the effective photoneutron energy is 1.8-2.1 MeV within the 10-18 MV x-ray beams, and it is 0.5-0.8 MeV for photoneutrons transmitted through the accelerator head. Data from this work cover most of the x-ray beam energies in clinical use and permit an assessment of integral dose values as well as specific organ doses to a radiotherapy patient.

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Section: Monte Carlo Calculationsmentioning

confidence: 99%

Depth Dose-Equivalent and Effective Energies of Photoneutrons Generated by 6–18 Mv X-Ray Beams for Radiotherapy

D’Errico¹,

Luszik-Bhadra²,

Nath³

et al. 2001

Health Physics

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“…Progressive improvement of modelling the human anatomy has had a formative influence on the development of computational phantoms. Early radiation transport studies used semi-infinite homogeneous 30 cm slab phantoms (Snyder 1950, Alsmiller and Moran 1968, Alsmiller et al 1970, Beck 1970, Irving et al 1967, then homogeneous elliptical cylinders (Auxier et al 1969, Sidewell et al 1969, Snyder 1971, also with embedded inhomogeneous parts to simulate the lungs (Sidewell and Burlin 1973), later a homogeneous (Snyder 1965) and finally a heterogeneous human phantom, which became to be known as the MIRD5 phantom (Snyder et al 1968(Snyder et al , 1978. Body and organs of this stylized human phantom and of its derivations (Cristy 1980, Kramer et al 1982, Stabin et al 1995 were based on mathematical equations of geometrical bodies, like ellipsoids, truncated cones, tori, planes and intersections between them.…”

Section: Computational Phantomsmentioning

confidence: 99%

FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: I. Development of the anatomy

et al. 2009

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Among computational models, voxel phantoms based on computer tomographic (CT), nuclear magnetic resonance (NMR) or colour photographic images of patients, volunteers or cadavers have become popular in recent years. Although being true to nature representations of scanned individuals, voxel phantoms have limitations, especially when walled organs have to be segmented or when volumes of organs or body tissues, like adipose, have to be changed. Additionally, the scanning of patients or volunteers is usually made in supine position, which causes a shift of internal organs towards the ribcage, a compression of the lungs and a reduction of the sagittal diameter especially in the abdominal region compared to the regular anatomy of a person in the upright position, which in turn can influence organ and tissue absorbed or equivalent dose estimates. This study applies tools developed recently in the areas of computer graphics and animated films to the creation and modelling of 3D human organs, tissues, skeletons and bodies based on polygon mesh surfaces. Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been designed using software, such as MakeHuman, Blender, Binvox and ImageJ, based on anatomical atlases, observing at the same time organ masses recommended by the International Commission on Radiological Protection for the male and female reference adult in report no 89. 113 organs, bones and tissues have been modelled in the FASH and the MASH phantoms representing locations for adults in standing posture. Most organ and tissue masses of the voxelized versions agree with corresponding data from ICRP89 within a margin of 2.6%. Comparison with the mesh-based male RPI_AM and female RPI_AF phantoms shows differences with respect to the material used, to the software and concepts applied, and to the anatomies created.

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“…Emax > 25 For convenience, we use a polynomial fit of PER(Ep). Values from the fit are compared in Table 6 with those from Equation (16). The correction factor CP(Ep) is related to PER(Ep) by , .…”

Section: Packing Of Track Coordinate Datamentioning

confidence: 99%

Nuclear Emulsion Spectrometry at Low and Intermediate Neutron Energies (An Updating of Hasl--162).

Sanna¹,

McLaughlin²,

O’Brien³

1970

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Tissue current-to-dose conversion factors for neutrons with energies from 0.5 to 60 MeV

Cited by 18 publications

References 5 publications

Depth Dose-Equivalent and Effective Energies of Photoneutrons Generated by 6–18 Mv X-Ray Beams for Radiotherapy

Depth Dose-Equivalent and Effective Energies of Photoneutrons Generated by 6–18 Mv X-Ray Beams for Radiotherapy

FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: I. Development of the anatomy

Nuclear Emulsion Spectrometry at Low and Intermediate Neutron Energies (An Updating of Hasl--162).

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