Computational methods in beam therapy planning

Geijn, J. Van de

doi:10.1016/0010-468x(72)90026-8

Cited by 17 publications

(1 citation statement)

References 47 publications

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“…Analytical beam models, widely known as beam generating function methods, are purely empirical methods based on a mathematical representation of beam data [van de Geijn, 1972], [Redpath and Wright, 1981]. The calculation of the relative dose value at a point results from the evaluation of a function which is given as a product of two terms which are evaluated separately.…”

Section: Analytical Beam Modelsmentioning

confidence: 99%

A study to assess and improve dose computations in photon beam therapy

Aspradakis

1997

Medical Physics

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This thesis is concerned with the calculation of dose at a point for megavoltage photon therapy. The review of dose calculation algorithms provides a comprehen¬ sive and critical analysis of the models developed to date. Emphasis is given to the dimensionality of density information utilised by these algorithms in relation to their capability of producing accurate dose information in three dimensions. Two applications of the Monte Carlo method to radiotherapy have been stud¬ ied. Namely, the generation of energy deposition kernels (EDK) and the use of the method as a benchmarking tool. EDKs represent the fractional energy deposited around a single photon interaction site. Dose distributions in homogeneous and heterogeneous media were calculated in absolute units of absorbed dose per in¬ cident photon fluence (Gy • cm2). Both applications were carried out using the EGS4 code system. A superposition model was developed from the dose deposition point of view. Dose at a point was obtained from knowledge of the total energy released per unit mass in the medium (TERMA) and the EDK. Effective energy spectrum information was used to calculate dose for clinical beams. The performance of this model was verified in homogeneous and heterogeneous media against both Monte Carlo generated and measured data. The necessity for computation speed is addressed. As a trade off between accuracy and speed, a method was developed which reduces the calculation time required to obtain a true three dimensional dose matrix. 12 2.2.2 Power-Law (BATHO) method 15 2.2.3 The Extended Net Fractional Dose (ENFD) method .... 20 2.3 Three dimensional (3D) methods 2.3.1 The Equivalent Tissue-Air Ratio method (ETAR) 2.3.2 Modified or extended versions of ETAR 2.3.3 The FFT Convolution Method 2.3.4 Volume integration of Differential Scatter-Air Ratios (DSAR) 2.3.5 The Delta Volume (DV) method 2.4

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Section: Analytical Beam Modelsmentioning

confidence: 99%