Journal ArticleDOI
Electron beam dose calculations.
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TLDR
Electron beam dose distributions in the presence of inhomogeneous tissue are calculated by an algorithm that sums the dose distribution of individual pencil beams and the theory suggests an alternative method for the calculation of depth-dose of rectangular fields.Abstract:
Electron beam dose distributions in the presence of inhomogeneous tissue are calculated by an algorithm that sums the dose distribution of individual pencil beams. The off-axis dependence of the pencil beam dose distribution is described by the Fermi-Eyges theory of thick-target multiple Coulomb scattering. Measured square-field depth-dose data serve as input for the calculations. Air gap corrections are incorporated and use data from 'in-air' measurements in the penumbra of the beam. The effective depth, used to evaluate depth-dose, and the sigma of the off-axis Gaussian spread against depth are calculated by recursion relations from a CT data matrix for the material underlying individual pencil beams. The correlation of CT number with relative linear stopping power and relative linear scattering power for various tissues is shown. The results of calculations are verified by comparison with measurements in a 17 MeV electron beam from the Therac 20 linear accelerator. Calculated isodose lines agree nominally to within 2 mm of measurements in a water phantom. Similar agreement is observed in cork slabs simulating lung. Calculations beneath a bone substitute illustrate a weakness in the calculation. Finally a case of carcinoma in the maxillary antrum is studied. The theory suggests an alternative method for the calculation of depth-dose of rectangular fields.read more
Citations
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Correlation between CT numbers and tissue parameters needed for Monte Carlo simulations of clinical dose distributions
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The physics of proton therapy
TL;DR: The basic aspects of the physics of proton therapy are reviewed, including proton interaction mechanisms, proton transport calculations, the determination of dose from therapeutic and stray radiations, and shielding design.
Journal ArticleDOI
A pencil beam algorithm for proton dose calculations
Linda Hong,Michael Goitein,Marta Bucciolini,R. Comiskey,Bernard Gottschalk,Skip Rosenthal,Chris Serago,Marcia Urie +7 more
TL;DR: A pencil beam algorithm for proton dose calculations which takes accurate account of the effects of materials upstream of the patient and of the air gap between them and the patient is developed.
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Optimisation of conformal radiotherapy dose distributions by simulated annealing.
TL;DR: It is shown using published 'difficult' clinical treatment planning problems that the high-dose region can be very precisely tailored to the tumour volume even when this has a re-entrant (concave) periphery.
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Acute radiation-induced pulmonary damage: A clinical study on the response to fractionated radiation therapy
TL;DR: A prospective, clinical study was conducted to obtain dose-response data on acute pulmonary damage caused by fractionated radiation therapy of the thorax and predicted a 50% incidence level at an ED value (ED50) of 1000 +/- 40 ED units.
References
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Photon cross sections, attenuation coefficients, and energy absorption coefficients from 10 keV to 100 GeV
Journal ArticleDOI
Multiple Scattering of Fast Electrons and Alpha-Particles, and "Curvature" of Cloud Tracks Due to Scattering
TL;DR: In this paper, the authors consider the multiple scattering of fast electrons by thin foils and give a new formula which represents the mean projected deflection within 1 percent over the whole range of experimental conditions.
Journal ArticleDOI
The direct use of CT numbers in radiotherapy dosage calculations for inhomogeneous media.
TL;DR: Techniques by which the quantitative anatomical data inherent in a CT scan can be directly used in treatment planning are described, and the correction algorithms used in the RAD-8 system have been extended to a pixel-by-pixel approach.
Journal ArticleDOI
A technique for calculating the influence of thin inhomogeneities on charged particle beams
TL;DR: A method has been developed for calculating the fluence and dose perturbations which occur in the shadow of inhomogeneous structures exposed to beams of charged particles and provisions for the important modifying effects of beam divergence, of overlying or underlying homogeneous material, and of nonuniform beam profiles are developed.