Beam geometry selection using sequential beam addition

Popple, Richard A.; Brezovich, I; Fiveash, John B.

doi:10.1118/1.4870977

Cited by 6 publications

(7 citation statements)

References 26 publications

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“…In particular, Popple et al [18] consider convex breast and mediastinal tumors which according to our classification fall into type II. The authors report that no more then 6–7 beams (11 beams for the most complicated head case) are needed for adequate PTV coverage/OAR sparing.…”

Section: Discussionmentioning

confidence: 99%

Characteristics of non-coplanar IMRT in the presence of target-embedded organs at risk

Bratengeier

Holubyev

2015

Radiat Oncol

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BackgroundThe aim is to analyze characteristics and to study the potentials of non-coplanar intensity modulated radiation therapy (IMRT) techniques. The planning study applies to generalized organ at risk (OAR) – planning target volume (PTV) geometries.MethodsThe authors focus on OARs embedded in the PTV. The OAR shapes are spherically symmetric (A), cylindrical (B), and bended (C). Several IMRT techniques are used for the planning study: a) non-coplanar quasi-isotropic; b) two sets of equidistant coplanar beams, half of beams incident in a plane perpendicular to the principal plane; c) coplanar equidistant (reference); d) coplanar plus one orthogonal beam. The number of beam directions varies from 9 to 16. The orientation of the beam sets is systematically changed; dose distributions resulting from optimal fluence are explored. A selection of plans is optimized with direct machine parameter optimization (DMPO) allowing 120 and 64 segments. The overall plan quality, PTV coverage, and OAR sparing are evaluated.ResultsFor all fluence based techniques in cases A and C, plan quality increased considerably if more irradiation directions were used. For the cylindrically symmetric case B, however, only a weak beam number dependence was observed for the best beam set orientation, for which non-coplanar directions could be found where OAR- and PTV-projections did not overlap. IMRT plans using quasi-isotropical distributed non-coplanar beams showed stable results for all topologies A, B, C, as long as 16 beams were chosen; also the most unfavorable beam arrangement created results of similar quality as the optimally oriented coplanar configuration. For smaller number of beams or application in the trunk, a coplanar technique with additional orthogonal beam could be recommended. Techniques using 120 segments created by DMPO could qualitatively reproduce the fluence based results. However, for a reduced number of segments the beam number dependence declined or even reversed for the used planning system and the plan quality degraded substantially.ConclusionsTopologies with targets encompassing sensitive OAR require sufficient number of beams of 15 or more. For the subgroup of topologies where beam incidences are possible which cover the whole PTV without direct OAR irradiation, the quality dependence on the number of beams is much less pronounced above 9 beams. However, these special non-coplanar beam directions have to be found. On the basis of this work the non-coplanar IMRT techniques can be chosen for further clinical planning studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-015-0494-5) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Characteristics of non-coplanar IMRT in the presence of target-embedded organs at risk

Bratengeier

Holubyev

2015

Radiat Oncol

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“…Mathematically, it is defined as a highly non-convex multi-modal optimization problem with many local minima [5][6][7], requiring optimization methods that avoid being trapped in a local minimum. For IMRT, the beam angle optimization problem considering non-coplanar geometries has been extensively studied for brain [3,[8][9][10], head-and-neck [10][11][12][14][15][16], lung [17], gastric [12], liver [14,18,19], pancreas [10], cervix [14] and prostate [10,12,13] sites. The reported beam angle optimization methods can be grouped into two classes.…”

Section: Introductionmentioning

confidence: 99%

Comparison of non-coplanar optimization of static beams and arc trajectories for intensity-modulated treatments of meningioma cases

et al. 2021

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Two methods for non-coplanar beam direction optimization, one for static beams and another for arc trajectories, were proposed for intracranial tumours. The results of the beam angle optimizations were compared with the beam directions used in the clinical plans. Ten meningioma cases already treated were selected for this retrospective planning study. Algorithms for non-coplanar beam angle optimization (BAO) and arc trajectory optimization (ATO) were used to generate the corresponding plans. A plan quality score, calculated by a graphical method for plan assessment and comparison, was used to guide the beam angle optimization process. For each patient, the clinical plans (CLIN), created with the static beam orientations used for treatment, and coplanar VMAT approximated plans (VMAT) were also generated. To make fair plan comparisons, all plan optimizations were performed in an automated multicriteria calculation engine and the dosimetric plan quality was assessed. BAO and ATO plans presented, on average, moderate global plan score improvements over VMAT and CLIN plans. Nevertheless, while BAO and CLIN plans assured a more efficient OARs sparing, the ATO and VMAT plans presented a higher coverage and conformity of the PTV. Globally, all plans presented high-quality dose distributions. No statistically significant quality differences were found, on average, between BAO, ATO and CLIN plans. However, automated plan solution optimizations (BAO or ATO) may improve plan generation efficiency and standardization. In some individual patients, plan quality improvements were achieved with ATO plans, demonstrating the possible benefits of this automated optimized delivery technique.

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“…A number of approaches have previously been used for beam orientation selection in radiotherapy. As well as the implementation of methods for conformal radiotherapy [4], the more complex problem of determining beam orientations and fluence maps for intensity-modulated radiotherapy (IMRT) has been approached by beam's eye view score methods [5], [6], combination of individually selected beams [7], successive addition of beams to a pool [8], [9], [10], angle perturbation [11], [12], [13] and cluster analysis [14]. Other methods have also been reported [15], [16], [17], [18], [19], [20], [21].…”

Section: Introductionmentioning

confidence: 99%

Beam selection for stereotactic ablative radiotherapy using Cyberknife with multileaf collimation

Bedford

Ziegenhein

Nill

et al. 2019

Medical Engineering & Physics

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Beam geometry selection using sequential beam addition

Cited by 6 publications

References 26 publications

Characteristics of non-coplanar IMRT in the presence of target-embedded organs at risk

Characteristics of non-coplanar IMRT in the presence of target-embedded organs at risk

Comparison of non-coplanar optimization of static beams and arc trajectories for intensity-modulated treatments of meningioma cases

Beam selection for stereotactic ablative radiotherapy using Cyberknife with multileaf collimation

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