The use of a microcomputer for non-linear optimisation of doses in external radiotherapy

Legras, Jean; Legras, Bernard; Lambert, Jean-Pierre; Alleti, P

doi:10.1088/0031-9155/31/12/004

Cited by 16 publications

(3 citation statements)

References 8 publications

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“…The main advantage of this model is its simplicity, and it can give a satisfactory result in most cases. Also, the computation time is less than the constrained model adapted by Legras et al (1986) and Morrill et al (1991). However, it is important to make a good choice for the values for weighted factors α and β when such a model is used.…”

Section: Discussionmentioning

confidence: 99%

Treatment planning optimization by quasi-Newton and simulated annealing methods for gamma unit treatment system

Yan

Bao

et al. 1998

Phys. Med. Biol.

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The gamma unit is used to irradiate a target within the brain. During such a treatment many parameters, including the number of shots, the coordinates, the collimator size and the weight associated with each shot, affect the amount of dose delivered to the target volume and to the surrounding normal tissues. Hence it is not easy to determine an appropriate set of these parameters by a trial and error method. For this reason, we present here an optimization method to determine mathematically those parameters. This method is composed of two steps: firstly, a quasi-Newton method is used to deal with the continuous variables such as position and weight of shots; the result obtained at the end of this step then serves as the initial configuration for the next step, in which a simulated annealing method is applied to optimize all the aforementioned parameters. Application of the proposed methods to two examples shows that our optimization algorithm runs in a satisfactory way.

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Section: Discussionmentioning

confidence: 99%

Treatment planning optimization by quasi-Newton and simulated annealing methods for gamma unit treatment system

Yan

Bao

et al. 1998

Phys. Med. Biol.

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“…In order to apply the optimization technique to a stereotactic radiosurgery treatment plan, the following threshold conditions are defined. 11 ͑1͒ At the target volume points, and particularly at definite points on its perimeter, the total dose must be greater than or equal to a threshold L 1 . ͑2͒ If there exist one or more sensitive zones, we define that the total dose in each of them is less than or equal to a threshold L 2 j , for jрN S where N S is the number of the sensitive zones and L 2 i can be different to L 2 j for i j.…”

Section: Mathematical Model Of Problemmentioning

confidence: 99%

Three‐dimensional optimization of treatment planning for gamma unit treatment system

Yan

Luo

et al. 1998

Medical Physics

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During a treatment using the Leksell gamma unit, the physician and physicist need to determine a treatment plan by changing the parameters such as collimator sizes, the position of isocenters and isocenters' weights. This is a complex problem because the set of parameters is large, especially when targets are geometrically close to a critical structure. For this reason, we present here an optimization algorithm, namely the multiplier penalty method, to mathematically determine those parameters. Two cases are presented in this article: the first one is really planned by a physicist in a clinical treatment, and is redone in our optimization algorithm to show the effectiveness of this method; the second one is theoretical where a critical structure is placed close to the target volume. The results show that this method achieves an excellent conformation to the specified isodose curve with the contour of the target volume, allowing minimal damage to surrounding healthy tissue.

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“…However, as pointed out in [18], in practice the optimal choice of beam directions is one of the most difficult problems of medical treatment optimization, and there should be as great an effort expended on optimizing beam directions [12]. While there are quite a few 2-D and 3-D results [5,6,7,8,9,10,11,12,13,18,19,22,23,24,26,29,34, 351 on treatment optimization with respect to one of the first two parameters, or even both, optimizing the beam directions has remained an elusive goal. The few papers which consider the optimization of the beam directions discretize the problem and use brute force methods (i.e., trying a large number of combinations of directions and selecting the best).…”

Section: Introductionmentioning

confidence: 99%

Determining an optimal penetration among weighted regions in two and three dimensions

Chen

Daescu

et al. 1999

Proceedings of the Fifteenth Annual Symposium on Computational Geometry

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We present efficient algorithms for solving the problem of computing an optimal penetration (a ray or a line segment) among weighted regions in 2-D and 3-D spaces. This problem finds applications in several areas, such as radiation therapy, geological exploration, and environmental engineering. Our algorithms are based on a combination of geometric techniques and optimization methods. Our geometric analysis shows that the optimal penetration problem in d-D (d = 2,3) can be reduced to solving O(n2td-l)) instances of certain special types of nonlinear optimization problems, where n is the total number of vertices of the regions. We also give implementation results of our 2-D algorithms.

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The use of a microcomputer for non-linear optimisation of doses in external radiotherapy

Cited by 16 publications

References 8 publications

Treatment planning optimization by quasi-Newton and simulated annealing methods for gamma unit treatment system

Treatment planning optimization by quasi-Newton and simulated annealing methods for gamma unit treatment system

Three‐dimensional optimization of treatment planning for gamma unit treatment system

Determining an optimal penetration among weighted regions in two and three dimensions

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