Comparison of beam angle selection strategies for intracranial IMRT

Bangert, Mark; Ziegenhein, Peter; Oelfke, Uwe

doi:10.1118/1.4771932

Cited by 42 publications

(65 citation statements)

References 58 publications

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“…45 For step&shoot IMRT, it has been established that such noncoplanar irradiation fields may allow for substantial dose reductions in OARs, especially if the OARs are close to irregularly shaped target volumes that are located asymmetrically within the body. [46][47][48][49] Leaving potential issues regarding patient immobilization on a robotic couch aside, the first treatment planning studies investigating noncoplanar VMAT have reconfirmed a benefit of noncoplanar irradiation with regard to OAR sparing. 33,45,47,[50][51][52][53] From the mathematical and technical side, the optimization of an irradiation trajectory shares the known issues of beam angle optimization (BAO) for step&shoot IMRT.…”

Section: E Noncoplanar Generalizations Of Vmatmentioning

confidence: 99%

“…The trajectories used for the above treatment planning studies were either found through inspection by a human planner, [50][51][52] using geometric heuristics, 45,53 or exhaustive search considering nine different couch tilts. 47 Wild et al 33 use a noncoplanar beam ensemble which was optimized with a genetic algorithm 49 for step&shoot IMRT to construct a noncoplanar VMAT trajectory. By connecting the optimized discrete beam orientations to a rotation trajectory, they could reproduce the dosimetric quality of the noncoplanar step&shoot IMRT treatment plan.…”

Section: E Noncoplanar Generalizations Of Vmatmentioning

confidence: 99%

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Optimization approaches to volumetric modulated arc therapy planning

et al. 2015

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Volumetric modulated arc therapy (VMAT) has found widespread clinical application in recent years. A large number of treatment planning studies have evaluated the potential for VMAT for different disease sites based on the currently available commercial implementations of VMAT planning. In contrast, literature on the underlying mathematical optimization methods used in treatment planning is scarce. VMAT planning represents a challenging large scale optimization problem. In contrast to fluence map optimization in intensity-modulated radiotherapy planning for static beams, VMAT planning represents a nonconvex optimization problem. In this paper, the authors review the state-of-the-art in VMAT planning from an algorithmic perspective. Different approaches to VMAT optimization, including arc sequencing methods, extensions of direct aperture optimization, and direct optimization of leaf trajectories are reviewed. Their advantages and limitations are outlined and recommendations for improvements are discussed. C 2015 American Association of Physicists in Medicine. [http://dx

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Section: E Noncoplanar Generalizations Of Vmatmentioning

confidence: 99%

Section: E Noncoplanar Generalizations Of Vmatmentioning

confidence: 99%

Optimization approaches to volumetric modulated arc therapy planning

et al. 2015

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“…Furthermore, for some types of cancers cases, e.g. intra-cranial tumors, the use of noncoplanar incidence directions improves substantially the treatment plan quality [5].…”

Section: Introductionmentioning

confidence: 99%

A Global Score-Driven Beam Angle Optimization in IMRT

Rocha

Dias

Ventura

et al. 2017

Computational Science and Its Applications – ICCSA 2017

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Abstract. Radiation therapy is one of the main treatment modalities for cancer. The objective of radiation therapy is to eliminate all cancer cells by delivering a prescribed dose of radiation to the tumor volume while sparing at the same time the surrounding tissues. Intensitymodulated radiation therapy (IMRT) is a sophisticated technologicallydriven type of radiation therapy where non-uniform radiation fields are used to irradiate the patient from different beam angle directions. Appropriate selection of beam irradiation directions -beam angle optimization (BAO) problem -enhance the quality of the treatment plan. The BAO problem is a very difficult global non-convex optimization problem for which there are few or none commercial solutions. Typically, the BAO procedure is driven by the outcome of the fluence map optimization (FMO) problem -the problem of calculating the most adequate radiation intensities. However, functions used for modeling the FMO problem have little clinical meaning. Typically, selection/validation of treatment plans is done considering a set of dosimetric measures. In this study, we propose a treatment plan global score, based on dosimetric criteria and its relative importance, as alternative plan's quality measure to drive the BAO procedure. For the clinical case of nasopharyngeal tumor, the use of a global score to drive the BAO procedure lead to higher quality treatment plans. For similar target coverage, an improved organ sparing was obtained.

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“…The difficulty of solving the BAO problem, a highly non-convex problem with many local minima on a large search space [14], is one possible justification for the manual selection or the use of coplanar incidence directions. However, evidence shows that noncoplanar incidence directions can lead to better treatment plans compared to plans obtained with coplanar incidence directions [5,33,38]. Moreover, the use of noncoplanar incidence directions is decisive for some types of cancers cases, e.g., brain tumors.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the fact that almost every angle is possible for radiation delivery, the use of coplanar angles, i.e., angles that lay in the plane of rotation of the gantry, is predominant. Furthermore, regardless of the evidence presented in the literature that selecting appropriate radiation beam incidence directions -beam angle optimization (BAO) problemcan lead to a plan's quality improvement [4,5,37], in clinical practice, most of the time, beam directions continue to be either manually selected by the treatment planner in a time-consuming trial and error iterative process or patients are irradiated using evenly spaced coplanar beams. The difficulty of solving the BAO problem, a highly non-convex problem with many local minima on a large search space [14], is one possible justification for the manual selection or the use of coplanar incidence directions.…”

Section: Introductionmentioning

confidence: 99%