An Algorithm for Calculating Dose Profiles in Multi-Layered Devices Using a Personal Computer

Garth, J.C.

doi:10.1109/tns.1986.4334590

Cited by 9 publications

(1 citation statement)

References 7 publications

(15 reference statements)

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“…An attractive alternative is to combine the experimental readings obtained by adding additional foils with calculations using a code such as that developed by Garth [13]. Since the CO-60 generated spectra tend to fall within narrow bounds the experimental determinations should be sufficient to enable a useful dose profile to be generated.…”

Section: Resultsmentioning

confidence: 99%

The direct measurement of dose enhancement in gamma test facilities

Burke¹,

Lowe²,

Snowden³

et al. 1989

IEEE Trans. Nucl. Sci.

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The design and use of a dual cavity ionization chamber for routine measurement of dose enhancement factors in CO-60 gamma test facilities is described. The enhancement factors can be derived directly from the chamber measurements without recourse to reference data that may be difficult to obtain. It is shown, in agreement with earlier work, that the maximum dose enhancement factors can be altered by a factor two as a result of Compton scatter from relatively small amounts of low or high atomic number materials next to the target. The dual chamber permits the ready detection of such effects. This relatively simple device reliably reproduced earlier results obtained by more involved equipment and procedures. Measured enhancement factors are reported for new material combinations not previously examined and compared with recent calculations.

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Section: Resultsmentioning

confidence: 99%

The direct measurement of dose enhancement in gamma test facilities

Burke¹,

Lowe²,

Snowden³

et al. 1989

IEEE Trans. Nucl. Sci.

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Systematic survey of the dose enhancement in tissue-equivalent materials facing medium- and high-Z backscatterers exposed to X-rays with energies from 5 to 250 keV

Seidenbusch

Harder

Regulla

2014

Radiat Environ Biophys

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The present study has been inspired by the results of earlier dose measurements in tissue-equivalent materials adjacent to thin foils of aluminum, copper, tin, gold, and lead. Large dose enhancements have been observed in low-Z materials near the interface when this ensemble was irradiated with X-rays of qualities known from diagnostic radiology. The excess doses have been attributed to photo-, Compton, and Auger electrons released from the metal surfaces. Correspondingly, high enhancements of biological effects have been observed in single cell layers arranged close to gold surfaces. The objective of the present work is to systematically survey, by calculation, the values of the dose enhancement in low-Z media facing backscattering materials with a variety of atomic numbers and over a large range of photon energies. Further parameters to be varied are the distance of the point of interest from the interface and the kind of the low-Z material. The voluminous calculations have been performed using the PHOTCOEF algorithm, a proven set of interpolation functions fitted to long-established Monte Carlo results, for primary photon energies between 5 and 250 keV and for atomic numbers varying over the periodic system up to Z = 100. The calculated results correlate well with our previous experimental results. It is shown that the values of the dose enhancement (a) vary strongly in dependence upon Z and photon energy; (b) have maxima in the energy region from 40 to 60 keV, determined by the K and L edges of the backscattering materials; and (c) are valued up to about 130 for "International Commission on Radiological Protection (ICRP) soft tissue" (soft tissue composition recommended by the ICRP) as the adjacent low-Z material. Maximum dose enhancement associated with the L edge occurs for materials with atomic numbers between 50 and 60, e.g., barium (Z = 56) and iodine (Z = 53). Such materials typically serve as contrast media in medical X-ray diagnostics. The gradual reduction in the dose enhancement with increasing distance from the material interface, owed to the limited ranges of the emitted secondary electrons, has been documented in detail. The discussion is devoted to practical radiological aspects of the dose enhancement phenomenon. Cytogenetic effects in cell layers closely proximate to surfaces of medium-Z materials might vary over two orders of magnitude, because the dose enhancement is accompanied by the earlier observed about twofold increase in the low-dose RBEM at a tissue-to-gold interface.

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Avalanche amplification in silicon drift detectors

Kushpil

1998

Czech J Phys

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An Algorithm for Calculating Dose Profiles in Multi-Layered Devices Using a Personal Computer

Cited by 9 publications

References 7 publications

The direct measurement of dose enhancement in gamma test facilities

The direct measurement of dose enhancement in gamma test facilities

Systematic survey of the dose enhancement in tissue-equivalent materials facing medium- and high-Z backscatterers exposed to X-rays with energies from 5 to 250 keV

Avalanche amplification in silicon drift detectors

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