The associated targets methodology and the multi-isocenters radiosurgery treatment planning ARTEMIS-3D

Lefkopoulos, D.; Schlienaer, M.; Merienne, L; Lévrier, M

doi:10.1016/0360-3016(92)90315-9

Cited by 7 publications

(10 citation statements)

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“…The ARTEMIS 3D stereotactic radiotherapy dose calculation software was first developed on a VaxStation DEC 3200 in the VMS environment and then adapted to a more powerful computer, the DecStation 5000/240 (DEC) in the Unix environment. The programming languages are FORTRAN and C (21)(22)(23). The ARTEMIS 3D permits both qualitative evaluation such as isodose displays or dose-distribution profiles, and quantitative evaluation, such as dose-volume histograms.…”

Section: Methodsmentioning

confidence: 99%

Dose-volume Analysis of Different Stereotactic Radiotherapy Mono-isocentric Techniques

Theodorou

Platoni²,

Lefkopoulos³

et al. 2000

Acta Oncologica

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Several stereotactic irradiation techniques, using Linacs with the patient in lying and sitting position and a Gamma Knife Unit, were compared with regard to mono-isocentric three-dimensional dose distributions. Three types of target volumes, a sphere and two ellipsoids, were used for the comparisons. All three targets were centered on a real head, reconstructed from transversal CT scans. The ARTEMIS 3D Treatment Planning System, developed by the Tenon Hospital, Paris, was used for the dosimetry and the dose-volume histogram (DVH) calculation. For the comparative study, several quantitative parameters were used, derived from the dose-volume histogram calculation. Differential DVHs were plotted for each target volume and beam arrangement. Irradiation techniques were compared by deriving quantitative parameters from the DVHs such as mean and integral dose delivered to the target and normal tissue irradiated, as well as by the relative volume of the examined areas. All techniques used in this study produced very similar dose distributions. The small differences confirm the capability of the studied techniques to produce the same irradiation effects. By changing from the spherical target shape to a more elliptical shape, more of the normal tissue was irradiated with higher doses. For elliptical cases we therefore identified a need for more conformal stereotactic planning.

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Section: Methodsmentioning

confidence: 99%

Dose-volume Analysis of Different Stereotactic Radiotherapy Mono-isocentric Techniques

Theodorou

Platoni²,

Lefkopoulos³

et al. 2000

Acta Oncologica

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“…The main components of the stereotactic sitting position irradiation technique for which this study has been carried out are: a) an isocentric linear accelerator with a set of circular secondary collimators with diameters ranging from 6 mm to 20 mm in steps of 2 mm; b) a Betti (17) special moveable chair incorporating a stereotactic frame of Talairach (18); c) anatomical data obtained from stereotactic angiography, CT and MRI imaging; and d) our computerized treatment planning system ARTEMIS-3D and SVD optimization algorithm, which were firstly developed on a Vaxstation 3200 (Digital Company) in the VMS environment and the last version ARTEMIS-3D/Dosigray adapted to a more powerful computer the Dec station 5000/240 (Digital Company) in the ULTRIX 4.3 environment (19).…”

Section: The Con6ergent Multi-arcs Stereotactic Irradiationmentioning

confidence: 99%

Study of Ill-conditioning of Linac Stereotactic Irradiation Subspaces using Singular Values Decomposition Analysis

Platoni

Lefkopoulos²,

Grandjean³

et al. 1999

Acta Oncologica

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A Linac stereotactic irradiation space is characterized by different angular separations of beams because of the geometry of the stereotactic irradiation. The regions of the stereotactic space characterized by low angular separations are one of the causes of ill-conditioning of the stereotactic irradiation inverse problem. The singular value decomposition (SVD) is a powerful mathematical analysis that permits the measurement of the ill-conditioning of the stereotactic irradiation problem. This study examines the ill-conditioning of the stereotactic irradiation space, provoked by the different angular separations of beams, using the SVD analysis. We subdivided the maximum irradiation space (MIS: (AA)AP x (AA)RL = 180 degrees x 180 degrees) into irradiation subspaces (ISSs), each characterized by its own angular separation. We studied the influence of ISSs on the SVD analysis and the evolution of the reconstruction quality of well defined three-dimensional dose matrices in each configuration. The more the ISS is characterized by low angular separation the more the condition number and the reconstruction inaccuracy are increased. Based on the above results we created two reduced irradiation spaces (RIS: (AA)AP x (AA)RL = 180 degrees x 140 degrees and (AA)AP x (AA)RL = 180 degrees x 120 degrees) and compared the reconstruction quality of the RISs with respect to the MIS. The more an irradiation space is free of low angular separations the more the irradiation space contains useful singular components.

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“…6 , 104-113 (1995) each voxel of the three-dimensional matrix; w is the weighting vector containing each beam weight; and M is the minibeam transmission matrix. The elements of M are computed using the ARTEMIS-three-dimensional software [12,13,15,191 using the experimental data of percentage depth doses (PDD), the profiles at different practical source skin distances (SSD), tissue maximum ratios (TMR), and collimator factor data. All minibeams contained into M are calculated for a weight equal to one.…”

Section: Modeling Radiosurgical Dose Distributionmentioning

confidence: 99%

Study of the degree of III conditioning of the phase space of pencil‐beam radiotherapy using singular value decomposition

Lefkopoulos

Grandjean

Laouar

et al. 1995

Int J Imaging Syst Tech

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Dose distribution optimization algorithms are necessary in pencilbeam radiotherapy to exploit efficiently the multiple parameters of this powerful irradiation technique. We propose as an optimization technique singular value decomposition (SVD) analysis, which allows the measurement of ill conditioning of the stereotactic radiotherapy inverse problem and yields optimal weights for conformal treatment. Our approach to dose distribution optimization is to recover estimates of the minibeams weights from well-defined previsional dose matrices to study the influence of the different parameters on the stereotactic radiotherapy inverse procedure. The adjustment of the different parameters of the stereotactic irradiation to the "SVD optimizer" procedure is realized taking into account the ratio of the quality reconstruction to the calculation time. It will permit a more efficient use of the SVD optimizer in clinical applications with real threedimensional lesions. We show the efficiency of the SVD optimizer in analyzing and predicting ill conditioning in stereotactic radiotherapy and in recognizing the topography of the different beams to create an optimal vector containing the beam weights (reconstructed weighting Vector). 0 1995 John Wiley 8 Sons, Inc.

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The associated targets methodology and the multi-isocenters radiosurgery treatment planning ARTEMIS-3D

Cited by 7 publications

References 0 publications

Dose-volume Analysis of Different Stereotactic Radiotherapy Mono-isocentric Techniques

Dose-volume Analysis of Different Stereotactic Radiotherapy Mono-isocentric Techniques

Study of Ill-conditioning of Linac Stereotactic Irradiation Subspaces using Singular Values Decomposition Analysis

Study of the degree of III conditioning of the phase space of pencil‐beam radiotherapy using singular value decomposition

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